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Singh A, Jain N, Shankar U, Sharma TK, Kumar A. Characterization of G-quadruplex structures in genes involved in survival and pathogenesis of Acinetobacter baumannii as a potential drug target. Int J Biol Macromol 2024; 269:131806. [PMID: 38670179 DOI: 10.1016/j.ijbiomac.2024.131806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 03/21/2024] [Accepted: 03/30/2024] [Indexed: 04/28/2024]
Abstract
Acinetobacter baumannii is a notorious pathogen that commonly thrives in hospital environments and is responsible for numerous nosocomial infections in humans. The burgeoning multi-drug resistance leaves relatively minimal options for treating the bacterial infection, posing a significant problem and prompting the identification of new approaches for tackling the same. This motivated us to focus on non-canonical nucleic acid structures, mainly G-quadruplexes, as drug targets. G-quadruplexes have recently been gaining attention due to their involvement in multiple bacterial and viral pathogenesis. Herein, we sought to explore conserved putative G-quadruplex motifs in A. baumannii. In silico analysis revealed the presence of eight conserved motifs in genes involved in bacterial survival and pathogenesis. The biophysical and biomolecular analysis confirmed stable G-quadruplex formation by the motifs and showed a high binding affinity with the well-reported G-quadruplex binding ligand, BRACO-19. BRACO-19 exposure also decreased the growth of bacteria and downregulated the expression of G-quadruplex-harboring genes. The biofilm-forming ability of the bacteria was also affected by BRACO-19 addition. Taking all these observations into account, we have shown here for the first time the potential of G-quadruplex structures as a promising drug target in Acinetobacter baumannii, for addressing the challenges posed by this infamous pathogen.
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Affiliation(s)
- Aakriti Singh
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore 453552, India
| | - Neha Jain
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore 453552, India
| | - Uma Shankar
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore 453552, India
| | - Tarun Kumar Sharma
- Department of Medical Biotechnology, Gujarat Biotechnology University, Gandhinagar 382355, India
| | - Amit Kumar
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore 453552, India.
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Toh YH, Lin GH. Roles of DJ41_1407 and DJ41_1408 in Acinetobacter baumannii ATCC19606 Virulence and Antibiotic Response. Int J Mol Sci 2024; 25:3862. [PMID: 38612672 PMCID: PMC11011904 DOI: 10.3390/ijms25073862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 03/26/2024] [Accepted: 03/28/2024] [Indexed: 04/14/2024] Open
Abstract
Acinetobacter baumannii is a major cause of nosocomial infections, and its highly adaptive nature and broad range of antibiotic resistance enable it to persist in hospital environments. A. baumannii often employs two-component systems (TCSs) to regulate adaptive responses and virulence-related traits. This study describes a previously uncharacterized TCS in the A. baumannii ATCC19606 strain, consisting of a transcriptional sensor, DJ41_1407, and its regulator, DJ41_1408, located adjacent to GacA of the GacSA TCS. Markerless mutagenesis was performed to construct DJ41_1407 and DJ41_1408 single and double mutants. DJ41_1408 was found to upregulate 49 genes and downregulate 43 genes, most of which were associated with carbon metabolism and other metabolic pathways, such as benzoate degradation. MEME analysis revealed a putative binding box for DJ41_1408, 5'TGTAAATRATTAYCAWTWAT3'. Colony size, motility, biofilm-forming ability, virulence, and antibiotic resistance of DJ41_1407 and DJ41_1408 single and double mutant strains were assessed against wild type. DJ41_1407 was found to enhance motility, while DJ41_1408 was found to upregulate biofilm-forming ability, and may also modulate antibiotic response. Both DJ41_1407 and DJ41_1408 suppressed virulence, based on results from a G. mellonella infection assay. These results showcase a novel A. baumannii TCS involved in metabolism, with effects on motility, biofilm-forming ability, virulence, and antibiotic response.
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Affiliation(s)
- Yee-Huan Toh
- Master Program in Biomedical Sciences, School of Medicine, Tzu Chi University, Hualien 970374, Taiwan;
| | - Guang-Huey Lin
- Department of Microbiology and Immunology, School of Medicine, Tzu Chi University, Hualien 970374, Taiwan
- International College, Tzu Chi University, Hualien 970374, Taiwan
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3
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Khanna N, Girija A.S S, Priyadharsini J V. Detection of the early putative biofilm marker pgaB among the MDR strains of A.baumannii. Heliyon 2024; 10:e27020. [PMID: 38495170 PMCID: PMC10943332 DOI: 10.1016/j.heliyon.2024.e27020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Revised: 02/20/2024] [Accepted: 02/22/2024] [Indexed: 03/19/2024] Open
Abstract
Background pgaB associated biofilm formation in Acinetobacter baumannii enhances the virulence in concert with the high propensity of drug resistance. This research is thus aimed to characterize the pgaB gene molecularly and to examine its co-occurrence with MDR. Methodology MDR strains of A. baumannii (N = 73) were selected to detect the formation of biofilms. Genomic DNA was extracted further and screened for pgaB followed by amplicon sequencing from the representative strains. Frequency of its distribution in different groups of drug resistant strains at a significant p-value of <0.05 was further checked. Results The biofilm assay showed high, low and negative biofilm formers in 58.9%, 31.5% and 0.9% of the strains respectively. The pgaB gene was detected in 14 strains of MDR A. baumannii (19.17%). Co-occurrence of pgaB gene was seen in all the strains that showed resistance to β-lactam inhibitors, cephems, carbapenems, fluoroquinolones and folates followed by 96% for the aminoglycosides and 25% in the efflux pump groups. Conclusion The study findings showed the occurrence of biofilms associated with pgaB in MDR A. baumannii strains. The results also suggest to track its role in varying the pattern of drug resistance with further experimentation.
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Affiliation(s)
- Navya Khanna
- Department of Microbiology, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences [SIMATS], Saveetha University, P.H.Road, Chennai, Tamilnadu, 600077, India
| | - Smiline Girija A.S
- Department of Microbiology, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences [SIMATS], Saveetha University, P.H.Road, Chennai, Tamilnadu, 600077, India
| | - Vijayashree Priyadharsini J
- Department of Microbiology, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences [SIMATS], Saveetha University, P.H.Road, Chennai, Tamilnadu, 600077, India
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Tobin LA, Jarocki VM, Kenyon J, Drigo B, Donner E, Djordjevic SP, Hamidian M. Genomic analysis of diverse environmental Acinetobacter isolates identifies plasmids, antibiotic resistance genes, and capsular polysaccharides shared with clinical strains. Appl Environ Microbiol 2024; 90:e0165423. [PMID: 38206028 PMCID: PMC10885009 DOI: 10.1128/aem.01654-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 11/30/2023] [Indexed: 01/12/2024] Open
Abstract
Acinetobacter baumannii, an important pathogen known for its widespread antibiotic resistance, has been the focus of extensive research within its genus, primarily involving clinical isolates. Consequently, data on environmental A. baumannii and other Acinetobacter species remain limited. Here, we utilized Illumina and Nanopore sequencing to analyze the genomes of 10 Acinetobacter isolates representing 6 different species sourced from aquatic environments in South Australia. All 10 isolates were phylogenetically distinct compared to clinical and other non-clinical Acinetobacter strains, often tens of thousands of single-nucleotide polymorphisms from their nearest neighbors. Despite the genetic divergence, we identified pdif modules (sections of mobilized DNA) carrying clinically important antimicrobial resistance genes in species other than A. baumannii, including carbapenemase oxa58, tetracycline resistance gene tet(39), and macrolide resistance genes msr(E)-mph(E). These pdif modules were located on plasmids with high sequence identity to those circulating in globally distributed A. baumannii ST1 and ST2 clones. The environmental A. baumannii isolate characterized here (SAAb472; ST350) did not possess any native plasmids; however, it could capture two clinically important plasmids (pRAY and pACICU2) with high transfer frequencies. Furthermore, A. baumannii SAAb472 possessed virulence genes and a capsular polysaccharide type analogous to clinical strains. Our findings highlight the potential for environmental Acinetobacter species to acquire and disseminate clinically important antimicrobial resistance genes, underscoring the need for further research into the ecology and evolution of this important genus.IMPORTANCEAntimicrobial resistance (AMR) is a global threat to human, animal, and environmental health. Studying AMR in environmental bacteria is crucial to understand the emergence and dissemination of resistance genes and pathogens, and to identify potential reservoirs and transmission routes. This study provides novel insights into the genomic diversity and AMR potential of environmental Acinetobacter species. By comparing the genomes of aquatic Acinetobacter isolates with clinical and non-clinical strains, we revealed that they are highly divergent yet carry pdif modules that encode resistance to antibiotics commonly used in clinical settings. We also demonstrated that an environmental A. baumannii isolate can acquire clinically relevant plasmids and carries virulence factors similar to those of hospital-associated strains. These findings suggest that environmental Acinetobacter species may serve as reservoirs and vectors of clinically important genes. Consequently, further research is warranted to comprehensively understand the ecology and evolution of this genus.
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Affiliation(s)
- Liam A. Tobin
- Australian Institute for Microbiology and Infection, University of Technology Sydney, Ultimo, New South Wales, Australia
| | - Veronica M. Jarocki
- Australian Institute for Microbiology and Infection, University of Technology Sydney, Ultimo, New South Wales, Australia
- The Australian Centre for Genomic Epidemiological Microbiology, University of Technology Sydney, Ultimo, Australia
| | - Johanna Kenyon
- Centre for Immunology and Infection Control, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Barbara Drigo
- Future Industries Institute, University of South Australia, Mawson Lakes, SA, Australia
- UniSA STEM, University of South Australia, Mawson Lakes, SA, Australia
| | - Erica Donner
- Future Industries Institute, University of South Australia, Mawson Lakes, SA, Australia
- Cooperative Research Centre for Solving Antimicrobial Resistance in Agribusiness, Food, and Environments (CRC SAAFE), Adelaide, SA, Australia
| | - Steven P. Djordjevic
- Australian Institute for Microbiology and Infection, University of Technology Sydney, Ultimo, New South Wales, Australia
- The Australian Centre for Genomic Epidemiological Microbiology, University of Technology Sydney, Ultimo, Australia
| | - Mehrad Hamidian
- Australian Institute for Microbiology and Infection, University of Technology Sydney, Ultimo, New South Wales, Australia
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Wantanatavatod M, Wongkulab P. Clinical Efficacy of Sitafloxacin-Colistin-Meropenem and Colistin-Meropenem in Patients with Carbapenem-Resistant and Multidrug-Resistant Acinetobacter baumannii Hospital-Acquired Pneumonia (HAP)/Ventilator-Associated Pneumonia (VAP) in One Super-Tertiary Hospital in Bangkok, Thailand: A Randomized Controlled Trial. Antibiotics (Basel) 2024; 13:137. [PMID: 38391523 PMCID: PMC10886248 DOI: 10.3390/antibiotics13020137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2023] [Revised: 01/24/2024] [Accepted: 01/26/2024] [Indexed: 02/24/2024] Open
Abstract
BACKGROUND Carbapenem-resistant A. baumannii (CRAB) hospital-acquired pneumonia (HAP)/ventilator-associated pneumonia (VAP) is now a therapeutic problem worldwide. METHOD An open-label, randomized, superiority, single-blind trial was conducted in Rajavithi Hospital, a super-tertiary care facility in Bangkok, Thailand. CRAB HAP/VAP patients were randomly assigned to receive either sitafloxacin-colistin-meropenem or colistin-meropenem. Outcomes in the two groups were then assessed with respect to mortality, clinical response, and adverse effects. RESULT Between April 2021 and April 2022, 77 patients were treated with combinations of either sitafloxacin plus colistin plus meropenem (n = 40) or colistin plus meropenem (n = 37). There were no significant differences between the two groups with respect to all-cause mortality rates at 7 days and 14 days (respectively, 7.5% vs. 2.7%; p = 0.616, and 10% vs. 10%; p = 1). Patients who received sitafloxacin-colistin-meropenem showed improved clinical response compared with patients who received colistin-meropenem in terms of both intention-to-treat (87.5% vs. 62.2%; p = 0.016) and per-protocol analysis (87.2% vs. 67.7%; p = 0.049). There were no significant differences between the two groups with respect to adverse effects. CONCLUSIONS Adding sitafloxacin as a third agent to meropenem plus colistin could improve clinical outcomes in CRAB HAP/VAP with little or no impact on adverse effects. In short, sitafloxacin-meropenem-colistin could be another therapeutic option for combatting CRAB HAP/VAP.
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Affiliation(s)
- Manasawee Wantanatavatod
- Division of Infectious Disease, Department of Medicine, Rajavithi Hospital, Bangkok 10400, Thailand
| | - Panuwat Wongkulab
- Division of Infectious Disease, Department of Medicine, Rajavithi Hospital, Bangkok 10400, Thailand
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Odih EE, Sunmonu GT, Okeke IN, Dalsgaard A. NDM-1- and OXA-23-producing Acinetobacter baumannii in wastewater of a Nigerian hospital. Microbiol Spectr 2023; 11:e0238123. [PMID: 37796014 PMCID: PMC10714947 DOI: 10.1128/spectrum.02381-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 08/22/2023] [Indexed: 10/06/2023] Open
Abstract
IMPORTANCE Acinetobacter baumannii is a leading cause of hospital-associated infections globally. A. baumannii reservoirs outside hospital settings are still unknown, and their occurrence in the environment is linked to clinical and anthropogenic activities. Although the risk of transmission of A. baumannii from environmental sources to humans is not fully understood, these sources pose significant risks for the continued dissemination of A. baumannii and their resistance traits. This study provides evidence that diverse and clinically relevant A. baumannii strains, many of which are resistant to carbapenems, are constantly being discharged into the environment through inadequately treated hospital wastewater. We further elucidate potential transmission routes between the environment and clinical infections and demonstrate the high prevalence of carbapenem resistance genes on highly mobile transposons among these strains. Our findings highlight the pressing need to address hospital wastewater as a crucial factor in curtailing the spread of carbapenem-resistant A. baumannii.
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Affiliation(s)
- Erkison Ewomazino Odih
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Global Health Research Unit for the Genomic Surveillance of Antimicrobial Resistance, Department of Pharmaceutical Microbiology, Faculty of Pharmacy, University of Ibadan, Ibadan, Oyo State, Nigeria
| | - Gabriel Temitope Sunmonu
- Global Health Research Unit for the Genomic Surveillance of Antimicrobial Resistance, Department of Pharmaceutical Microbiology, Faculty of Pharmacy, University of Ibadan, Ibadan, Oyo State, Nigeria
| | - Iruka N. Okeke
- Global Health Research Unit for the Genomic Surveillance of Antimicrobial Resistance, Department of Pharmaceutical Microbiology, Faculty of Pharmacy, University of Ibadan, Ibadan, Oyo State, Nigeria
| | - Anders Dalsgaard
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Asghar MU, Haneef K, Fatima F, Asghar A, Ain NU. Investigating Oxidative Stress Levels in Pregnant Patients Infected with Hepatitis C Virus and Bacterial Vaginosis for Better Treatment Option. Oman Med J 2023; 38:e549. [PMID: 38249133 PMCID: PMC10800022 DOI: 10.5001/omj.2023.102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 03/19/2023] [Indexed: 01/23/2024] Open
Abstract
Objectives Hepatitis C virus (HCV) and bacterial vaginosis (BV) coinfection generate sustained inflammation with bulk production of reactive oxygen species. They have the potency to cause hepatocellular carcinoma, vaginal apoptosis, disturb pregnancy, and influence drug treatment and follow-up. This case-control study aimed to compare the redox status in HCV and BV coinfection with respect to BV mono-infection among pregnant females (PFs). Methods Blood samples and vaginal secretions were drawn from 75 PFs divided into three groups: coinfection (n = 25), monoinfection (n = 25), and control PFs (n = 25) who are presumed healthy subjects. Blood samples were analyzed for HCV detection based on conserved 5' untranslated region via real-time polymerase chain reaction and hematological parameters. Markers of oxidative stress (malondialdehyde and peroxidase) and antioxidants (catalase and superoxide dismutase) were checked in plasma as well as vaginal secretions of patients among all three groups. Results Hematological analysis reveals that hemoglobin levels, platelets, and lymphocytes decreased significantly (p < 0.050) among the coinfection followed by mono-infection group compared to the control group. Moreover, the higher isolation frequency of pathogenic bacteria (Acinetobacter spp.) and Nugent score trend was observed among the coinfection group. Antioxidant levels were significantly lower (p < 0.050) among the vaginal secretions and blood plasma of patients having coinfection with respect to the mono-infection and control groups. While oxidative stress marker was significantly highest (p < 0.050) among vaginal secretions and blood plasma of coinfection followed by mono-infection and control group. These results validate that overall redox severity was more among the coinfection compared to the mono-infection and control groups. Conclusions Redox indexes should be considered in early diagnosis and treatment of HCV and BV coinfection which may also facilitate the better treatment of hepatocellular carcinoma and vaginal apoptosis.
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Affiliation(s)
- Muhammad Umer Asghar
- Institute of Microbiology, University of Agriculture Faisalabad, Faisalabad, Pakistan
- National Institute for Biotechnology and Genetic Engineering, Faisalabad, Pakistan
- Pakistan Institute of Engineering and Applied Sciences, Nilore-Islamabad, Pakistan
| | - Kabeer Haneef
- Institute of Microbiology, University of Agriculture Faisalabad, Faisalabad, Pakistan
- School of Life Sciences, Institute for Immunology, Tsinghua University, Beijing, China
| | - Fizza Fatima
- Department of Gynecology and Obstetrics, Rawalpindi Medical University, Rawalpindi, Pakistan
| | - Aisha Asghar
- Department of Gynecology and Obstetrics, District Headquarters Hospital, Toba Tek Singh, Pakistan
| | - Noor Ul Ain
- Institute of Microbiology and Molecular Genetics, University of the Punjab, Lahore, Pakistan
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Cavallo I, Oliva A, Pages R, Sivori F, Truglio M, Fabrizio G, Pasqua M, Pimpinelli F, Di Domenico EG. Acinetobacter baumannii in the critically ill: complex infections get complicated. Front Microbiol 2023; 14:1196774. [PMID: 37425994 PMCID: PMC10325864 DOI: 10.3389/fmicb.2023.1196774] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 06/05/2023] [Indexed: 07/11/2023] Open
Abstract
Acinetobacter baumannii is increasingly associated with various epidemics, representing a serious concern due to the broad level of antimicrobial resistance and clinical manifestations. During the last decades, A. baumannii has emerged as a major pathogen in vulnerable and critically ill patients. Bacteremia, pneumonia, urinary tract, and skin and soft tissue infections are the most common presentations of A. baumannii, with attributable mortality rates approaching 35%. Carbapenems have been considered the first choice to treat A. baumannii infections. However, due to the widespread prevalence of carbapenem-resistant A. baumannii (CRAB), colistin represents the main therapeutic option, while the role of the new siderophore cephalosporin cefiderocol still needs to be ascertained. Furthermore, high clinical failure rates have been reported for colistin monotherapy when used to treat CRAB infections. Thus, the most effective antibiotic combination remains disputed. In addition to its ability to develop antibiotic resistance, A. baumannii is also known to form biofilm on medical devices, including central venous catheters or endotracheal tubes. Thus, the worrisome spread of biofilm-producing strains in multidrug-resistant populations of A. baumannii poses a significant treatment challenge. This review provides an updated account of antimicrobial resistance patterns and biofilm-mediated tolerance in A. baumannii infections with a special focus on fragile and critically ill patients.
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Affiliation(s)
- Ilaria Cavallo
- Microbiology and Virology, San Gallicano Dermatological Institute, IRCCS, Rome, Italy
| | - Alessandra Oliva
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy
| | - Rebecca Pages
- Microbiology and Virology, San Gallicano Dermatological Institute, IRCCS, Rome, Italy
| | - Francesca Sivori
- Microbiology and Virology, San Gallicano Dermatological Institute, IRCCS, Rome, Italy
| | - Mauro Truglio
- Microbiology and Virology, San Gallicano Dermatological Institute, IRCCS, Rome, Italy
| | - Giorgia Fabrizio
- Microbiology and Virology, San Gallicano Dermatological Institute, IRCCS, Rome, Italy
| | - Martina Pasqua
- Department of Biology and Biotechnology "C. Darwin" Sapienza University of Rome, Rome, Italy
| | - Fulvia Pimpinelli
- Microbiology and Virology, San Gallicano Dermatological Institute, IRCCS, Rome, Italy
| | - Enea Gino Di Domenico
- Department of Biology and Biotechnology "C. Darwin" Sapienza University of Rome, Rome, Italy
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Liu C, Wang L, Wang P, Xiao D, Zou Q. The Mechanism of Tigecycline Resistance in Acinetobacter baumannii Revealed by Proteomic and Genomic Analysis. Int J Mol Sci 2023; 24:ijms24108652. [PMID: 37239993 DOI: 10.3390/ijms24108652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Revised: 05/09/2023] [Accepted: 05/09/2023] [Indexed: 05/28/2023] Open
Abstract
The mechanism of tigecycline resistance in A. baumannii remains largely unclear. In this study, we selected a tigecycline-resistant and a tigecycline-susceptible strain from a tigecycline-susceptible and a resistant strain, respectively. Proteomic and genomic analyses were performed to elucidate the variations associated with tigecycline resistance. Our study showed proteins associated with efflux pump, biofilm formation, iron acquisition, stress response, and metabolic ability are upregulated in tigecycline resistant strains, and efflux pump should be the key mechanism for tigecycline resistance. By genomic analysis, we found several changes in the genome that can explain the increased level of efflux pump, including the loss of the global negative regulator hns in the plasmid and the disruption of the hns gene and acrR gene on the chromosome by the insertion of IS5. Collectively, we not only revealed the phenomenon that the efflux pump is mainly responsible for tigecycline resistance, but also highlighted the mechanism at the genomic level, which will help in understanding the resistance mechanism in detail and provide clues for the treatment of clinical multiple drug-resistant A. baumannii.
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Affiliation(s)
- Cunwei Liu
- Department of Microbiology and Infectious Disease Center, School of Basic Medical Sciences, Peking University, Beijing 100191, China
| | - Lei Wang
- State Key Laboratory of Communicable Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
| | - Ping Wang
- Department of Microbiology and Infectious Disease Center, School of Basic Medical Sciences, Peking University, Beijing 100191, China
| | - Di Xiao
- State Key Laboratory of Communicable Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
| | - Qinghua Zou
- Department of Microbiology and Infectious Disease Center, School of Basic Medical Sciences, Peking University, Beijing 100191, China
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10
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Prity FT, Tobin LA, Maharajan R, Paulsen IT, Cain AK, Hamidian M. The evolutionary tale of eight novel plasmids in a colistin-resistant environmental Acinetobacter baumannii isolate. Microb Genom 2023; 9. [PMID: 37171842 DOI: 10.1099/mgen.0.001010] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023] Open
Abstract
Acinetobacter baumannii is an important opportunistic pathogen known for its high levels of resistance to many antibiotics, particularly those considered last resorts such as colistin and carbapenems. Plasmids of this organism are increasingly associated with the spread of clinically important antibiotic resistance genes. Although A. baumannii is a ubiquitous organism, to date, most of the focus has been on studying strains recovered from clinical samples ignoring those isolated in the environment (soil, water, food, etc.). Here, we analysed the genetic structures of eight novel plasmids carried by an environmental colistin-resistant A. baumannii (strain E-072658) recovered in a recycled fibre pulp in a paper mill in Finland. It was shown that E-072658 carries a new variant of the mcr-4 colistin resistance gene (mcr-4.7) in a novel Tn3-family transposon (called Tn6926) carried by a novel plasmid p8E072658. E-072658 is also resistant to sulphonamide compounds; consistent with this, the sul2 sulphonamide resistance gene was found in a pdif module. E-072658 also carries six additional plasmids with no antibiotic resistance genes, but they contained several pdif modules shared with plasmids carried by clinical strains. Detailed analysis of the genetic structure of all eight plasmids carried by E-072658 showed a complex evolutionary history revealing genetic exchange events within the genus Acinetobacter beyond the clinical or environmental origin of the strains. This work provides evidence that environmental strains might act as a source for some of the clinically significant antibiotic resistance genes.
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Affiliation(s)
- Farzana T Prity
- ARC Centre of Excellence in Synthetic Biology, School of Natural Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Liam A Tobin
- Australian Institute for Microbiology & Infection, University of Technology Sydney, Ultimo, NSW, 2007, Australia
| | - Ram Maharajan
- ARC Centre of Excellence in Synthetic Biology, School of Natural Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Ian T Paulsen
- ARC Centre of Excellence in Synthetic Biology, School of Natural Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Amy K Cain
- ARC Centre of Excellence in Synthetic Biology, School of Natural Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Mehrad Hamidian
- Australian Institute for Microbiology & Infection, University of Technology Sydney, Ultimo, NSW, 2007, Australia
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Santajit S, Bhoopong P, Kong-Ngoen T, Tunyong W, Horpet D, Paehoh-ele W, Zahedeng T, Pumirat P, Sookrung N, Hinthong W, Indrawattana N. Phenotypic and Genotypic Investigation of Carbapenem-Resistant Acinetobacter baumannii in Maharaj Nakhon Si Thammarat Hospital, Thailand. Antibiotics (Basel) 2023; 12:antibiotics12030580. [PMID: 36978447 PMCID: PMC10044629 DOI: 10.3390/antibiotics12030580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 03/10/2023] [Accepted: 03/13/2023] [Indexed: 03/17/2023] Open
Abstract
(1) Background: Acinetobacter baumannii is well known as a causative agent of severe hospital-acquired infections, especially in intensive care units. The present study characterised the genetic traits of biofilm-forming carbapenem-resistant A. baumannii (CRAB) clinical isolates. Additionally, this study determined the prevalence of biofilm-producing A. baumannii isolates from a tertiary care hospital and investigated the association of biofilms with the distribution of biofilm-related and antibiotic resistance-associated genotypes. (2) Methods: The 995 non-duplicate A. baumannii isolates were identified, and their susceptibilities to different antibiotics were determined using the disk diffusion method. Using the modified microtiter plate assay, the CRAB isolates were investigated for their biofilm formation ability. Hemolysin and protease activities were determined. CRABs were subjected to polymerase chain reaction (PCR) assays targeting blaVIM, blaNDM, blaIMP, blaOXA-23-like, blaOXA-24-like, blaOXA-51-like, csuE and pgaB genes. Individual CRAB isolates were identified for their DNA fingerprint by repetitive element sequence-based (REP)-PCR. (3) Results: Among all A. baumannii isolates, 172 CRABs were identified. The major antibiotic resistance gene among the CRAB isolates was blaOXA-51-like (100%). Ninety-nine isolates (57.56%) were biofilm producers. The most prevalent biofilm gene was pgaB (79.65%), followed by csuE (76.74%). Evidence of virulence phenotypes revealed that all CRAB exhibited proteolytic activity; however, only four isolates (2.33%) were positive for the hemolytic-producing phenotype. REP-PCR showed that 172 CRAB isolates can be divided into 36-DNA fingerprint patterns. (4) Conclusions: The predominance of biofilm-producing CRAB isolates identified in this study is concerning. The characterisation of risk factors could aid in controlling the continual selection and spreading of the A. baumannii phenotype in hospitals, thereby improving patient care quality.
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Affiliation(s)
- Sirijan Santajit
- Department of Medical Technology, School of Allied Health Sciences, Walailak University, Nakhon Si Thammarat 80160, Thailand
- Research Center in Tropical Pathobiology, Walailak University, Nakhon Si Thammarat 80160, Thailand
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
| | - Phuangthip Bhoopong
- Department of Medical Technology, School of Allied Health Sciences, Walailak University, Nakhon Si Thammarat 80160, Thailand
| | - Thida Kong-Ngoen
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
| | - Witawat Tunyong
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
| | - Dararat Horpet
- Department of Medical Technology, School of Allied Health Sciences, Walailak University, Nakhon Si Thammarat 80160, Thailand
| | - Wanfudhla Paehoh-ele
- Department of Medical Technology, School of Allied Health Sciences, Walailak University, Nakhon Si Thammarat 80160, Thailand
| | - Tasneem Zahedeng
- Department of Medical Technology, School of Allied Health Sciences, Walailak University, Nakhon Si Thammarat 80160, Thailand
| | - Pornpan Pumirat
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
| | - Nitat Sookrung
- Siriraj Center of Research Excellence in Allergy and Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
- Biomedical Research Incubator Unit, Department of Research, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Woranich Hinthong
- Princess Srisavangavadhana College of Medicine, Chulabhorn Royal Academy, Bangkok 10210, Thailand
| | - Nitaya Indrawattana
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
- Correspondence: ; Tel.: +66-2-354-9100 (ext. 1598)
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Kalpana S, Lin WY, Wang YC, Fu Y, Lakshmi A, Wang HY. Antibiotic Resistance Diagnosis in ESKAPE Pathogens-A Review on Proteomic Perspective. Diagnostics (Basel) 2023; 13:1014. [PMID: 36980322 PMCID: PMC10047325 DOI: 10.3390/diagnostics13061014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 02/26/2023] [Accepted: 02/28/2023] [Indexed: 03/11/2023] Open
Abstract
Antibiotic resistance has emerged as an imminent pandemic. Rapid diagnostic assays distinguish bacterial infections from other diseases and aid antimicrobial stewardship, therapy optimization, and epidemiological surveillance. Traditional methods typically have longer turn-around times for definitive results. On the other hand, proteomic studies have progressed constantly and improved both in qualitative and quantitative analysis. With a wide range of data sets made available in the public domain, the ability to interpret the data has considerably reduced the error rates. This review gives an insight on state-of-the-art proteomic techniques in diagnosing antibiotic resistance in ESKAPE pathogens with a future outlook for evading the "imminent pandemic".
