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Li R, Zhu X, Zhang P, Wu X, Jin Q, Pan J. Ser/Thr protein kinase Stk1 phosphorylates the key transcriptional regulator AlgR to modulate virulence and resistance in Pseudomonas aeruginosa. Virulence 2024; 15:2367649. [PMID: 38898809 PMCID: PMC11197903 DOI: 10.1080/21505594.2024.2367649] [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: 01/25/2024] [Accepted: 06/09/2024] [Indexed: 06/21/2024] Open
Abstract
Pseudomonas aeruginosa is one of the leading causes of nosocomial infections worldwide and has emerged as a serious public health threat, due in large part to its multiple virulence factors and remarkable resistance capabilities. Stk1, a eukaryotic-type Ser/Thr protein kinase, has been shown in our previous work to be involved in the regulation of several signalling pathways and biological processes. Here, we demonstrate that deletion of stk1 leads to alterations in several virulence- and resistance-related physiological functions, including reduced pyocyanin and pyoverdine production, attenuated twitching motility, and enhanced biofilm production, extracellular polysaccharide secretion, and antibiotic resistance. Moreover, we identified AlgR, an important transcriptional regulator, as a substrate for Stk1, with its phosphorylation at the Ser143 site catalysed by Stk1. Intriguingly, both the deletion of stk1 and the mutation of Ser143 of AlgR to Ala result in similar changes in the above-mentioned physiological functions. Furthermore, assays of algR expression in these strains suggest that changes in the phosphorylation state of AlgR, rather than its expression level, underlie changes in these physiological functions. These findings uncover Stk1-mediated phosphorylation of AlgR as an important mechanism for regulating virulence and resistance in P. aeruginosa.
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Affiliation(s)
- Rui Li
- Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Xuan Zhu
- Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Pengfei Zhang
- Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Xuan Wu
- Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Qian Jin
- Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Jianyi Pan
- Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
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Zhao C, Yan S, Luo Y, Song Y, Xia X. Analyzing resistome in soil and Human gut: a study on the characterization and risk evaluation of antimicrobial peptide resistance. Front Microbiol 2024; 15:1352531. [PMID: 38591036 PMCID: PMC10999558 DOI: 10.3389/fmicb.2024.1352531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 02/26/2024] [Indexed: 04/10/2024] Open
Abstract
Objective The limited existing knowledge regarding resistance to antimicrobial peptides (AMPs) is hindering their broad utilization. The aim of this study is to enhance the understanding of AMP resistance, a pivotal factor in the exploration of alternative drug development in response to the escalating challenge of antibiotic resistance. Methods We utilized metagenomic functional selection to analyze genes resistant to AMPs, with a specific focus on the microbiota in soil and the human gut. Through a combination of experimental methods and bioinformatics analyses, our investigation delved into the possibilities of the evolution of resistance to AMPs, as well as the transfer or interchange of resistance genes among the environment, the human body, and pathogens. Additionally, we examined the cross-resistance between AMPs and evaluated interactions among AMPs and conventional antibiotics. Results The presence of AMP resistance, including various resistance mechanisms, was observed in both soil and the human gut microbiota, as indicated by our findings. Significantly, the study underscored the facile evolution of AMP resistance and the potential for gene sharing or exchange among different environments. Notably, cross-resistance among AMPs was identified as a phenomenon, while cross-resistance between AMPs and antibiotics was found to be relatively infrequent. Conclusion The results of our study highlight the significance of taking a cautious stance when considering the extensive application of AMPs. It is imperative to thoroughly assess potential resistance risks, with a particular focus on the development of resistance to AMPs across diverse domains. A comprehensive grasp of these aspects is essential for making well-informed decisions and ensuring the responsible utilization of AMPs in the ongoing fight against antibiotic resistance.
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Affiliation(s)
| | | | | | - Yuzhu Song
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China
| | - Xueshan Xia
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China
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Ching C, Brychcy M, Nguyen B, Muller P, Pearson AR, Downs M, Regan S, Isley B, Fowle W, Chai Y, Godoy VG. RecA levels modulate biofilm development in Acinetobacter baumannii. Mol Microbiol 2024; 121:196-212. [PMID: 37918886 DOI: 10.1111/mmi.15188] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 10/06/2023] [Accepted: 10/17/2023] [Indexed: 11/04/2023]
Abstract
Infections caused by Acinetobacter baumannii, a Gram-negative opportunistic pathogen, are difficult to eradicate due to the bacterium's propensity to quickly gain antibiotic resistances and form biofilms, a protective bacterial multicellular community. The A. baumannii DNA damage response (DDR) mediates the antibiotic resistance acquisition and regulates RecA in an atypical fashion; both RecALow and RecAHigh cell types are formed in response to DNA damage. The findings of this study demonstrate that the levels of RecA can influence formation and dispersal of biofilms. RecA loss results in surface attachment and prominent biofilms, while elevated RecA leads to diminished attachment and dispersal. These findings suggest that the challenge to treat A. baumannii infections may be explained by the induction of the DDR, common during infection, as well as the delicate balance between maintaining biofilms in low RecA cells and promoting mutagenesis and dispersal in high RecA cells. This study underscores the importance of understanding the fundamental biology of bacteria to develop more effective treatments for infections.
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Affiliation(s)
- Carly Ching
- Department of Biology, Northeastern University, Boston, Massachusetts, USA
| | - Merlin Brychcy
- Department of Biology, Northeastern University, Boston, Massachusetts, USA
| | - Brian Nguyen
- Department of Biology, Northeastern University, Boston, Massachusetts, USA
| | - Paul Muller
- Department of Biology, Northeastern University, Boston, Massachusetts, USA
| | | | - Margaret Downs
- Department of Biology, Northeastern University, Boston, Massachusetts, USA
| | - Samuel Regan
- Department of Biology, Northeastern University, Boston, Massachusetts, USA
| | - Breanna Isley
- Department of Biology, Northeastern University, Boston, Massachusetts, USA
| | - William Fowle
- Department of Biology, Northeastern University, Boston, Massachusetts, USA
| | - Yunrong Chai
- Department of Biology, Northeastern University, Boston, Massachusetts, USA
| | - Veronica G Godoy
- Department of Biology, Northeastern University, Boston, Massachusetts, USA
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Tang H, Liu Z, Hu B, Zhu L. D-Ring Modifications of Tetracyclines Determine Their Ability to Induce Resistance Genes in the Environment. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:1338-1348. [PMID: 38157442 DOI: 10.1021/acs.est.3c07559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
The widespread utilization of tetracyclines (TCs) in agriculture and medicine has led to the borderless spread of tetracycline resistance in humans, animals, and the environment, posing huge risks to both the ecosystem and human society. Changes in the functional group modifications resulted in a higher bacteriostatic efficacy of the new generation of TCs, but their effect on the emergence and evolution of antibiotic resistance genes (ARGs) is not yet known. To this end, four TCs from three generations were chosen to compare their structural effects on influencing the evolution of ARGs in soil microbial communities. The findings revealed that low-generation TCs, such as tetracycline and oxytetracycline, exhibited a greater propensity to stimulate the production and proliferation of ARGs than did high-generation tigecycline. Molecular docking analysis demonstrated that modifications of the D-ring functional group determined the binding capacity of TCs to the substrate-binding pocket of transcriptional regulators and efflux pumps mainly involved in drug resistance. This can be further evidenced by reverse transcription-quantitative polymerase chain reaction quantification and intracellular antibiotic accumulation assessment. This study sheds light on the mechanism of the structural effect of antibiotic-induced ARG production from the perspective of compound-protein binding, therefore providing theoretical support for controlling the dissemination of antibiotic resistance.
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Affiliation(s)
- Huiming Tang
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
- Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Zhejiang University, Hangzhou 310058, China
| | - Zishu Liu
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Baolan Hu
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Lizhong Zhu
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
- Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Zhejiang University, Hangzhou 310058, China
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Cook D, Flannigan MD, Chariker JH, Hare JM. DNA damage response coregulator ddrR affects many cellular pathways and processes in Acinetobacter baumannii 17978. Front Cell Infect Microbiol 2024; 13:1324091. [PMID: 38274737 PMCID: PMC10808703 DOI: 10.3389/fcimb.2023.1324091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 12/20/2023] [Indexed: 01/27/2024] Open
Abstract
Introduction Acinetobacter baumannii strain 17978 is an opportunistic pathogen possessing a DNA damage response (DDR) in which multiple error-prone polymerase genes are co-repressed by a UmuD homolog, UmuDAb, and the small Acinetobacter-specific protein DdrR. Additionally, these regulators coactivate nine other genes. We identified the DNA damage-inducible transcriptome for wildtype, umuDAb, and recA strains, and later established the ddrR DDR transcriptome. However, the ATCC 17978 reference genome had several assembly errors and lacked the 44 kb virulence locus, AbaAL44, that is present in the strain 17978 UN. Methods For this project, we combined our earlier single-end read RNAseq data with the ddrR paired-end reads and aligned these data to the improved 17978 UN genome assembly that resembled our laboratory strain, 17978 JH. Results New DESeq2 analyses verified previous differentially expressed genes (DEGs) but also found 339 genes in 17978 JH that were not annotated or physically present in the older genome assembly. Sixty-three were differentially expressed after DNA damage, and 182 had differential basal expression when comparing umuDAb, ddrR, or recA strains to wildtype, with 94 genes' expression unchanged. This work identified and characterized the 55 gene DNA damage-repressible transcriptome, 98% of which required either umuDAb or ddrR for repression. Two-thirds of these DEGs required both regulators. We also identified 110 genes repressed only in the ddrR strain, ~50% of which were due to increased basal expression levels. Basal gene expression in the ddrR mutant was further dysregulated independent of the DDR. Over 800 genes were upregulated, and over 1200 genes were downregulated compared to wildtype expression. Half of A. baumannii's essential genes were upregulated in the ddrR strain, including cell division genes, and two-thirds of these were downregulated in the umuDAb strain. Discussion The ddrR mutant upregulated genes enriched in translation, RNA metabolism, protein metabolism, AA/FA/cell-structure synthesis, and transport, while downregulating genes enriched in quorum sensing, biofilm production, secretion systems, pilus production, cell adhesion, and aromatics and chlorine degradation. Our data underscore the need for accurate and appropriately matched genome assemblies and indicate that ddrR affects approximately 60% of the genome, rendering it a potential target for Acinetobacter baumannii infection treatment.
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Affiliation(s)
- Deborah Cook
- Department of Biology and Chemistry, Morehead State University, Morehead, KY, United States
| | - Mollee D. Flannigan
- Department of Biology and Chemistry, Morehead State University, Morehead, KY, United States
| | - Julia H. Chariker
- Kentucky IDeA Networks of Biomedical Research Excellence (KY INBRE) Bioinformatics Core, University of Louisville, Louisville, KY, United States
| | - Janelle M. Hare
- Department of Biology and Chemistry, Morehead State University, Morehead, KY, United States
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Du J, Dong Y, Zuo W, Deng Y, Zhu H, Yu Q, Li M. Mec1-Rad53 Signaling Regulates DNA Damage-Induced Autophagy and Pathogenicity in Candida albicans. J Fungi (Basel) 2023; 9:1181. [PMID: 38132782 PMCID: PMC10744610 DOI: 10.3390/jof9121181] [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: 11/09/2023] [Revised: 12/03/2023] [Accepted: 12/07/2023] [Indexed: 12/23/2023] Open
Abstract
DNA damage activates the DNA damage response and autophagy in C. albicans; however, the relationship between the DNA damage response and DNA damage-induced autophagy in C. albicans remains unclear. Mec1-Rad53 signaling is a critical pathway in the DNA damage response, but its role in DNA damage-induced autophagy and pathogenicity in C. albicans remains to be further explored. In this study, we compared the function of autophagy-related (Atg) proteins in DNA damage-induced autophagy and traditional macroautophagy and explored the role of Mec1-Rad53 signaling in regulating DNA damage-induced autophagy and pathogenicity. We found that core Atg proteins are required for these two types of autophagy, while the function of Atg17 is slightly different. Our results showed that Mec1-Rad53 signaling specifically regulates DNA damage-induced autophagy but has no effect on macroautophagy. The recruitment of Atg1 and Atg13 to phagophore assembly sites (PAS) was significantly inhibited in the mec1Δ/Δ and rad53Δ/Δ strains. The formation of autophagic bodies was obviously affected in the mec1Δ/Δ and rad53Δ/Δ strains. We found that DNA damage does not induce mitophagy and ER autophagy. We also identified two regulators of DNA damage-induced autophagy, Psp2 and Dcp2, which regulate DNA damage-induced autophagy by affecting the protein levels of Atg1, Atg13, Mec1, and Rad53. The deletion of Mec1 or Rad53 significantly reduces the ability of C. albicans to systematically infect mice and colonize the kidneys, and it makes C. albicans more susceptible to being killed by macrophages.
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Affiliation(s)
| | | | | | | | | | | | - Mingchun Li
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, 94 Weijin Road, Nankai District, Tianjin 300071, China; (J.D.); (Y.D.); (W.Z.); (Y.D.); (H.Z.); (Q.Y.)
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McGuffey JC, Jackson-Litteken CD, Di Venanzio G, Zimmer AA, Lewis JM, Distel JS, Kim KQ, Zaher HS, Alfonzo J, Scott NE, Feldman MF. The tRNA methyltransferase TrmB is critical for Acinetobacter baumannii stress responses and pulmonary infection. mBio 2023; 14:e0141623. [PMID: 37589464 PMCID: PMC10653896 DOI: 10.1128/mbio.01416-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 07/10/2023] [Indexed: 08/18/2023] Open
Abstract
IMPORTANCE As deficiencies in tRNA modifications have been linked to human diseases such as cancer and diabetes, much research has focused on the modifications' impacts on translational regulation in eukaryotes. However, the significance of tRNA modifications in bacterial physiology remains largely unexplored. In this paper, we demonstrate that the m7G tRNA methyltransferase TrmB is crucial for a top-priority pathogen, Acinetobacter baumannii, to respond to stressors encountered during infection, including oxidative stress, low pH, and iron deprivation. We show that loss of TrmB dramatically attenuates a murine pulmonary infection. Given the current efforts to use another tRNA methyltransferase, TrmD, as an antimicrobial therapeutic target, we propose that TrmB, and other tRNA methyltransferases, may also be viable options for drug development to combat multidrug-resistant A. baumannii.
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Affiliation(s)
- Jenna C. McGuffey
- Department of Molecular Microbiology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - Clay D. Jackson-Litteken
- Department of Molecular Microbiology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - Gisela Di Venanzio
- Department of Molecular Microbiology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - Aubree A. Zimmer
- Department of Microbiology and The Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
| | - Jessica M. Lewis
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - Jesus S. Distel
- Department of Molecular Microbiology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - Kyusik Q. Kim
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Hani S. Zaher
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Juan Alfonzo
- Department of Microbiology and The Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
| | - Nichollas E. Scott
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - Mario F. Feldman
- Department of Molecular Microbiology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
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Lariviere PJ, Ashraf AHMZ, Leonard SP, Miller LG, Moran NA, Barrick JE. Single-step genome engineering in the bee gut symbiont Snodgrassella alvi. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.19.558440. [PMID: 37786689 PMCID: PMC10541602 DOI: 10.1101/2023.09.19.558440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
Honey bees are economically relevant pollinators experiencing population declines due to a number of threats. As in humans, the health of bees is influenced by their microbiome. The bacterium Snodgrassella alvi is a key member of the bee gut microbiome and has a role in excluding pathogens. Despite this importance, there are not currently any easy-to-use methods for modifying the S. alvi chromosome to study its genetics. To solve this problem, we developed a one-step procedure that uses electroporation and homologous recombination, which we term SnODIFY (Snodgrassella-specific One-step gene Deletion or Insertion to alter FunctionalitY). We used SnODIFY to create seven single-gene knockout mutants and recovered mutants for all constructs tested. Nearly all transformants had the designed genome modifications, indicating that SnODIFY is highly accurate. Mutant phenotypes were validated through knockout of Type 4 pilus genes, which led to reduced biofilm formation. We also used SnODIFY to insert heterologous sequences into the genome by integrating fluorescent protein-coding genes. Finally, we confirmed that genome modification is dependent on S. alvi's endogenous RecA protein. Because it does not require expression of exogenous recombination machinery, SnODIFY is a straightforward, accurate, and lightweight method for genome editing in S. alvi. This workflow can be used to study the functions of S. alvi genes and to engineer this symbiont for applications including protection of honey bee health.
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Affiliation(s)
- Patrick J. Lariviere
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
- Department of Integrative Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - A. H. M. Zuberi Ashraf
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
| | - Sean P. Leonard
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
- Department of Integrative Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Laurel G. Miller
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
| | - Nancy A. Moran
- Department of Integrative Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Jeffrey E. Barrick
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
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Sun C, Yu Y, Hua X. Resistance mechanisms of tigecycline in Acinetobacter baumannii. Front Cell Infect Microbiol 2023; 13:1141490. [PMID: 37228666 PMCID: PMC10203620 DOI: 10.3389/fcimb.2023.1141490] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 04/14/2023] [Indexed: 05/27/2023] Open
Abstract
Acinetobacter baumannii is widely distributed in nature and in hospital settings and is a common pathogen causing various infectious diseases. Currently, the drug resistance rate of A. baumannii has been persistently high, showing a worryingly high resistance rate to various antibiotics commonly used in clinical practice, which greatly limits antibiotic treatment options. Tigecycline and polymyxins show rapid and effective bactericidal activity against CRAB, and they are both widely considered to be the last clinical line of defense against multidrug resistant A. baumannii. This review focuses with interest on the mechanisms of tigecycline resistance in A. baumannii. With the explosive increase in the incidence of tigecycline-resistant A. baumannii, controlling and treating such resistance events has been considered a global challenge. Accordingly, there is a need to systematically investigate the mechanisms of tigecycline resistance in A. baumannii. Currently, the resistance mechanism of A. baumannii to tigecycline is complex and not completely clear. This article reviews the proposed resistance mechanisms of A. baumannii to tigecycline, with a view to providing references for the rational clinical application of tigecycline and the development of new candidate antibiotics.
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Affiliation(s)
- Chunli Sun
- Zhejiang University-University of Edinburgh (ZJU-UoE) Institute, Zhejiang University, Haining, Zhejiang, China
| | - Yunsong Yu
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Xiaoting Hua
- Zhejiang University-University of Edinburgh (ZJU-UoE) Institute, Zhejiang University, Haining, Zhejiang, China
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
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Zeng L, Lin F, Ling B. Effect of traditional Chinese medicine monomers interfering with quorum-sensing on virulence factors of extensively drug-resistant Acinetobacter baumannii. Front Pharmacol 2023; 14:1135180. [PMID: 37063277 PMCID: PMC10097947 DOI: 10.3389/fphar.2023.1135180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Accepted: 03/20/2023] [Indexed: 04/03/2023] Open
Abstract
The antimicrobial resistance of Acinetobacter baumannii (A. baumannii) clinical isolates has emerged as a great threat to public health. Quorum sensing (QS) is one of the resistance mechanisms for drug-resistant A. baumannii. Interfering with QS is a promising strategy to combat infections caused by drug-resistant bacteria. This study explored the QS inhibition ability of thirty-four traditional Chinese medicine monomers (TCMMs) and assessed the effect of QS inhibitors (QSIs) on the virulence factors of twelve extensively drug-resistant A. baumannii (XDRAB) strains. Nine traditional Chinese medicine monomers, such as caffeic acid, cinnamic acid, and myricetin, were found to be able to inhibit the bacterial QS. Then, at 1/8 of the minimal inhibitory concentration, we found that these QSIs inhibited extensively drug-resistant A. baumannii adhesion and biofilm formation and downregulated the expression levels of virulence-associated genes (abaI, abaR, csuE, pgaA, and bap). In conclusion, nine traditional Chinese medicine monomers have QS inhibitory activity and may downregulate QS genes to interfere with the QS system, which could inhibit the expression of extensively drug-resistant A. baumannii virulence factors. These results suggest that traditional Chinese medicine monomers could develop as novel anti-virulence compounds to control extensively drug-resistant A. baumannii infections.
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Affiliation(s)
- Li Zeng
- School of Pharmacy, Chengdu Medical College, Chengdu, China
- Department of Pharmacy, The Third People’s Hospital of Yibin, Yibin, China
| | - Fei Lin
- Department of Pharmacy, The First Affiliated Hospital of Chengdu Medical College, Chengdu Medical College, Chengdu, China
| | - Baodong Ling
- School of Pharmacy, Chengdu Medical College, Chengdu, China
- *Correspondence: Baodong Ling,
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Al-Shamiri MM, Wang J, Zhang S, Li P, Odhiambo WO, Chen Y, Han B, Yang E, Xun M, Han L, Han S. Probiotic Lactobacillus Species and Their Biosurfactants Eliminate Acinetobacter baumannii Biofilm in Various Manners. Microbiol Spectr 2023; 11:e0461422. [PMID: 36920192 PMCID: PMC10100725 DOI: 10.1128/spectrum.04614-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 02/27/2023] [Indexed: 03/16/2023] Open
Abstract
Acinetobacter baumannii is a critical biofilm-forming pathogen that has presented great challenges in the clinic due to multidrug resistance. Thus, new methods of intervention are needed to control biofilm-associated infections. In this study, among three tested Lactobacillus species, Lactobacillus rhamnosus showed significant antimaturation and antiadherence effects against A. baumannii biofilm. Lactic acid (LA) and acetic acid (AA) were the most effective antibiofilm biosurfactants (BSs) produced by L. rhamnosus. This antibiofilm phenomenon produced by LA and AA was due to the strong bactericidal effect, which worked from very early time points, as determined by colony enumeration and confocal laser scanning microscope. The cell destruction of A. baumannii appeared in both the cell envelope and cytoplasm. A discontinuous cell envelope, the leakage of cell contents, and the increased extracellular activity of ATPase demonstrated the disruption of the cell membrane by LA and AA. These effects also demonstrated the occurrence of protein lysis. In addition, bacterial DNA interacted with and was damaged by LA and AA, resulting in significantly reduced expression of biofilm and DNA repair genes. The results highlight the possibility and importance of using probiotics in clinical prevention. Probiotics can be utilized as novel biocides to block and decrease biofilm formation and microbial contamination in medical equipment and during the treatment of infections. IMPORTANCE A. baumannii biofilm is a significant virulence factor that causes the biofilm colonization of invasive illnesses. Rising bacterial resistance to synthetic antimicrobials has prompted researchers to look at natural alternatives, such as probiotics and their derivatives. In this study, L. rhamnosus and its BSs (LA and AA) demonstrated remarkable antibiofilm and antimicrobial characteristics, with a significant inhibitory effect on A. baumannii. These effects were achieved by several mechanisms, including the disruption of the cell envelope membrane, protein lysis, reduced expression of biofilm-related genes, and destruction of bacterial DNA. The results provide support for the possibility of using probiotics and their derivatives in the clinical prevention and therapy of A. baumannii infections.
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Affiliation(s)
- Mona Mohamed Al-Shamiri
- Department of Microbiology and Immunology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, China
| | - Jingdan Wang
- School of Public Health, Xi’an Jiaotong University Health Science Center, Xi’an, China
| | - Sirui Zhang
- Department of Microbiology and Immunology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, China
| | - Pu Li
- School of Public Health, Xi’an Jiaotong University Health Science Center, Xi’an, China
| | - Woodvine Otieno Odhiambo
- Department of Microbiology and Immunology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, China
| | - Yanjiong Chen
- Department of Microbiology and Immunology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, China
| | - Bei Han
- School of Public Health, Xi’an Jiaotong University Health Science Center, Xi’an, China
| | - E. Yang
- Department of Microbiology and Immunology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, China
| | - Meng Xun
- Department of Microbiology and Immunology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, China
| | - Lei Han
- Department of Microbiology and Immunology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, China
| | - Shaoshan Han
- Department of Hepatobiliary Surgery, First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, China
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12
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Shadan A, Pathak A, Ma Y, Pathania R, Singh RP. Deciphering the virulence factors, regulation, and immune response to Acinetobacter baumannii infection. Front Cell Infect Microbiol 2023; 13:1053968. [PMID: 36968113 PMCID: PMC10038080 DOI: 10.3389/fcimb.2023.1053968] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 02/06/2023] [Indexed: 02/25/2023] Open
Abstract
Deciphering the virulence factors, regulation, and immune response to Acinetobacter baumannii infectionAcinetobacter baumannii is a gram-negative multidrug-resistant nosocomial pathogen and a major cause of hospital acquired infetions. Carbapenem resistant A. baumannii has been categorised as a Priority1 critial pathogen by the World Health Organisation. A. baumannii is responsible for infections in hospital settings, clinical sectors, ventilator-associated pneumonia, and bloodstream infections with a mortality rates up to 35%. With the development of advanced genome sequencing, molecular mechanisms of manipulating bacterial genomes, and animal infection studies, it has become more convenient to identify the factors that play a major role in A. baumannii infection and its persistence. In the present review, we have explored the mechanism of infection, virulence factors, and various other factors associated with the pathogenesis of this organism. Additionally, the role of the innate and adaptive immune response, and the current progress in the development of innovative strategies to combat this multidrug-resistant pathogen is also discussed.
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Affiliation(s)
- Afreen Shadan
- Department of Microbiology, Dr. Shyama Prasad Mukherjee University, Ranchi, Jharkhand, India
| | - Avik Pathak
- Department of Biosciences and Bioengineering, Indian Institute of Technology, Roorkee, India
| | - Ying Ma
- College of Resources and Environment, Southwest University, Chongqing, China
- *Correspondence: Ying Ma, ; Ranjana Pathania, ; Rajnish Prakash Singh,
| | - Ranjana Pathania
- Department of Biosciences and Bioengineering, Indian Institute of Technology, Roorkee, India
- *Correspondence: Ying Ma, ; Ranjana Pathania, ; Rajnish Prakash Singh,
| | - Rajnish Prakash Singh
- Department of Bioengineering and Biotechnology, Birla Institute of Technology, Ranchi, Jharkhand, India
- *Correspondence: Ying Ma, ; Ranjana Pathania, ; Rajnish Prakash Singh,
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13
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Mohamad F, Alzahrani RR, Alsaadi A, Alrfaei BM, Yassin AEB, Alkhulaifi MM, Halwani M. An Explorative Review on Advanced Approaches to Overcome Bacterial Resistance by Curbing Bacterial Biofilm Formation. Infect Drug Resist 2023; 16:19-49. [PMID: 36636380 PMCID: PMC9830422 DOI: 10.2147/idr.s380883] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 12/06/2022] [Indexed: 01/05/2023] Open
Abstract
The continuous emergence of multidrug-resistant pathogens evoked the development of innovative approaches targeting virulence factors unique to their pathogenic cascade. These approaches aimed to explore anti-virulence or anti-infective therapies. There are evident concerns regarding the bacterial ability to create a superstructure, the biofilm. Biofilm formation is a crucial virulence factor causing difficult-to-treat, localized, and systemic infections. The microenvironments of bacterial biofilm reduce the efficacy of antibiotics and evade the host's immunity. Producing a biofilm is not limited to a specific group of bacteria; however, Pseudomonas aeruginosa, Acinetobacter baumannii, and Staphylococcus aureus biofilms are exemplary models. This review discusses biofilm formation as a virulence factor and the link to antimicrobial resistance. In addition, it explores insights into innovative multi-targeted approaches and their physiological mechanisms to combat biofilms, including natural compounds, phages, antimicrobial photodynamic therapy (aPDT), CRISPR-Cas gene editing, and nano-mediated techniques.
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Affiliation(s)
- F Mohamad
- Infectious Diseases Research Department, King Abdullah International Medical Research Center, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
| | - Raghad R Alzahrani
- Nanomedicine Department, King Abdullah International Medical Research Center, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia,Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, 11451, Saudi Arabia
| | - Ahlam Alsaadi
- Infectious Diseases Research Department, King Abdullah International Medical Research Center, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
| | - Bahauddeen M Alrfaei
- Stem Cells and Regenerative Medicine, King Abdullah International Medical Research Center, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
| | - Alaa Eldeen B Yassin
- College of Pharmacy, King Saud bin Abdulaziz University for Health Sciences, King Abdullah International Medical Research Center, Riyadh, Saudi Arabia
| | - Manal M Alkhulaifi
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, 11451, Saudi Arabia,Manal M Alkhulaifi, P.O. Box 55670, Riyadh, 11544, Tel +966 (11) 805-1685, Email
| | - Majed Halwani
- Nanomedicine Department, King Abdullah International Medical Research Center, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia,Correspondence: Majed Halwani, P.O. Box 3660, Mail Code 1515 (KAIMRC), Riyadh, 11481, Tel +966 (11) 429-4433, Fax +966 (11) 429-4440, Email ;
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14
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Paudel L, Ghimire N, Han SR, Park H, Jung SH, Oh TJ. Complete genome of Nakamurella sp. PAMC28650: genomic insights into its environmental adaptation and biotechnological potential. Funct Integr Genomics 2022; 23:18. [PMID: 36564681 PMCID: PMC9789016 DOI: 10.1007/s10142-022-00937-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 11/21/2022] [Accepted: 11/21/2022] [Indexed: 12/24/2022]
Abstract
The mechanisms underlying the survival of bacteria in low temperature and high radiation are not yet fully understood. Nakamurella sp. PAMC28650 was isolated from a glacier of Rwenzori Mountain, Uganda, which species belonged to Nakamurella genus based on 16S rRNA phylogeny, ANI (average nucleotide identity), and BLAST Ring Image Generator (BRIG) analysis among Frankineae suborder. We conducted the whole genome sequencing and comparative genomics of Nakamurella sp. PAMC28650, to understand the genomic features pertaining to survival in cold environment, along with high UV (ultraviolet) radiation. This study highlights the role of polysaccharide in cold adaptation, mining of the UV protection-related secondary metabolites and other related to cold adaptation mechanism through different bioinformatics tools, and providing a brief overview of the genes present in DNA repair systems. Nakamurella sp. PAMC28650 contained glycogen and cellulose metabolism pathways, mycosporine-like amino acids and isorenieratene-synthesizing gene cluster, and a number of DNA repair systems. Also, the genome analysis showed osmoregulation-related genes and cold shock proteins. We infer these genomic features are linked to bacterial survival in cold and UV radiation.
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Affiliation(s)
- Lakshan Paudel
- Department of Life Science and Biochemical Engineering, Graduate School, Sun-Moon University, Asan, 31460, Korea
| | - Nisha Ghimire
- Department of Life Science and Biochemical Engineering, Graduate School, Sun-Moon University, Asan, 31460, Korea
| | - So-Ra Han
- Department of Life Science and Biochemical Engineering, Graduate School, Sun-Moon University, Asan, 31460, Korea
| | - Hyun Park
- Division of Biotechnology, College of Life Science and Biotechnology, Korea University, Seoul, 02841, Korea
| | - Sang-Hee Jung
- Department of Dental Hygiene, Gangneung Yeongdong University, Gangneung, 25521, Korea
| | - Tae-Jin Oh
- Department of Life Science and Biochemical Engineering, Graduate School, Sun-Moon University, Asan, 31460, Korea. .,Genome-Based Bio-IT Convergence Institute, Asan, 31460, Korea. .,Department of Pharmaceutical Engineering and Biotechnology, Sun-Moon University, Asan, 31460, Korea.
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15
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Tierney BT, Singh NK, Simpson AC, Hujer AM, Bonomo RA, Mason CE, Venkateswaran K. Multidrug-resistant Acinetobacter pittii is adapting to and exhibiting potential succession aboard the International Space Station. MICROBIOME 2022; 10:210. [PMID: 36503581 PMCID: PMC9743659 DOI: 10.1186/s40168-022-01358-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Accepted: 08/11/2022] [Indexed: 05/22/2023]
Abstract
BACKGROUND Monitoring the adaptation of microorganisms to the extreme environment of the International Space Station (ISS) is crucial to understanding microbial evolution and infection prevention. Acinetobacter pittii is an opportunistic nosocomial pathogen, primarily impacting immunocompromised patients, that was recently isolated from two missions aboard the ISS. RESULTS Here, we report how ISS-associated A. pittii (n = 20 genomes) has formed its own genetically and functionally discrete clade distinct from most Earth-bound isolates (n = 291 genomes). The antimicrobial susceptibility testing of ISS strains and two related clinical isolates demonstrated that ISS strains acquired more resistance, specifically with regard to expanded-spectrum cephalosporins, despite no prediction of increased resistance based on genomic analysis of resistance genes. By investigating 402 longitudinal environmental and host-associated ISS metagenomes, we observed that viable A. pittii is increasing in relative abundance and therefore potentially exhibiting succession, being identified in >2X more metagenomic samples in back-to-back missions. ISS strains additionally contain functions that enable them to survive in harsh environments, including the transcriptional regulator LexA. Via a genome-wide association study, we identified a high level of mutational burden in methionine sulfoxide reductase genes relative to the most closely related Earth strains. CONCLUSIONS Overall, these results indicated a step forward in understanding how microorganisms might evolve and alter their antibiotic resistance phenotype in extreme, resource-limited, human-built environments. Video Abstract.
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Affiliation(s)
- Braden T Tierney
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY, 10065, USA
| | - Nitin K Singh
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, 91109, USA
| | - Anna C Simpson
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, 91109, USA
| | - Andrea M Hujer
- Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
- Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH, 44106, USA
| | - Robert A Bonomo
- Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
- Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH, 44106, USA
- Departments of Biochemistry, Pharmacology, Molecular Biology and Microbiology, and Proteomics and Bioinformatics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
- CWRU-Cleveland VAMC Center for Antimicrobial Resistance and Epidemiology (Case VA CARES), Cleveland, OH, 44106, USA
| | - Christopher E Mason
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY, 10065, USA.
| | - Kasthuri Venkateswaran
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, 91109, USA.
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16
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Revitt‐Mills SA, Wright EK, Vereker M, O'Flaherty C, McPherson F, Dawson C, van Oijen AM, Robinson A. Defects in DNA double‐strand break repair resensitize antibiotic‐resistant
Escherichia coli
to multiple bactericidal antibiotics. Microbiologyopen 2022; 11:e1316. [PMCID: PMC9500592 DOI: 10.1002/mbo3.1316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 09/03/2022] [Accepted: 09/03/2022] [Indexed: 11/11/2022] Open
Affiliation(s)
- Sarah A. Revitt‐Mills
- School of Chemistry and Molecular Bioscience, Molecular Horizons Institute University of Wollongong Wollongong New South Wales Australia
- Illawarra Health and Medical Research Institute Wollongong New South Wales Australia
| | - Elizabeth K. Wright
- School of Chemistry and Molecular Bioscience, Molecular Horizons Institute University of Wollongong Wollongong New South Wales Australia
- Illawarra Health and Medical Research Institute Wollongong New South Wales Australia
| | - Madaline Vereker
- School of Chemistry and Molecular Bioscience, Molecular Horizons Institute University of Wollongong Wollongong New South Wales Australia
- Illawarra Health and Medical Research Institute Wollongong New South Wales Australia
| | - Callum O'Flaherty
- School of Chemistry and Molecular Bioscience, Molecular Horizons Institute University of Wollongong Wollongong New South Wales Australia
- Illawarra Health and Medical Research Institute Wollongong New South Wales Australia
| | - Fairley McPherson
- School of Chemistry and Molecular Bioscience, Molecular Horizons Institute University of Wollongong Wollongong New South Wales Australia
- Illawarra Health and Medical Research Institute Wollongong New South Wales Australia
| | - Catherine Dawson
- School of Chemistry and Molecular Bioscience, Molecular Horizons Institute University of Wollongong Wollongong New South Wales Australia
- Illawarra Health and Medical Research Institute Wollongong New South Wales Australia
| | - Antoine M. van Oijen
- School of Chemistry and Molecular Bioscience, Molecular Horizons Institute University of Wollongong Wollongong New South Wales Australia
- Illawarra Health and Medical Research Institute Wollongong New South Wales Australia
| | - Andrew Robinson
- School of Chemistry and Molecular Bioscience, Molecular Horizons Institute University of Wollongong Wollongong New South Wales Australia
- Illawarra Health and Medical Research Institute Wollongong New South Wales Australia
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17
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Wang J, Liu C, Sun H, Wang S, Liao X, Zhang L. Membrane disruption boosts iron overload and endogenous oxidative stress to inactivate Escherichia coli by nanoscale zero-valent iron. JOURNAL OF HAZARDOUS MATERIALS 2022; 435:128951. [PMID: 35472538 DOI: 10.1016/j.jhazmat.2022.128951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Revised: 04/07/2022] [Accepted: 04/15/2022] [Indexed: 06/14/2023]
Abstract
The inactivation of microorganisms by nanoscale zero-valent iron (nZVI) was extensively reported, but what happens inside the cells is rarely explored. Herein, we revealed that nZVI caused the drastic increase of intracellular iron concentrations, which subsequently catalyzed the Haber-Weiss reaction to produce high levels of endogenous reactive oxygen species (ROSs) and inactivated E. coli cells by oxidative damage of DNA, evidenced by the significantly higher inactivation efficiencies of E. coli mutant strains deficient in iron uptake regulation and DNA repair than the parental strain. The intracellular iron levels, endogenous ROSs levels and the inactivation efficiencies of E. coli were positively correlated. The permeabilized cytomembrane due to the close contact between nZVI and E. coli was responsible for the iron overload. This work demonstrates experimentally for the first time that nZVI causes iron overload and endogenous oxidative stress to inactivate E. coli, thus deepening our knowledge of the nZVI antimicrobial mechanism.
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Affiliation(s)
- Jian Wang
- Hubei Key Lab of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan 430079, PR China
| | - Congcong Liu
- Hubei Key Lab of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan 430079, PR China
| | - Hongwei Sun
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, PR China.
| | - Shaohui Wang
- Hubei Key Lab of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan 430079, PR China
| | - Xiaomei Liao
- Hubei Key Lab of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan 430079, PR China.
| | - Lizhi Zhang
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, PR China
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18
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Tiwari V. Pharmacophore screening, denovo designing, retrosynthetic analysis, and combinatorial synthesis of a novel lead VTRA1.1 against RecA protein of Acinetobacter baumannii. Chem Biol Drug Des 2022; 99:839-856. [PMID: 35278346 DOI: 10.1111/cbdd.14037] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 02/15/2022] [Accepted: 03/05/2022] [Indexed: 01/08/2023]
Abstract
Antibiotics and disinfectants resistance is acquired by activating RecA-mediated DNA repair, which maintains ROS-dependent DNA damage caused by the antimicrobial molecules. To increase the efficacy of different antimicrobials, an inhibitor can be developed against RecA protein. The present study aims to design a denovo inhibitor against RecA protein of Acinetobacter baumannii. Pharmacophore-based screening, molecular mechanics, molecular dynamics simulation (MDS), retrosynthetic analysis, and combinatorial synthesis were used to design lead VTRA1.1 against RecA of A. baumannii. Pharmacophore models (structure-based and ligand-based) were created, and a phase library of FDA-approved drugs was prepared. Screening of the phase library against these pharmacophore models selected thirteen lead molecules. These filtered leads were used for the denovo fragment-based design, which produced 253 combinations. These designed molecules were further analyzed for its interaction with active site of RecA that selected a hybrid VTRA1. Further, retrosynthetic analysis and combinatorial synthesis produced 1000 analogs of VTRA1 by more than 100 modifications. These analogs were used for XP docking, binding free energy calculation, and MDS analysis which finally select lead VTRA1.1 against RecA protein. Further, mutations at the interacting residues of RecA with VTRA1.1, alter the unfolding rate of RecA, which suggests the binding of VTRA1.1 to these residues may alter the stability of RecA. It is also found that VTRA1.1 had reduced interaction of RecA with LexA and ssDNA polydT, showing the lead's efficacy in controlling the SOS response. Further, it was also observed that VTRA1.1 does not contain any predicted human off-targets and no cytotoxicity to cell lines. As functional RecA is involved in antimicrobial resistance, denovo designed lead VTRA1.1 against RecA may be further developed as a significant combination for therapeutic uses against A. baumannii.
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Affiliation(s)
- Vishvanath Tiwari
- Department of Biochemistry, Central University of Rajasthan, Ajmer, India
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19
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Nogbou ND, Ramashia M, Nkawane GM, Allam M, Obi CL, Musyoki AM. Whole-Genome Sequencing of a Colistin-Resistant Acinetobacter baumannii Strain Isolated at a Tertiary Health Facility in Pretoria, South Africa. Antibiotics (Basel) 2022; 11:594. [PMID: 35625238 PMCID: PMC9138137 DOI: 10.3390/antibiotics11050594] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 04/19/2022] [Accepted: 04/20/2022] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Acinetobacter baumannii's (A. baumannii) growing resistance to all available antibiotics is of concern. The study describes a colistin-resistant A. baumannii isolated at a clinical facility from a tracheal aspirate sample. Furthermore, it determines the isolates' niche establishment ability within the tertiary health facility. METHODS An antimicrobial susceptibility test, conventional PCR, quantitative real-time PCR, phenotypic evaluation of the efflux pump, and whole-genome sequencing and analysis were performed on the isolate. RESULTS The antimicrobial susceptibility pattern revealed a resistance to piperacillin/tazobactam, ceftazidime, cefepime, cefotaxime/ceftriaxone, imipenem, meropenem, gentamycin, ciprofloxacin, trimethoprim/sulfamethoxazole, tigecycline, and colistin. A broth microdilution test confirmed the colistin resistance. Conventional PCR and quantitative real-time PCR investigations revealed the presence of adeB, adeR, and adeS, while mcr-1 was not detected. A MIC of 0.38 µg/mL and 0.25 µg/mL was recorded before and after exposure to an AdeABC efflux pump inhibitor. The whole-genome sequence analysis of antimicrobial resistance-associated genes detected beta-lactam: blaOXA-66; blaOXA-23; blaADC-25; blaADC-73; blaA1; blaA2, and blaMBL; aminoglycoside: aph(6)-Id; aph(3″)-Ib; ant(3″)-IIa and armA) and a colistin resistance-associated gene lpsB. The whole-genome sequence virulence analysis revealed a biofilm formation system and cell-cell adhesion-associated genes: bap, bfmR, bfmS, csuA, csuA/B, csuB, csuC, csuD, csuE, pgaA, pgaB, pgaC, and pgaD; and quorum sensing-associated genes: abaI and abaR and iron acquisition system associated genes: barA, barB, basA, basB, basC, basD, basF, basG, basH, basI, basJ, bauA, bauB, bauC, bauD, bauE, bauF, and entE. A sequence type classification based on the Pasteur scheme revealed that the isolate belongs to sequence type ST2. CONCLUSIONS The mosaic of the virulence factors coupled with the resistance-associated genes and the phenotypic resistance profile highlights the risk that this strain is at this South African tertiary health facility.
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Affiliation(s)
- Noel-David Nogbou
- Microbiological Pathology Department, School of Medicine, Sefako Makgatho Health Sciences University, Pretoria 0204, South Africa; (N.-D.N.); (M.R.); (G.M.N.)
| | - Mbudzeni Ramashia
- Microbiological Pathology Department, School of Medicine, Sefako Makgatho Health Sciences University, Pretoria 0204, South Africa; (N.-D.N.); (M.R.); (G.M.N.)
| | - Granny Marumo Nkawane
- Microbiological Pathology Department, School of Medicine, Sefako Makgatho Health Sciences University, Pretoria 0204, South Africa; (N.-D.N.); (M.R.); (G.M.N.)
| | - Mushal Allam
- Department of Genetics and Genomics, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain 15551, United Arab Emirates;
| | - Chikwelu Lawrence Obi
- School of Sciences and Technology, Sefako Makgatho Health Sciences University, Pretoria 0204, South Africa;
| | - Andrew Munyalo Musyoki
- Microbiological Pathology Department, School of Medicine, Sefako Makgatho Health Sciences University, Pretoria 0204, South Africa; (N.-D.N.); (M.R.); (G.M.N.)
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20
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Bacterial hydrophilins promote pathogen desiccation tolerance. Cell Host Microbe 2022; 30:975-987.e7. [PMID: 35413266 DOI: 10.1016/j.chom.2022.03.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 02/14/2022] [Accepted: 03/17/2022] [Indexed: 11/21/2022]
Abstract
Acinetobacter baumannii is a leading cause of hospital-acquired infections, where outbreaks are driven by its ability to persist on surfaces in a desiccated state. Here, we show that A. baumannii causes more virulent pneumonia following desiccation and profile the genetic requirements for desiccation. We find that desiccation tolerance is enhanced upon the disruption of Lon protease, which targets unfolded and aggregated proteins for degradation. Notably, two bacterial hydrophilins, DtpA and DtpB, are transcriptionally upregulated in Δlon via the two-component regulator, BfmR. These proteins, both hydrophilic and intrinsically disordered, promote desiccation tolerance in A. baumannii. Additionally, recombinant DtpA protects purified enzymes from inactivation and improves the desiccation tolerance of a probiotic bacterium when heterologously expressed. These results demonstrate a connection between environmental persistence and pathogenicity in A. baumannii, provide insight into the mechanisms of extreme desiccation tolerance, and reveal potential applications for bacterial hydrophilins in the preservation of protein- and live bacteria-based pharmaceuticals.
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21
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CsrA-Controlled Proteins Reveal New Dimensions of Acinetobacter baumannii Desiccation Tolerance. J Bacteriol 2022; 204:e0047921. [PMID: 35285725 DOI: 10.1128/jb.00479-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Hospital environments are excellent reservoirs for the opportunistic pathogen Acinetobacter baumannii in part because it is exceptionally tolerant to desiccation. We found that relative to other A. baumannii strains, the virulent strain AB5075 was strikingly desiccation resistant at 2% relative humidity (RH), suggesting that it is a good model for studies of the functional basis of this trait. Consistent with results from other A. baumannii strains at 40% RH, we found the global posttranscriptional regulator CsrA to be critically important for desiccation tolerance of AB5075 at 2% RH. Proteomics experiments identified proteins that were differentially present in wild-type and csrA mutant cells. Subsequent analysis of mutants in genes encoding some of these proteins revealed six genes that were required for wild-type levels of desiccation tolerance. These include genes for catalase, a universal stress protein, a hypothetical protein, and a biofilm-associated protein. Two genes of unknown function had very strong desiccation phenotypes, with one of the two genes predicting an intrinsically disordered protein (IDP) that binds to DNA. Intrinsically disordered proteins are widespread in eukaryotes but less so in prokaryotes. Our results suggest there are new mechanisms underlying desiccation tolerance in bacteria and identify several key functions involved. IMPORTANCE Acinetobacter baumannii is found in terrestrial environments but can cause nosocomial infections in very sick patients. A factor that contributes to the prevalence of A. baumannii in hospital settings is that it is intrinsically resistant to dry conditions. Here, we established the virulent strain A. baumannii AB5075 as a model for studies of desiccation tolerance at very low relative humidity. Our results show that this trait depends on two proteins of unknown function, one of which is predicted to be an intrinsically disordered protein. This category of protein is critical for the small animals named tardigrades to survive desiccation. Our results suggest that A. baumannii may have novel strategies to survive desiccation that have not previously been seen in bacteria.
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22
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The small DdrR protein directly interacts with the UmuDAb regulator of the mutagenic DNA damage response in Acinetobacter baumannii. J Bacteriol 2022; 204:e0060121. [PMID: 35191762 DOI: 10.1128/jb.00601-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Acinetobacter baumannii poses a great threat in healthcare settings worldwide with clinical isolates displaying an ever-evolving multidrug-resistance. In strains of A. baumannii, expression of multiple error-prone polymerase genes is co-repressed by UmuDAb, a member of the LexA superfamily, and a small protein, DdrR. It is currently unknown how DdrR establishes this repression. Here, we use surface plasmon resonance spectrometry to show that DdrR forms a stable complex with the UmuDAb regulator. Our results indicate that the carboxy-terminal dimerization domain of UmuDAb forms the interaction interface with DdrR. Our in vitro data also show that RecA-mediated inactivation of UmuDAb is inhibited when this transcription factor is bound to its target DNA. In addition, we show that DdrR interacts with a putative prophage repressor, homologous to LexA superfamily proteins. These data suggest that DdrR modulates DNA damage response and prophage induction in A. baumannii by binding to LexA-like regulators. Importance We previously identified a 50-residue bacteriophage protein, gp7, which interacts with and modulates the function of the LexA transcription factor from Bacillus thuringiensis. Here we present data that indicates that the small DdrR protein from A. baumannii likely coordinates the SOS response and prophage processes by also interacting with LexA superfamily members. We suggest that similar small proteins that interact with LexA-like proteins to coordinate DNA repair and bacteriophage functions may be common to many bacteria that mount the SOS response.
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23
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Zhu J, Jiang X, Guan D, Kang Y, Li L, Cao F, Zhao B, Ma M, Zhao J, Li J. Effects of rehydration on physiological and transcriptional responses of a water-stressed rhizobium. J Microbiol 2022; 60:31-46. [PMID: 34826097 DOI: 10.1007/s12275-022-1325-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 09/23/2021] [Accepted: 09/29/2021] [Indexed: 01/02/2023]
Abstract
As a microsymbiont of soybean, Bradyrhizobium japonicum plays an important role in symbiotic nitrogen fixation and sustainable agriculture. However, the survival of B. japonicum cells under water-deplete (e.g., drought) and water-replete (e.g., flood) conditions is a major concern affecting their nitrogen-fixing ability by establishing the symbiotic relationship with the host. In this study, we isolated a water stress tolerant rhizobium from soybean root nodules and tested its survival under water-deplete conditions. The rhizobium was identified as Bradyrhizobium japonicum and named strain 5038. Interestingly, both plate counting and live/dead fluorescence staining assays indicate that a number of viable but non-culturable cells exist in the culture medium upon the rehydration process which could cause dilution stress. Bradyrhizobium japonicum 5038 cells increased production of exopolysaccharide (EPS) and trehalose when dehydrated, suggesting that protective responses were stimulated. As expected, cells reduced their production upon the subsequent rehydration. To examine differential gene expression of B. japonicum 5038 when exposed to water-deplete and subsequent water-replete conditions, whole-genome transcriptional analysis was performed under 10% relative humidity (RH), and subsequent 100% RH, respectively. A total of 462 differentially expressed genes (DEGs, > 2.0-fold) were identified under the 10% RH condition, while 3,776 genes showed differential expression during the subsequent rehydration (100% RH) process. Genes involved in signal transduction, inorganic ion transport, energy production and metabolisms of carbohydrates, amino acids, and lipids were far more up-regulated than down-regulated in the 10% RH condition. Notably, trehalose biosynthetic genes (otsAB, treS, and treYZ), genes ligD, oprB, and a sigma factor rpoH were significantly induced by 10% RH. Under the subsequent 100% RH condition, genes involved in transcription, translation, cell membrane regulation, replication and repair, and protein processing were highly up-regulated. Interestingly, most of 10%-RH inducible genes displayed rehydration-repressed, except three genes encoding heat shock (Hsp20) proteins. Therefore, this study provides molecular evidence for the switch of gene expression of B. japonicum cells when encountered the opposite water availability from water-deplete to water-replete conditions.
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Affiliation(s)
- Jie Zhu
- Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, 100081, P. R. China
- School of Ecology and Environment, Inner Mongolia University, Hohhot, 010021, P. R. China
| | - Xin Jiang
- Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, 100081, P. R. China.
- Laboratory of Quality & Safety Risk Assessment for Microbial Products (Beijing), Ministry of Agriculture, Beijing, 100081, P. R. China.
| | - Dawei Guan
- Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, 100081, P. R. China
| | - Yaowei Kang
- Life Sciences College of Zhaoqing University, Zhaoqing, 526061, P. R. China
| | - Li Li
- Laboratory of Quality & Safety Risk Assessment for Microbial Products (Beijing), Ministry of Agriculture, Beijing, 100081, P. R. China
| | - Fengming Cao
- Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, 100081, P. R. China
- Laboratory of Quality & Safety Risk Assessment for Microbial Products (Beijing), Ministry of Agriculture, Beijing, 100081, P. R. China
| | - Baisuo Zhao
- Laboratory of Quality & Safety Risk Assessment for Microbial Products (Beijing), Ministry of Agriculture, Beijing, 100081, P. R. China
| | - Mingchao Ma
- Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, 100081, P. R. China
- Laboratory of Quality & Safety Risk Assessment for Microbial Products (Beijing), Ministry of Agriculture, Beijing, 100081, P. R. China
| | - Ji Zhao
- School of Ecology and Environment, Inner Mongolia University, Hohhot, 010021, P. R. China
| | - Jun Li
- Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, 100081, P. R. China.
- Laboratory of Quality & Safety Risk Assessment for Microbial Products (Beijing), Ministry of Agriculture, Beijing, 100081, P. R. China.
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Pourhajibagher M, Talaei N, Bahador A. Evaluation of antimicrobial effects of photo-sonodynamic antimicrobial chemotherapy based on nano-micelle curcumin on virulence gene expression patterns in Acinetobacter baumannii. Infect Disord Drug Targets 2021; 22:e201221199163. [PMID: 34931970 DOI: 10.2174/1871526522666211220121725] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 06/30/2021] [Accepted: 09/16/2021] [Indexed: 11/22/2022]
Abstract
BACKGROUND Abaumannii baumannii rapidly resistance to a wide range of antimicrobial agents. The combination of antimicrobial photodynamic therapy (aPDT) and sonodynamic antimicrobial chemotherapy (SACT) known as photo-sonodynamic antimicrobial chemotherapy (PSACT) has received considerable attention as one of the emerging and promising strategies against microbial infections. OBJECTIVE This study aimed to investigate the antimicrobial effects of PSACT based on nano-micelle curcumin (N-MCur) on the virulence gene expression patterns in A. baumannii. MATERIALS AND METHODS N-MCur as a photo-sonosensitizer was synthesized and confirmed. To determine sub-significant reduction dose of PSACT, sub-significant reduction dose of N-MCur and blue laser light during aPDT, and ultrasound power output during SACT were assessed. Finally, changes in the expression of genes involved in treated A. baumannii by minimum sub-significant reduction dose of PSACT were determined using quantitative real-time-PCR (qRT-PCR). RESULTS PSACT using 12.5 mM N-MCur at the ultrasound power outputs of 28.7, 36.9, and 45.2 mW/cm2 with 4 min irradiation time of blue laser, as well as, 6.2 mM N-MCur at an ultrasound power output of 45.2 mW/cm2 plus 3 min blue laser irradiation time exhibited the significant dose-dependent reduction against A. baumannii cell viability compared to the control group (P<0.05). After treatment of A. baumannii using 3.1 mM N-MCur + 2 min blue laser irradiation time + 28.7 mW/cm2 ultrasound as the minimum sub-significant reduction doses of PSACT, mRNA expression was significantly upregulated to 6.0-, 11.2-, and 13.7-folds in recA, blsA, and dnaK and downregulated to 8.6-, 10.1-, and 14.5-folds in csuE, espA, and abaI, respectively. CONCLUSIONS N-MCur-mediated PSACT could regulate the expression of genes involved in A. baumannii pathogenesis. Therefore, PSACT can be proposed as a promising application to treat infections caused by A. baumannii.
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Affiliation(s)
- Maryam Pourhajibagher
- Dental Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Narjes Talaei
- Department of Microbiology, North Tehran Branch, Islamic Azad University, Tehran, Iran
| | - Abbas Bahador
- Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
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25
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Acinetobacter baumannii regulates its stress responses via the BfmRS two-component regulatory system. J Bacteriol 2021; 204:e0049421. [PMID: 34871031 DOI: 10.1128/jb.00494-21] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Acinetobacter baumannii is a common nosocomial pathogen that utilizes numerous mechanisms to aid its survival in both the environment and in the host. Coordination of such mechanisms requires an intricate regulatory network. We report here that A. baumannii can directly regulate several stress-related pathways via the two-component regulatory system, BfmRS. Similar to previous studies, results from transcriptomic analysis showed that mutation of the BfmR response regulator causes dysregulation of genes required for the oxidative stress response, the osmotic stress response, the misfolded protein/heat shock response, Csu pili/fimbriae production, and capsular polysaccharide biosynthesis. We also found that the BfmRS system is involved in controlling siderophore biosynthesis and transport, and type IV pili production. We provide evidence that BfmR binds to various stress-related promoter regions and show that BfmR alone can directly activate transcription of some stress-related genes. Additionally, we show that the BfmS sensor kinase acts as a BfmR phosphatase to negatively regulate BfmR activity. This work highlights the importance of the BfmRS system in promoting survival of A. baumannii. Importance Acinetobacter baumannii is a nosocomial pathogen that has extremely high rates of multidrug resistance. This organism's ability to endure stressful conditions is a key part of its ability to spread in the hospital environment and cause infections. Unlike other members of the γ-proteobacteria, A. baumannii does not encode a homolog of the RpoS sigma factor to coordinate its stress response. Here, we demonstrate that the BfmRS two-component system directly controls the expression of multiple stress resistance genes. Our findings suggest that BfmRS is central to a unique scheme of general stress response regulation by A. baumannii.
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Acinetobacter baumannii: An Ancient Commensal with Weapons of a Pathogen. Pathogens 2021; 10:pathogens10040387. [PMID: 33804894 PMCID: PMC8063835 DOI: 10.3390/pathogens10040387] [Citation(s) in RCA: 85] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 03/19/2021] [Accepted: 03/23/2021] [Indexed: 12/22/2022] Open
Abstract
Acinetobacter baumannii is regarded as a life-threatening pathogen associated with community-acquired and nosocomial infections, mainly pneumonia. The rise in the number of A. baumannii antibiotic-resistant strains reduces effective therapies and increases mortality. Bacterial comparative genomic studies have unraveled the innate and acquired virulence factors of A. baumannii. These virulence factors are involved in antibiotic resistance, environmental persistence, host-pathogen interactions, and immune evasion. Studies on host–pathogen interactions revealed that A. baumannii evolved different mechanisms to adhere to in order to invade host respiratory cells as well as evade the host immune system. In this review, we discuss current data on A. baumannii genetic features and virulence factors. An emphasis is given to the players in host–pathogen interaction in the respiratory tract. In addition, we report recent investigations into host defense systems using in vitro and in vivo models, providing new insights into the innate immune response to A. baumannii infections. Increasing our knowledge of A. baumannii pathogenesis may help the development of novel therapeutic strategies based on anti-adhesive, anti-virulence, and anti-cell to cell signaling pathways drugs.
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27
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Huang M, Liu M, Liu J, Zhu D, Tang Q, Jia R, Chen S, Zhao X, Yang Q, Wu Y, Zhang S, Huang J, Ou X, Mao S, Gao Q, Sun D, Wang M, Cheng A. Functional characterization of Fur in iron metabolism, oxidative stress resistance and virulence of Riemerella anatipestifer. Vet Res 2021; 52:48. [PMID: 33741064 PMCID: PMC7976709 DOI: 10.1186/s13567-021-00919-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 03/01/2021] [Indexed: 12/11/2022] Open
Abstract
Iron is essential for most bacteria to survive, but excessive iron leads to damage by the Fenton reaction. Therefore, the concentration of intracellular free iron must be strictly controlled in bacteria. Riemerella anatipestifer (R. anatipestifer), a Gram-negative bacterium, encodes the iron uptake system. However, the iron homeostasis mechanism remains largely unknown. In this study, it was shown that compared with the wild type R. anatipestifer CH-1, R. anatipestifer CH-1Δfur was more sensitive to streptonigrin, and this effect was alleviated when the bacteria were cultured in iron-depleted medium, suggesting that the fur mutant led to excess iron accumulation inside cells. Similarly, compared with R. anatipestifer CH-1∆recA, R. anatipestifer CH-1∆recAΔfur was more sensitive to H2O2-induced oxidative stress when the bacteria were grown in iron-rich medium rather than iron-depleted medium. Accordingly, it was shown that R. anatipestifer CH-1∆recAΔfur produced more intracellular ROS than R. anatipestifer CH-1∆recA in iron-rich medium. Electrophoretic mobility shift assays showed that R. anatipestifer CH-1 Fur suppressed the transcription of putative iron uptake genes through binding to their promoter regions. Finally, it was shown that compared with the wild type, R. anatipestifer CH-1Δfur was significantly attenuated in ducklings and that the colonization ability of R. anatipestifer CH-1Δfur in various tissues or organs was decreased. All these results suggested that Fur is important for iron homeostasis in R. anatipestifer and its pathogenic mechanism.
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Affiliation(s)
- Mi Huang
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.,Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, 611130, Sichuan, China
| | - Mafeng Liu
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.,Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, 611130, Sichuan, China
| | - Jiajun Liu
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.,Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, 611130, Sichuan, China
| | - Dekang Zhu
- Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, 611130, Sichuan, China
| | - Qianying Tang
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.,Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, 611130, Sichuan, China
| | - Renyong Jia
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.,Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, 611130, Sichuan, China
| | - Shun Chen
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.,Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, 611130, Sichuan, China
| | - Xinxin Zhao
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.,Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, 611130, Sichuan, China
| | - Qiao Yang
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.,Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, 611130, Sichuan, China
| | - Ying Wu
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.,Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, 611130, Sichuan, China
| | - Shaqiu Zhang
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.,Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, 611130, Sichuan, China
| | - Juan Huang
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.,Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, 611130, Sichuan, China
| | - Xumin Ou
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.,Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, 611130, Sichuan, China
| | - Sai Mao
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.,Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, 611130, Sichuan, China
| | - Qun Gao
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.,Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, 611130, Sichuan, China
| | - Di Sun
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.,Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, 611130, Sichuan, China
| | - Mingshu Wang
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, 611130, Sichuan, China. .,Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, 611130, Sichuan, China. .,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, 611130, Sichuan, China.
| | - Anchun Cheng
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, 611130, Sichuan, China. .,Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, 611130, Sichuan, China. .,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, 611130, Sichuan, China.
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28
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Maliszewska I, Goldeman W. Pentamidine enhances photosensitization of Acinetobacter baumannii using diode lasers with emission of light at wavelength of ʎ = 405 nm and ʎ = 635 nm. Photodiagnosis Photodyn Ther 2021; 34:102242. [PMID: 33662618 DOI: 10.1016/j.pdpdt.2021.102242] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 01/22/2021] [Accepted: 02/26/2021] [Indexed: 12/01/2022]
Abstract
Antimicrobial photodynamic inactivation is currently one of the most promising trends in the modern bactericidal protocols. Under the conditions defined in our studies, we found that in vitro photosensitization of A. baumannii with 5-ALA as a precursor of protoporphyrin IX (photosensitizer) reduces the concentration of viable cells in planktonic cultures, and this process can be strongly enhanced by pentamidine. Diode lasers with the peak-power wavelength of ʎ = 405 nm (radiation intensity of 26 mW cm-2) and ʎ = 635 nm (radiation intensity of 55 mW cm-2) were used in this study. It was found that a blue laser light (energy fluence of 64 J cm-2; no external photosensitizer) in the presence of pentamidine resulted in a reduction of CFU of 99.992 % compared to 99.97 % killing without pentamidine. When a red laser light was used in the experiments (energy fluence of 136 J cm-2; no external photosensitizer), the mortality rate was 99.98 % in the presence of pentamidine compared to 99.93 % of those killed without the addition of this drug. The lethal effect with 5-ALA was achieved under blue light fluence of 16 J cm-2 (in the presence of pentamidine) and 32 J cm-2 (without pentamidine). In the case of laser light of 635 nm, the lethal effect with 5-ALA was attained with energy fluence of 51 J cm-2 (with pentamidine) and 102 J cm-2 (without pentamidine). The possible roles of pentamidine in enhancing photodynamic inactivation of A. baumannii have been discussed.
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Affiliation(s)
- Irena Maliszewska
- Department of Organic and Medicinal Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370, Wrocław, Poland.
| | - Waldemar Goldeman
- Department of Organic and Medicinal Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370, Wrocław, Poland
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29
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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: 53] [Impact Index Per Article: 17.7] [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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30
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Corral J, Pérez-Varela M, Barbé J, Aranda J. Direct interaction between RecA and a CheW-like protein is required for surface-associated motility, chemotaxis and the full virulence of Acinetobacter baumannii strain ATCC 17978. Virulence 2021; 11:315-326. [PMID: 32255384 PMCID: PMC7161683 DOI: 10.1080/21505594.2020.1748923] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Acinetobacter baumannii is a nosocomial pathogen that causes multi-drug resistant infections mainly in immunocompromised patients. Although this gram-negative species lacks flagella, it is able to move over wet surfaces through a not well characterized type of movement known as surface-associated motility. In this study we demonstrate through the inactivation of the A1S_2813 gene (coding a CheW-like protein) and recA (coding a DNA damage repair and recombination protein) that both genes are involved in the surface-associated motility and chemotaxis of A. baumannii ATCC 17978 strain. In addition, we also point out that the lack of either RecA or CheW-like proteins reduces its virulence in the Caenorhabditis elegans and the Galleria mellonella animal models. Furthermore, we show through co-immunoprecipitation assays that the CheW-like protein and RecA interact and that this interaction is abolished by the introduction of the mutation S97A in one of the domains of CheW-like protein that is structurally conserved in Salmonella enterica and necessary for the RecA-CheW interaction in this bacterial species. Finally, we show that the replacement of the wild-type CheW-like protein by that presenting the S97A mutation impairs surface-associated motility, chemotaxis and virulence of A. baumannii strain ATCC 17978.
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Affiliation(s)
- Jordi Corral
- Departament de Genètica i Microbiologia, Facultat de Biociènces, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - María Pérez-Varela
- Departament de Genètica i Microbiologia, Facultat de Biociènces, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Jordi Barbé
- Departament de Genètica i Microbiologia, Facultat de Biociènces, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Jesús Aranda
- Departament de Genètica i Microbiologia, Facultat de Biociènces, Universitat Autònoma de Barcelona, Bellaterra, Spain
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31
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Akkaya Ö, Aparicio T, Pérez-Pantoja D, de Lorenzo V. The faulty SOS response of Pseudomonas putida KT2440 stems from an inefficient RecA-LexA interplay. Environ Microbiol 2021; 23:1608-1619. [PMID: 33393180 DOI: 10.1111/1462-2920.15384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Revised: 12/28/2020] [Accepted: 12/29/2020] [Indexed: 11/29/2022]
Abstract
Despite its environmental robustness Pseudomonas putida strain KT2440 is very sensitive to DNA damage and displays poor homologous recombination efficiencies. To gain an insight into this deficiency isogenic ∆recA and ∆lexA1 derivatives of prophage-free strain P. putida EM173 were generated and responses of the recA and lexA1 promoters to DNA damage tested with GFP reporter technology. Basal expression of recA and lexA1 of P. putida were high in the absence of DNA damage and only moderately induced by norfloxacin. A similar behaviour was observed when equivalent GFP fusions to the recA and lexA promoters of E. coli were placed in P. putida EM173. In contrast, all SOS promoters were subject to strong repression in E. coli, which was released only when cells were treated with the antibiotic. Replacement of P. putida's native LexA1 and RecA by E. coli homologues did not improve the responsiveness of the indigenous functions to DNA damage. Taken together, it seems that P. putida fails to mount a strong SOS response due to the inefficacy of the crucial RecA-LexA interplay largely tractable to the weakness of the corresponding promoters and the inability of the repressor to shut them down entirely in the absence of DNA damage.
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Affiliation(s)
- Özlem Akkaya
- Systems Biology Program, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, Madrid, 28049, Spain.,Department of Molecular Biology and Genetics, Gebze Technical University, Kocaeli, Turkey
| | - Tomás Aparicio
- Systems Biology Program, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, Madrid, 28049, Spain
| | - Danilo Pérez-Pantoja
- Programa Institucional de Fomento a la Investigación, Desarrollo e Innovación (PIDi), Universidad Tecnológica Metropolitana, Santiago, Chile
| | - Víctor de Lorenzo
- Systems Biology Program, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, Madrid, 28049, Spain
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32
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Recent Advances in the Pursuit of an Effective Acinetobacter baumannii Vaccine. Pathogens 2020; 9:pathogens9121066. [PMID: 33352688 PMCID: PMC7766458 DOI: 10.3390/pathogens9121066] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 12/15/2020] [Accepted: 12/17/2020] [Indexed: 12/22/2022] Open
Abstract
Acinetobacter baumannii has been a major cause of nosocomial infections for decades. The absence of an available vaccine coupled with emerging multidrug resistance has prevented the medical community from effectively controlling this human pathogen. Furthermore, the ongoing pandemic caused by SARS-CoV-2 has increased the risk of hospitalized patients developing ventilator-associated pneumonia caused by bacterial opportunists including A. baumannii. The shortage of antibiotics in the development pipeline prompted the World Health Organization to designate A. baumannii a top priority for the development of new medical countermeasures, such as a vaccine. There are a number of important considerations associated with the development of an A. baumannii vaccine, including strain characteristics, diverse disease manifestations, and target population. In the past decade, research efforts have revealed a number of promising new immunization strategies that could culminate in a safe and protective vaccine against A. baumannii. In this review, we highlight the recent progress in the development of A. baumannii vaccines, discuss potential challenges, and propose future directions to achieve an effective intervention against this human pathogen.
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CsrA Supports both Environmental Persistence and Host-Associated Growth of Acinetobacter baumannii. Infect Immun 2020; 88:IAI.00259-20. [PMID: 32989034 DOI: 10.1128/iai.00259-20] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 09/18/2020] [Indexed: 11/20/2022] Open
Abstract
Acinetobacter baumannii is an opportunistic and frequently multidrug-resistant Gram-negative bacterial pathogen that primarily infects critically ill individuals. Indirect transmission from patient to patient in hospitals can drive infections, supported by this organism's abilities to persist on dry surfaces and rapidly colonize susceptible individuals. To investigate how A. baumannii survives on surfaces, we cultured A. baumannii in liquid media for several days and then analyzed isolates that lost the ability to survive drying. One of these isolates carried a mutation that affected the gene encoding the carbon storage regulator CsrA. As we began to examine the role of CsrA in A. baumannii, we observed that the growth of ΔcsrA mutant strains was inhibited in the presence of amino acids. The ΔcsrA mutant strains had a reduced ability to survive drying and to form biofilms but an improved ability to tolerate increased osmolarity compared with the wild type. We also examined the importance of CsrA for A. baumannii virulence. The ΔcsrA mutant strains had a greatly reduced ability to kill Galleria mellonella larvae, could not replicate in G. mellonella hemolymph, and also had a growth defect in human serum. Together, these results show that CsrA is essential for the growth of A. baumannii on host-derived substrates and is involved in desiccation tolerance, implying that CsrA controls key functions involved in the transmission of A. baumannii in hospitals.
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Cook D, Carrington J, Johnson K, Hare J. Homodimerization and heterodimerization requirements of Acinetobacter baumannii SOS response coregulators UmuDAb and DdrR revealed by two-hybrid analyses. Can J Microbiol 2020; 67:358-371. [PMID: 33180570 DOI: 10.1139/cjm-2020-0219] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The multidrug-resistant pathogen Acinetobacter baumannii displays unusual control of its SOS mutagenesis genes, as it does not encode a LexA repressor, but instead employs the UmuDAb repressor and a small protein, DdrR, that is uniquely found in Acinetobacter species. We used bacterial adenylate cyclase two-hybrid analyses to determine if UmuDAb and DdrR coregulation might involve physical interactions. Neither quantitative nor qualitative assays showed UmuDAb interaction with DdrR. DdrR hybrid proteins, however, demonstrated modest head-to-tail interactions in a qualitative assay. The similarity of UmuDAb to the homodimer-forming polymerase manager UmuD and LexA repressor proteins suggested that it may form dimers, which we observed. UmuDAb homodimerization required a free C terminus, and either small truncations or addition of a histidine tag at the C terminus abolished this homodimerization. The amino acid N100, crucial for UmuD dimer formation, was dispensable if both C termini were free to interact. However, mutation of the amino acid G124, necessary for LexA dimerization, yielded significantly less UmuDAb dimerization, even if both C termini were free. This suggests that UmuDAb forms dimers like LexA does, but may not coregulate gene expression involving a physical association with DdrR. The homodimerization of these coregulators provides insight into a LexA-independent, coregulatory process of controlling a conserved bacterial action such as the mutagenic DNA damage response.
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Affiliation(s)
- Deborah Cook
- Department of Biology and Chemistry, Morehead State University, Morehead, KY 40351, USA
| | - Jordan Carrington
- Department of Biology and Chemistry, Morehead State University, Morehead, KY 40351, USA
| | - Kevin Johnson
- Department of Biology and Chemistry, Morehead State University, Morehead, KY 40351, USA.,Craft Academy for Excellence in Science and Mathematics, Morehead State University, Morehead, KY 40351, USA
| | - Janelle Hare
- Department of Biology and Chemistry, Morehead State University, Morehead, KY 40351, USA
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35
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Peng Q, Lin F, Ling B. In vitro activity of biofilm inhibitors in combination with antibacterial drugs against extensively drug-resistant Acinetobacter baumannii. Sci Rep 2020; 10:18097. [PMID: 33093606 PMCID: PMC7581519 DOI: 10.1038/s41598-020-75218-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 10/13/2020] [Indexed: 12/15/2022] Open
Abstract
Acinetobacter baumannii is a common pathogen of nosocomial infection, and its ability to form biofilms further contributes to its virulence and multidrug resistance, posing a great threat to global public health. In this study, we investigated the inhibitory effects of five biofilm inhibitors (BFIs) (zinc lactate, stannous fluoride, furanone, azithromycin, and rifampicin) on biofilm formation of nine extensively drug-resistant A. baumannii (XDRAB), and assessed the synergistic antibacterial effects of these BFIs when combined with one of four conventional anti-A. baumannii antibiotics (imipenem, meropenem, tigecycline, and polymyxin B). Each of the five BFIs tested was found to be able to significantly inhibit biofilm formation of all the clinical isolates tested under sub-minimal inhibitory concentrations. Then, we observed synergistic effects (in 22%, 56% and 11% of the isolates) and additive effects (56%, 44% and 44%) when zinc lactate, stannous fluoride and furanone were combined with tigecycline, respectively. When zinc lactate and stannous fluoride were each used with a carbapenem (imipenem or meropenem), in 33% and 56-67% of the isolates, they showed synergistic and additive effects, respectively. Additivity in > 50% of the isolates was detected when rifampicin was combined with imipenem, meropenem, tigecycline, or polymyxin B; and a 100% additivity was noted with azithromycin-polymyxin B combination. However, antagonism and indifference were noted for polymyxin B in its combination with zinc lactate and stannous fluoride, respectively. In conclusion, five BFIs in combination with four antibacterial drugs showed different degrees of in vitro synergistic and additive antibacterial effects against XDRAB.
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Affiliation(s)
- Qin Peng
- Sichuan Province College Key Laboratory of Structure-Specific Small Molecule Drugs, Chengdu Medical College, Chengdu, 610500, China
- School of Pharmacy, Chengdu Medical College, Chengdu, 610500, China
- Department of Pharmacy, Nanchong Central Hospital, Nanchong, 637000, China
| | - Fei Lin
- Clinical Medical College and The First Affiliated Hospital of Chengdu Medical College, Chengdu, 610500, China
| | - Baodong Ling
- Sichuan Province College Key Laboratory of Structure-Specific Small Molecule Drugs, Chengdu Medical College, Chengdu, 610500, China.
- School of Pharmacy, Chengdu Medical College, Chengdu, 610500, China.
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36
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Léger L, Budin-Verneuil A, Cacaci M, Benachour A, Hartke A, Verneuil N. β-Lactam Exposure Triggers Reactive Oxygen Species Formation in Enterococcus faecalis via the Respiratory Chain Component DMK. Cell Rep 2020; 29:2184-2191.e3. [PMID: 31747593 DOI: 10.1016/j.celrep.2019.10.080] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 09/19/2019] [Accepted: 10/18/2019] [Indexed: 01/15/2023] Open
Abstract
Whereas the primary actions of β-lactams are well characterized, their downstream effects are less well understood. Although their targets are extracellular, β-lactams stimulate respiration in Escherichia coli leading to increased intracellular accumulation of reactive oxygen species (ROS). Here, we show that β-lactams over a large concentration range trigger a strong increase in ROS production in Enterococcus faecalis under aerobic, but not anaerobic, conditions. Both amoxicillin, to which the bacterium is susceptible, and cefotaxime, to which E. faecalis is resistant, triggers this response. This stimulation of ROS formation depends mainly on demethylmenaquinone (DMK), a component of the E. faecalis respiratory chain, but in contrast to E. coli is observed only in the absence of respiration. Our results suggest that in E. faecalis, β-lactams increase electron flux through the respiratory chain, thereby stimulating the auto-oxidation of reduced DMK in the absence of respiration, which triggers increased extracellular ROS production.
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Affiliation(s)
- Loïc Léger
- UR Risques Microbiens, Normandie Univ, UNICAEN, U2RM, 14000 Caen, France
| | | | - Margherita Cacaci
- Università Cattolica del Sacro Cuore, Instituto di Microbiologia, Rome, Italy
| | - Abdellah Benachour
- UR Risques Microbiens, Normandie Univ, UNICAEN, U2RM, 14000 Caen, France
| | - Axel Hartke
- UR Risques Microbiens, Normandie Univ, UNICAEN, U2RM, 14000 Caen, France.
| | - Nicolas Verneuil
- UR Risques Microbiens, Normandie Univ, UNICAEN, U2RM, 14000 Caen, France
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37
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Monem S, Furmanek-Blaszk B, Łupkowska A, Kuczyńska-Wiśnik D, Stojowska-Swędrzyńska K, Laskowska E. Mechanisms Protecting Acinetobacter baumannii against Multiple Stresses Triggered by the Host Immune Response, Antibiotics and Outside-Host Environment. Int J Mol Sci 2020; 21:E5498. [PMID: 32752093 PMCID: PMC7432025 DOI: 10.3390/ijms21155498] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 07/29/2020] [Accepted: 07/30/2020] [Indexed: 02/06/2023] Open
Abstract
Acinetobacter baumannii is considered one of the most persistent pathogens responsible for nosocomial infections. Due to the emergence of multidrug resistant strains, as well as high morbidity and mortality caused by this pathogen, A. baumannii was placed on the World Health Organization (WHO) drug-resistant bacteria and antimicrobial resistance research priority list. This review summarizes current studies on mechanisms that protect A. baumannii against multiple stresses caused by the host immune response, outside host environment, and antibiotic treatment. We particularly focus on the ability of A. baumannii to survive long-term desiccation on abiotic surfaces and the population heterogeneity in A. baumannii biofilms. Insight into these protective mechanisms may provide clues for the development of new strategies to fight multidrug resistant strains of A. baumannii.
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Affiliation(s)
- Soroosh Monem
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland; (S.M.); (A.Ł.); (D.K.-W.); (K.S.-S.)
| | - Beata Furmanek-Blaszk
- Department of Microbiology, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland;
| | - Adrianna Łupkowska
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland; (S.M.); (A.Ł.); (D.K.-W.); (K.S.-S.)
| | - Dorota Kuczyńska-Wiśnik
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland; (S.M.); (A.Ł.); (D.K.-W.); (K.S.-S.)
| | - Karolina Stojowska-Swędrzyńska
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland; (S.M.); (A.Ł.); (D.K.-W.); (K.S.-S.)
| | - Ewa Laskowska
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland; (S.M.); (A.Ł.); (D.K.-W.); (K.S.-S.)
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38
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Ramirez MS, Bonomo RA, Tolmasky ME. Carbapenemases: Transforming Acinetobacter baumannii into a Yet More Dangerous Menace. Biomolecules 2020; 10:biom10050720. [PMID: 32384624 PMCID: PMC7277208 DOI: 10.3390/biom10050720] [Citation(s) in RCA: 113] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 04/27/2020] [Accepted: 04/29/2020] [Indexed: 02/07/2023] Open
Abstract
Acinetobacter baumannii is a common cause of serious nosocomial infections. Although community-acquired infections are observed, the vast majority occur in people with preexisting comorbidities. A. baumannii emerged as a problematic pathogen in the 1980s when an increase in virulence, difficulty in treatment due to drug resistance, and opportunities for infection turned it into one of the most important threats to human health. Some of the clinical manifestations of A. baumannii nosocomial infection are pneumonia; bloodstream infections; lower respiratory tract, urinary tract, and wound infections; burn infections; skin and soft tissue infections (including necrotizing fasciitis); meningitis; osteomyelitis; and endocarditis. A. baumannii has an extraordinary genetic plasticity that results in a high capacity to acquire antimicrobial resistance traits. In particular, acquisition of resistance to carbapenems, which are among the antimicrobials of last resort for treatment of multidrug infections, is increasing among A. baumannii strains compounding the problem of nosocomial infections caused by this pathogen. It is not uncommon to find multidrug-resistant (MDR, resistance to at least three classes of antimicrobials), extensively drug-resistant (XDR, MDR plus resistance to carbapenems), and pan-drug-resistant (PDR, XDR plus resistance to polymyxins) nosocomial isolates that are hard to treat with the currently available drugs. In this article we review the acquired resistance to carbapenems by A. baumannii. We describe the enzymes within the OXA, NDM, VIM, IMP, and KPC groups of carbapenemases and the coding genes found in A. baumannii clinical isolates.
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Affiliation(s)
- Maria Soledad Ramirez
- Center for Applied Biotechnology Studies, Department of Biological Science, California State University Fullerton, Fullerton, CA 92831, USA;
| | - Robert A. Bonomo
- Medical Service and GRECC, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH 44106, USA;
- Departments of Medicine, Pharmacology, Molecular Biology and Microbiology, Biochemistry, Proteomics and Bioinformatics; Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
- WRU-Cleveland VAMC Center for Antimicrobial Resistance and Epidemiology (Case VA CARES), Cleveland, OH 44106, USA
| | - Marcelo E. Tolmasky
- Center for Applied Biotechnology Studies, Department of Biological Science, California State University Fullerton, Fullerton, CA 92831, USA;
- Correspondence: ; Tel.: +657-278-5263
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39
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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: 11] [Impact Index Per Article: 2.8] [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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40
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Kaur K, Sidhu H, Capalash N, Sharma P. Multicopper oxidase of Acinetobacter baumannii: Assessing its role in metal homeostasis, stress management and virulence. Microb Pathog 2020; 143:104124. [PMID: 32169492 DOI: 10.1016/j.micpath.2020.104124] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 02/17/2020] [Accepted: 03/06/2020] [Indexed: 12/25/2022]
Abstract
A putative multicopper oxidase, encoded as CopA in the proteome of Acinetobacter baumannii 19606, and designated as AbMCO, was expressed heterologously in E. coli (pET-28a) and purified by Ni-NTA affinity chromatography. The purified AbMCO exhibited in vitro oxidase activities upon exogenous addition of ≥1 μM copper ions. Kinetic studies revealed its phenol oxidase activity as it could catalyze the oxidation of substrates viz. 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), guaiacol, pyrogallol and catechol. Additionally, AbMCO displayed siderophore oxidase activity which depicted its role in metal homeostasis and protection from the toxic redox states of copper and iron. Importantly, expression of abMCO increased manifold upon challenge with high concentrations of copper sulphate (CuSO4, 1.5 mM) and sodium chloride (NaCl, 700 mM) which suggested its protective role in stress adaptation and management. Intra-macrophage assay of abMCO-expressing and abMCO-non expressing cells depicted no significant change in the survival rate of A. baumannii inside the macrophages. These findings indicate that A. baumannii encodes a multicopper oxidase, conferring copper tolerance and survival under stress conditions but had no role in virulence of this pathogen.
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Affiliation(s)
- Kavleen Kaur
- Department of Microbiology, Panjab University, Chandigarh, India
| | - Harsimran Sidhu
- Department of Biotechnology, Panjab University, Chandigarh, India
| | - Neena Capalash
- Department of Biotechnology, Panjab University, Chandigarh, India
| | - Prince Sharma
- Department of Microbiology, Panjab University, Chandigarh, India.
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41
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Greffe VRG, Michiels J. Desiccation-induced cell damage in bacteria and the relevance for inoculant production. Appl Microbiol Biotechnol 2020; 104:3757-3770. [PMID: 32170388 DOI: 10.1007/s00253-020-10501-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 02/18/2020] [Accepted: 02/26/2020] [Indexed: 12/21/2022]
Abstract
Plant growth-promoting bacteria show great potential for use in agriculture although efficient application remains challenging to achieve. Cells often lose viability during inoculant production and application, jeopardizing the efficacy of the inoculant. Since desiccation has been documented to be the primary stress factor affecting the decrease in survival, obtaining xerotolerance in plant growth-promoting bacteria is appealing. The molecular damage that occurs by drying bacteria has been broadly investigated, although a complete view is still lacking due to the complex nature of the process. Mechanic, structural, and metabolic changes that occur as a result of water depletion may potentially afflict lethal damage to membranes, DNA, and proteins. Bacteria respond to these harsh conditions by increasing production of exopolysaccharides, changing composition of the membrane, improving the stability of proteins, reducing oxidative stress, and repairing DNA damage. This review provides insight into the complex nature of desiccation stress in bacteria in order to facilitate strategic choices to improve survival and shelf life of newly developed inoculants. KEY POINTS: Desiccation-induced damage affects most major macromolecules in bacteria. Most bacteria are not xerotolerant despite multiple endogenous adaption mechanisms. Sensitivity to drying severely hampers inoculant quality.
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Affiliation(s)
- Vincent Robert Guy Greffe
- Centre of Microbial and Plant Genetics, KU Leuven, Leuven, Belgium.,VIB Center for Microbiology, Flanders Institute for Biotechnology, Leuven, Belgium
| | - Jan Michiels
- Centre of Microbial and Plant Genetics, KU Leuven, Leuven, Belgium. .,VIB Center for Microbiology, Flanders Institute for Biotechnology, Leuven, Belgium.
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42
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Protein Aggregation is Associated with Acinetobacter baumannii Desiccation Tolerance. Microorganisms 2020; 8:microorganisms8030343. [PMID: 32121206 PMCID: PMC7142981 DOI: 10.3390/microorganisms8030343] [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: 01/06/2020] [Revised: 02/20/2020] [Accepted: 02/24/2020] [Indexed: 12/23/2022] Open
Abstract
Desiccation tolerance has been implicated as an important characteristic that potentiates the spread of the bacterial pathogen Acinetobacter baumannii on dry surfaces. Here we explore several factors influencing desiccation survival of A. baumannii. At the macroscale level, we find that desiccation tolerance is influenced by cell density and growth phase. A transcriptome analysis indicates that desiccation represents a unique state for A. baumannii compared to commonly studied growth phases and strongly influences pathways responsible for proteostasis. Remarkably, we find that an increase in total cellular protein aggregates, which is often considered deleterious, correlates positively with the ability of A. baumannii to survive desiccation. We show that inducing protein aggregate formation prior to desiccation increases survival and, importantly, that proteins incorporated into cellular aggregates can retain activity. Our results suggest that protein aggregates may promote desiccation tolerance in A. baumannii through preserving and protecting proteins from damage during desiccation until rehydration occurs.
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43
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Jiang B, Xing Y, Li G, Zhang N, Lian L, Sun G, Zhang D. iTRAQ-Based Comparative Proteomic Analysis of Acinetobacter baylyi ADP1 Under DNA Damage in Relation to Different Carbon Sources. Front Microbiol 2020; 10:2906. [PMID: 31993023 PMCID: PMC6971185 DOI: 10.3389/fmicb.2019.02906] [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: 06/20/2019] [Accepted: 12/02/2019] [Indexed: 12/27/2022] Open
Abstract
DNA damage response allows microorganisms to repair or bypass DNA damage and maintain the genome integrity. It has attracted increasing attention but the underlying influential factors affecting DNA damage response are still unclear. In this work, isobaric tags for relative and absolute quantification (iTRAQ)-based proteomic analysis was used to investigate the influence of carbon sources on the translational response of Acinetobacter baylyi ADP1 to DNA damage. After cultivating in a nutrient-rich medium (LB) and defined media supplemented with four different carbon sources (acetate, citrate, pyruvate, and succinate), a total of 2807 proteins were identified. Among them, 84 proteins involved in stress response were significantly altered, indicating the strong influence of carbon source on the response of A. baylyi ADP1 to DNA damage and other stresses. As the first study on the comparative global proteomic changes in A. baylyi ADP1 under DNA damage across nutritional environments, our findings revealed that DNA damage response in A. baylyi ADP1 at the translational level is significantly altered by carbon source, providing an insight into the complex protein interactions across carbon sources and offering theoretical clues for further study to elucidate their general regulatory mechanism to adapt to different nutrient environments.
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Affiliation(s)
- Bo Jiang
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, China.,Beijing Key Laboratory of Resource-Oriented Treatment of Industrial Pollutants, University of Science and Technology Beijing, Beijing, China
| | - Yi Xing
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, China.,Beijing Key Laboratory of Resource-Oriented Treatment of Industrial Pollutants, University of Science and Technology Beijing, Beijing, China
| | - Guanghe Li
- School of Environment, Tsinghua University, Beijing, China.,State Key Joint Laboratory of Environmental Simulation and Pollution Control, Tsinghua University, Beijing, China
| | - Nana Zhang
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, China.,Beijing Key Laboratory of Resource-Oriented Treatment of Industrial Pollutants, University of Science and Technology Beijing, Beijing, China
| | - Luning Lian
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, China.,Beijing Key Laboratory of Resource-Oriented Treatment of Industrial Pollutants, University of Science and Technology Beijing, Beijing, China
| | - Guangdong Sun
- School of Environment, Tsinghua University, Beijing, China.,State Key Joint Laboratory of Environmental Simulation and Pollution Control, Tsinghua University, Beijing, China
| | - Dayi Zhang
- School of Environment, Tsinghua University, Beijing, China.,State Key Joint Laboratory of Environmental Simulation and Pollution Control, Tsinghua University, Beijing, China
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44
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Shin Y, Park J, Park W. Sterilization efficiency of pathogen-contaminated cottons in a laundry machine. J Microbiol 2019; 58:30-38. [PMID: 31768938 DOI: 10.1007/s12275-020-9391-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 10/16/2019] [Accepted: 10/24/2019] [Indexed: 12/17/2022]
Abstract
Pathogenic bacteria on abiotic surfaces such as fabrics, bedding, patient wears, and surgical tools are known to increase the risk of bacterial diseases in infants and the elderly. The desiccation tolerance of bacteria affects their viability in cotton. Thus, washing and drying machines are required to use conditions that ensure the sterilization of bacteria in cotton. The objective of this study is to determine the effects of various sterilization conditions of washing and drying machines on the survival of three pathogenic bacteria (Acinetobacter baumannii, Pseudomonas aeruginosa, and Staphylococcus aureus) commonly presented in contaminated cotton and two non-pathogenic bacteria (Bacillus subtilis and Escherichia coli) in cotton. High survival rates of A. baumannii and S. aureus in desiccated cotton were observed based on scanning electron microscope and replicate organism direct agar contact assay. The survival rates of A. baumannii and S. aureus exposed in desiccated cotton for 8 h were higher (14.4 and 5.0%, respectively) than those of other bacteria (< 0.5%). All tested bacteria were eradicated at low-temperature (< 40°C) washing with activated oxygen bleach (AOB). However, bacterial viability was shown in low temperature washing without AOB. High-temperature (> 60°C) washing was required to achieve 99.9% of the sterilization rate in washing without AOB. The sterilization rate was 93.2% using a drying machine at 60°C for 4 h. This level of sterilization was insufficient in terms of time and energy efficiency. High sterilization efficiency (> 99.9%) at 75°C for 3 h using a drying machine was confirmed. This study suggests standard conditions of drying machines to remove bacterial contamination in cotton by providing practical data.
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Affiliation(s)
- