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He M, Yin S, Huang X, Li Y, Li B, Gong T, Liu Q. Insights into the regulatory role of bacterial sncRNA and its extracellular delivery via OMVs. Appl Microbiol Biotechnol 2024; 108:29. [PMID: 38159117 DOI: 10.1007/s00253-023-12855-z] [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: 05/23/2023] [Revised: 10/11/2023] [Accepted: 10/20/2023] [Indexed: 01/03/2024]
Abstract
Small noncoding RNAs (sncRNAs) play important regulatory roles in bacterial physiological processes and host-pathogen interactions. Meanwhile, bacterial outer membrane vesicles (OMVs), as naturally secreted outer membrane structures, play a vital role in the interaction between bacteria and their living environment, including the host environment. However, most current studies focus on the biological functions of sncRNAs in bacteria or hosts, while neglecting the roles and regulatory mechanisms of the OMVs that encapsulate these sncRNAs. Therefore, this review aims to summarize the intracellular regulatory roles of bacterial sncRNAs in promoting pathogen survival by regulating virulence, modulating bacterial drug resistance, and regulating iron metabolism, and their extracellular regulatory function for influencing host immunity through host-pathogen interactions. Additionally, we introduce the key role played by OMVs, which serve as important cargoes in bacterial sncRNA-host interactions. We propose emerging pathways of sncRNA action to further discuss the mode of host-pathogen interactions, highlighting that the inhibition of sncRNA delivery by OMVs may prevent the occurrence of infection to some extent. Hence, this review lays the foundation for future prophylactic treatments against bacterial infections and strategies for addressing bacterial drug resistance. KEY POINTS: •sncRNAs have intracellular and extracellular regulatory functions in bacterial physiological processes and host-pathogen interactions. •OMVs are potential mediators between bacterial sncRNAs and host cells. •OMVs encapsulating sncRNAs have more potential biological functions.
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Affiliation(s)
- Mengdan He
- Center for Molecular Diagnosis and Precision Medicine, The Department of Clinical Laboratory, Jiangxi Provincial Center for Advanced Diagnostic Technology and Precision Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, 330006, China
- Department of Medical Microbiology, School of Medicine, Nanchang University, Nanchang, 330006, China
| | - Shuanshuan Yin
- Center for Molecular Diagnosis and Precision Medicine, The Department of Clinical Laboratory, Jiangxi Provincial Center for Advanced Diagnostic Technology and Precision Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, 330006, China
- Department of Medical Microbiology, School of Medicine, Nanchang University, Nanchang, 330006, China
| | - Xinlei Huang
- Gannan Medical University, Ganzhou, 341000, Jiangxi, China
| | - Yi Li
- Center for Molecular Diagnosis and Precision Medicine, The Department of Clinical Laboratory, Jiangxi Provincial Center for Advanced Diagnostic Technology and Precision Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, 330006, China
- Department of Medical Microbiology, School of Medicine, Nanchang University, Nanchang, 330006, China
| | - Biaoxian Li
- Center for Molecular Diagnosis and Precision Medicine, The Department of Clinical Laboratory, Jiangxi Provincial Center for Advanced Diagnostic Technology and Precision Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, 330006, China
| | - Tian Gong
- Center for Molecular Diagnosis and Precision Medicine, The Department of Clinical Laboratory, Jiangxi Provincial Center for Advanced Diagnostic Technology and Precision Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, 330006, China.
| | - Qiong Liu
- Center for Molecular Diagnosis and Precision Medicine, The Department of Clinical Laboratory, Jiangxi Provincial Center for Advanced Diagnostic Technology and Precision Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, 330006, China.
- Department of Medical Microbiology, School of Medicine, Nanchang University, Nanchang, 330006, China.