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Affiliation(s)
- Sriram Kalpana
- Department of Laboratory Medicine, Linkou Chang Gung Memorial Hospital, Taoyuan 333423, Taiwan
| | | | - Yu-Chiang Wang
- Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
- Department of Medicine, Brigham and Women’s Hospital, Boston, MA 02115, USA
| | - Yiwen Fu
- Department of Medicine, Kaiser Permanente Santa Clara Medical Center, Santa Clara, CA 95051, USA
| | - Amrutha Lakshmi
- Department of Biochemistry, University of Madras, Guindy Campus, Chennai 600025, India
| | - Hsin-Yao Wang
- Department of Laboratory Medicine, Linkou Chang Gung Memorial Hospital, Taoyuan 333423, Taiwan
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13
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Giacone L, Cameranesi MM, Sanchez RI, Limansky AS, Morán-Barrio J, Viale AM. Dynamic state of plasmid genomic architectures resulting from XerC/D-mediated site-specific recombination in Acinetobacter baumannii Rep_3 superfamily resistance plasmids carrying blaOXA-58 - and Tn aphA6-resistance modules. Front Microbiol 2023; 14:1057608. [PMID: 36846794 PMCID: PMC9947245 DOI: 10.3389/fmicb.2023.1057608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 01/04/2023] [Indexed: 02/11/2023] Open
Abstract
The acquisition of bla OXA genes encoding different carbapenem-hydrolyzing class-D β-lactamases (CHDL) represents a main determinant of carbapenem resistance in the nosocomial pathogen Acinetobacter baumannii. The blaOXA-58 gene, in particular, is generally embedded in similar resistance modules (RM) carried by plasmids unique to the Acinetobacter genus lacking self-transferability. The ample variations in the immediate genomic contexts in which blaOXA-58 -containing RMs are inserted among these plasmids, and the almost invariable presence at their borders of non-identical 28-bp sequences potentially recognized by the host XerC and XerD tyrosine recombinases (pXerC/D-like sites), suggested an involvement of these sites in the lateral mobilization of the gene structures they encircle. However, whether and how these pXerC/D sites participate in this process is only beginning to be understood. Here, we used a series of experimental approaches to analyze the contribution of pXerC/D-mediated site-specific recombination to the generation of structural diversity between resistance plasmids carrying pXerC/D-bounded bla OXA-58- and TnaphA6-containing RM harbored by two phylogenetically- and epidemiologically-closely related A. baumannii strains of our collection, Ab242 and Ab825, during adaptation to the hospital environment. Our analysis disclosed the existence of different bona fide pairs of recombinationally-active pXerC/D sites in these plasmids, some mediating reversible intramolecular inversions and others reversible plasmid fusions/resolutions. All of the identified recombinationally-active pairs shared identical GGTGTA sequences at the cr spacer separating the XerC- and XerD-binding regions. The fusion of two Ab825 plasmids mediated by a pair of recombinationally-active pXerC/D sites displaying sequence differences at the cr spacer could be inferred on the basis of sequence comparison analysis, but no evidence of reversibility could be obtained in this case. The reversible plasmid genome rearrangements mediated by recombinationally-active pairs of pXerC/D sites reported here probably represents an ancient mechanism of generating structural diversity in the Acinetobacter plasmid pool. This recursive process could facilitate a rapid adaptation of an eventual bacterial host to changing environments, and has certainly contributed to the evolution of Acinetobacter plasmids and the capture and dissemination of bla OXA-58 genes among Acinetobacter and non-Acinetobacter populations co-residing in the hospital niche.
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Affiliation(s)
| | | | - Rocío I. Sanchez
- Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, CONICET, Instituto de Biología Molecular y Celular de Rosario (IBR), Universidad Nacional de Rosario (UNR), Rosario, Argentina
| | - Adriana S. Limansky
- Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, CONICET, Instituto de Biología Molecular y Celular de Rosario (IBR), Universidad Nacional de Rosario (UNR), Rosario, Argentina
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14
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Novović K, Kuzmanović Nedeljković S, Poledica M, Nikolić G, Grujić B, Jovčić B, Kojić M, Filipić B. Virulence potential of multidrug-resistant Acinetobacter baumannii isolates from COVID-19 patients on mechanical ventilation: The first report from Serbia. Front Microbiol 2023; 14:1094184. [PMID: 36825087 PMCID: PMC9941878 DOI: 10.3389/fmicb.2023.1094184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 01/13/2023] [Indexed: 02/10/2023] Open
Abstract
Since the WHO declared the COVID-19 pandemic in March 2020, the disease has spread rapidly leading to overload of the health system and many of the patients infected with SARS-CoV-2 needed to be admitted to the intensive care unit (ICU). Around 10% of patients with the severe manifestation of COVID-19 need noninvasive or invasive mechanical ventilation, which represent a risk factor for Acinetobacter baumannii superinfection. The 64 A. baumannii isolates were recovered from COVID-19 patients admitted to ICU at General Hospital "Dr Laza K. Lazarević" Šabac, Serbia, during the period from December 2020 to February 2021. All patients required mechanical ventilation and mortality rate was 100%. The goal of this study was to evaluate antibiotic resistance profiles and virulence potential of A. baumannii isolates recovered from patients with severe form of COVID-19 who had a need for mechanical ventilation. All tested A. baumannii isolates (n = 64) were sensitive to colistin, while resistant to meropenem, imipenem, gentamicin, tobramycin, and levofloxacin according to the broth microdilution method and MDR phenotype was confirmed. In all tested isolates, representatives of international clone 2 (IC2) classified by multiplex PCR for clonal lineage identification, bla AmpC, bla OXA-51, and bla OXA-23 genes were present, as well as ISAba1 insertion sequence upstream of bla OXA-23. Clonal distribution of one dominant strain was found, but individual strains showed phenotypic differences in the level of antibiotic resistance, biofilm formation, and binding to mucin and motility. According to PFGE, four isolates were sequenced and antibiotic resistance genes as well as virulence factors genes were analyzed in these genomes. The results of this study represent the first report on virulence potential of MDR A. baumannii from hospital in Serbia.
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Affiliation(s)
- Katarina Novović
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
| | | | | | - Gordana Nikolić
- General Hospital “Dr Laza K. Lazarević” Šabac, Šabac, Serbia
| | - Bojana Grujić
- General Hospital “Dr Laza K. Lazarević” Šabac, Šabac, Serbia
| | - Branko Jovčić
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia,Faculty of Biology, University of Belgrade, Belgrade, Serbia
| | - Milan Kojić
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
| | - Brankica Filipić
- Faculty of Pharmacy, University of Belgrade, Belgrade, Serbia,*Correspondence: Brankica Filipić,
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15
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Swain A, Pan A. Protein Therapeutic Target Candidates Against Acinetobacter baumannii, a Pathogen of Concern to Planetary Health: A Network-Based Integrative Omics Drug Discovery Approach. OMICS : A JOURNAL OF INTEGRATIVE BIOLOGY 2023; 27:62-74. [PMID: 36735546 DOI: 10.1089/omi.2022.0180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Acinetobacter baumannii, an opportunistic gram-negative pathogen responsible for several nosocomial infections, has developed resistance to various antibiotics. Proteins involved in the two-component system (TCS), virulence, and antibiotic resistance (AR), help this pathogen in regulating antibiotic susceptibility and virulence mechanisms. The present study reports a network-based integrative omics approach to drug discovery to identify key regulatory proteins as therapeutic candidates against A. baumannii. We collected data on the TCS, virulence, and AR proteins from various databases (P2CS, VFDB, ARDB, and PAIDB), which were subjected to network, host-pathogen, and gene expression data analysis. Network analysis identified 43 hubs, and 10 proteins were found to be interacting with human proteins associated with vital pathways. Of the 53 (43 + 10) pathogen proteins, 46 had no orthologs in the human host. Twelve proteins, namely, RpfC, Wzc, OmpR, EnvZ, BfmS, PilG, histidine kinase, ABC 3 transport family protein, outer membrane porin OprD family, CsuD, Pgm, and LpxA, were differentially expressed in the resistant strain. We propose these proteins as key regulators that warrant evaluation as therapeutic target candidates in the future. Furthermore, structure prediction of ABC 3 transport family protein was performed as a case study. The findings from this study are poised to facilitate and inform drug discovery and development against A. baumannii.
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Affiliation(s)
- Aishwarya Swain
- Department of Bioinformatics, School of Life Sciences, Pondicherry University, Puducherry, India
| | - Archana Pan
- Department of Bioinformatics, School of Life Sciences, Pondicherry University, Puducherry, India
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16
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Hubloher JJ, Van der Sande L, Schaudinn C, Müller V, Averhoff B. The Tol-Pal system of Acinetobacter baumannii is important for cell morphology, antibiotic resistance and virulence. Int Microbiol 2023:10.1007/s10123-022-00319-9. [PMID: 36648597 PMCID: PMC10397113 DOI: 10.1007/s10123-022-00319-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Revised: 12/27/2022] [Accepted: 12/30/2022] [Indexed: 01/18/2023]
Abstract
Acinetobacter baumannii is an opportunistic human pathogen that has become a global threat to healthcare institutions. This Gram-negative bacterium is one of the most successful human pathogens worldwide and responsible for hospital-acquired infections. This is due to its outstanding potential to adapt to very different environments, to persist in the human host and most important, its ability to develop multidrug resistance. Our combined approach of genomic and phenotypic analyses led to the identification of the envelope spanning Tol-Pal system in A. baumannii. We found that the deletion of the tolQ, tolR, tolA, tolB, and pal genes affects cell morphology and increases antibiotic sensitivity, such as the ∆tol-pal mutant exhibits a significantly increased gentamicin and bacitracin sensitivity. Furthermore, Galleria mellonella caterpillar killing assays revealed that the ∆tol-pal mutant exhibits a decreased killing phenotype. Taken together, our findings suggest that the Tol-Pal system is important for cell morphology, antibiotic resistance, and virulence of A. baumannii.
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Affiliation(s)
- Josephine Joy Hubloher
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Goethe-University Frankfurt Am Main, Max-Von-Laue-Str. 9, 60438, Frankfurt, Germany
| | - Lisa Van der Sande
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Goethe-University Frankfurt Am Main, Max-Von-Laue-Str. 9, 60438, Frankfurt, Germany
| | - Christoph Schaudinn
- Advanced Light and Electron Microscopy ZBS4, Robert-Koch-Institut, Berlin, Germany
| | - Volker Müller
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Goethe-University Frankfurt Am Main, Max-Von-Laue-Str. 9, 60438, Frankfurt, Germany
| | - Beate Averhoff
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Goethe-University Frankfurt Am Main, Max-Von-Laue-Str. 9, 60438, Frankfurt, Germany.
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17
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Shayea RH, Ali MR. Whole-genome Study of Carbapenem-resistant Acinetobacter baumannii Virulence and Resistance. IRANIAN JOURNAL OF MEDICAL MICROBIOLOGY 2023. [DOI: 10.30699/ijmm.17.1.90] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/14/2023]
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18
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Suzuki S, Subsomwong P, Narita K, Kawai N, Ishiai T, Teng W, Sukchawalit R, Nakane A, Tasaka S, Asano K. Differential proteomic analysis and pathogenic effects of outer membrane vesicles derived from Acinetobacter baumannii under normoxia and hypoxia. PLoS One 2023; 18:e0283109. [PMID: 36920961 PMCID: PMC10016710 DOI: 10.1371/journal.pone.0283109] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 03/01/2023] [Indexed: 03/16/2023] Open
Abstract
Acinetobacter baumannii is a major causative agent of nosocomial infections and its outer membrane vesicles (AbOMVs) have been shown to be involved in pathogenicity by transporting virulence factors and transferring information for communication between pathogens and host cells. Despite the fact that the infected sites of A. baumannii such as lungs and skin soft tissues are hypoxic, most studies on AbOMV virulence have used AbOMVs prepared under aerobic conditions. The present study aims to elucidate the protein profile and pathogenic impact of AbOMVs released under hypoxic condition. AbOMVs were isolated from A. baumannii under normoxic and hypoxic conditions, and their protein profiles were compared. The different effects of both normoxic and hypoxic AbOMVs in cytokine response from mouse macrophages, cytotoxicity to the human lung epithelial cells, and bacterial invasion were then investigated. Our results showed that A. baumannii under hypoxia released larger amounts of OMVs with different protein profiles. Although the cytotoxic effect of AbOMVs from normoxia and hypoxia were comparable, AbOMVs from normoxia induced higher TNF-α production and invasion of Staphylococcus aureus and Pseudomonas aeruginosa than those from hypoxia. On the other hand, AbOMVs significantly enhanced A. baumannii invasion into lung epithelial cells in a dose-dependent manner. These results clearly demonstrate that AbOMVs released from normoxic and hypoxic have different impacts in pathogenesis. This finding provides new insight into the complex interactions between A. baumannii, coinfecting pathogens and host cells via OMVs, in particular the different pathogenic effects of AbOMVs under normoxic and hypoxic conditions.
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Affiliation(s)
- Sachio Suzuki
- Department of Respiratory Medicine, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
| | - Phawinee Subsomwong
- Department of Microbiology and Immunology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
| | - Kouji Narita
- Department of Microbiology and Immunology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
- Institute for Animal Experimentation, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
| | - Noriaki Kawai
- Department of Microbiology and Immunology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
| | - Takahito Ishiai
- Department of Microbiology and Immunology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
| | - Wei Teng
- Department of Microbiology and Immunology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
| | - Rojana Sukchawalit
- Laboratory of Biotechnology, Chulabhorn Research Institute, Lak Si, Bangkok, Thailand
| | - Akio Nakane
- Department of Biopolymer and Health Science, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
| | - Sadatomo Tasaka
- Department of Respiratory Medicine, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
| | - Krisana Asano
- Department of Microbiology and Immunology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
- Department of Biopolymer and Health Science, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
- * E-mail:
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Bai B, Eales BM, Huang W, Ledesma KR, Merlau PR, Li G, Yu Z, Tam VH. Clinical and genomic analysis of virulence-related genes in bloodstream infections caused by Acinetobacter baumannii. Virulence 2022; 13:1920-1927. [PMID: 36308002 PMCID: PMC9621070 DOI: 10.1080/21505594.2022.2132053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Acinetobacter baumannii has emerged as a common cause of bloodstream infections, which is associated with high mortality and long periods of hospitalization. To advance the medical care of our patients, the study was designed to identify microbial characteristics associated with poor clinical outcomes. A collection of 32 A. baumannii bloodstream isolates with diverse genetic backgrounds (as determined by multilocus sequence typing) was studied. These isolates were recovered by unique patients (18 males, 14 females; age range: 17 days to 87 years) between 2011 and 2018. A sequential screening approach (cross-referencing analyses using different endpoints) was used to identify isolates with the best correlation between bacterial virulence and clinical prognosis. Isolates associated with more rapid in vitro growth rate, shorter median survival time in pre-clinical infection models, and hospital mortality were selected as candidates for high virulence, while those with opposite characteristics were selected as controls with low virulence. Whole genome sequencing was undertaken in the most promising clinical isolates. We found five virulence genes (beta-hemolysin/cytolysin, Cpi-1a + Cpi-1 (SPI-1 like), enhanced entry proteins, FbpABC, Paa) and 1 secretory system (T6SS) only present in a highly virulent isolate (AB23), compared to a low virulence control isolate (AB6). These genetic elements could be associated with the poor prognosis of A. baumannii bacteraemia and further investigations are warranted.
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Affiliation(s)
- Bing Bai
- Department of Infectious Diseases and Shenzhen Key Laboratory for Endogenous Infections, The 6th Affiliated Hospital of Shenzhen University Health Center, Shenzhen, Guangdong, China,Department of Pharmacy Practice and Translational Research, University of Houston, Houston, Texas, USA
| | - Brianna M. Eales
- Department of Pharmacy Practice and Translational Research, University of Houston, Houston, Texas, USA
| | - Wei Huang
- Bacteriology & Antibacterial Resistance Surveillance Laboratory, Shenzhen Institute of Respiratory Diseases, Shenzhen People’s Hospital (The Second Clinical Medical College, Jinan University, The First Affiliated Hospital, Southern University of Science and Technology), Shenzhen, Guangdong, China
| | - Kimberly R. Ledesma
- Department of Pharmacy Practice and Translational Research, University of Houston, Houston, Texas, USA
| | - Paul R. Merlau
- Department of Pharmacy Practice and Translational Research, University of Houston, Houston, Texas, USA
| | - Guiqiu Li
- Department of Infectious Diseases and Shenzhen Key Laboratory for Endogenous Infections, The 6th Affiliated Hospital of Shenzhen University Health Center, Shenzhen, Guangdong, China
| | - Zhijian Yu
- Department of Infectious Diseases and Shenzhen Key Laboratory for Endogenous Infections, The 6th Affiliated Hospital of Shenzhen University Health Center, Shenzhen, Guangdong, China,Department of Pharmacy Practice and Translational Research, University of Houston, Houston, Texas, USA
| | - Vincent H. Tam
- Department of Pharmacy Practice and Translational Research, University of Houston, Houston, Texas, USA,CONTACT Vincent H. Tam
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Kundar R, Gokarn K. CRISPR-Cas System: A Tool to Eliminate Drug-Resistant Gram-Negative Bacteria. Pharmaceuticals (Basel) 2022; 15:ph15121498. [PMID: 36558949 PMCID: PMC9781512 DOI: 10.3390/ph15121498] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 11/18/2022] [Accepted: 11/24/2022] [Indexed: 12/04/2022] Open
Abstract
Rapidly emerging drug-resistant superbugs, especially Gram-negative bacteria, pose a serious threat to healthcare systems all over the globe. Newer strategies are being developed to detect and overcome the arsenal of weapons that these bacteria possess. The development of antibiotics is time-consuming and may not provide full proof of action on evolving drug-resistant pathogens. The clustered regularly interspaced short palindromic repeats/CRISPR-associated protein (CRISPR/Cas) systems are promising in curbing drug-resistant bacteria. This review focuses on the pathogenesis of Gram-negative bacteria, emergence of antimicrobial drug resistance, and their treatment failures. It also draws attention to the present status of the CRISPR-Cas system in diagnosisand treatment of Gram-negative bacterial infections.
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Affiliation(s)
- Rajeshwari Kundar
- Department of Microbiology, Sir H.N. Medical Research Society, Sir H.N. Reliance Foundation Hospital & Research Centre, Mumbai 400004, Maharashtra, India
| | - Karuna Gokarn
- Department of Microbiology, Sir H.N. Medical Research Society, Sir H.N. Reliance Foundation Hospital & Research Centre, Mumbai 400004, Maharashtra, India
- Department of Microbiology, St. Xavier’s College, 5- Mahapalika Marg, Mumbai 400001, Maharashtra, India
- Correspondence: or
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21
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Acar MB, Ayaz-Güner Ş, Güner H, Dinç G, Ulu Kılıç A, Doğanay M, Özcan S. A subtractive proteomics approach for the identification of immunodominant Acinetobacter baumannii vaccine candidate proteins. Front Immunol 2022; 13:1001633. [DOI: 10.3389/fimmu.2022.1001633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Accepted: 10/10/2022] [Indexed: 11/11/2022] Open
Abstract
BackgroundAcinetobacter baumannii is one of the most life-threatening multidrug-resistant pathogens worldwide. Currently, 50%–70% of clinical isolates of A. baumannii are extensively drug-resistant, and available antibiotic options against A. baumannii infections are limited. There is still a need to discover specific de facto bacterial antigenic proteins that could be effective vaccine candidates in human infection. With the growth of research in recent years, several candidate molecules have been identified for vaccine development. So far, no public health authorities have approved vaccines against A. baumannii.MethodsThis study aimed to identify immunodominant vaccine candidate proteins that can be immunoprecipitated specifically with patients’ IgGs, relying on the hypothesis that the infected person’s IgGs can capture immunodominant bacterial proteins. Herein, the outer-membrane and secreted proteins of sensitive and drug-resistant A. baumannii were captured using IgGs obtained from patient and healthy control sera and identified by Liquid Chromatography- Tandem Mass Spectrometry (LC-MS/MS) analysis.ResultsUsing the subtractive proteomic approach, we determined 34 unique proteins captured only in drug-resistant A. baumannii strain via patient sera. After extensively evaluating the predicted epitope regions, solubility, transverse membrane characteristics, and structural properties, we selected several notable vaccine candidates.ConclusionWe identified vaccine candidate proteins that triggered a de facto response of the human immune system against the antibiotic-resistant A. baumannii. Precipitation of bacterial proteins via patient immunoglobulins was a novel approach to identifying the proteins that could trigger a response in the patient immune system.
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22
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Gu Y, Zhang W, Lei J, Zhang L, Hou X, Tao J, Wang H, Deng M, Zhou M, Weng R, Xu J. Molecular epidemiology and carbapenem resistance characteristics of Acinetobacter baumannii causing bloodstream infection from 2009 to 2018 in northwest China. Front Microbiol 2022; 13:983963. [PMID: 36071964 PMCID: PMC9441628 DOI: 10.3389/fmicb.2022.983963] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 07/26/2022] [Indexed: 01/10/2023] Open
Abstract
Bloodstream infection (BSI) caused by Acinetobacter baumannii poses a serious threat to health and is correlated with high mortality in patients with hospital-acquired infections, so the molecular epidemiology and antimicrobial resistance characteristics of this pathogen urgently need to be explored. A. baumannii isolates from BSI patients were collected in three tertiary hospitals in northwest China from 2009 to 2018. Antimicrobial susceptibility testing was used to determine the MICs of the A. baumannii isolates. Whole-genome sequencing based on the Illumina platform was performed for molecular epidemiological analyses and acquired resistance gene screening. The efflux pump phenotype was detected by examining the influence of an efflux pump inhibitor. The expression of efflux pump genes was evaluated by RT-PCR. In total, 47 A. baumannii isolates causing BSI were collected and they presented multidrug resistance, including resistance to carbapenems. Clone complex (CC) 92 was the most prevalent with 30 isolates, among which a cluster was observed in the phylogenetic tree based on the core genome multi-locus sequence type, indicating the dissemination of a dominant clone. BSI-related A. baumannii isolates normally harbour multiple resistance determinants, of which oxacillinase genes are most common. Except for the intrinsic blaOXA-51 family, there are some carbapenem-resistant determinants in these A. baumannii isolates, including blaOXA-23, which is encoded within the Tn2006, Tn2008 or Tn2009 transposon structures and blaOXA-72. The transfer of blaOXA-72 was suggested by XerC/D site-specific recombination. The AdeABC efflux pump system contributed to carbapenem resistance in A. baumannii isolates, as evidenced by the high expression of some of its encoding genes. Both the clone dissemination and carbapenem resistance mediated by oxacillinase or efflux pumps suggest an effective strategy for hospital infection control.
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Affiliation(s)
- Yihai Gu
- Department of Microbiology and Immunology, School of Basic Medical Sciences, Xi'an Jiaotong University, Xi'an, Shaanxi, China
- Department of Microbiology, 3201 hospital, School of Medicine, Xi'an Jiaotong University, Hanzhong, Shaanxi, China
| | - Wei Zhang
- Department of Microbiology, 3201 hospital, School of Medicine, Xi'an Jiaotong University, Hanzhong, Shaanxi, China
| | - Jine Lei
- Department of Clinical Laboratory, First Affiliated Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Lixia Zhang
- Department of Clinical Laboratory, Shaanxi Provincial People's Hospital, Xi'an, Shaanxi, China
| | - Xuan Hou
- Department of Microbiology, 3201 hospital, School of Medicine, Xi'an Jiaotong University, Hanzhong, Shaanxi, China
| | - Junqi Tao
- Department of Microbiology, 3201 hospital, School of Medicine, Xi'an Jiaotong University, Hanzhong, Shaanxi, China
| | - Hui Wang
- Department of Microbiology, 3201 hospital, School of Medicine, Xi'an Jiaotong University, Hanzhong, Shaanxi, China
| | - Minghui Deng
- Department of Microbiology, 3201 hospital, School of Medicine, Xi'an Jiaotong University, Hanzhong, Shaanxi, China
| | - Mengrong Zhou
- Department of Microbiology, 3201 hospital, School of Medicine, Xi'an Jiaotong University, Hanzhong, Shaanxi, China
| | - Rui Weng
- Department of Microbiology, 3201 hospital, School of Medicine, Xi'an Jiaotong University, Hanzhong, Shaanxi, China
| | - Jiru Xu
- Department of Microbiology and Immunology, School of Basic Medical Sciences, Xi'an Jiaotong University, Xi'an, Shaanxi, China
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Comparative genomics of Acinetobacter baumannii and therapeutic bacteriophages from a patient undergoing phage therapy. Nat Commun 2022; 13:3776. [PMID: 35773283 PMCID: PMC9247103 DOI: 10.1038/s41467-022-31455-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Accepted: 06/17/2022] [Indexed: 12/12/2022] Open
Abstract
In 2016, a 68-year-old patient with a disseminated multidrug-resistant Acinetobacter baumannii infection was successfully treated using lytic bacteriophages. Here we report the genomes of the nine phages used for treatment and three strains of A. baumannii isolated prior to and during treatment. The phages used in the initial treatment are related, T4-like myophages. Analysis of 19 A. baumannii isolates collected before and during phage treatment shows that resistance to the T4-like phages appeared two days following the start of treatment. We generate complete genomic sequences for three A. baumannii strains (TP1, TP2 and TP3) collected before and during treatment, supporting a clonal relationship. Furthermore, we use strain TP1 to select for increased resistance to five of the phages in vitro, and identify mutations that are also found in phage-insensitive isolates TP2 and TP3 (which evolved in vivo during phage treatment). These results support that in vitro investigations can produce results that are relevant to the in vivo environment.
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Khan MA, Allemailem KS, Maswadeh H, Younus H. Safety and Prophylactic Efficacy of Liposome-Based Vaccine against the Drug-Resistant Acinetobacter baumannii in Mice. Pharmaceutics 2022; 14:pharmaceutics14071357. [PMID: 35890253 PMCID: PMC9318010 DOI: 10.3390/pharmaceutics14071357] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Revised: 06/23/2022] [Accepted: 06/24/2022] [Indexed: 12/01/2022] Open
Abstract
In recent years, the emergence of multidrug-resistant Acientobacter baumannii has greatly threatened public health and depleted our currently available antibacterial armory. Due to limited therapeutic options, the development of an effective vaccine formulation becomes critical in order to fight this drug-resistant pathogen. The objective of the present study was to develop a safe vaccine formulation that can be effective against A. baumannii infection and its associated complications. Here, we prepared liposomes-encapsulated whole cell antigens (Lip-WCAgs) as a vaccine formulation and investigated its prophylactic efficacy against the systemic infection of A. baumannii. The immunization with Lip-WCAgs induced the higher production of antigen-specific antibody titers, greater lymphocyte proliferation, and increased secretion of Th1 cytokines, particularly IFN-γ and IL-12. Antisera from Lip-WCAgs-immunized mice showed the utmost bactericidal activity and potently inhibited the biofilm formation by A. baumannii. Interestingly, Lip-WCAgs-induced immune response was translated in in vivo protection studies as the immunized mice exhibited the highest resistance to A. baumannii infection. Mice in the group immunized with Lip-WCAgs had an 80% survival rate and a bacterial burden of 5464 ± 1193 CFUs per gram of the lung tissue, whereas the mice immunized with IFA-WCAgs had a 50% survival rate and 51,521 ± 8066 CFUs. In addition, Lip-WCAgs vaccinated mice had lower levels of the inflammatory markers, including CRP, IL-6, IL-1β, and TNF-α. The findings of this study suggest that Lip-WCAgs may be considered a potential vaccine formulation to protect individuals against A. baumannii infection.
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Affiliation(s)
- Masood Alam Khan
- Department of Basic Health Sciences, College of Applied Medical Sciences, Qassim University, Buraydah 51452, Saudi Arabia
- Correspondence: ; Tel.: +966-(50)-7059437; Fax: +966-(63)-801628
| | - Khaled S. Allemailem
- Department of Medical Laboratories, College of Applied Medical Sciences, Qassim University, Buraydah 51452, Saudi Arabia;
| | - Hamzah Maswadeh
- Department of Pharmaceutics, College of Pharmacy, Qassim University, Buraydah 51452, Saudi Arabia;
| | - Hina Younus
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh 202002, India;
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Vijayakumar S, Jacob JJ, Vasudevan K, Mathur P, Ray P, Neeravi A, Baskaran A, Kirubananthan A, Anandan S, Biswas I, Walia K, Veeraraghavan B. Genomic Characterization of Mobile Genetic Elements Associated With Carbapenem Resistance of Acinetobacter baumannii From India. Front Microbiol 2022; 13:869653. [PMID: 35783393 PMCID: PMC9240704 DOI: 10.3389/fmicb.2022.869653] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 05/20/2022] [Indexed: 11/13/2022] Open
Abstract
With the excessive genome plasticity, Acinetobacter baumannii can acquire and disseminate antimicrobial resistance (AMR) genes often associated with mobile genetic elements (MGEs). Analyzing the genetic environment of resistance genes often provides valuable information on the origin, emergence, evolution, and spread of resistance. Thus, we characterized the genomic features of some clinical isolates of carbapenem-resistant A. baumannii (CRAb) to understand the role of diverse MGEs and their genetic context responsible for disseminating carbapenem resistance genes. For this, 17 clinical isolates of A. baumannii obtained from multiple hospitals in India between 2018 and 2019 were analyzed. AMR determinants, the genetic context of resistance genes, and molecular epidemiology were studied using whole-genome sequencing. This study observed an increased prevalence of blaOXA–23 followed by dual carbapenemases, blaOXA–23, and blaNDM. This study identified three novel Oxford MLST sequence types. The majority of the isolates belonged to the dominant clone, IC2, followed by less prevalent clones such as IC7 and IC8. This study identified variations of AbaR4 and AbGRI belonging to the IC2 lineage. To the best of our knowledge, this is the first study that provides comprehensive profiling of resistance islands, their related MGEs, acquired AMR genes, and the distribution of clonal lineages of CRAb from India.
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Affiliation(s)
| | | | | | - Purva Mathur
- Jai Prakash Narayan Apex Trauma Center, All India Institute of Medical Sciences, New Delhi, India
| | - Pallab Ray
- Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | | | | | | | | | - Indranil Biswas
- Microbiology Department, Molecular Genetics and Immunology, University of Kansas, Lawrence, KS, United States
| | - Kamini Walia
- Indian Council of Medical Research (ICMR), New Delhi, National Capital Territory of Delhi, New Delhi, India
| | - Balaji Veeraraghavan
- Christian Medical College & Hospital, Vellore, India
- *Correspondence: Balaji Veeraraghavan,
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Hubeny J, Korzeniewska E, Buta-Hubeny M, Zieliński W, Rolbiecki D, Harnisz M. Characterization of carbapenem resistance in environmental samples and Acinetobacter spp. isolates from wastewater and river water in Poland. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 822:153437. [PMID: 35122847 DOI: 10.1016/j.scitotenv.2022.153437] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 01/21/2022] [Accepted: 01/22/2022] [Indexed: 05/29/2023]
Abstract
The aim of this study was to analyze the prevalence of carbapenem resistance genes in Acinetobacter spp. isolated from wastewater in a municipal WWTP and to determine their spread from treated wastewater to river water with the use of conventional and molecular microbiology methods (qualitative and quantitative PCR and metagenomic analysis). Samples of untreated and treated wastewater and samples of river water obtained upstream and downstream from the wastewater discharge point were collected in 3 seasons (February, June, and September) of 2019. Acinetobacter spp. isolates were obtained by the culture method on the CHROMagar™ Acinetobacter medium. Additionally, environmental DNA was extracted from the samples for metagenomic and qPCR analyses. The presence of beta-lactam resistance genes (Ambler class B and D), insertion sequence ISAba1, and class I, II, and III integron-integrase genes was determined, and the bacterial taxonomic structure and wastewater and river samples was analyzed. Out of the 301 isolates obtained on the CHROMagar™ Acinetobacter medium, 258 belonged to the genus Acinetobacter, including 21 isolates that were identified as Acinetobacter baumannii. The highest number of Acinetobacter spp. and A. baumannii isolates were obtained from wastewater and river water samples collected in June and September. The ISAba1/blaOXA-51 complex was identified in 13 isolates, which confirms the occurrence of carbapenem-resistance isolates in the analyzed samples. The number of Acinetobacter isolates carrying antibiotic resistance genes (ARGs) increased in river water samples collected downstream from the wastewater discharge point (48 out of 258 isolates - 18.6%) compared to river water samples collected upstream from the wastewater discharge point (34 out of 258 isolates - 13.2%), which suggests that WWTP is a source of pollution in the natural environment. The conducted research provides evidence that bacteria of the genus Acinetobacter may spread alarming beta-lactam resistance in the environment and, therefore, pose a serious epidemiological threat.
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Affiliation(s)
- Jakub Hubeny
- Department of Water Protection Engineering and Environmental Microbiology, Faculty of Geoengineering, University of Warmia and Mazury in Olsztyn, Prawocheńskiego 1, 10-720 Olsztyn, Poland
| | - Ewa Korzeniewska
- Department of Water Protection Engineering and Environmental Microbiology, Faculty of Geoengineering, University of Warmia and Mazury in Olsztyn, Prawocheńskiego 1, 10-720 Olsztyn, Poland
| | - Martyna Buta-Hubeny
- Department of Water Protection Engineering and Environmental Microbiology, Faculty of Geoengineering, University of Warmia and Mazury in Olsztyn, Prawocheńskiego 1, 10-720 Olsztyn, Poland
| | - Wiktor Zieliński
- Department of Water Protection Engineering and Environmental Microbiology, Faculty of Geoengineering, University of Warmia and Mazury in Olsztyn, Prawocheńskiego 1, 10-720 Olsztyn, Poland
| | - Damian Rolbiecki
- Department of Water Protection Engineering and Environmental Microbiology, Faculty of Geoengineering, University of Warmia and Mazury in Olsztyn, Prawocheńskiego 1, 10-720 Olsztyn, Poland
| | - Monika Harnisz
- Department of Water Protection Engineering and Environmental Microbiology, Faculty of Geoengineering, University of Warmia and Mazury in Olsztyn, Prawocheńskiego 1, 10-720 Olsztyn, Poland.
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Unidirectional mannitol synthesis of Acinetobacter baumannii MtlD is facilitated by the helix-loop-helix-mediated dimer formation. Proc Natl Acad Sci U S A 2022; 119:e2107994119. [PMID: 35363566 PMCID: PMC9168451 DOI: 10.1073/pnas.2107994119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mannitol biosynthesis is essential for Acinetobacter baumannii to cope with osmotic stress. Currently, only Pseudomonas putida, Acinetobacter baylyi, and A. baumannii are able to de novo synthesize mannitol by a structurally unique bifunctional mannitol-1-phosphate dehydrogenase/phosphatase (AbMtlD). The molecular mechanism of reduction and dephosphorylation of fructose-6-phosphate to mannitol is highly dependent on the substrate shuffling from one protomer to the other protomer by a unique helix–loop–helix domain–mediated dimer formation, thus ensuring unidirectional and efficient biosynthesis of mannitol. These observations support an evolutionary adaptation of AbMtlD by fusion of dehydrogenase and phosphatase domains to facilitate efficient unidirectional enzymatic production of mannitol, unifying regulatory control and minimizing the intracellular concentration of toxic mannitol-1-phosphate during salt stress. Persistence of Acinetobacter baumannii in environments with low water activity is largely attributed to the biosynthesis of compatible solutes. Mannitol is one of the key compatible solutes in A. baumannii, and it is synthesized by a bifunctional mannitol-1-phosphate dehydrogenase/phosphatase (AbMtlD). AbMtlD catalyzes the conversion of fructose-6-phosphate to mannitol in two consecutive steps. Here, we report the crystal structure of dimeric AbMtlD, constituting two protomers each with a dehydrogenase and phosphatase domain. A proper assembly of AbMtlD dimer is facilitated by an intersection comprising a unique helix–loop–helix (HLH) domain. Reduction and dephosphorylation catalysis of fructose-6-phosphate to mannitol is dependent on the transient dimerization of AbMtlD. AbMtlD presents as a monomer under lower ionic strength conditions and was found to be mainly dimeric under high-salt conditions. The AbMtlD catalytic efficiency was markedly increased by cross-linking the protomers at the intersected HLH domain via engineered disulfide bonds. Inactivation of the AbMtlD phosphatase domain results in an intracellular accumulation of mannitol-1-phosphate in A. baumannii, leading to bacterial growth impairment upon salt stress. Taken together, our findings demonstrate that salt-induced dimerization of the bifunctional AbMtlD increases catalytic dehydrogenase and phosphatase efficiency, resulting in unidirectional catalysis of mannitol production.
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28
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An Outer Membrane Protein YiaD Contributes to Adaptive Resistance of Meropenem in Acinetobacter baumannii. Microbiol Spectr 2022; 10:e0017322. [PMID: 35377216 PMCID: PMC9045393 DOI: 10.1128/spectrum.00173-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Acinetobacter baumannii is an important nosocomial pathogen that can develop various resistance mechanisms to many antibiotics. However, little is known about how it evolves from an antibiotic sensitive to a resistant phenotype. In this study, we investigated the transition of outer membrane proteins (OMPs) under antibiotic stress and identified YiaD as an OMP marker involved in the development of adaptive resistance to meropenem (MEM) in A. baumannii. Following stimulation of a carbapenem-sensitive strain AB5116 with sub-MIC of MEM, yiaD showed significantly decreased expression, and this decrease continued with prolonged stimulation for 8 h. The downregulation of yiaD was not only observed in clinically sensitive strains but also in 45 carbapenem-resistant isolates that produced the β-lactamases TEM and OXA-23. However, the extent of the reduction of yiaD expression in resistant strains was less than that in sensitive strains. Lack of yiaD resulted in a 4-fold increase in the MIC of AB5116 to MEM. The same level of depressed susceptibility induced by yiaD deletion was observed in both a growth curve test and a survival rate assay. Moreover, the colony shape became enlarged and irregular after loss of yiaD, and the biofilm formation ability of A. baumannii was influenced by YiaD. These results suggest that YiaD could respond to the stimulus of MEM in A. baumannii with a downregulation trend that kept pace with the prolonged stimulation time, indicating that it participates in various routes to benefit MEM resistance evolution in both carbapenem-sensitive and -resistant A. baumannii strains. IMPORTANCEAcinetobacter baumannii can develop various resistance mechanisms to carbapenems. However, the factors involved in the evolutionary process that leads from transition to the sensitive to resistant phenotype are not clear. The outer membrane protein YiaD of A. baumannii was downregulated under the stress of meropenem (MEM), and its expression level was continuously reduced with prolonged stimulation time. The downregulation of yiaD was not only observed in sensitive strains but also in carbapenem-resistant isolates producing the β-lactamases TEM and OXA-23. However, the extent of yiaD reduction was less in resistant strains than in sensitive strains. Lack of yiaD resulted in an increased MEM MIC, enlarged and irregular colonies, and decreased biofilm formation ability. These results suggest that YiaD responds to MEM stimulus in A. baumannii and participates in the adaptive resistance of MEM in both carbapenem-sensitive and -resistant strains.
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29
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Ahmad N, Singh A, Gupta A, Pant P, Singh TP, Sharma S, Sharma P. Discovery of the Lead Molecules Targeting the First Step of the Histidine Biosynthesis Pathway of Acinetobacter baumannii. J Chem Inf Model 2022; 62:1744-1759. [PMID: 35333517 DOI: 10.1021/acs.jcim.1c01421] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Acinetobacter baumannii is a multidrug-resistant, opportunistic, nosocomial pathogen for which a new line of treatments is desperately needed. We have targeted the enzyme of the first step of the histidine biosynthesis pathway, viz., ATP-phosphoribosyltransferase (ATP-PRT). The three-dimensional structure of ATP-PRT was predicted on the template of the known three-dimensional structure of ATP-PRT from Psychrobacter arcticus (PaATPPRT) using a homology modeling approach. High-throughput virtual screening (HTVS) of the antibacterial library of Life Chemicals Inc., Ontario, Canada was carried out followed by molecular dynamics simulations of the top hit compounds. In silico results were then biochemically validated using surface plasmon resonance spectroscopy. We found that two compounds, namely, F0843-0019 and F0608-0626, were binding with micromolar affinities to the ATP-phosphoribosyltransferase from Acinetobacter baumannii (AbATPPRT). Both of these compounds were binding in the same way as AMP in PaATPPRT, and the important residues of the active site, viz., Val4, Ser72, Thr76, Tyr77, Glu95, Lys134, Val136, and Tyr156, were also interacting via hydrogen bonds. The calculated binding energies of these compounds were -10.5 kcal/mol and -11.1 kcal/mol, respectively. These two compounds can be used as the potential lead molecules for designing antibacterial compounds in the future, and this information will help in drug discovery programs against Acinetobacter worldwide.
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Affiliation(s)
- Nabeel Ahmad
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi 110029, India
| | - Anamika Singh
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi 110029, India
| | - Akshita Gupta
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi 110029, India
| | - Pradeep Pant
- Department of Chemistry, Indian Institute of Technology, Delhi 110016, India
| | - Tej P Singh
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi 110029, India
| | - Sujata Sharma
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi 110029, India
| | - Pradeep Sharma
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi 110029, India
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Hamidian M, Maharjan RP, Farrugia DN, Delgado NN, Dinh H, Short FL, Kostoulias X, Peleg AY, Paulsen IT, Cain AK. Genomic and phenotypic analyses of diverse non-clinical Acinetobacter baumannii strains reveals strain-specific virulence and resistance capacity. Microb Genom 2022; 8. [PMID: 35166651 PMCID: PMC8942024 DOI: 10.1099/mgen.0.000765] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Acinetobacter baumannii is a critically important pathogen known for its widespread antibiotic resistance and ability to persist in hospital-associated environments. Whilst the majority of A. baumannii infections are hospital-acquired, infections from outside the hospital have been reported with high mortality. Despite this, little is known about the natural environmental reservoir(s) of A. baumannii and the virulence potential underlying non-clinical strains. Here, we report the complete genome sequences of six diverse strains isolated from environments such as river, soil, and industrial sites around the world. Phylogenetic analyses showed that four of these strains were unrelated to representative nosocomial strains and do not share a monophyletic origin, whereas two had sequence types belonging to the global clone lineages GC1 and GC2. Further, the majority of these strains harboured genes linked to virulence and stress protection in nosocomial strains. These genotypic properties correlated well with in vitro virulence phenotypic assays testing resistance to abiotic stresses, serum survival, and capsule formation. Virulence potential was confirmed in vivo, with most environmental strains able to effectively kill Galleria mellonella greater wax moth larvae. Using phenomic arrays and antibiotic resistance profiling, environmental and nosocomial strains were shown to have similar substrate utilisation patterns although environmental strains were distinctly more sensitive to antibiotics. Taken together, these features of environmental A. baumannii strains suggest the existence of a strain-specific distinct gene pools for niche specific adaptation. Furthermore, environmental strains appear to be equally virulent as contemporary nosocomial strains but remain largely antibiotic sensitive.
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Affiliation(s)
- Mohammad Hamidian
- The iThree institute, University of Technology Sydney, Ultimo, NSW 2007, Australia
| | - Ram P Maharjan
- ARC Centre of Excellence in Synthetic Biology, Department of Molecular Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Daniel N Farrugia
- ARC Centre of Excellence in Synthetic Biology, Department of Molecular Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Natasha N Delgado
- ARC Centre of Excellence in Synthetic Biology, Department of Molecular Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Hue Dinh
- ARC Centre of Excellence in Synthetic Biology, Department of Molecular Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Francesca L Short
- Infection & Immunity Program Monash Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton, VIC 3800, Australia
| | - Xenia Kostoulias
- Infection & Immunity Program Monash Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton, VIC 3800, Australia
| | - Anton Y Peleg
- Infection & Immunity Program Monash Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton, VIC 3800, Australia.,Department of Infectious Diseases, The Alfred Hospital and Central Clinical School, Monash University, Melbourne, VIC, 3004, Australia
| | - Ian T Paulsen
- ARC Centre of Excellence in Synthetic Biology, Department of Molecular Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Amy K Cain
- ARC Centre of Excellence in Synthetic Biology, Department of Molecular Sciences, Macquarie University, Sydney, NSW 2109, Australia
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Breisch J, Huber LS, Kraiczy P, Hubloher J, Averhoff B. The ß-ketoadipate pathway of Acinetobacter baumannii is involved in complement resistance and affects resistance against aromatic antibiotics. ENVIRONMENTAL MICROBIOLOGY REPORTS 2022; 14:170-178. [PMID: 35023294 DOI: 10.1111/1758-2229.13042] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 12/29/2021] [Indexed: 06/14/2023]
Abstract
Acinetobacter baumannii can thrive on a broad range of substrates such as sugars, alcohols, lipids, amino acids and aromatic compounds. The latter three are abundant in the human host and are potential candidates as carbon sources for the metabolic adaptation of A. baumannii to the human host. In this study we determined the biodegradative activities of A. baumannii AYE with monocyclic aromatic compounds. Deletion of genes encoding the key enzymes of the ß-ketoadipate pathway, the protocatechuate-3,4-dioxygenase (ΔpcaHG) and the catechol-1,2-dioxygenase (ΔcatA), led to a complete loss of growth on benzoate and p-hydroxybenzoate, suggesting that these substrates are metabolized via the two distinct branches (pca and cat) of this pathway. Furthermore, we investigated the potential role of these gene products in host adaptation by analyzing the capability of the mutants to resist complement-mediated killing. These studies revealed that the mutants exhibit a decreased complement resistance, but a dramatic increase in survival in normal human serum in the presence of p-hydroxybenzoate or protocatechuate. These results indicate that the ß-ketoadipate pathway plays a role in adaptation of A. baumannii to the human host. Moreover, the single and double mutants exhibited increased antibiotic resistances indicating a link between the two dioxygenases and antibiotic resistance.
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Affiliation(s)
- Jennifer Breisch
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Goethe-University Frankfurt am Main, Frankfurt, Germany
| | - Lisa Sophie Huber
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Goethe-University Frankfurt am Main, Frankfurt, Germany
| | - Peter Kraiczy
- Institute of Medical Microbiology and Infection Control, University Hospital Frankfurt, Goethe-University Frankfurt am Main, Frankfurt, Germany
| | - Josephine Hubloher
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Goethe-University Frankfurt am Main, Frankfurt, Germany
| | - Beate Averhoff
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Goethe-University Frankfurt am Main, Frankfurt, Germany
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32
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Assessment of In Vitro Cefiderocol Susceptibility and Comparators against an Epidemiologically Diverse Collection of Acinetobacter baumannii Clinical Isolates. Antibiotics (Basel) 2022; 11:antibiotics11020187. [PMID: 35203791 PMCID: PMC8868317 DOI: 10.3390/antibiotics11020187] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 01/24/2022] [Accepted: 01/29/2022] [Indexed: 12/10/2022] Open
Abstract
Cefiderocol is a catechol-substituted siderophore cephalosporin combining rapid penetration into the periplasmic space with increased stability against β-lactamases. This study provides additional data on the in vitro antimicrobial activity of cefiderocol and commercially available comparators against an epidemiologically diverse collection of Acinetobacter baumannii clinical isolates. Antimicrobial susceptibility was tested using pre-prepared frozen 96-well microtiter plates containing twofold serial dilutions of: cefepime, ceftazidime/avibactam, imipenem/relebactam, ampicillin/sulbactam, meropenem, meropenem/vaborbactam, ciprofloxacin, minocycline, tigecycline, trimethoprim/sulfamethoxazole and colistin using the standard broth microdilution procedure in cation-adjusted Mueller–Hinton broth (CAMHB). For cefiderocol, iron-depleted CAMHB was used. A collection of 113 clinical strains of A. baumannii isolated from Argentina, Azerbaijan, Croatia, Greece, Italy, Morocco, Mozambique, Peru and Spain were included. The most active antimicrobial agents against our collection were colistin and cefiderocol, with 12.38% and 21.23% of non-susceptibility, respectively. A high proportion of multidrug-resistant (76.77%) and carbapenem-resistant (75.28%) A. baumannii isolates remained susceptible to cefiderocol, which was clearly superior to novel β-lactam/β-lactamase inhibitor combinations. Cefiderocol-resistance was higher among carbapenem-resistant isolates and isolates belonging to ST2, but could not be associated with any particular resistance mechanism or clonal lineage. Our data suggest that cefiderocol is a good alternative to treat infections caused by MDR A. baumanni, including carbapenem-resistant strains.
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Selim S, Faried OA, Almuhayawi MS, Mohammed OA, Saleh FM, Warrad M. Dynamic Gene Clusters Mediating Carbapenem-Resistant Acinetobacter baumannii Clinical Isolates. Antibiotics (Basel) 2022; 11:antibiotics11020168. [PMID: 35203771 PMCID: PMC8868416 DOI: 10.3390/antibiotics11020168] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 01/24/2022] [Accepted: 01/26/2022] [Indexed: 02/04/2023] Open
Abstract
Acinetobacter baumanni (A. baumannii), a nonfermenting Gram-negative bacterium, has recently been associated with a broad range of nosocomial infections. To gain more meaningful insight into the problem of nosocomial illnesses caused by the multidrug-resistant (MDR) A. baumannii, as well as the factors that increase the risk of catching these infections, this investigation included a total of 86 clinical A. baumannii infections. Repetitive extragenic palindromic (REP)-PCR was used to investigate imipenem-resistant A. baumannii isolates for dynamic gene clusters causing carbapenem resistance. Four distinct A. baumannii lineages were found in the REP-PCR-DNA fingerprints of all isolates, with 95% of the samples coming from two dominant lineages. Imipenem, amikacin, and ciprofloxacin were less effective against genotype (A) isolates because of enhanced antibiotic tolerance. Lastly, to gain more insight into the mode of action of imipenem, we explored the binding affinity of imipenem toward different Acinetobacter baumannii OXA beta-lactamase class enzymes.
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Affiliation(s)
- Samy Selim
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Jouf University, Sakaka 72341, Saudi Arabia
- Correspondence:
| | - Osama Ahmed Faried
- Medical Microbiology and Immunology Department, Faculty of Medicine, Beni-Suef University, Beni-Suef 62513, Egypt;
| | - Mohamed S. Almuhayawi
- Department of Medical Microbiology and Parasitology, Faculty of Medicine, King Abdulaziz University, Jeddah 21589, Saudi Arabia;
| | - Osama A. Mohammed
- Department of Clinical Pharmacology, Faculty of Medicine, Ain Shams University, Cairo 11566, Egypt;
- Department of Clinical Pharmacology, Faculty of Medicine, Bisha University, Bisha 61922, Saudi Arabia
| | - Fayez M. Saleh
- Department of Medical Microbiology, Faculty of Medicine, University of Tabuk, Tabuk 71491, Saudi Arabia;
| | - Mona Warrad
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences at Al-Quriat, Jouf University, Al-Quriat 77454, Saudi Arabia;
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Farshadzadeh Z, Pourhajibagher M, Taheri B, Ekrami A, Modarressi MH, Azimzadeh M, Bahador A. Antimicrobial and anti-biofilm potencies of dermcidin-derived peptide DCD-1L against Acinetobacter baumannii: an in vivo wound healing model. BMC Microbiol 2022; 22:25. [PMID: 35026999 PMCID: PMC8756727 DOI: 10.1186/s12866-022-02439-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 01/06/2022] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND The global emergence of Acinetobacter baumannii resistance to most conventional antibiotics presents a major therapeutic challenge and necessitates the discovery of new antibacterial agents. The purpose of this study was to investigate in vitro and in vivo anti-biofilm potency of dermcidin-1L (DCD-1L) against extensively drug-resistant (XDR)-, pandrug-resistant (PDR)-, and ATCC19606-A. baumannii. METHODS After determination of minimum inhibitory concentration (MIC) of DCD-1L, in vitro anti-adhesive and anti-biofilm activities of DCD-1L were evaluated. Cytotoxicity, hemolytic activity, and the effect of DCD-1L treatment on the expression of various biofilm-associated genes were determined. The inhibitory effect of DCD-1L on biofilm formation in the model of catheter-associated infection, as well as, histopathological examination of the burn wound sites of mice treated with DCD-1L were assessed. RESULTS The bacterial adhesion and biofilm formation in all A. baumannii isolates were inhibited at 2 × , 4 × , and 8 × MIC of DCD-1L, while only 8 × MIC of DCD-1L was able to destroy the pre-formed biofilm in vitro. Also, reduce the expression of genes involved in biofilm formation was observed following DCD-1L treatment. DCD-1L without cytotoxic and hemolytic activities significantly reduced the biofilm formation in the model of catheter-associated infection. In vivo results showed that the count of A. baumannii in infected wounds was significantly decreased and the promotion in wound healing by the acceleration of skin re-epithelialization in mice was observed following treatment with 8 × MIC of DCD-1L. CONCLUSIONS Results of this study demonstrated that DCD-1L can inhibit bacterial attachment and biofilm formation and prevent the onset of infection. Taking these properties together, DCD-1L appears as a promising candidate for antimicrobial and anti-biofilm drug development.
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Affiliation(s)
- Zahra Farshadzadeh
- Infectious and Tropical Diseases Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
- Department of Microbiology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Maryam Pourhajibagher
- Dental Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran.
| | - Behrouz Taheri
- Infectious and Tropical Diseases Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
- Department of Medical Laboratory Sciences, School of Allied Medical Sciences, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Alireza Ekrami
- Infectious and Tropical Diseases Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
- Department of Medical Laboratory Sciences, School of Allied Medical Sciences, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | | | - Masoud Azimzadeh
- Department of Microbiology, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Abbas Bahador
- Fellowship in Clinical Laboratory Sciences, BioHealth Lab, Tehran, Iran.
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Alam MZ. Molecular Characterization of Integrons and Their Association with Antibiotic Resistance in Acinetobacter baumannii Isolated from Hospitals in Jeddah. APPL BIOCHEM MICRO+ 2021. [DOI: 10.1134/s0003683821100021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Abstract
Infection by multidrug-resistant (MDR) Acinetobacter baumannii is one of the major causes of hospital-acquired infections worldwide. The ability of A. baumannii to survive in adverse conditions as well as its extensive antimicrobial resistance make it one of the most difficult to treat pathogens associated with high mortality rates. The aim of this study was to investigate MDR A. baumannii that has spread among pediatric cancer patients in the Children’s Cancer Hospital Egypt 57357. Whole-genome sequencing was used to characterize 31 MDR A. baumannii clinical isolates. Phenotypically, the isolates were MDR, with four isolates showing resistance to the last-resort antibiotic colistin. Multilocus sequence typing showed the presence of eight clonal groups, two of which were previously reported to cause outbreaks in Egypt, and one novel sequence type (ST), Oxf-ST2246. Identification of the circulating plasmids showed the presence of two plasmid lineages in the isolates, strongly governed by sequence type. A large number of antimicrobial genes with a range of resistance mechanisms were detected in the isolates, including β-lactamases and antibiotic efflux pumps. Analysis of insertion sequences (ISs) revealed the presence of ISAba1 and ISAba125 in all the samples, which amplify β-lactamase expression, causing extensive carbapenem resistance. Mutation analysis was used to decipher underlying mutations responsible for colistin resistance and revealed novel mutations in several outer membrane proteins, in addition to previously reported mutations in pmrB. Altogether, understanding the transmissibility of A. baumannii as well as its resistance and virulence mechanisms will help develop novel treatment options for better management of hospital-acquired infections. IMPORTANCEAcinetobacter baumannii represents a major health threat, in particular among immunocompromised cancer patients. The rise in carbapenem-resistant A. baumannii, and the development of resistance to the last-resort antimicrobial agent colistin, complicates the management of A. baumannii outbreaks and increases mortality rates. Here, we investigate 31 multidrug resistant A. baumannii isolates from pediatric cancer patients in Children’s Cancer Hospital Egypt (CCHE) 57357 via whole-genome sequencing. Multilocus sequence typing (MLST) showed the presence of eight clonal groups including a novel sequence type. In silico detection of antimicrobial-resistant genes and virulence factors revealed a strong correlation between certain virulence genes and mortality as well as several point mutations in outer membrane proteins contributing to colistin resistance. Detection of CRISPR/Cas sequences in the majority of the samples was strongly correlated with the presence of prophage sequences and associated with failure of bacteriophage therapy. Altogether, understanding the genetic makeup of circulating A. baumannii is essential for better management of outbreaks.
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Virulence Characteristics of Biofilm-Forming Acinetobacter baumannii in Clinical Isolates Using a Galleria mellonella Model. Microorganisms 2021; 9:microorganisms9112365. [PMID: 34835490 PMCID: PMC8625498 DOI: 10.3390/microorganisms9112365] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 11/08/2021] [Accepted: 11/10/2021] [Indexed: 12/15/2022] Open
Abstract
Acinetobacter baumannii is a Gram-negative coccobacillus responsible for severe hospital-acquired infections, particularly in intensive care units (ICUs). The current study was designed to characterize the virulence traits of biofilm-forming carbapenem-resistant A. baumannii causing pneumonia in ICU patients using a Galleria mellonella model. Two hundred and thirty patients with hospital-acquired or ventilator-associated pneumonia were included in our study. Among the total isolates, A. baumannii was the most frequently isolated etiological agent in ICU patients with pneumonia (54/165, 32.7%). All A. baumannii isolates were subjected to antimicrobial susceptibility testing by the Kirby–Bauer disk diffusion method, while the minimum inhibitory concentrations of imipenem and colistin were estimated using the broth microdilution technique. The biofilm formation activity of the isolates was tested using the microtiter plate technique. Biofilm quantification showed that 61.1% (33/54) of the isolates were strong biofilm producers, while 27.7% (15/54) and 11.1% (6/54) showed moderate or weak biofilm production. By studying the prevalence of carbapenemases-encoding genes among isolates, blaOXA-23-like was positive in 88.9% of the isolates (48/54). The BlaNDM gene was found in 27.7% of the isolates (15/54 isolates). BlaOXA-23-like and blaNDM genes coexisted in 25.9% (14/54 isolates). Bap and blaPER-1 genes, the biofilm-associated genes, coexisted in 5.6% (3/54) of the isolates. For in vivo assessment of A. baumannii pathogenicity, a Galleria mellonella survival assay was used. G. mellonella survival was statistically different between moderate and poor biofilm producers (p < 0.0001). The killing effect of the strong biofilm-producing group was significantly higher than that of the moderate and poor biofilm producers (p < 0.0001 for each comparison). These findings highlight the role of biofilm formation as a powerful virulence factor for carbapenem-resistant A. baumannii that causes pneumonia in the ICU.
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Javkar K, Rand H, Hoffmann M, Luo Y, Sarria S, Thirunavukkarasu N, Pillai CA, McGann P, Johnson JK, Strain E, Pop M. Whole-Genome Assessment of Clinical Acinetobacter baumannii Isolates Uncovers Potentially Novel Factors Influencing Carbapenem Resistance. Front Microbiol 2021; 12:714284. [PMID: 34659144 PMCID: PMC8518998 DOI: 10.3389/fmicb.2021.714284] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 09/01/2021] [Indexed: 12/30/2022] Open
Abstract
Carbapenems-one of the important last-line antibiotics for the treatment of gram-negative infections-are becoming ineffective for treating Acinetobacter baumannii infections. Studies have identified multiple genes (and mechanisms) responsible for carbapenem resistance. In some A. baumannii strains, the presence/absence of putative resistance genes is not consistent with their resistance phenotype-indicating the genomic factors underlying carbapenem resistance in A. baumannii are not fully understood. Here, we describe a large-scale whole-genome genotype-phenotype association study with 349 A. baumannii isolates that extends beyond the presence/absence of individual antimicrobial resistance genes and includes the genomic positions and pairwise interactions of genes. Ten known resistance genes exhibited statistically significant associations with resistance to imipenem, a type of carbapenem: blaOXA-23, qacEdelta1, sul1, mphE, msrE, ant(3")-II, aacC1, yafP, aphA6, and xerD. A review of the strains without any of these 10 genes uncovered a clade of isolates with diverse imipenem resistance phenotypes. Finer resolution evaluation of this clade revealed the presence of a 38.6 kbp conserved chromosomal region found exclusively in imipenem-susceptible isolates. This region appears to host several HTH-type DNA binding transcriptional regulators and transporter genes. Imipenem-susceptible isolates from this clade also carried two mutually exclusive plasmids that contain genes previously known to be specific to imipenem-susceptible isolates. Our analysis demonstrates the utility of using whole genomes for genotype-phenotype correlations in the context of antibiotic resistance and provides several new hypotheses for future research.
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Affiliation(s)
- Kiran Javkar
- Department of Computer Science, University of Maryland, College Park, MD, United States.,Joint Institute for Food Safety and Applied Nutrition, University of Maryland, College Park, MD, United States
| | - Hugh Rand
- Center for Food Safety and Applied Nutrition, United States Food and Drug Administration, Department of Health and Human Services, College Park, MD, United States
| | - Maria Hoffmann
- Center for Food Safety and Applied Nutrition, United States Food and Drug Administration, Department of Health and Human Services, College Park, MD, United States
| | - Yan Luo
- Center for Food Safety and Applied Nutrition, United States Food and Drug Administration, Department of Health and Human Services, College Park, MD, United States
| | - Saul Sarria
- Center for Veterinary Medicine, United States Food and Drug Administration, Department of Health and Human Services, Laurel, MD, United States
| | - Nagarajan Thirunavukkarasu
- Center for Food Safety and Applied Nutrition, United States Food and Drug Administration, Department of Health and Human Services, College Park, MD, United States
| | - Christine A Pillai
- Center for Food Safety and Applied Nutrition, United States Food and Drug Administration, Department of Health and Human Services, College Park, MD, United States
| | - Patrick McGann
- Multidrug Resistant Organism Repository and Surveillance Network, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - J Kristie Johnson
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Errol Strain
- Center for Veterinary Medicine, United States Food and Drug Administration, Department of Health and Human Services, Laurel, MD, United States
| | - Mihai Pop
- Department of Computer Science, University of Maryland, College Park, MD, United States
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Buxser S. Has resistance to chlorhexidine increased among clinically-relevant bacteria? A systematic review of time course and subpopulation data. PLoS One 2021; 16:e0256336. [PMID: 34411140 PMCID: PMC8376095 DOI: 10.1371/journal.pone.0256336] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 08/03/2021] [Indexed: 12/03/2022] Open
Abstract
Chlorhexidine (CHX) was introduced for use as an antimicrobial more than 70 years ago. CHX has been and continues to be used broadly for disinfecting surfaces in medical and food service facilities as well as directly on skin of humans and animals. Considering its widespread use over many decades, questions of resistance to CHX have been raised. Additionally, questions of possible coincident resistance to the biocide and resistance to clinically relevant antibiotics have also been raised. A number of important questions remain, including is there consistent evidence of resistance, what is the degree of resistance, especially among clinically isolated microbial strains, and what is the degree of resistance compared to the typical concentrations of the biocide used? Data for microbial species isolated over the last 70+ years were compiled to construct as complete a picture as practical regarding possible resistance, especially among species in which resistance to commonly used antibiotics has been noted to be increasing. This is a compilation and analysis of individual MIC values for CHX reported in the literature, not a compilation of the conclusions individual authors reached. The data were analyzed using straight-forward and robust statistical procedures to detect changes in susceptibility to CHX over time, i.e. linear regression. Linear regression was supplemented with the use of nonlinear least squares regression analysis to detect the presence of population parameters associated with subpopulations of microbial strains which exhibit increased resistance to CHX. Pseudomonas aeruginosa, Klebsiella pneumoniae, and Acinetobacter baumannii were all found to have an increased resistance to CHX over time with the most profound change detected in A. baumannii. Additionally, subpopulations with log-normal distributions were found consistent with the presence of a baseline subpopulation of susceptible strains and a subpopulation with increased resistance to CHX. However, the CHX-resistant subpopulations did not correlate exactly with antibiotic resistance, so details of the relationship remain to be addressed. Increased resistance over time was not detected for Escherichia coli, Enterobacter faecalis, Staphylococcus aureus, or Candida albicans, although a subpopulation with greater than baseline resistance to CHX was detected among strains of E. faecalis and C. albicans. A difference in susceptibility to CHX was also detected between methicillin-resistant (MRSA) and methicillin-sensitive (MSSA) S. aureus strains. The levels of resistance to CHX detected were all markedly lower than concentrations routinely used in medical and food service applications. Reaching conclusions regarding the relationship between antibiotic and CHX resistance was complicated by the limited overlap between tests of CHX and antibiotic resistance for several species. The results compiled here may serve as a foundation for monitoring changes in resistance to CHX and possible relationships between the use of CHX and resistance to antibiotics commonly used in clinical medicine.
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Affiliation(s)
- Stephen Buxser
- Select Bio Consult, LLC, Indianapolis, Indiana, United States of America
- * E-mail:
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Yayan EH, Demırel Öner P, Coşkun Şımşek D, Zengın M. Hand Microbial Flora of Hospitalized Children at the Beginning of Hospitalization and Before Discharge: A Cross-Sectional Study. Ethiop J Health Sci 2021; 30:875-880. [PMID: 33883831 PMCID: PMC8047244 DOI: 10.4314/ejhs.v30i6.4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Background Hospital infections in pediatric units increase the length of hospital stay and the use of antibiotics, and this causes exposure to more procedures. This study was aimed to determine the microorganisms represented in the hand flora of pediatric patients at the beginning of hospitalization and before discharge. Methods The study was designed as a prospective cross-sectional study. This prospective study was performed with 124 pediatric patients. After completion of the admission procedures, an initial sample was taken from the hands of the hospitalized patients. Another sample was taken from the patients just before discharging. Results Growth of coagulase-negative staphylococcus (CNS) was observed in the culture samples of 28 patients. Cultures from 23 patients showed different microorganisms such as Staphylococcus aureus, Escherichia coli, and S. epidermis. Examination of final discharge cultures showed CNS in 43 patients, S. aureus in 5 patients, E. coli in 8 patients, Acinetobacter baumannii in 11 patients, and Kocuria rhizophila, K. kristinae, Candida spp., Pseudomonas spp., and Enterococcus in 1 patient. Conclusion The cultures from samples obtained at discharge showed the presence of antibiotic-resistant pathogenic microorganisms causing healthcare associated infection.
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Affiliation(s)
- Emriye Hilal Yayan
- Department of Child Health and Diseases Nursing, Nursing Faculty, İnönü University, Malatya, Turkey. orcid.org/0000-0003-0075-4171
| | - Pınar Demırel Öner
- Elazığ Fethi Sekin City Hospital, Elazığ, Turkey orcid.org/0000-0001-9592-5986
| | - Didem Coşkun Şımşek
- Department of Child Health and Diseases Nursing, Health Sciences Faculty, Fırat University, Elazığ, Turkey orcid.org/0000-0003-0364-5667
| | - Mürşide Zengın
- Department of Child Health and Diseases Nursing, Health Sciences Faculty, Adıyaman University, Adıyaman, Turkey. https://orcid.org/0000-0003-1453-6028
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Efflux Pump Overexpression Profiling in Acinetobacter baumannii and Study of New 1-(1-Naphthylmethyl)-Piperazine Analogs as Potential Efflux Inhibitors. Antimicrob Agents Chemother 2021; 65:e0071021. [PMID: 34097483 DOI: 10.1128/aac.00710-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Overexpression of efflux pumps extruding antibiotics currently used for the treatment of Acinetobacter baumannii infections has been described as an important mechanism causing antibiotic resistance. The first aim of this work was to phenotypically evaluate the overexpression of efflux pumps on a collection of 124 ciprofloxacin-resistant A. baumannii strains. An overexpression of genes encoding one or more efflux pumps was obtained for 19 out of the 34 strains with a positive phenotypic efflux (56%). The most frequent genes overexpressed were those belonging to the RND family, with adeJ being the most prevalent (50%). Interestingly, efflux pump genes coding for MATE and MFS families were also overexpressed quite frequently: abeM (32%) and abaQ (26%). The second aim was to synthesize 1-(1-naphthylmethyl)-piperazine analogs as potential new efflux pump inhibitors and biologically evaluate them against strains with a positive phenotypic efflux. Quinoline and pyridine analogs were found to be more effective than their parent compound, 1-(1-naphthyl methyl)-piperazine. Stereochemistry also played an important part in the inhibitory activity, as quinoline derivative (R)-3a was identified as being the most effective and less cytotoxic. Its inhibitory activity was also correlated with the number of efflux pumps expressed by a strain. The results obtained in this work suggest that quinoline analogs of 1-(1-naphthylmethyl)-piperazine are promising leads in the development of new anti-Acinetobacter baumannii therapeutic alternatives in combination with antibiotics for which an efflux-mediated resistance is suspected.
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Cameranesi MM, Kurth D, Repizo GD. Acinetobacter defence mechanisms against biological aggressors and their use as alternative therapeutic applications. Crit Rev Microbiol 2021; 48:21-41. [PMID: 34289313 DOI: 10.1080/1040841x.2021.1939266] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Several Acinetobacter strains are important nosocomial pathogens, with Acinetobacter baumannii being the species of greatest worldwide concern due to its multi-drug resistance and the recent appearance of hyper-virulent strains in the clinical setting. Colonisation of this environment is associated with a multitude of bacterial factors, and the molecular features that promote environmental persistence in abiotic surfaces, including intrinsic desiccation resistance, biofilm formation and motility, have been previously addressed. On the contrary, mechanisms enabling Acinetobacter spp. survival when faced against other biological competitors are starting to be characterised. Among them, secretion systems (SS) of different types, such as the T5bSS (Contact-dependent inhibition systems) and the T6SS, confer adaptive advantages against bacterial aggressors. Regarding mechanisms of defence against bacteriophages, such as toxin-antitoxin, restriction-modification, Crispr-Cas and CBASS, among others, have been identified but remain poorly characterised. In view of this, we aimed to summarise the present knowledge on defence mechanisms that enable niche establishment in members of the Acinetobacter genus. Different proposals are also described for the use of some components of these systems as molecular tools to treat Acinetobacter infections.
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Affiliation(s)
- María Marcela Cameranesi
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET), Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Daniel Kurth
- Planta Piloto de Procesos Industriales Microbiológicos (PROIMI, CONICET), San Miguel de Tucumán, Argentina
| | - Guillermo Daniel Repizo
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET), Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
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Alfei S, Caviglia D, Piatti G, Zuccari G, Schito AM. Bactericidal Activity of a Self-Biodegradable Lysine-Containing Dendrimer against Clinical Isolates of Acinetobacter Genus. Int J Mol Sci 2021; 22:7274. [PMID: 34298891 PMCID: PMC8306826 DOI: 10.3390/ijms22147274] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 07/03/2021] [Accepted: 07/05/2021] [Indexed: 12/19/2022] Open
Abstract
The genus Acinetobacter consists of Gram-negative obligate aerobic pathogens, including clinically relevant species, such as A. baumannii, which frequently cause hospital infections, affecting debilitated patients. The growing resistance to antimicrobial therapies shown by A. baumannii is reaching unacceptable levels in clinical practice, and there is growing concern that the serious conditions it causes may soon become incurable. New therapeutic possibilities are, therefore, urgently needed to circumvent this important problem. Synthetic cationic macromolecules, such as cationic antimicrobial peptides (AMPs), which act as membrane disrupters, could find application in these conditions. A lysine-modified cationic polyester-based dendrimer (G5-PDK), capable of electrostatically interacting with bacterial surfaces as AMPs do, has been synthesized and characterized here. Given its chemical structure, similar to that of a fifth-generation lysine containing dendrimer (G5K) with a different core, and previously found inactive against Gram-positive bacterial species and Enterobacteriaceae, the new G5-PDK was also ineffective on the species mentioned above. In contrast, it showed minimum inhibitory concentration values (MICs) lower than reported for several AMPs and other synthetic cationic compounds on Acinetobacter genus (3.2-12.7 µM). Time-kill experiments on A. baumannii, A. pittii, and A. ursingii ascertained the rapid bactericidal effects of G5-PDK, while subsequent bacterial regrowth supported its self-biodegradability.
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Affiliation(s)
- Silvana Alfei
- Department of Pharmacy, University of Genoa, Viale Cembrano, 16148 Genoa, Italy;
| | - Debora Caviglia
- Department of Surgical Sciences and Integrated Diagnostics (DISC), University of Genoa, Viale Benedetto XV, 6, 16132 Genova, Italy; (D.C.); (G.P.); (A.M.S.)
| | - Gabriella Piatti
- Department of Surgical Sciences and Integrated Diagnostics (DISC), University of Genoa, Viale Benedetto XV, 6, 16132 Genova, Italy; (D.C.); (G.P.); (A.M.S.)
| | - Guendalina Zuccari
- Department of Pharmacy, University of Genoa, Viale Cembrano, 16148 Genoa, Italy;
| | - Anna Maria Schito
- Department of Surgical Sciences and Integrated Diagnostics (DISC), University of Genoa, Viale Benedetto XV, 6, 16132 Genova, Italy; (D.C.); (G.P.); (A.M.S.)
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Antimicrobial Resistance Determinants in Genomes and Plasmids from Acinetobacter baumannii Clinical Isolates. Antibiotics (Basel) 2021; 10:antibiotics10070753. [PMID: 34206348 PMCID: PMC8300758 DOI: 10.3390/antibiotics10070753] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 06/13/2021] [Indexed: 12/30/2022] Open
Abstract
Acinetobacter baumannii is a Gram-negative coccoid rod species, clinically relevant as a human pathogen, included in the ESKAPE group. Carbapenem-resistant A. baumannii (CRAB) are considered by the World Health Organization (WHO) as a critical priority pathogen for the research and development of new antibiotics. Some of the most relevant features of this pathogen are its intrinsic multidrug resistance and its ability to acquire rapid and effective new resistant determinants against last-resort clinical antibiotics, mostly from other ESKAPE species. The presence of plasmids and mobile genetic elements in their genomes contributes to the acquisition of new antimicrobial resistance determinants. However, although A. baumannii has arisen as an important human pathogen, information about these elements is still not well understood. Current genomic analysis availability has increased our ability to understand the microevolution of bacterial pathogens, including point mutations, genetic dissemination, genomic stability, and pan- and core-genome compositions. In this work, we deeply studied the genomes of four clinical strains from our hospital, and the reference strain ATCC®19606TM, which have shown a remarkable ability to survive and maintain their effective capacity when subjected to long-term stress conditions. With that, our aim was presenting a detailed analysis of their genomes, including antibiotic resistance determinants and plasmid composition.
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Mat Rahim N, Lee H, Strych U, AbuBakar S. Facing the challenges of multidrug-resistant Acinetobacter baumannii: progress and prospects in the vaccine development. Hum Vaccin Immunother 2021; 17:3784-3794. [PMID: 34106809 PMCID: PMC8437540 DOI: 10.1080/21645515.2021.1927412] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
In 2017, the World Health Organization (WHO) named A. baumannii as one of the three antibiotic-resistant bacterial species on its list of global priority pathogens in dire need of novel and effective treatment. With only polymyxin and tigecycline antibiotics left as last-resort treatments, the need for novel alternative approaches to the control of this bacterium becomes imperative. Vaccines against numerous bacteria have had impressive records in reducing the burden of the respective diseases and addressing antimicrobial resistance; as in the case of Haemophilus influenzae type b . A similar approach could be appropriate for A. baumannii. Toward this end, several potentially protective antigens against A. baumannii were identified and evaluated as vaccine antigen candidates. A licensed vaccine for the bacteria, however, is still not in sight. Here we explore and discuss challenges in vaccine development against A. baumannii and the promising approaches for improving the vaccine development process.
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Affiliation(s)
- NorAziyah Mat Rahim
- Tropical Infectious Diseases Research and Education Center (TIDREC), Universiti Malaya, Kuala Lumpur, Malaysia.,Texas Children's Hospital Center for Vaccine Development, Baylor College of Medicine, Houston, TX, USA.,Virology Unit, Institute for Medical Research, National Institute of Health Complex, Setia Alam, Malaysia
| | - HaiYen Lee
- Tropical Infectious Diseases Research and Education Center (TIDREC), Universiti Malaya, Kuala Lumpur, Malaysia
| | - Ulrich Strych
- Texas Children's Hospital Center for Vaccine Development, Baylor College of Medicine, Houston, TX, USA
| | - Sazaly AbuBakar
- Tropical Infectious Diseases Research and Education Center (TIDREC), Universiti Malaya, Kuala Lumpur, Malaysia
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46
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Blaschke U, Skiebe E, Wilharm G. Novel Genes Required for Surface-Associated Motility in Acinetobacter baumannii. Curr Microbiol 2021; 78:1509-1528. [PMID: 33666749 PMCID: PMC7997844 DOI: 10.1007/s00284-021-02407-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 02/10/2021] [Indexed: 01/28/2023]
Abstract
Acinetobacter baumannii is an opportunistic and increasingly multi-drug resistant human pathogen rated as a critical priority one pathogen for the development of new antibiotics by the WHO in 2017. Despite the lack of flagella, A. baumannii can move along wet surfaces in two different ways: via twitching motility and surface-associated motility. While twitching motility is known to depend on type IV pili, the mechanism of surface-associated motility is poorly understood. In this study, we established a library of 30 A. baumannii ATCC® 17978™ mutants that displayed deficiency in surface-associated motility. By making use of natural competence, we also introduced these mutations into strain 29D2 to differentiate strain-specific versus species-specific effects of mutations. Mutated genes were associated with purine/pyrimidine/folate biosynthesis (e.g. purH, purF, purM, purE), alarmone/stress metabolism (e.g. Ap4A hydrolase), RNA modification/regulation (e.g. methionyl-tRNA synthetase), outer membrane proteins (e.g. ompA), and genes involved in natural competence (comEC). All tested mutants originally identified as motility-deficient in strain ATCC® 17978™ also displayed a motility-deficient phenotype in 29D2. By contrast, further comparative characterization of the mutant sets of both strains regarding pellicle biofilm formation, antibiotic resistance, and virulence in the Galleria mellonella infection model revealed numerous strain-specific mutant phenotypes. Our studies highlight the need for comparative analyses to characterize gene functions in A. baumannii and for further studies on the mechanisms underlying surface-associated motility.
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Affiliation(s)
- Ulrike Blaschke
- Robert Koch Institute, Project group P2, Burgstr. 37, 38855, Wernigerode, Germany.
| | - Evelyn Skiebe
- Robert Koch Institute, Project group P2, Burgstr. 37, 38855, Wernigerode, Germany
| | - Gottfried Wilharm
- Robert Koch Institute, Project group P2, Burgstr. 37, 38855, Wernigerode, Germany.
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47
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Martinez J, Razo-Gutierrez C, Le C, Courville R, Pimentel C, Liu C, Fung SE, Tuttobene MR, Phan K, Vila AJ, Shahrestani P, Jimenez V, Tolmasky ME, Becka SA, Papp-Wallace KM, Bonomo RA, Soler-Bistue A, Sieira R, Ramirez MS. Cerebrospinal fluid (CSF) augments metabolism and virulence expression factors in Acinetobacter baumannii. Sci Rep 2021; 11:4737. [PMID: 33637791 PMCID: PMC7910304 DOI: 10.1038/s41598-021-81714-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 01/06/2021] [Indexed: 12/14/2022] Open
Abstract
In a recent report by the Centers for Disease Control and Prevention (CDC), multidrug resistant (MDR) Acinetobacter baumannii is a pathogen described as an "urgent threat." Infection with this bacterium manifests as different diseases such as community and nosocomial pneumonia, bloodstream infections, endocarditis, infections of the urinary tract, wound infections, burn infections, skin and soft tissue infections, and meningitis. In particular, nosocomial meningitis, an unwelcome complication of neurosurgery caused by extensively-drug resistant (XDR) A. baumannii, is extremely challenging to manage. Therefore, understanding how A. baumannii adapts to different host environments, such as cerebrospinal fluid (CSF) that may trigger changes in expression of virulence factors that are associated with the successful establishment and progress of this infection is necessary. The present in-vitro work describes, the genetic changes that occur during A. baumannii infiltration into CSF and displays A. baumannii's expansive versatility to persist in a nutrient limited environment while enhancing several virulence factors to survive and persist. While a hypervirulent A. baumannii strain did not show changes in its transcriptome when incubated in the presence of CSF, a low-virulence isolate showed significant differences in gene expression and phenotypic traits. Exposure to 4% CSF caused increased expression of virulence factors such as fimbriae, pilins, and iron chelators, and other virulence determinants that was confirmed in various model systems. Furthermore, although CSF's presence did not enhance bacterial growth, an increase of expression of genes encoding transcription, translation, and the ATP synthesis machinery was observed. This work also explores A. baumannii's response to an essential component, human serum albumin (HSA), within CSF to trigger the differential expression of genes associated with its pathoadaptibility in this environment.
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Affiliation(s)
- Jasmine Martinez
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, Fullerton, CA, 92831, USA
| | - Chelsea Razo-Gutierrez
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, Fullerton, CA, 92831, USA
| | - Casin Le
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, Fullerton, CA, 92831, USA
| | - Robert Courville
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, Fullerton, CA, 92831, USA
| | - Camila Pimentel
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, Fullerton, CA, 92831, USA
| | - Christine Liu
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, Fullerton, CA, 92831, USA
| | - Sammie E Fung
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, Fullerton, CA, 92831, USA
| | - Marisel R Tuttobene
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, Fullerton, CA, 92831, USA
| | - Kimberly Phan
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, Fullerton, CA, 92831, USA
| | - Alejandro J Vila
- Instituto de Biología Molecular Y Celular de Rosario (IBR, CONICET-UNR), Rosario, Argentina
- Área Biofísica, Facultad de Ciencias Bioquímicas Y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Parvin Shahrestani
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, Fullerton, CA, 92831, USA
| | - Veronica Jimenez
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, Fullerton, CA, 92831, USA
| | - Marcelo E Tolmasky
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, Fullerton, CA, 92831, USA
| | - Scott A Becka
- Research Service and GRECC, Department of Veterans Affairs Medical Center, Louis Stokes Cleveland, Cleveland, OH, USA
| | - Krisztina M Papp-Wallace
- Research Service and GRECC, Department of Veterans Affairs Medical Center, Louis Stokes Cleveland, Cleveland, OH, USA
- Departments of Medicine, Pharmacology, Molecular Biology and Microbiology, Biochemistry, Proteomics and Bioinformatics, Case Western Reserve University School of Medicine, Cleveland, OH, USA
- CWRU-Cleveland VAMC Center for Antimicrobial Resistance and Epidemiology (Case VA CARES), Cleveland, OH, USA
| | - Robert A Bonomo
- Research Service and GRECC, Department of Veterans Affairs Medical Center, Louis Stokes Cleveland, Cleveland, OH, USA
- Departments of Medicine, Pharmacology, Molecular Biology and Microbiology, Biochemistry, Proteomics and Bioinformatics, Case Western Reserve University School of Medicine, Cleveland, OH, USA
- CWRU-Cleveland VAMC Center for Antimicrobial Resistance and Epidemiology (Case VA CARES), Cleveland, OH, USA
| | - Alfonso Soler-Bistue
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín-Consejo Nacional de Investigaciones Científicas Y Técnicas, San Martín, Buenos Aires, Argentina
| | - Rodrigo Sieira
- Fundación Instituto Leloir - IIBBA CONICET, Buenos Aires, Argentina
| | - Maria Soledad Ramirez
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, Fullerton, CA, 92831, USA.
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Lin J, Jiang W, Shi Y, Cai W. Metagenomic Sequencing Revealed the Potential Pathogenic Threats of Banknotes. ACS OMEGA 2021; 6:3499-3507. [PMID: 33585735 PMCID: PMC7876676 DOI: 10.1021/acsomega.0c04546] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 01/08/2021] [Indexed: 06/12/2023]
Abstract
Banknotes have long been suspected to be biologically "dirty" due to their frequent human contact, which may transmit human microbial pathogens. Still, it is an unsettled issue whether the microbes on banknotes pose a real threat to human health. In several previous studies, metagenomic sequencing was used to reveal the diversities of microbes on banknotes but live microorganism culture and functional verification were lacking. In this study, we collected banknotes of RMB in China as well as dollar bills in the United States and analyzed the microbial biodiversity and drug resistance genes carried by the identified microbes by metagenomic sequencing and in vitro culture methods. We identified eight major genera of drug-resistant bacteria through screening of 30 antibiotics, and the blood agar plate culture uncovered six pathogenic fungal species. Numerous phage and six dangerous viral sequences were also found. These results should substantiate our concern about the potential risk of banknotes to human health.
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Affiliation(s)
- Jun Lin
- Institute
of Applied Genomics, Fuzhou University, Fuzhou 350108, China
- School
of Basic Medical Sciences, Fujian Medical
University, Fuzhou 350108, China
- College
of Biological Science and Engineering, Fuzhou
University, Fuzhou 350108, China
- Fujian
Key Laboratory of Marine Enzyme Engineering, Fuzhou University, No.2 Xueyuan Road, Fuzhou 350108, China
| | - Wenqian Jiang
- Institute
of Applied Genomics, Fuzhou University, Fuzhou 350108, China
- College
of Biological Science and Engineering, Fuzhou
University, Fuzhou 350108, China
| | - Yang Shi
- Institute
of Applied Genomics, Fuzhou University, Fuzhou 350108, China
- College
of Biological Science and Engineering, Fuzhou
University, Fuzhou 350108, China
| | - Weiwen Cai
- Institute
of Applied Genomics, Fuzhou University, Fuzhou 350108, China
- College
of Biological Science and Engineering, Fuzhou
University, Fuzhou 350108, China
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Moreno-Morales J, Vergara A, Kostyanev T, Rodriguez-Baño J, Goossens H, Vila J. Evaluation of a Loop-Mediated Isothermal Amplification Assay to Detect Carbapenemases Directly From Bronchoalveolar Lavage Fluid Spiked With Acinetobacter spp. Front Microbiol 2021; 11:597684. [PMID: 33519735 PMCID: PMC7838357 DOI: 10.3389/fmicb.2020.597684] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 12/07/2020] [Indexed: 11/13/2022] Open
Abstract
Carbapenem-resistant Acinetobacter spp. mainly Acinetobacter baumannii are frequently causing nosocomial infections with high mortality. In this study, the efficacy of the Eazyplex® SuperBug Complete A system, based on loop-mediated isothermal amplification (LAMP), to detect the presence of carbapenemases in Acinetobacter spp. directly from bronchoalveolar lavage (BAL) samples was assessed. A total of 22 Acinetobacter spp. strains producing OXA-23, OXA-40, OXA-58, NDM, and IMP were selected. Eazyplex SuperBug Complete A kit, used with the Genie II device, is a molecular diagnostics kit that detects a selection of genes that express carbapenemases (bla KPC , bla NDM , bla VIM , bla OXA-48 , bla OXA-23 , bla OXA-40 , and bla OXA-58 ). Negative BAL samples were identified, McFarland solutions were prepared from each of the 22 Acinetobacter strains and serial dilutions in saline solution were made to finally spike BAL samples to a concentration of 102 and 103 CFU/ml. Fifteen concentrations out of the 44 tested out did not provide detection of the carbapenemase-producing gene, all but one being at the lowest concentration tested at 102 CFU/ml; therefore, the limit of sensitivity is 103 CFU/ml. This assay represents the kind of advantages that investing in molecular diagnostics brings to the clinical practice, allowing the identification of carbapenemases in less than 30 min with a sensitivity of 103 CFU/ml.
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Affiliation(s)
- Javier Moreno-Morales
- Institute for Global Health (ISGlobal), Hospital Clínic – Universitat de Barcelona, Barcelona, Spain
| | - Andrea Vergara
- Department of Clinical Microbiology – CDB, Hospital Clínic, University of Barcelona, Barcelona, Spain
| | - Tomislav Kostyanev
- Department of Medical Microbiology, Vaccine and Infectious Disease Institute, University of Antwerp, Antwerp, Belgium
| | - Jesús Rodriguez-Baño
- Unidad Clínica de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospital Universitario Virgen Macarena/Departamento de Medicina, Universidad de Sevilla/Instituto de Biomedicina de Sevilla (IBiS), Seville, Spain
| | - Herman Goossens
- Department of Medical Microbiology, Vaccine and Infectious Disease Institute, University of Antwerp, Antwerp, Belgium
- Laboratory of Medical Microbiology, University Hospital Antwerp, Antwerp, Belgium
| | - Jordi Vila
- Institute for Global Health (ISGlobal), Hospital Clínic – Universitat de Barcelona, Barcelona, Spain
- Department of Clinical Microbiology – CDB, Hospital Clínic, University of Barcelona, Barcelona, Spain
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50
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GigC, a LysR Family Transcription Regulator, Is Required for Cysteine Metabolism and Virulence in Acinetobacter baumannii. Infect Immun 2020; 89:IAI.00180-20. [PMID: 33077621 DOI: 10.1128/iai.00180-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 10/11/2020] [Indexed: 11/20/2022] Open
Abstract
A critical facet of mammalian innate immunity involves the hosts' attempts to sequester and/or limit the availability of key metabolic products from pathogens. For example, nutritional immunity encompasses host approaches to limit the availability of key heavy metal ions such as zinc and iron. Previously, we identified several hundred genes in a multidrug-resistant isolate of Acinetobacter baumannii that are required for growth and/or survival in the Galleria mellonella infection model. In the present study, we further characterize one of these genes, a LysR family transcription regulator that we previously named GigC. We show that mutant strains lacking gigC have impaired growth in the absence of the amino acid cysteine and that gigC regulates the expression of several genes involved in the sulfur assimilation and cysteine biosynthetic pathways. We further show that cells harboring a deletion of the gigC gene are attenuated in two murine infection models, suggesting that the GigC protein, likely through its regulation of the cysteine biosynthetic pathway, plays a key role in the virulence of A. baumannii.
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