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Naseef Pathoor N, Viswanathan A, Wadhwa G, Ganesh PS. Understanding the biofilm development of Acinetobacter baumannii and novel strategies to combat infection. APMIS 2024; 132:317-335. [PMID: 38444124 DOI: 10.1111/apm.13399] [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: 12/08/2023] [Accepted: 02/22/2024] [Indexed: 03/07/2024]
Abstract
Acinetobacter baumannii (A. baumannii) is a Gram-negative, nonmotile, and aerobic bacillus emerged as a superbug, due to increasing the possibility of infection and accelerating rates of antimicrobial agents. It is recognized as a nosocomial pathogen due to its ability to form biofilms. These biofilms serve as a defensive barrier, increase antibiotic resistance, and make treatment more difficult. As a result, the current situation necessitates the rapid emergence of novel therapeutic approaches to ensure successful treatment outcomes. This review explores the intricate relationship between biofilm formation and antibiotic resistance in A. baumannii, emphasizing the role of key virulence factors and quorum sensing (QS) mechanisms that will lead to infections and facilitate insight into developing innovative method to control A. baumannii infections. Furthermore, the review article looks into promising approaches for preventing biofilm formation on medically important surfaces and potential therapeutic methods for eliminating preformed biofilms, which can address biofilm-associated A. baumannii infections. Modern advances in emerging therapeutic options such as antimicrobial peptide (AMPs), nanoparticles (NPs), bacteriophage therapy, photodynamic therapy (PDT), and other biofilm inhibitors can assist readers understand the current landscape and future prospects for effectively treating A. baumannii biofilm infections.
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Affiliation(s)
- Naji Naseef Pathoor
- Department of Microbiology, Centre for Infectious Diseases, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences (SIMATS), Saveetha University (Deemed to be University), Chennai, Tamil Nadu, India
| | - Akshaya Viswanathan
- Department of Microbiology, Centre for Infectious Diseases, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences (SIMATS), Saveetha University (Deemed to be University), Chennai, Tamil Nadu, India
| | - Gulshan Wadhwa
- Department of Biotechnology, Ministry of Science and Technology, New Delhi, India
| | - Pitchaipillai Sankar Ganesh
- Department of Microbiology, Centre for Infectious Diseases, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences (SIMATS), Saveetha University (Deemed to be University), Chennai, Tamil Nadu, India
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Nayak S, Akshay SD, Deekshit VK, Raj JM, Maiti B. Exposure to imipenem at sub-minimum inhibitory concentration leads to altered expression of major outer membrane proteins in Acinetobacter baumannii. J Appl Microbiol 2024; 135:lxae105. [PMID: 38653725 DOI: 10.1093/jambio/lxae105] [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: 02/06/2024] [Revised: 04/15/2024] [Accepted: 04/22/2024] [Indexed: 04/25/2024]
Abstract
AIMS Acinetobacter baumannii is a nosocomial pathogen known to be multidrug-resistant (MDR), especially to drugs of the carbapenem class. Several factors contribute to resistance, including efflux pumps, β-lactamases, alteration of target sites, and permeability defects. In addition, outer membrane proteins (OMPs), like porins are involved in the passage of antibiotics, and their alteration could lead to resistance development. This study aimed to explore the possible involvement of porins and OMPs in developing carbapenem resistance due to differential expression. METHODS AND RESULTS The antibiotic-susceptible and MDR isolates of A. baumannii were first studied for differences in their transcriptional levels of OMP expression and OMP profiles. The antibiotic-susceptible isolates were further treated with imipenem, and it was found that the omp genes were differentially expressed. Six of the nine genes studied were upregulated at 1 h of exposure to imipenem. Their expression gradually decreased with time, further confirmed by their OMP profile and two-dimensional gel electrophoresis. CONCLUSIONS This study could identify OMPs that were differentially expressed on exposure to imipenem. Hence, this study provides insights into the role of specific OMPs in antibiotic resistance in A. baumannii.
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Affiliation(s)
- Srajana Nayak
- Nitte (Deemed to be University), Nitte University Centre for Science Education and Research, Department of Bio & Nano Technology, Deralakatte, Mangaluru 575018, India
| | - Sadanand Dangari Akshay
- Nitte (Deemed to be University), Nitte University Centre for Science Education and Research, Department of Bio & Nano Technology, Deralakatte, Mangaluru 575018, India
| | - Vijaya Kumar Deekshit
- Nitte (Deemed to be University), Nitte University Centre for Science Education and Research, Department of Infectious Diseases & Microbial Genomics, Deralakatte, Mangaluru 575018, India
| | - Juliet Mohan Raj
- Nitte (Deemed to be University), Nitte University Centre for Science Education and Research, Department of Infectious Diseases & Microbial Genomics, Deralakatte, Mangaluru 575018, India
| | - Biswajit Maiti
- Nitte (Deemed to be University), Nitte University Centre for Science Education and Research, Department of Bio & Nano Technology, Deralakatte, Mangaluru 575018, India
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Yousefi Nojookambari N, Eslami G, Sadredinamin M, Vaezjalali M, Nikmanesh B, Dehbanipour R, Yazdansetad S, Ghalavand Z. Sub-minimum inhibitory concentrations (sub-MICs) of colistin on Acinetobacter baumannii biofilm formation potency, adherence, and invasion to epithelial host cells: an experimental study in an Iranian children's referral hospital. Microbiol Spectr 2024; 12:e0252323. [PMID: 38230925 PMCID: PMC10846280 DOI: 10.1128/spectrum.02523-23] [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: 06/17/2023] [Accepted: 11/07/2023] [Indexed: 01/18/2024] Open
Abstract
Here, we described the efficacy of colistin sub-minimum inhibitory concentrations (sub-MICs) on biofilm-forming activity, host epithelial cell adherence, and invasion capacity of Acinetobacter baumannii strains collected from children admitted to the Children's Medical Center Hospital. Biofilm formation potency of A. baumannii clinical isolates was measured using a 96-well microtiter plate assay. Distribution of biofilm-related genes, including bap, abaI, ompA, csuE, and blaPER-1, was detected by PCR. The mRNA expression level of ompA and csuE was measured by qPCR in the presence of ¼ and ½ MICs of colistin. A. baumannii adhesion and invasion to eukaryotic host cells were phenotypically assayed at sub-MICs of colistin. Eighty percent (56/70) and 35.7% (25/70) of A. baumannii isolates were multidrug-resistant (MDR) and extensively drug-resistant (XDR) phenotypes, respectively. The strong, moderate, and weak biofilm producers of A. baumannii were 37.1% (26/70), 32.8%, (23/70), and 22.8% (16/70), respectively. The frequencies of biofilm-associated genes were 100% for abaI, ompA, and csuE, followed by 22.8% (16/70) and 24.3% (17/70) for bap and blaPER-1, respectively. The downregulation of csuE and ompA expression levels was observed in the sub-MIC of colistin. In vitro cell culture study showed a decreased capability of A. baumannii to adhere to the human epithelial cells at sub-inhibitory doses of colistin; however, none of the isolates could invade HEp-2 cells. Our study showed that the genes encoding biofilm-associated proteins undergo downregulation in expression levels after exposure to sub-MICs of colistin in A. baumannii. Longitudinal in vivo studies are needed to fully understand the clinical aspects of pathogenicity mechanisms and evolutionary dynamics of drug resistance.IMPORTANCESince the toxicity of colistin is dose dependent, there is a focus on strategies that reduce the dose while maintaining the therapeutic effect of the drug. Our findings about sub-inhibitory doses of colistin provide a novel insight into the logical use of colistin to treat and control Acinetobacter baumannii-related infections in clinical practice.