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2
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Shenkutie AM, Gebrelibanos D, Yao M, Bedada Hundie G, Chow FWN, Leung PHM. Impairment of novel non-coding small RNA00203 inhibits biofilm formation and reduces biofilm-specific antibiotic resistance in Acinetobacter baumannii. Int J Antimicrob Agents 2023; 62:106889. [PMID: 37315907 DOI: 10.1016/j.ijantimicag.2023.106889] [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: 01/03/2023] [Revised: 05/12/2023] [Accepted: 06/09/2023] [Indexed: 06/16/2023]
Abstract
Small RNAs (sRNAs) are post-transcriptional regulators of many biological processes in bacteria, including biofilm formation and antibiotic resistance. The mechanisms by which sRNA regulates the biofilm-specific antibiotic resistance in Acinetobacter baumannii have not been reported to date. This study aimed to investigate the influence of sRNA00203 (53 nucleotides) on biofilm formation, antibiotic susceptibility, and expression of genes associated with biofilm formation and antibiotic resistance. The results showed that deletion of the sRNA00203-encoding gene decreased the biomass of biofilm by 85%. Deletion of the sRNA00203-encoding gene also reduced the minimum biofilm inhibitory concentrations for imipenem and ciprofloxacin 1024- and 128-fold, respectively. Knocking out of sRNA00203 significantly downregulated genes involved in biofilm matrix synthesis (pgaB), efflux pump production (novel00738), lipopolysaccharide biosynthesis (novel00626), preprotein translocase subunit (secA) and the CRP transcriptional regulator. Overall, the suppression of sRNA00203 in an A. baumannii ST1894 strain impaired biofilm formation and sensitized the biofilm cells to imipenem and ciprofloxacin. As sRNA00203 was found to be conserved in A. baumannii, a therapeutic strategy targeting sRNA00203 may be a potential solution for the treatment of biofilm-associated infections caused by A. baumannii. To the best of the authors' knowledge, this is the first study to show the impact of sRNA00203 on biofilm formation and biofilm-specific antibiotic resistance in A. baumannii.
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Affiliation(s)
- Abebe Mekuria Shenkutie
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong SAR, China; Department of Microbiology, Immunology and Parasitology, St. Paul's Hospital Millennium Medical College, Addis Ababa, Ethiopia
| | - Daniel Gebrelibanos
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong SAR, China
| | - Mianzhi Yao
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong SAR, China
| | - Gadissa Bedada Hundie
- Department of Microbiology, Immunology and Parasitology, St. Paul's Hospital Millennium Medical College, Addis Ababa, Ethiopia
| | - Franklin W N Chow
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong SAR, China
| | - Polly H M Leung
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong SAR, China.
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3
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Regulation of biofilm formation by non-coding RNA in prokaryotes. CURRENT RESEARCH IN PHARMACOLOGY AND DRUG DISCOVERY 2022; 4:100151. [PMID: 36636617 PMCID: PMC9829692 DOI: 10.1016/j.crphar.2022.100151] [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: 06/30/2022] [Revised: 09/30/2022] [Accepted: 12/21/2022] [Indexed: 12/31/2022] Open
Abstract
Biofilm refers to microbes that associate with each other or to a surface via self-synthesized exopolysaccharides and other surface-related structures. The presence of biofilms consisting of pathogenic microbes in the food and clinical environment can pose a threat to human health as microbes in biofilms are highly robust and are difficult to remove. Understanding the process of biofilm formation is crucial for the development of novel strategies to control or harness biofilm. The complex network of proteins, small RNA, and diverse molecules regulate biofilm formation at different steps in biofilm development, including triggering the switch from planktonic to sessile cells, maturation of biofilms, and eventual dispersion of microbes from the biofilms. Small non-coding RNAs are relatively small RNAs that are not translated into proteins and play diverse roles in metabolism, physiology, pathogenesis, and biofilm formation. In this review, we primarily focused on non-coding regulatory RNA that regulates biofilm formation in clinically relevant pathogens or threatens human health. Even though many ncRNA have recently been identified in Archaea, much characterization work remains. The mechanisms and regulatory processes controlled by ncRNA in prokaryotes are covered in this review.
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Sarshar M, Scribano D, Palamara AT, Ambrosi C, Masotti A. The Acinetobacter baumannii model can explain the role of small non-coding RNAs as potential mediators of host-pathogen interactions. Front Mol Biosci 2022; 9:1088783. [PMID: 36619166 PMCID: PMC9810633 DOI: 10.3389/fmolb.2022.1088783] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 12/07/2022] [Indexed: 12/24/2022] Open
Abstract
Bacterial small RNAs (sRNAs) research has accelerated over the past decade, boosted by advances in RNA-seq technologies and methodologies for capturing both protein-RNA and RNA-RNA interactions. The emerging picture is that these regulatory sRNAs play important roles in controlling complex physiological processes and are required to survive the antimicrobial challenge. In recent years, the RNA content of OMVs/EVs has also gained increasing attention, particularly in the context of infection. Secreted RNAs from several bacterial pathogens have been characterized but the exact mechanisms promoting pathogenicity remain elusive. In this review, we briefly discuss how secreted sRNAs interact with targets in infected cells, thus representing a novel perspective of host cell manipulation during bacterial infection. During the last decade, Acinetobacter baumannii became clinically relevant emerging pathogens responsible for nosocomial and community-acquired infections. Therefore, we also summarize recent findings of regulation by sRNAs in A. baumannii and discuss how this emerging bacterium utilizes many of these sRNAs to adapt to its niche and become successful human pathogen.
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Affiliation(s)
- Meysam Sarshar
- Research Laboratories, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy,*Correspondence: Meysam Sarshar, ; Andrea Masotti,
| | - Daniela Scribano
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy
| | - Anna Teresa Palamara
- Laboratory Affiliated to Institute Pasteur Italia-Cenci Bolognetti Foundation, Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy,Department of Infectious Diseases, National Institute of Health, Rome, Italy
| | - Cecilia Ambrosi
- Department of Human Sciences and Promotion of the Quality of Life, San Raffaele Roma Open University, Rome, Italy,IRCCS San Raffaele Roma, Rome, Italy
| | - Andrea Masotti
- Research Laboratories, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy,*Correspondence: Meysam Sarshar, ; Andrea Masotti,
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Gao L, Ma X. Transcriptome Analysis of Acinetobacter baumannii in Rapid Response to Subinhibitory Concentration of Minocycline. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:16095. [PMID: 36498165 PMCID: PMC9741440 DOI: 10.3390/ijerph192316095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 11/23/2022] [Accepted: 11/28/2022] [Indexed: 06/17/2023]
Abstract
The increasing emergence of multidrug-resistant Acinetobacter baumannii brings great threats to public health. Minocycline is a kind of semisynthetic derivative of the antibacterial drug tetracycline and is often used to treat infections caused by multidrug-resistant A. baumannii with other antibiotics. However, minocycline-resistant A. baumannii appears constantly. To rapidly explore the response of A. baumannii to minocycline stress, RNA-seq was carried out to compare the difference in the transcriptome of A. baumannii ATCC19606 in the presence or absence of minocycline. The results showed that 25 genes were differentially expressed, including 10 downregulated genes and 15 upregulated genes, and 24 sRNA were upregulated and 24 were downregulated based on the filter criteria (Log2FC > 1 or <−1 and FDR < 0.05). RtcB family protein and ABC transporter ATP-binding protein were upregulated by 2.6- and 11.3-fold, and molecular chaperone GroES, chaperonin GroL, class C beta-lactamase ADC-158, amino acid ABC transporter permease, and APC family permease were downregulated by at least two-fold in the presence of half-MIC minocycline. The differentially expressed genes are mainly involved in the stress response, the GroES/GroEL chaperonin system, and transport metabolic pathways. sRNA 1248 was significantly upregulated, and sRNA 1767, 5182, and 6984 were downregulated in a rapid response to minocycline. These results provide insights into the adaptive mechanism of A. baumannii to minocycline.
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Affiliation(s)
- Lili Gao
- College of Grassland Science, Qingdao Agricultural University, Qingdao 266109, China
| | - Xiaochun Ma
- Experimental Animal Center, Zunyi Medical University, Zunyi 563003, China
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6
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Lazar V, Holban AM, Curutiu C, Chifiriuc MC. Modulation of Quorum Sensing and Biofilms in Less Investigated Gram-Negative ESKAPE Pathogens. Front Microbiol 2021; 12:676510. [PMID: 34394026 PMCID: PMC8359898 DOI: 10.3389/fmicb.2021.676510] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 06/30/2021] [Indexed: 01/20/2023] Open
Abstract
Pathogenic bacteria have the ability to sense their versatile environment and adapt by behavioral changes both to the external reservoirs and the infected host, which, in response to microbial colonization, mobilizes equally sophisticated anti-infectious strategies. One of the most important adaptive processes is the ability of pathogenic bacteria to turn from the free, floating, or planktonic state to the adherent one and to develop biofilms on alive and inert substrata; this social lifestyle, based on very complex communication networks, namely, the quorum sensing (QS) and response system, confers them an increased phenotypic or behavioral resistance to different stress factors, including host defense mechanisms and antibiotics. As a consequence, biofilm infections can be difficult to diagnose and treat, requiring complex multidrug therapeutic regimens, which often fail to resolve the infection. One of the most promising avenues for discovering novel and efficient antibiofilm strategies is targeting individual cells and their QS mechanisms. A huge amount of data related to the inhibition of QS and biofilm formation in pathogenic bacteria have been obtained using the well-established gram-positive Staphylococcus aureus and gram-negative Pseudomonas aeruginosa models. The purpose of this paper was to revise the progress on the development of antibiofilm and anti-QS strategies in the less investigated gram-negative ESKAPE pathogens Klebsiella pneumoniae, Acinetobacter baumannii, and Enterobacter sp. and identify promising leads for the therapeutic management of these clinically significant and highly resistant opportunistic pathogens.
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Affiliation(s)
- Veronica Lazar
- Department of Microbiology and Immunology, Faculty of Biology, University of Bucharest, Bucharest, Romania
- The Research Institute of the University of Bucharest, Bucharest, Romania
| | - Alina Maria Holban
- Department of Microbiology and Immunology, Faculty of Biology, University of Bucharest, Bucharest, Romania
- The Research Institute of the University of Bucharest, Bucharest, Romania
| | - Carmen Curutiu
- Department of Microbiology and Immunology, Faculty of Biology, University of Bucharest, Bucharest, Romania
- The Research Institute of the University of Bucharest, Bucharest, Romania
| | - Mariana Carmen Chifiriuc
- Department of Microbiology and Immunology, Faculty of Biology, University of Bucharest, Bucharest, Romania
- The Research Institute of the University of Bucharest, Bucharest, Romania
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7
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De Silva PM, Patidar R, Graham CI, Brassinga AKC, Kumar A. A response regulator protein with antar domain, AvnR, in Acinetobacter baumannii ATCC 17978 impacts its virulence and amino acid metabolism. MICROBIOLOGY-SGM 2021; 166:554-566. [PMID: 32324528 DOI: 10.1099/mic.0.000913] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Acinetobacter baumannii, a Gram-negative coccobacillus, is notorious for its involvement in opportunistic infections around the world. Its resistance to antibiotics makes treatment of infections challenging. In this study, we describe a novel response regulator protein, AvnR (A1S_2006) that regulates virulence-related traits in A. baumannii ATCC17978. Sequence analysis suggests that AvnR is a CheY-like response regulator and contains the RNA-binding ANTAR (AmiR and NasR transcription anti-termination regulators) domain. We show that AvnR plays a role in regulating biofilm formation (on glass and plastic surfaces), surface motility, adhesion to A549 cells as well as in nitrogen metabolism in A. baumannii. RNA-Seq analysis revealed that avnR deletion results in altered expression of more than 150 genes (116 upregulated and 42 downregulated). RNA-Seq data suggest that altered biofilm formation and surface motility observed in the avnR deletion mutant is likely mediated by previously unknown pathways. Of note, was the altered expression of genes predicted to be involved in amino acid transport and metabolism in avnR deletion mutant. Biolog phenotypic array showed that deletion of avnR hampered A. baumannii ATCC17978's ability to metabolize various nitrogen sources, particularly that of glutamic acid, serine, histidine, aspartic acid, isoleucine and arginine. Taken together our data show that AvnR, the first ANTAR protein described in A. baumannii, affects virulence phenotypes as well as its ability to metabolize nitrogen sources.
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Affiliation(s)
- P Malaka De Silva
- Department of Microbiology, University of Manitoba, Winnipeg, MB, Canada
| | - Rakesh Patidar
- Department of Microbiology, University of Manitoba, Winnipeg, MB, Canada
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8
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Yin L, Zhu W, Chen D, Zhou Y, Lin H. Small noncoding RNA sRNA0426 is involved in regulating biofilm formation in Streptococcus mutans. Microbiologyopen 2020; 9:e1096. [PMID: 32633012 PMCID: PMC7521000 DOI: 10.1002/mbo3.1096] [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: 02/24/2020] [Revised: 05/16/2020] [Accepted: 05/30/2020] [Indexed: 12/21/2022] Open
Abstract
Evidence suggests that small noncoding RNAs (sRNAs) are involved in the complex regulatory networks governing biofilm formation. Few studies have investigated the role of sRNAs in Streptococcus mutans (S. mutans). In the present study, the association between sRNA and biofilm formation in S. mutans was explored. sRNAs that are differentially expressed in the biofilm and planktonic states of this bacterium were identified by quantitative real‐time PCR (qRT‐PCR). Confocal laser scanning microscopy was used to investigate the characteristics of biofilm formation in a standard strain of S. mutans (UA159, ATCC 700610) and ten clinical strains. Bioinformatics analyses were employed to predict and examine potential sRNA regulatory pathways. The results showed that sRNA0426 has a strong positive relationship with dynamic biofilm formation. Moreover, sRNA0426 expression was positively correlated with exopolysaccharide (EPS) production. Bioinformatics analyses showed that sRNA0426 is involved in biofilm formation such as metabolic pathways, especially carbon metabolism. Five target mRNAs (GtfB, GtfC, GtfD, ComE, and CcpA) involved in the synthesis of EPS were selected for further evaluation; the expression levels of three of these mRNAs (GtfB, GtfC, and CcpA) were positively correlated with sRNA0426 expression levels, and the expression level of one (ComE) was negatively correlated. In conclusion, the results suggested that sRNA0426 may play an important and positive role in the biofilm formation of S. mutans and provide novel insight into the S. mutans biofilm regulatory network.
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Affiliation(s)
- Luoping Yin
- Guanghua School of Stomatology, Hospital of Stomatology, Sun Yat-Sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
| | - Wenhui Zhu
- Guanghua School of Stomatology, Hospital of Stomatology, Sun Yat-Sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
| | - Dongru Chen
- Guanghua School of Stomatology, Hospital of Stomatology, Sun Yat-Sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
| | - Yan Zhou
- Guanghua School of Stomatology, Hospital of Stomatology, Sun Yat-Sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
| | - Huancai Lin
- Guanghua School of Stomatology, Hospital of Stomatology, Sun Yat-Sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
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9
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Colquhoun JM, Rather PN. Insights Into Mechanisms of Biofilm Formation in Acinetobacter baumannii and Implications for Uropathogenesis. Front Cell Infect Microbiol 2020; 10:253. [PMID: 32547965 PMCID: PMC7273844 DOI: 10.3389/fcimb.2020.00253] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Accepted: 04/30/2020] [Indexed: 01/10/2023] Open
Abstract
Multidrug resistant Acinetobacter baumannii is a serious healthcare threat. In fact, the Center for Disease Control recently reported that carbapenem-resistant A. baumannii is responsible for more than 8,500 infections, 700 deaths, and $281 million in healthcare costs annually in the United States with few, if any, treatment options available, leading to its designation as a pathogen of urgent concern and a priority for novel antimicrobial development. It is hypothesized that biofilms are, at least in part, responsible for the high prevalence of A. baumannii nosocomial and recurrent infections because they frequently contaminate hospital surfaces and patient indwelling devices; therefore, there has been a recent push for mechanistic understanding of biofilm formation, maturation and dispersal. However, most research has focused on A. baumannii pneumonia and bloodstream infections, despite a recent retrospective study showing that 17.1% of A. baumannii isolates compiled from clinical studies over the last two decades were obtained from urinary samples. This highlights that A. baumannii is an underappreciated uropathogen. The following minireview will examine our current understanding of A. baumannii biofilm formation and how this influences urinary tract colonization and pathogenesis.
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Affiliation(s)
- Jennifer M Colquhoun
- Department of Microbiology and Immunology, Emory University, Atlanta, GA, United States
| | - Philip N Rather
- Department of Microbiology and Immunology, Emory University, Atlanta, GA, United States.,Research Service, Atlanta VA Healthcare System, Decatur, GA, United States
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10
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Allen JL, Tomlinson BR, Casella LG, Shaw LN. Regulatory networks important for survival of Acinetobacter baumannii within the host. Curr Opin Microbiol 2020; 55:74-80. [PMID: 32388085 DOI: 10.1016/j.mib.2020.03.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 02/28/2020] [Accepted: 03/02/2020] [Indexed: 12/25/2022]
Abstract
Acinetobacter baumannii is known for its intrinsic resistance to conventional antibiotic treatment and hypervirulence during infection. This coupled with its extraordinary capacity to survive in myriad harsh environments has led to increasing rates of infection in clinical settings. Numerous studies have characterized the virulence factors and resistance genes in A. baumannii responsible for the detrimental outcomes seen in patients; however, the role of regulatory factors in controlling the expression of these genes remains less well explored. Herein we discuss the latest and most influential findings on the regulatory network of A. baumannii, focusing on the transcription factors, two-component systems, and sRNAs. We place particular focus on those identified as being crucial for sensing and responding to continually changing environments, and influencing survival and virulence when engaging with the human host.
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Affiliation(s)
- Jessie L Allen
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, 4202 East Fowler Avenue, ISA 2015, Tampa, FL 33620-5150, USA
| | - Brooke R Tomlinson
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, 4202 East Fowler Avenue, ISA 2015, Tampa, FL 33620-5150, USA
| | - Leila G Casella
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, 4202 East Fowler Avenue, ISA 2015, Tampa, FL 33620-5150, USA
| | - Lindsey N Shaw
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, 4202 East Fowler Avenue, ISA 2015, Tampa, FL 33620-5150, USA.
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Cafiso V, Stracquadanio S, Lo Verde F, Dovere V, Zega A, Pigola G, Aranda J, Stefani S. COL R Acinetobacter baumannii sRNA Signatures: Computational Comparative Identification and Biological Targets. Front Microbiol 2020; 10:3075. [PMID: 32010115 PMCID: PMC6978653 DOI: 10.3389/fmicb.2019.03075] [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: 10/29/2019] [Accepted: 12/19/2019] [Indexed: 11/25/2022] Open
Abstract
Multidrug-Resistant (MDR) and Extensively Drug Resistant (XDR) Acinetobacter baumannii (Ab) represent a serious cause of healthcare-associated infections worldwide. Currently, the available treatment options are very restricted and colistin-based therapies are last-line treatments of these infections, even though colistin resistant (COLR) Ab have rarely been isolated yet. In bacteria, small non-coding RNAs (sRNAs) have been implicated in regulatory pathways of different biological functions, however, no knowledge exists about the sRNA role on the biological adaptation in COLRAb. Our study investigated two Italian XDR isogenic colistin-susceptible/resistant (COLS/R) Ab strain-pairs to discover new sRNA signatures. Comparative sRNA transcriptome (sRNAome) analyses were carried out by Illumina RNA-seq using both a Tru-Seq and a Short Insert library, whilst Ab ATCC 17978 and ACICU Reference Genome assembly, mapping, annotation and statistically significant differential expression (q-value ≤ 0.01) of the raw reads were performed by the Rockhopper tool. A computational filtering, sorting only similarly statistically significant differentially expressed (DE) sRNAs mapping on the same gene in both COLRAb isolates was conducted. COLR vs. COLS sRNAome, analyzed integrating the DE sRNAs obtained from the two different libraries, revealed some statistically significant DE sRNAs in COLRAb. In detail, we found: (i) two different under-expressed cis-acting sRNAs (AbsRNA1 and AbsRNA2) mapping in antisense orientation the 16S rRNA gene A1S_r01, (ii) one under-expressed cis-acting sRNA (AbsRNA3) targeting the A1S_2505 gene (hypothetical protein), (iii) one under-expressed microRNA-size small RNA fragment (AbsRNA4) and its pre-microAbsRNA4 targeting the A1S_0501 gene (hypothetical protein), (iv) as well as an over-expressed microRNA-size small RNA fragment (AbsRNA5) and its pre-microAbsRNA5 targeting the A1S_3097 gene (signal peptide). Custom TaqMan® probe-based real-time qPCRs validated the expression pattern of the selected sRNA candidates shown by RNA-seq. Furthermore, analysis on sRNA ΔA1S_r01, ΔA1S_2505 as well as the over-expressed A1S_3097 mutants revealed no effects on colistin resistance. Our study, for the first time, found the sRNAome signatures of clinical COLRAb with a computational prediction of their targets related to protein synthesis, host-microbe interaction and other different biological functions, including biofilm production, cell-cycle control, virulence, and antibiotic-resistance.
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Affiliation(s)
- Viviana Cafiso
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Stefano Stracquadanio
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Flavia Lo Verde
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Veronica Dovere
- Department of Translational Research and New Technology in Medicine and Surgery, Azienda Ospedaliero Universitaria Pisana, University of Pisa, Pisa, Italy
| | - Alessandra Zega
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Giuseppe Pigola
- Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Jesús Aranda
- Departament de Genètica i Microbiologia, Facultat de Biociènces, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Stefania Stefani
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
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12
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Eze EC, Chenia HY, El Zowalaty ME. Acinetobacter baumannii biofilms: effects of physicochemical factors, virulence, antibiotic resistance determinants, gene regulation, and future antimicrobial treatments. Infect Drug Resist 2018; 11:2277-2299. [PMID: 30532562 PMCID: PMC6245380 DOI: 10.2147/idr.s169894] [Citation(s) in RCA: 123] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Acinetobacter baumannii is a leading cause of nosocomial infections due to its increased antibiotic resistance and virulence. The ability of A. baumannii to form biofilms contributes to its survival in adverse environmental conditions including hospital environments and medical devices. A. baumannii has undoubtedly propelled the interest of biomedical researchers due to its broad range of associated infections especially in hospital intensive care units. The interplay among microbial physicochemistry, alterations in the phenotype and genotypic determinants, and the impact of existing ecological niche and the chemistry of antimicrobial agents has led to enhanced biofilm formation resulting in limited access of drugs to their specific targets. Understanding the triggers to biofilm formation is a step towards limiting and containing biofilm-associated infections and development of biofilm-specific countermeasures. The present review therefore focused on explaining the impact of environmental factors, antimicrobial resistance, gene alteration and regulation, and the prevailing microbial ecology in A. baumannii biofilm formation and gives insights into prospective anti-infective treatments.
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Affiliation(s)
- Emmanuel C Eze
- Virology and Microbiology Research Group, School of Health Sciences, College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa,
| | - Hafizah Y Chenia
- Discipline of Microbiology, School of Life Sciences, College of Agriculture, Engineering and Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Mohamed E El Zowalaty
- Virology and Microbiology Research Group, School of Health Sciences, College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa,
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