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Affiliation(s)
- Neda Yousefi Nojookambari
- Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Gita Eslami
- Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mehrzad Sadredinamin
- Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Maryam Vaezjalali
- Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Bahram Nikmanesh
- Department of Medical Laboratory Sciences, School of Allied Medical Sciences, Tehran University of Medical Sciences, Tehran, Iran
| | - Razieh Dehbanipour
- Department of Microbiology, School of Medicine, Yasuj University of Medical Sciences, Yasuj, Iran
| | - Sajjad Yazdansetad
- Infectious Diseases Research Center, Golestan University of Medical Sciences, Gorgan, Iran
| | - Zohreh Ghalavand
- Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Zhou J, Feng D, Li X, Chen Y, Zhang M, Wu W, Zhu J, Li H, Peng X, Zhang T. L-Serine enables reducing the virulence of Acinetobacter baumannii and modulating the SIRT1 pathway to eliminate the pathogen. Microbiol Spectr 2024; 12:e0322623. [PMID: 38240573 PMCID: PMC10913490 DOI: 10.1128/spectrum.03226-23] [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: 09/05/2023] [Accepted: 11/14/2023] [Indexed: 03/07/2024] Open
Abstract
The emergence of high-virulent Acinetobacter baumannii strains increases the mortality of patients and seriously affects their prognosis, which motivates us to explore novel ways to control such infections. In this study, gas chromatography-mass spectrometry was adopted to explore the metabolic difference between high- and low-virulent A. baumannii strains, and the decreased L-serine levels were identified as the most crucial biomarker in low-virulent A. baumannii strains. In vitro, L-serine reduced the virulence of A. baumannii to Beas 2B cells and inhibited the activation of NLRP3 inflammasome via decreasing the generation of ROS and mtROS and the release of inflammatory cytokines (IL-18 and IL-1β) through upregulating SIRT1. In vivo, the Galleria mellonella model was adopted. L-serine downregulated the levels of virulence genes (ompA, carO, and omp33-36), reduced the mortality of A. baumannii to G. mellonella, and decreased the blacking speed as well as the degree of G. mellonella after infection. Taken together, we found that L-serine can reduce the virulence of A. baumannii and enhance the host's defense against the pathogen, providing a novel strategy for the treatment of infections caused by A. baumannii.IMPORTANCEAcinetobacter baumannii has become one of the most common and severe opportunistic pathogens in hospitals. The high-virulent A. baumannii strains pose a great threat to patients and increase the risk of nosocomial infection. However, the mechanism of virulence in A. baumannii is still not well understood. In the present study, we identified potential biomarkers in low-virulent A. baumannii strains. Our analysis revealed the effect of L-serine on reducing the virulence of A.baumannii. This discovery suggests that targeting L-serine could be a promising strategy for the treatment or adjunctive treatment of A. baumannii infections. The development of treatments targeting virulence may provide a substitute for the increasingly failed traditional antibacterial treatment.
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Affiliation(s)
- Jianxia Zhou
- Department of Pulmonary and Critical Care Medicine, The Third Affiliated Hospital of Sun Yat-Sen University, Institute of Respiratory Disease of Sun Yat-Sen University, Guangzhou, People's Republic of China
| | - Dingyun Feng
- Department of Pulmonary and Critical Care Medicine, The Third Affiliated Hospital of Sun Yat-Sen University, Institute of Respiratory Disease of Sun Yat-Sen University, Guangzhou, People's Republic of China
| | - Xia Li
- Department of Pulmonary and Critical Care Medicine, The Third Affiliated Hospital of Sun Yat-Sen University, Institute of Respiratory Disease of Sun Yat-Sen University, Guangzhou, People's Republic of China
| | - Yuetao Chen
- School of Life Sciences, Sun Yat-Sen University, Guangzhou, People's Republic of China
| | - Min Zhang
- Department of Pulmonary and Critical Care Medicine, The Third Affiliated Hospital of Sun Yat-Sen University, Institute of Respiratory Disease of Sun Yat-Sen University, Guangzhou, People's Republic of China
| | - Wenbin Wu
- Department of Pulmonary and Critical Care Medicine, The Third Affiliated Hospital of Sun Yat-Sen University, Institute of Respiratory Disease of Sun Yat-Sen University, Guangzhou, People's Republic of China
| | - Jiaxin Zhu
- Department of Pulmonary and Critical Care Medicine, The Third Affiliated Hospital of Sun Yat-Sen University, Institute of Respiratory Disease of Sun Yat-Sen University, Guangzhou, People's Republic of China
| | - Hui Li
- School of Life Sciences, Sun Yat-Sen University, Guangzhou, People's Republic of China
| | - Xuanxian Peng
- School of Life Sciences, Sun Yat-Sen University, Guangzhou, People's Republic of China
| | - Tiantuo Zhang
- Department of Pulmonary and Critical Care Medicine, The Third Affiliated Hospital of Sun Yat-Sen University, Institute of Respiratory Disease of Sun Yat-Sen University, Guangzhou, People's Republic of China
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Yao Y, Chen Q, Zhou H. Virulence Factors and Pathogenicity Mechanisms of Acinetobacter baumannii in Respiratory Infectious Diseases. Antibiotics (Basel) 2023; 12:1749. [PMID: 38136783 PMCID: PMC10740465 DOI: 10.3390/antibiotics12121749] [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: 11/10/2023] [Revised: 12/14/2023] [Accepted: 12/16/2023] [Indexed: 12/24/2023] Open
Abstract
Acinetobacter baumannii (A. baumannii) has become a notorious pathogen causing nosocomial and community-acquired infections, especially ventilator-associated pneumonia. This opportunistic pathogen is found to possess powerful genomic plasticity and numerous virulence factors that facilitate its success in the infectious process. Although the interactions between A. baumannii and the pulmonary epitheliums have been extensively studied, a complete and specific description of its overall pathogenic process is lacking. In this review, we summarize the current knowledge of the antibiotic resistance and virulence factors of A. baumannii, specifically focusing on the pathogenic mechanisms of this detrimental pathogen in respiratory infectious diseases. An expansion of the knowledge regarding A. baumannii pathogenesis will contribute to the development of effective therapies based on immunopathology or intracellular signaling pathways to eliminate this harmful pathogen during infections.
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Affiliation(s)
| | | | - Hua Zhou
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China; (Y.Y.); (Q.C.)
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Kumari K, Aggarwal Y, Singh RP. Molecular characterization and in-depth genomic analysis to unravel the pathogenic features of an environmental isolate Enterobacter sp. S-33. Int Microbiol 2023:10.1007/s10123-023-00461-y. [PMID: 38044418 DOI: 10.1007/s10123-023-00461-y] [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: 08/17/2023] [Revised: 11/21/2023] [Accepted: 11/24/2023] [Indexed: 12/05/2023]
Abstract
Enterobacter species represent widely distributed opportunistic pathogens, commonly associated with plants and humans. In the present study, we performed a detailed molecular characterization as well as genomic study of a type VI secretion system (T6SS) bacterium belonging to member of the family Enterobacteriaceae and named Enterobacter sp. S-33. The comparative sequence analysis of the 16S rRNA gene showed that the strain was closely related to other Enterobacter species. The complete genome of the strain with a genome size of 4.6 Mbp and GC-content of 55.63% was obtained through high-quality sequencing. The genomic analysis with online tools unravelled the various genes belonging to the bacterial secretion system, antibiotic resistance, virulence, efflux pumps, etc. The isolate showed the motility behavior that contributes to Enterobacter persistence in a stressed environment and further supports infections. PCR amplification and further sequencing confirmed the presence of drug-efflux genes acrA, acrB, and outer membrane genes, viz. OmpA, OmpC, and OmpF. The cell surface hydrophobicity and co-aggregation assay against different bacterial strains illustrated its putative pathogenic nature. Genome mining identified various biosynthetic gene clusters (BGCs) corresponding to non-ribosomal proteins (NRPS), siderophore, and arylpolyene production. Briefly, genome sequencing and detailed characterization of environmental Enterobacter isolate will assist in understanding the epidemiology of Enterobacter species, and the further prevention and treatment of infectious diseases caused by these broad-host range species.
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Affiliation(s)
- Kiran Kumari
- Department of Bioengineering and Biotechnology, Birla Institute of Technology, Mesra, Ranchi, Jharkhand, 835215, India
| | - Yogender Aggarwal
- Department of Bioengineering and Biotechnology, Birla Institute of Technology, Mesra, Ranchi, Jharkhand, 835215, India
| | - Rajnish Prakash Singh
- Department of Biotechnology, Jaypee Institute of Information Technology, Noida, India.
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Maure A, Robino E, Van der Henst C. The intracellular life of Acinetobacter baumannii. Trends Microbiol 2023; 31:1238-1250. [PMID: 37487768 DOI: 10.1016/j.tim.2023.06.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 06/16/2023] [Accepted: 06/23/2023] [Indexed: 07/26/2023]
Abstract
Acinetobacter baumannii is a Gram-negative opportunistic bacterium responsible for nosocomial and community-acquired infections. This pathogen is globally disseminated and associated with high levels of antibiotic resistance, which makes it an important threat to human health. Recently, new evidence showed that several A. baumannii isolates can survive and proliferate within eukaryotic professional and/or nonprofessional phagocytic cells, with in vivo consequences. This review provides updated information and describes the tools that A. baumannii possesses to adhere, colonize, and replicate in host cells. Additionally, we emphasize the high genetic and phenotypic heterogeneity detected amongst A. baumannii isolates and its impact on the bacterial intracellular features. We also discuss the need for standardized methods to characterize this pathogen robustly and consequently consider some strains as facultative intracellular bacteria.
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Affiliation(s)
- Alexandra Maure
- Microbial Resistance and Drug Discovery, VIB-VUB Center for Structural Biology, VIB, Flanders Institute for Biotechnology, Brussels, Belgium; Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Etienne Robino
- Microbial Resistance and Drug Discovery, VIB-VUB Center for Structural Biology, VIB, Flanders Institute for Biotechnology, Brussels, Belgium; Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Charles Van der Henst
- Microbial Resistance and Drug Discovery, VIB-VUB Center for Structural Biology, VIB, Flanders Institute for Biotechnology, Brussels, Belgium; Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Brussels, Belgium.
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8
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Zhai X, Wu G, Tao X, Yang S, Lv L, Zhu Y, Dong D, Xiang H. Success stories of natural product-derived compounds from plants as multidrug resistance modulators in microorganisms. RSC Adv 2023; 13:7798-7817. [PMID: 36909750 PMCID: PMC9994607 DOI: 10.1039/d3ra00184a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 03/01/2023] [Indexed: 03/14/2023] Open
Abstract
Microorganisms evolve resistance to antibiotics as a function of evolution. Antibiotics have accelerated bacterial resistance through mutations and acquired resistance through a combination of factors. In some cases, multiple antibiotic-resistant determinants are encoded in these genes, immediately making the recipient organism a "superbug". Current antimicrobials are no longer effective against infections caused by pathogens that have developed antimicrobial resistance (AMR), and the problem has become a crisis. Microorganisms that acquire resistance to chemotherapy (multidrug resistance) are a major obstacle for successful treatments. Pharmaceutical industries should be highly interested in natural product-derived compounds, as they offer new sources of chemical entities for the development of new drugs. Phytochemical research and recent experimental advances are discussed in this review in relation to the antimicrobial efficacy of selected natural product-derived compounds as well as details of synergistic mechanisms and structures. The present review recognizesand amplifies the importance of compounds with natural origins, which can be used to create safer and more effective antimicrobial drugs by combating microorganisms that are resistant to multiple types of drugs.
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Affiliation(s)
- Xiaohan Zhai
- Department of Pharmacy, First Affiliated Hospital of Dalian Medical University Dalian China
| | - Guoyu Wu
- Department of Pharmacy, First Affiliated Hospital of Dalian Medical University Dalian China
| | - Xufeng Tao
- Department of Pharmacy, First Affiliated Hospital of Dalian Medical University Dalian China
| | - Shilei Yang
- Department of Pharmacy, First Affiliated Hospital of Dalian Medical University Dalian China
| | - Linlin Lv
- Department of Pharmacy, First Affiliated Hospital of Dalian Medical University Dalian China
| | - Yanna Zhu
- Department of Pharmacy, First Affiliated Hospital of Dalian Medical University Dalian China
| | - Deshi Dong
- Department of Pharmacy, First Affiliated Hospital of Dalian Medical University Dalian China
| | - Hong Xiang
- Laboratory of Integrative Medicine, First Affiliated Hospital of Dalian Medical University Dalian China
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Havenga B, Reyneke B, Waso-Reyneke M, Ndlovu T, Khan S, Khan W. Biological Control of Acinetobacter baumannii: In Vitro and In Vivo Activity, Limitations, and Combination Therapies. Microorganisms 2022; 10:microorganisms10051052. [PMID: 35630494 PMCID: PMC9147981 DOI: 10.3390/microorganisms10051052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 05/16/2022] [Accepted: 05/17/2022] [Indexed: 02/01/2023] Open
Abstract
The survival, proliferation, and epidemic spread of Acinetobacter baumannii (A. baumannii) in hospital settings is associated with several characteristics, including resistance to many commercially available antibiotics as well as the expression of multiple virulence mechanisms. This severely limits therapeutic options, with increased mortality and morbidity rates recorded worldwide. The World Health Organisation, thus, recognises A. baumannii as one of the critical pathogens that need to be prioritised for the development of new antibiotics or treatment. The current review will thus provide a brief overview of the antibiotic resistance and virulence mechanisms associated with A. baumannii’s “persist and resist strategy”. Thereafter, the potential of biological control agents including secondary metabolites such as biosurfactants [lipopeptides (surfactin and serrawettin) and glycolipids (rhamnolipid)] as well as predatory bacteria (Bdellovibrio bacteriovorus) and bacteriophages to directly target A. baumannii, will be discussed in terms of their in vitro and in vivo activity. In addition, limitations and corresponding mitigations strategies will be outlined, including curtailing resistance development using combination therapies, product stabilisation, and large-scale (up-scaling) production.
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Affiliation(s)
- Benjamin Havenga
- Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, Stellenbosch 7602, South Africa; (B.H.); (B.R.)
| | - Brandon Reyneke
- Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, Stellenbosch 7602, South Africa; (B.H.); (B.R.)
| | - Monique Waso-Reyneke
- Faculty of Health Sciences, University of Johannesburg, Doornfontein 2028, South Africa; (M.W.-R.); (S.K.)
| | - Thando Ndlovu
- Department of Biological Sciences, Faculty of Science, University of Botswana, Private Bag UB, Gaborone 0022, Botswana;
| | - Sehaam Khan
- Faculty of Health Sciences, University of Johannesburg, Doornfontein 2028, South Africa; (M.W.-R.); (S.K.)
| | - Wesaal Khan
- Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, Stellenbosch 7602, South Africa; (B.H.); (B.R.)
- Correspondence: ; Tel.: +27-21-808-5804
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10
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Sariyer E. The role of Acinetobacter baumannii CarO outer membrane protein in carbapenems influx. Res Microbiol 2022; 173:103966. [DOI: 10.1016/j.resmic.2022.103966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 04/27/2022] [Accepted: 05/18/2022] [Indexed: 10/18/2022]
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Identification of Two Variants of Acinetobacter baumannii Strain ATCC 17978 with Distinct Genotypes and Phenotypes. Infect Immun 2021; 89:e0045421. [PMID: 34460288 DOI: 10.1128/iai.00454-21] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Acinetobacter baumannii is a nosocomial pathogen that exhibits substantial genomic plasticity. Here, the identification of two variants of A. baumannii ATCC 17978 that differ based on the presence of a 44-kb accessory locus, named AbaAL44 (A. baumannii accessory locus 44 kb), is described. Analyses of existing deposited data suggest that both variants are found in published studies of A. baumannii ATCC 17978 and that American Type Culture Collection (ATCC)-derived laboratory stocks comprise a mix of these two variants. Yet, each variant exhibits distinct interactions with the host in vitro and in vivo. Infection with the variant that harbors AbaAL44 (A. baumannii 17978 UN) results in decreased bacterial burdens and increased neutrophilic lung inflammation in a mouse model of pneumonia, and affects the production of interleukin 1 beta (IL-1β) and IL-10 by infected macrophages. AbaAL44 harbors putative pathogenesis genes, including those predicted to encode a type I pilus cluster, a catalase, and a cardiolipin synthase. The accessory catalase increases A. baumannii resistance to oxidative stress and neutrophil-mediated killing in vitro. The accessory cardiolipin synthase plays a dichotomous role by promoting bacterial uptake and increasing IL-1β production by macrophages, but also by enhancing bacterial resistance to cell envelope stress. Collectively, these findings highlight the phenotypic consequences of the genomic dynamism of A. baumannii through the evolution of two variants of a common type strain with distinct infection-related attributes.
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12
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Andrade NL, da Cruz Campos AC, Cabral AM, Damasco PH, Lo-Ten-Foe J, Rosa ACP, Damasco PV. Infective endocarditis caused by Enterobacteriaceae: phenotypic and molecular characterization of Escherichia coli and Klebsiella pneumoniae in Rio de Janeiro, Brazil. Braz J Microbiol 2021; 52:1887-1896. [PMID: 34549374 PMCID: PMC8578509 DOI: 10.1007/s42770-021-00528-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 05/12/2021] [Indexed: 12/16/2022] Open
Abstract
The etiological agent for infective endocarditis (IE), a life-threatening disease, is usually gram-positive bacteria. However, gram-negative bacteria can rarely cause IE and 4% of cases are associated with morbidity and mortality. This study aimed to characterize Escherichia coli and Klebsiella pneumoniae isolates from the blood of patients with IE. The characteristics of blood isolates were compared with those of urinary isolates from patients with urinary tract infections (UTIs). The results of this study revealed that K. pneumoniae isolates from patients with IE were phylogenetically related to those from patients with UTI. Additionally, the resistance phenotype, resistance gene, virulence gene, and plasmid profiles were similar between the blood and urinary isolates. The isolates belonging to the sequence types (STs) 76, 36, 101 (K. pneumoniae), and 69 (E. coli) are reported to be associated with drug resistance. The Enterobacteriaceae isolates from patients with IE did not produce extended-spectrum β-lactamase or carbapenemase. Additionally, this study investigated the virulence phenotype, biofilm formation ability, and the ability to adhere to the epithelial cells in vitro of the isolates. The isolates from patients with IE exhibited weaker biofilm formation ability than the urinary isolates. All isolates from patients with IE could adhere to the renal epithelial cells. However, three isolates from patients with UTIs could not adhere to the epithelial cells. The closely related K. pneumoniae isolates (648, KP1, KP2, KP3, and KP4) could not form biofilms or adhere to the epithelial cells. In summary, the molecular analysis revealed that the genetic characteristics of IE-causing K. pneumoniae and E. coli were similar to those of UTI-causing isolates. These isolates belonged to the STs that are considered treatable. Genetically similar isolates did not exhibit the same virulence phenotype. Thus, these non-hypervirulent clones must be monitored as they can cause complex infections in susceptible hosts.
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Affiliation(s)
- Nathália L Andrade
- Department of Microbiology, Immunology and Parasitology, Biomedical Center, Rio de Janeiro State University, Blv 28 de Setembro, 87, 3th floor, Vila Isabel, Rio de Janeiro, Brazil
| | - Ana Carolina da Cruz Campos
- Department of Medical Microbiology and Infection Prevention, University of Groningen, University Medical Center Groningen, EB80 Hanzeplein 1, 9713, GZ, Groningen, The Netherlands.
| | - Andrea Maria Cabral
- Pedro Ernesto University Hospital, Rio de Janeiro State University, Vila Isabel, Rio de Janeiro, Brazil
| | | | - Jerome Lo-Ten-Foe
- Department of Medical Microbiology and Infection Prevention, University of Groningen, University Medical Center Groningen, EB80 Hanzeplein 1, 9713, GZ, Groningen, The Netherlands
| | - Ana Cláudia P Rosa
- Department of Microbiology, Immunology and Parasitology, Biomedical Center, Rio de Janeiro State University, Blv 28 de Setembro, 87, 3th floor, Vila Isabel, Rio de Janeiro, Brazil
| | - Paulo V Damasco
- Pedro Ernesto University Hospital, Rio de Janeiro State University, Vila Isabel, Rio de Janeiro, Brazil.,Department of Infectious and Parasitic Diseases, Graffrée e Guinle University Hospital, Federal University of the State of Rio de Janeiro, Rio de Janeiro, Brazil
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13
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Gedefie A, Demsis W, Ashagrie M, Kassa Y, Tesfaye M, Tilahun M, Bisetegn H, Sahle Z. Acinetobacter baumannii Biofilm Formation and Its Role in Disease Pathogenesis: A Review. Infect Drug Resist 2021; 14:3711-3719. [PMID: 34531666 PMCID: PMC8439624 DOI: 10.2147/idr.s332051] [Citation(s) in RCA: 68] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Accepted: 09/02/2021] [Indexed: 01/01/2023] Open
Abstract
Acinetobacter species, particularly Acinetobacter baumannii, is the first pathogen on the critical priority list of pathogens for novel antibiotics to become a "red-alert" human pathogen. Acinetobacter baumannii is an emerging global antibiotic-resistant gram-negative bacteria that most typically causes biofilm-associated infections such as ventilator-associated pneumonia and catheter-related infection, both of which are resistant to antibiotic therapy. A. baumannii's capacity to develop antibiotic resistance mechanisms allows the organism to thrive in hospital settings, facilitating the global spread of multidrug-resistant strains. Although Acinetobacter infections are quickly expanding throughout hospital environments around the world, the highest concentration of infections occurs in intensive care units (ICUs). Biofilms are populations of bacteria on biotic or abiotic surfaces that are encased in the extracellular matrix and play a crucial role in pathogenesis, making treatment options more difficult. Even though a variety of biological and environmental elements are involved in the production of A. baumannii biofilms, glucose is the most important component. Biofilm-mediated A. baumannii infections are the most common type of A. baumannii infection associated with medical equipment, and they are extremely difficult to treat. As a result, health care workers (HCWs) should focus on infection prevention and safety actions to avoid A. baumannii biofilm-related infections caused by medical devices, and they should be very selective when using treatments in combination with anti-biofilms. Therefore, this review discusses biofilm formation in A. baumannii, its role in disease pathogenesis, and its antimicrobial resistance mechanism.
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Affiliation(s)
- Alemu Gedefie
- Department of Medical Laboratory Sciences, College of Medicine and Health Science, Wollo University, Dessie, Ethiopia
| | - Wondmagegn Demsis
- Department of Medical Laboratory Sciences, College of Medicine and Health Science, Wollo University, Dessie, Ethiopia
| | - Melaku Ashagrie
- Department of Medical Laboratory Sciences, College of Medicine and Health Science, Wollo University, Dessie, Ethiopia
| | - Yeshimebet Kassa
- Department of Medical Laboratory Sciences, College of Medicine and Health Science, Wollo University, Dessie, Ethiopia
| | - Melkam Tesfaye
- Department of Medical Laboratory Sciences, College of Medicine and Health Science, Wollo University, Dessie, Ethiopia
| | - Mihret Tilahun
- Department of Medical Laboratory Sciences, College of Medicine and Health Science, Wollo University, Dessie, Ethiopia
| | - Habtye Bisetegn
- Department of Medical Laboratory Sciences, College of Medicine and Health Science, Wollo University, Dessie, Ethiopia
| | - Zenawork Sahle
- Department of Medical Laboratory Sciences, Debre Birhan Health Science College, Debre Birhan, Ethiopia
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14
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Mea HJ, Yong PVC, Wong EH. An overview of Acinetobacter baumannii pathogenesis: Motility, adherence and biofilm formation. Microbiol Res 2021; 247:126722. [PMID: 33618061 DOI: 10.1016/j.micres.2021.126722] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 01/29/2021] [Accepted: 02/01/2021] [Indexed: 12/13/2022]
Abstract
The Gram-negative opportunistic pathogen Acinetobacter baumannii has gain notoriety in recent decades, primarily due to its propensity to cause nosocomial infections in critically ill patients. Its global spread, multi-drug resistance features and plethora of virulence factors make it a serious threat to public health worldwide. Though much effort has been expended in uncovering its successes, it continues to confound researchers due to its highly adaptive nature, mutating to meet the needs of a given environment. Its persistence in the clinical setting allows it to be in close proximity to a potential host, where contact can be made facilitating infection and colonization. In this article, we aim to provide a current overview of the bacterial virulence factors, specifically focusing on factors involved in the initial stages of infection, highlighting the role of adaptation facilitated by two-component systems and biofilm formation. Finally, the study of host-pathogen interactions using available animal models, their suitability, notable findings and some perspectives moving forward are also discussed.
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Affiliation(s)
- Hing Jian Mea
- School of Biosciences, Faculty of Health and Medical Sciences, Taylor's University Lakeside Campus, 47500, Subang Jaya, Selangor Darul Ehsan, Malaysia
| | - Phelim Voon Chen Yong
- School of Biosciences, Faculty of Health and Medical Sciences, Taylor's University Lakeside Campus, 47500, Subang Jaya, Selangor Darul Ehsan, Malaysia
| | - Eng Hwa Wong
- School of Medicine, Faculty of Health and Medical Sciences, Taylor's University Lakeside Campus, 47500, Subang Jaya, Selangor Darul Ehsan, Malaysia.
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15
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Hamidian M, Blasco L, Tillman LN, To J, Tomas M, Myers GSA. Analysis of Complete Genome Sequence of Acinetobacter baumannii Strain ATCC 19606 Reveals Novel Mobile Genetic Elements and Novel Prophage. Microorganisms 2020; 8:E1851. [PMID: 33255319 PMCID: PMC7760358 DOI: 10.3390/microorganisms8121851] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 11/18/2020] [Accepted: 11/21/2020] [Indexed: 11/16/2022] Open
Abstract
Acinetobacter baumannii isolate ATCC 19606 was recovered in the US prior to 1948. It has been used as a reference and model organism in many studies involving antibiotic resistance and pathogenesis of A. baumannii, while, until recently, a complete genome of this strain was not available. Here, we present an analysis of the complete 3.91-Mbp genome sequence, generated via a combination of short-read sequencing (Illumina) and long-read sequencing (MinION), and show it contains two small cryptic plasmids and a novel complete prophage of size 41.2 kb. We also characterised several regions of the ATCC 19606 genome, leading to the identification of a novel cadmium/mercury transposon, which was named Tn6551. ATCC 19606 is an antibiotic-sensitive strain, but a comparative analysis of all publicly available ST52 strains predicts a resistance to modern antibiotics by the accumulation of antibiotic-resistance genes via plasmids in recent isolates that belong to this sequence type.
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Affiliation(s)
- Mohammad Hamidian
- The iThree Institute, University of Technology Sydney, Ultimo 2007, NSW, Australia; (L.N.T.); (J.T.); (G.S.A.M.)
| | - Lucia Blasco
- Microbiology Department-Research Institute Biomedical A Coruña (INIBIC), Hospital A Coruña (CHUAC), University of A Coruña (UDC), 15495 A Coruña, Spain; (L.B.); (M.T.)
| | - Lauren N. Tillman
- The iThree Institute, University of Technology Sydney, Ultimo 2007, NSW, Australia; (L.N.T.); (J.T.); (G.S.A.M.)
| | - Joyce To
- The iThree Institute, University of Technology Sydney, Ultimo 2007, NSW, Australia; (L.N.T.); (J.T.); (G.S.A.M.)
| | - María Tomas
- Microbiology Department-Research Institute Biomedical A Coruña (INIBIC), Hospital A Coruña (CHUAC), University of A Coruña (UDC), 15495 A Coruña, Spain; (L.B.); (M.T.)
| | - Garry S. A. Myers
- The iThree Institute, University of Technology Sydney, Ultimo 2007, NSW, Australia; (L.N.T.); (J.T.); (G.S.A.M.)
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16
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Sato Y, Tansho-Nagakawa S, Ubagai T, Ono Y. Analysis of Immune Responses in Acinetobacter baumannii-Infected Klotho Knockout Mice: A Mouse Model of Acinetobacter baumannii Infection in Aged Hosts. Front Immunol 2020; 11:601614. [PMID: 33329595 PMCID: PMC7719750 DOI: 10.3389/fimmu.2020.601614] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 10/27/2020] [Indexed: 12/24/2022] Open
Abstract
Acinetobacter baumannii is an important opportunistic pathogen that primarily afflicts elderly people. To clarify the pathogenicity of A. baumannii in the elderly, we investigated immune responses to A. baumannii ATCC 19606 infection in klotho knockout (KO) mice, the mouse model of aging. Following intravenous inoculation, the mice seldom displayed severe symptoms. However, the survival rate was 56% at 7 days post-infection. Bacteria were detected in the lungs of klotho KO mice but not klotho wildtype (WT) mice at 7 days post-infection. Neutrophils, eosinophils, interstitial macrophages, and monocyte/dendritic cell subset in the lungs of klotho KO mice were transiently induced after infection with A. baumannii. The number of alveolar macrophages in klotho KO mice was lower than that in klotho WT mice, except for 1 day post-infection. CD11b expression on neutrophils and alveolar macrophages in the lungs of klotho KO mice was seldom upregulated by the infection. These results suggested that immune functions eliminating bacteria in the lungs of klotho KO mice were insufficient. CD11blow conventional DC cells hardly increased in klotho KO mice infected with A. baumannii. Additionally, the production of interleukin (IL)-10 in the sera of klotho KO mice was significantly higher than that in klotho WT mice, whereas that production of interferon-gamma was not detected in the sera of klotho KO mice. These results suggested that acquired immune responses were hardly induced in klotho KO mice. IL-1β, CXCL1, CXCL2, and CCL2 expression was significantly higher in the lungs of klotho KO mice infected with A. baumannii than in those of klotho WT mice at 1 day post-infection. These results suggested that pulmonary inflammation was elicited in klotho KO mice during early infection. The expression levels of proinflammatory cytokines significantly correlated with TLR9 expression in the lungs of klotho KO mice. The collective results demonstrate an A. baumannii infection state in aged hosts and suggest that pulmonary inflammation and bacterial burden should be noted in aged hosts even in the absence of severe symptoms of A. baumannii infection.
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Affiliation(s)
- Yoshinori Sato
- Department of Microbiology and Immunology, Teikyo University School of Medicine, Tokyo, Japan
| | - Shigeru Tansho-Nagakawa
- Department of Microbiology and Immunology, Teikyo University School of Medicine, Tokyo, Japan
| | - Tsuneyuki Ubagai
- Department of Microbiology and Immunology, Teikyo University School of Medicine, Tokyo, Japan
| | - Yasuo Ono
- Department of Microbiology and Immunology, Teikyo University School of Medicine, Tokyo, Japan
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17
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Vijayakumar K, Thirunanasambandham R. 5-Hydroxymethylfurfural inhibits Acinetobacter baumannii biofilms: an in vitro study. Arch Microbiol 2020; 203:673-682. [PMID: 33037454 DOI: 10.1007/s00203-020-02061-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 09/12/2020] [Accepted: 09/30/2020] [Indexed: 01/23/2023]
Abstract
The present study was aimed to investigate the antibiofilm activity of 5-hydroxymethylfurfural against Acinetobacter baumanni and Vellar estuary isolates v3 (Acinetobacter nosocomialis). The biofilm inhibitory concentration (BIC) of 5HMF against A. baumannii and v3 (A. nosocomialis) was found to be 100 µg/ml) exhibited non-bactericidal concentration-dependent antibiofilm activities against Acinetobacter species. The present study found that 5HMF treatment is very effective in the initial stage of A. baumannii biofilms and it significantly disrupted the mature biofilms. Moreover, 5HMF treatment inhibited the extracellular polymeric substances (EPS), including polysaccharides and proteins production. Results from gene expression and in vitro assays further demonstrated the 5HMF treatment downregulated the expression of bfmR, bap, csuA/B, ompA and katE virulence genes, which consistently affects biofilm formation and its mediated virulence property. The present study suggests that 5HMF unveil its antibiofilm activity by interfering initial biofilm formation and suppressing the virulence regulator genes in A. baumannii. Further studies are required to explore the 5HMF mode of action responsible for the antibiofilm activity.
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Affiliation(s)
- Karuppiah Vijayakumar
- Centre of Advanced Study in Marine Biology, Annamalai University, Tamil Nadu, Parangipettai, 608 502, India.
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18
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Uppalapati SR, Sett A, Pathania R. The Outer Membrane Proteins OmpA, CarO, and OprD of Acinetobacter baumannii Confer a Two-Pronged Defense in Facilitating Its Success as a Potent Human Pathogen. Front Microbiol 2020; 11:589234. [PMID: 33123117 PMCID: PMC7573547 DOI: 10.3389/fmicb.2020.589234] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 09/11/2020] [Indexed: 12/12/2022] Open
Abstract
Of all the ESKAPE pathogens, carbapenem-resistant and multidrug-resistant Acinetobacter baumannii is the leading cause of hospital-acquired and ventilator-associated pneumonia. A. baumannii infections are notoriously hard to eradicate due to its propensity to rapidly acquire multitude of resistance determinants and the virulence factor cornucopia elucidated by the bacterium that help it fend off a wide range of adverse conditions imposed upon by host and environment. One such weapon in the arsenal of A. baumannii is the outer membrane protein (OMP) compendium. OMPs in A. baumannii play distinctive roles in facilitating the bacterial acclimatization to antibiotic- and host-induced stresses, albeit following entirely different mechanisms. OMPs are major immunogenic proteins in bacteria conferring bacteria host-fitness advantages including immune evasion, stress tolerance, and resistance to antibiotics and antibacterials. In this review, we summarize the current knowledge of major A. baumannii OMPs and discuss their versatile role in antibiotic resistance and virulence. Specifically, we explore how OmpA, CarO, and OprD-like porins mediate antibiotic and amino acid shuttle and host virulence.
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Affiliation(s)
- Siva R Uppalapati
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, India
| | - Abhiroop Sett
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, India
| | - Ranjana Pathania
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, India
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19
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Weidensdorfer M, Ishikawa M, Hori K, Linke D, Djahanschiri B, Iruegas R, Ebersberger I, Riedel-Christ S, Enders G, Leukert L, Kraiczy P, Rothweiler F, Cinatl J, Berger J, Hipp K, Kempf VAJ, Göttig S. The Acinetobacter trimeric autotransporter adhesin Ata controls key virulence traits of Acinetobacter baumannii. Virulence 2020; 10:68-81. [PMID: 31874074 PMCID: PMC6363060 DOI: 10.1080/21505594.2018.1558693] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Acinetobacter baumannii is a Gram-negative pathogen that causes a multitude of nosocomial infections. The Acinetobacter trimeric autotransporter adhesin (Ata) belongs to the superfamily of trimeric autotransporter adhesins which are important virulence factors in many Gram-negative species. Phylogenetic profiling revealed that ata is present in 78% of all sequenced A. baumannii isolates but only in 2% of the closely related species A. calcoaceticus and A. pittii. Employing a markerless ata deletion mutant of A. baumannii ATCC 19606 we show that adhesion to and invasion into human endothelial and epithelial cells depend on Ata. Infection of primary human umbilical cord vein endothelial cells (HUVECs) with A. baumannii led to the secretion of interleukin (IL)-6 and IL-8 in a time- and Ata-dependent manner. Furthermore, infection of HUVECs by WT A. baumannii was associated with higher rates of apoptosis via activation of caspases-3 and caspase-7, but not necrosis, in comparison to ∆ata. Ata deletion mutants were furthermore attenuated in their ability to kill larvae of Galleria mellonella and to survive in larvae when injected at sublethal doses. This indicates that Ata is an important multifunctional virulence factor in A. baumannii that mediates adhesion and invasion, induces apoptosis and contributes to pathogenicity in vivo.
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Affiliation(s)
- Marko Weidensdorfer
- Institute for Medical Microbiology and Infection Control, University Hospital, Goethe University, Frankfurt, Germany
| | - Masahito Ishikawa
- Department of Biotechnology, Graduate School of Engineering, Nagoya University, Nagoya, Japan
| | - Katsutoshi Hori
- Department of Biotechnology, Graduate School of Engineering, Nagoya University, Nagoya, Japan
| | - Dirk Linke
- Department of Biosciences, Section for Genetics and Evolutionary Biology, University of Oslo, Oslo, Norway
| | - Bardya Djahanschiri
- Department for Applied Bioinformatics, Institute of Cell Biology and Neuroscience, Goethe University, Frankfurt, Germany
| | - Ruben Iruegas
- Department for Applied Bioinformatics, Institute of Cell Biology and Neuroscience, Goethe University, Frankfurt, Germany
| | - Ingo Ebersberger
- Department for Applied Bioinformatics, Institute of Cell Biology and Neuroscience, Goethe University, Frankfurt, Germany.,Senckenberg Biodiversity and Climate Research Centre Frankfurt (BIK-F), Frankfurt, Germany
| | - Sara Riedel-Christ
- Institute for Medical Microbiology and Infection Control, University Hospital, Goethe University, Frankfurt, Germany
| | - Giulia Enders
- Institute for Medical Microbiology and Infection Control, University Hospital, Goethe University, Frankfurt, Germany
| | - Laura Leukert
- Institute for Medical Microbiology and Infection Control, University Hospital, Goethe University, Frankfurt, Germany
| | - Peter Kraiczy
- Institute for Medical Microbiology and Infection Control, University Hospital, Goethe University, Frankfurt, Germany
| | - Florian Rothweiler
- Institute of Medical Virology, University Hospital, Goethe University, Frankfurt, Germany
| | - Jindrich Cinatl
- Institute of Medical Virology, University Hospital, Goethe University, Frankfurt, Germany
| | - Jürgen Berger
- Electron Microscopy Facility, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Katharina Hipp
- Electron Microscopy Facility, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Volkhard A J Kempf
- Institute for Medical Microbiology and Infection Control, University Hospital, Goethe University, Frankfurt, Germany
| | - Stephan Göttig
- Institute for Medical Microbiology and Infection Control, University Hospital, Goethe University, Frankfurt, Germany
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20
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Antibiotic Resistance Profiles, Molecular Mechanisms and Innovative Treatment Strategies of Acinetobacter baumannii. Microorganisms 2020; 8:microorganisms8060935. [PMID: 32575913 PMCID: PMC7355832 DOI: 10.3390/microorganisms8060935] [Citation(s) in RCA: 80] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 06/19/2020] [Accepted: 06/19/2020] [Indexed: 12/18/2022] Open
Abstract
Antibiotic resistance is one of the biggest challenges for the clinical sector and industry, environment and societal development. One of the most important pathogens responsible for severe nosocomial infections is Acinetobacter baumannii, a Gram-negative bacterium from the Moraxellaceae family, due to its various resistance mechanisms, such as the β-lactamases production, efflux pumps, decreased membrane permeability and altered target site of the antibiotic. The enormous adaptive capacity of A. baumannii and the acquisition and transfer of antibiotic resistance determinants contribute to the ineffectiveness of most current therapeutic strategies, including last-line or combined antibiotic therapy. In this review, we will present an update of the antibiotic resistance profiles and underlying mechanisms in A. baumannii and the current progress in developing innovative strategies for combating multidrug-resistant A. baumannii (MDRAB) infections.
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21
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Qin QM, Pei J, Gomez G, Rice-Ficht A, Ficht TA, de Figueiredo P. A Tractable Drosophila Cell System Enables Rapid Identification of Acinetobacter baumannii Host Factors. Front Cell Infect Microbiol 2020; 10:240. [PMID: 32528902 PMCID: PMC7264411 DOI: 10.3389/fcimb.2020.00240] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Accepted: 04/27/2020] [Indexed: 12/11/2022] Open
Abstract
Acinetobacter baumannii is an important causative agent of nosocomial infections worldwide. The pathogen also readily acquires resistance to antibiotics, and pan-resistant strains have been reported. A. baumannii is widely regarded as an extracellular bacterial pathogen. However, accumulating evidence demonstrates that the pathogen can invade, survive or persist in infected mammalian cells. Unfortunately, the molecular mechanisms controlling these processes remain poorly understood. Here, we show that Drosophila S2 cells provide several attractive advantages as a model system for investigating the intracellular lifestyle of the pathogen, including susceptibility to bacterial intracellular replication and limited infection-induced host cell death. We also show that the Drosophila system can be used to rapidly identify host factors, including MAP kinase proteins, which confer susceptibility to intracellular parasitism. Finally, analysis of the Drosophila system suggested that host proteins that regulate organelle biogenesis and membrane trafficking contribute to regulating the intracellular lifestyle of the pathogen. Taken together, these findings establish a novel model system for elucidating interactions between A. baumannii and host cells, define new factors that regulate bacterial invasion or intracellular persistence, and identify subcellular compartments in host cells that interact with the pathogen.
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Affiliation(s)
- Qing-Ming Qin
- College of Plant Sciences, Key Laboratory of Zoonosis Research, Ministry of Education, Jilin University, Changchun, China.,Department of Microbial Pathogenesis and Immunology, Texas A&M Health Science Center, Bryan TX, United States
| | - Jianwu Pei
- Department of Veterinary Pathobiology, Texas A&M University, College Station, TX, United States
| | - Gabriel Gomez
- Department of Veterinary Pathobiology, Texas A&M University, College Station, TX, United States
| | - Allison Rice-Ficht
- Department of Molecular and Cellular Medicine, Texas A&M Health Science Center, Bryan, TX, United States
| | - Thomas A Ficht
- Department of Veterinary Pathobiology, Texas A&M University, College Station, TX, United States
| | - Paul de Figueiredo
- Department of Microbial Pathogenesis and Immunology, Texas A&M Health Science Center, Bryan TX, United States.,Department of Veterinary Pathobiology, Texas A&M University, College Station, TX, United States.,Norman Borlaug Center, Texas A&M University, College Station, TX, United States
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22
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Ayoub Moubareck C, Hammoudi Halat D. Insights into Acinetobacter baumannii: A Review of Microbiological, Virulence, and Resistance Traits in a Threatening Nosocomial Pathogen. Antibiotics (Basel) 2020; 9:antibiotics9030119. [PMID: 32178356 PMCID: PMC7148516 DOI: 10.3390/antibiotics9030119] [Citation(s) in RCA: 186] [Impact Index Per Article: 46.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 03/01/2020] [Accepted: 03/02/2020] [Indexed: 12/12/2022] Open
Abstract
Being a multidrug-resistant and an invasive pathogen, Acinetobacter baumannii is one of the major causes of nosocomial infections in the current healthcare system. It has been recognized as an agent of pneumonia, septicemia, meningitis, urinary tract and wound infections, and is associated with high mortality. Pathogenesis in A. baumannii infections is an outcome of multiple virulence factors, including porins, capsules, and cell wall lipopolysaccharide, enzymes, biofilm production, motility, and iron-acquisition systems, among others. Such virulence factors help the organism to resist stressful environmental conditions and enable development of severe infections. Parallel to increased prevalence of infections caused by A. baumannii, challenging and diverse resistance mechanisms in this pathogen are well recognized, with major classes of antibiotics becoming minimally effective. Through a wide array of antibiotic-hydrolyzing enzymes, efflux pump changes, impermeability, and antibiotic target mutations, A. baumannii models a unique ability to maintain a multidrug-resistant phenotype, further complicating treatment. Understanding mechanisms behind diseases, virulence, and resistance acquisition are central to infectious disease knowledge about A. baumannii. The aims of this review are to highlight infections and disease-producing factors in A. baumannii and to touch base on mechanisms of resistance to various antibiotic classes.
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Affiliation(s)
- Carole Ayoub Moubareck
- College of Natural and Health Sciences, Zayed University, Dubai P.O. Box 144534, UAE
- Correspondence: ; Tel.: +971-4-402-1745
| | - Dalal Hammoudi Halat
- Department of Pharmaceutical Sciences, School of Pharmacy, Lebanese International University, Beirut, Bekaa Campuses 1103, Lebanon;
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23
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Mishra M, Panda S, Barik S, Sarkar A, Singh DV, Mohapatra H. Antibiotic Resistance Profile, Outer Membrane Proteins, Virulence Factors and Genome Sequence Analysis Reveal Clinical Isolates of Enterobacter Are Potential Pathogens Compared to Environmental Isolates. Front Cell Infect Microbiol 2020; 10:54. [PMID: 32154188 PMCID: PMC7047878 DOI: 10.3389/fcimb.2020.00054] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Accepted: 01/31/2020] [Indexed: 01/02/2023] Open
Abstract
Outer membrane proteins (OMPs) of gram-negative bacteria play an important role in mediating antibacterial resistance, bacterial virulence and thus affect pathogenic ability of the bacteria. Over the years, prevalence of environmental antibiotic resistant organisms, their transmission to clinics and ability to transfer resistance genes, have been studied extensively. Nevertheless, how successful environmental bacteria can be in establishing as pathogenic bacteria under clinical setting, is less addressed. In the present study, we utilized an integrated approach of investigating the antibiotic resistance profile, presence of outer membrane proteins and virulence factors to understand extent of threat posed due to multidrug resistant environmental Enterobacter isolates. Also, we investigated clinical Enterobacter isolates and compared the results thereof. Results of the study showed that multidrug resistant environmental Enterobacter isolates lacked OmpC, lacked cell invasion abilities and exhibited low reactive oxygen species (ROS) production in neutrophils. In contrast, clinical isolates possessed OmpF, exhibited high invasive and adhesive property and produced higher amounts of ROS in neutrophils. These attributes indicated limited pathogenic potential of environmental Enterobacter isolates. Informations obtained from whole genome sequence of two representative bacterial isolates from environment (DL4.3) and clinical sources (EspIMS6) corroborated well with the observed results. Findings of the present study are significant as it highlights limited fitness of multidrug resistant environmental Enterobacter isolates.
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Affiliation(s)
- Mitali Mishra
- School of Biological Sciences, National Institute of Science Education and Research, HBNI, Bhubaneswar, India.,Homi Bhabha National Institute (HBNI), Mumbai, India
| | - Sasmita Panda
- Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, India
| | - Susmita Barik
- Trident School of Biotech Sciences, Trident Academy of Creative and Technology, Bhubaneswar, India
| | - Arup Sarkar
- Trident School of Biotech Sciences, Trident Academy of Creative and Technology, Bhubaneswar, India
| | - Durg Vijai Singh
- Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, India
| | - Harapriya Mohapatra
- School of Biological Sciences, National Institute of Science Education and Research, HBNI, Bhubaneswar, India.,Homi Bhabha National Institute (HBNI), Mumbai, India
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24
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Multidrug-resistant Acinetobacter baumannii resists reactive oxygen species and survives in macrophages. Sci Rep 2019; 9:17462. [PMID: 31767923 PMCID: PMC6877552 DOI: 10.1038/s41598-019-53846-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 11/06/2019] [Indexed: 01/27/2023] Open
Abstract
We investigated the intracellular survival of multidrug-resistant Acinetobacter baumannii (MDRAB) clinical isolates in macrophages, after phagocytosis, to determine their virulence characteristics. After ATCC 19606 and 5 clinical isolates of MDRAB were phagocytosed by mouse and human macrophages, the bacterial count of MDRAB strains, R4 and R5, increased in the mouse macrophages, 24 hours after phagocytosis. Bacterial count of the strains, R1 and R2, was almost equal 4 and 24 hours after phagocytosis. Intracellular reactive oxygen species was detected in the macrophages after phagocytosis of these bacteria. Further, the strains R1, R2, R4, and R5 showed higher catalase activity than ATCC 19606. Additionally, strains R1, R4, and R5 grew more efficiently than ATCC 19606 in the presence of H2O2, whereas growth of strains R2 and R3 was marginally more than that of ATCC 19606 in the presence of H2O2. The MDRAB clinical isolates altered the expression of TNF-α, IL-1β, IL-6, and MIP-2 mRNA induced in J774A.1 cells, 24 hours after phagocytosis. These results provide insights into the renewed virulence characteristics of MDRAB clinical isolates. Finally, tigecycline killed MDRAB phagocytosed by the macrophages more effectively than colistin, although colistin and tigecycline are both considered effective antibiotics for the treatment of MDRAB.
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Yeong EK, Huang WL. Risk Factors for Multidrug-Resistant Acinetobacter baumannii Infections in a Mass Burn Casualty Incident. J Burn Care Res 2019; 40:823-827. [PMID: 31197367 DOI: 10.1093/jbcr/irz092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
They investigated the risk factors of multidrug-resistant Acinetobacter baumannii infections in 33 burn patients in a mass burn casualty. The independent variables included sex, burn size, vancomycin, ampicillin/sulbactam, cefazolin, meropenem, third-/fourth-generation cephalosporin, the number of classes of antibiotic used, and the number of days of antibiotic use. Multidrug-resistant A. baumannii infection was the outcome variable. Logistic regressions and structural equation model were used for statistical analysis. The average age was 21.7 years (range, 17-32 years; M = 11 [33%], F = 22 [67%]; mean burn area, 42% of the total body surface area; study period, June 28, 2015 to July 31, 2015). The incidence of infection was 39% (n = 13/33). For every percent increase in burn size, the odds of developing A. baumannii infections increased by 1.1 (P < .05). Similarly, the odds increased by 2.5 in every number increase in the classes of antibiotic used, by 1.2 in everyday increase in the days of antibiotic used, and by 12 in patients treated with vancomycin (P < .05). The correlations of these risk factors were demonstrated in a hypothetical structural equation model (P-value of chi-squared test > .05 and root mean square error of approximation < 0.05) in which burn size was the fundamental risk factor of multidrug-resistant A. baumannii infections. The model did not predict the emergence of multidrug-resistant A. baumannii infections. Conclusively, the risks of multidrug-resistant A. baumannii infections in burns are correlated with burn size, the number of classes of antibiotic used, the number of days of antibiotic use, and the prior use of vancomycin.
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Affiliation(s)
- Eng-Kean Yeong
- Department of Surgery, National Taiwan University Hospital, National Taiwan.,Department of Surgery, National Taiwan University Hospital Yunlin Branch, Douliou City of Yunlin County, Douliu City, Yunlin County, Taiwan
| | - Wei-Lieh Huang
- Department of Psychiatry, National Taiwan University Hospital, Yun-Lin Branch, Douliu City, Yunlin County, Taiwan.,Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei City, Taiwan
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Giardina BJ, Shahzad S, Huang W, Wilks A. Heme uptake and utilization by hypervirulent Acinetobacter baumannii LAC-4 is dependent on a canonical heme oxygenase (abHemO). Arch Biochem Biophys 2019; 672:108066. [PMID: 31398314 DOI: 10.1016/j.abb.2019.108066] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 08/02/2019] [Accepted: 08/06/2019] [Indexed: 02/06/2023]
Abstract
Acinetobacter baumannii is an opportunistic pathogen that causes serious infections in critically ill and immune compromised patients. The ability to acquire iron from the hosts iron and heme containing proteins is critical to their survival and virulence. The majority of A. baumannii hypervirulent strains encode a heme uptake system that includes a putative heme oxygenase (hemO). Despite reports indicating A. baumannii can grow on heme direct evidence of extracellular heme uptake and metabolism has not been shown. Through isotopic labeling (13C-heme) we show the hypervirulent A. baumannii LAC-4 metabolizes heme to biliverdin IXα (BVIXα), whereas ATC 17978 that lacks the hemO gene cluster cannot efficiently utilize heme. Expression and purification of the protein encoded by the A. baumannii LAC-4 hemO gene confirmed catalytic conversion of heme to BVIX. We further show inhibition of abHemO with previously characterized P. aeruginosa HemO inhibitors in a fluorescence based assay that couples HemO catalytic activity to the BVIXα binding phytochrome IFP1.4. Furthermore, the hemO gene cluster encodes genes with homology to heme-dependent extra cytoplasmic function (ECF) σ factor systems. The hemophore-dependent ECF system in Pseudomonas aeruginosa has been shown to play a critical role in heme sensing and virulence within the host. The prevalence of a hemO gene cluster in A. baumannii LAC4 and other hypervirulent strains suggests it is required within the host to adapt and utilize heme and is a major contributor to virulence.
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Affiliation(s)
- Bennett J Giardina
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD, 21201, USA
| | - Saba Shahzad
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD, 21201, USA
| | - Weiliang Huang
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD, 21201, USA
| | - Angela Wilks
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD, 21201, USA.
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Hassannejad N, Bahador A, Rudbari NH, Modarressi MH, Parivar K. In vivo antibacterial activity of
Zataria multiflora
Boiss extract and its components, carvacrol, and thymol, against colistin‐resistant
Acinetobacter baumannii
in a pneumonic BALB/c mouse model. J Cell Biochem 2019; 120:18640-18649. [DOI: 10.1002/jcb.28908] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 02/01/2019] [Accepted: 02/04/2019] [Indexed: 11/10/2022]
Affiliation(s)
- Niloofar Hassannejad
- Department of Cellular and Molecular BiologyFaculty of SciencesScience and Research Brand of Islamic Azad University Tehran Iran
| | - Abbas Bahador
- Department of MicrobiologySchool of MedicineTehran University of Medical Sciences Tehran Iran
| | - Nasim Hayati Rudbari
- Department of BiologyFaculty of SciencesScience and Research Brand of Islamic Azad University Tehran Iran
| | | | - Kazem Parivar
- Department of BiologyFaculty of SciencesScience and Research Brand of Islamic Azad University Tehran Iran
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Li FJ, Starrs L, Burgio G. Tug of war between Acinetobacter baumannii and host immune responses. Pathog Dis 2019; 76:5290314. [PMID: 30657912 DOI: 10.1093/femspd/ftz004] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 01/16/2019] [Indexed: 02/06/2023] Open
Abstract
Acinetobacter baumannii is an emerging nosocomial, opportunistic pathogen with growing clinical significance. Acinetobacter baumannii has an exceptional ability to rapidly develop drug resistance and to adhere to abiotic surfaces, including medical equipment, significantly promoting bacterial spread and also limiting our ability to control A. baumannii infections. Consequently, A. baumannii is frequently responsible for ventilator-associated pneumonia in clinical settings. In order to develop an effective treatment strategy, understanding host-pathogen interactions during A. baumannii infection is crucial. Various A. baumannii virulence factors have been identified as targets of host innate pattern-recognition receptors, which leads to activation of downstream inflammasomes to develop inflammatory responses, and the recruitment of innate immune effectors against A. baumannii infection. To counteract host immune attack, A. baumannii regulates its expression of different virulence factors. This review summarizes the significance of mechanisms of host-bacteria interaction, as well as different bacteria and host defense mechanisms during A. baumannii infection.
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Affiliation(s)
- Fei-Ju Li
- Department of Immunology and infectious Diseases, John Curtin School of Medical Research, Australian National University, 131 Garran Road, Acton, ACT 2601, Australia
| | - Lora Starrs
- Department of Immunology and infectious Diseases, John Curtin School of Medical Research, Australian National University, 131 Garran Road, Acton, ACT 2601, Australia
| | - Gaetan Burgio
- Department of Immunology and infectious Diseases, John Curtin School of Medical Research, Australian National University, 131 Garran Road, Acton, ACT 2601, Australia
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Acinetobacter baumannii outer membrane protein A induces HeLa cell autophagy via MAPK/JNK signaling pathway. Int J Med Microbiol 2019; 309:97-107. [DOI: 10.1016/j.ijmm.2018.12.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 12/14/2018] [Accepted: 12/28/2018] [Indexed: 12/13/2022] Open
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Kwon HI, Kim S, Oh MH, Shin M, Lee JC. Distinct role of outer membrane protein A in the intrinsic resistance of Acinetobacter baumannii and Acinetobacter nosocomialis. INFECTION GENETICS AND EVOLUTION 2019; 67:33-37. [DOI: 10.1016/j.meegid.2018.10.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2017] [Revised: 08/29/2018] [Accepted: 10/27/2018] [Indexed: 10/28/2022]
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Kwon HI, Kim S, Oh MH, Na SH, Kim YJ, Jeon YH, Lee JC. Outer membrane protein A contributes to antimicrobial resistance of Acinetobacter baumannii through the OmpA-like domain. J Antimicrob Chemother 2018; 72:3012-3015. [PMID: 28981866 DOI: 10.1093/jac/dkx257] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 06/30/2017] [Indexed: 01/29/2023] Open
Abstract
Objectives Acinetobacter baumannii outer membrane protein A (AbOmpA) is involved in bacterial pathogenesis. However, the role of AbOmpA in the antimicrobial resistance of A. baumannii has not been fully elucidated. This study aimed to investigate the role of the OmpA-like domain of AbOmpA in the antimicrobial resistance of A. baumannii. Methods The MICs of antimicrobial agents for the WT A. baumannii ATCC 17978, ΔompA mutant, OmpA-like domain-deleted (amino acids 223-356) AbOmpA mutant and single-copy ompA-complemented strain were determined by the Etest method. The MICs of antimicrobial agents for MDR strain 1656-2 and its ΔompA mutant strains were also determined. Results The ΔompA mutant strain of ATCC 17978 was more susceptible to trimethoprim (>5.3-fold) and other antimicrobial agents tested (<2.0-fold), except tigecycline, than the WT strain. The ΔompA mutant strain of 1656-2 was more susceptible to trimethoprim (>4.0-fold), tetracycline (2.3-fold) and other antimicrobial agents (<2.0-fold), including tigecycline, colistin and imipenem, than the WT strain. The MICs of gentamicin, imipenem and nalidixic acid for the WT ATCC 17978 and ΔompA mutant strains were decreased in the presence of an efflux pump inhibitor. A mutant strain of ATCC 17978 with the OmpA-like domain of AbOmpA deleted was more susceptible (≥2.0-fold) to substrates of the resistance-nodulation-division efflux pumps, including aztreonam, gentamicin, imipenem and trimethoprim, than the WT strain. Conclusions This study demonstrates that AbOmpA contributes to the antimicrobial resistance of A. baumannii through the OmpA-like domain.
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Affiliation(s)
- Hyo Il Kwon
- Department of Microbiology, Kyungpook National University School of Medicine, Daegu 41944, Korea
| | - Shukho Kim
- Department of Microbiology, Kyungpook National University School of Medicine, Daegu 41944, Korea
| | - Man Hwan Oh
- Department of Nanobiomedical Science, Dankook University, Cheonan 31116, Korea
| | - Seok Hyeon Na
- Department of Microbiology, Kyungpook National University School of Medicine, Daegu 41944, Korea
| | - Yoo Jeong Kim
- Department of Microbiology, Kyungpook National University School of Medicine, Daegu 41944, Korea
| | - Young Ho Jeon
- College of Pharmacy, Korea University, Sejong 30019, Korea
| | - Je Chul Lee
- Department of Microbiology, Kyungpook National University School of Medicine, Daegu 41944, Korea
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Sub-minimum inhibitory concentrations of colistin and polymyxin B promote Acinetobacter baumannii biofilm formation. PLoS One 2018; 13:e0194556. [PMID: 29554105 PMCID: PMC5858813 DOI: 10.1371/journal.pone.0194556] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 03/06/2018] [Indexed: 01/29/2023] Open
Abstract
We investigated the numbers of planktonic and biofilm cells and the expression levels of genes encoding efflux pumps and biofilm-related proteins in 10 clinical isolates of multi-drug resistant Acinetobacter baumannii (MDRA) as well as in its standard strain ATCC 19606 in the presence of colistin (CST), polymyxin B (PMB), minomycin (MIN), and tigecycline (TGC) at their respective sub-MICs. The number of planktonic and biofilm cells of ATCC 19606 decreased in the presence of all aforementioned antibiotics in a dose-dependent manner. Cell number also decreased in two representative MDRA strains, R2 and R3, in the presence of MIN and TGC in a dose-dependent manner. In contrast, the number of biofilm cells in these two strains increased in the presence of CST, while they increased significantly in the presence of PMB in R2 only. Pearson correlation analysis revealed that the number of biofilm cells was positively and significantly correlated with the mRNA levels of genes encoding efflux pumps (adeB and adeG) and autoinducer synthase (abaI) in strain R2 and adeB, adeG, adeJ, poly-acetyl-glucosamine-porin (pgaA), and abaI in strain R3 in the presence of CST. It was positively and significantly correlated with the mRNA levels of genes encoding adeB in strain R2 and an outer membrane protein A (ompA) and biofilm-associated protein (bap) in strain R3 in the presence of PMB. These results provide valuable insights into the biofilm formation potency of clinical isolates of MDRA that depends on efflux pumps and biofilm-related genes and its regulation by antibiotics.
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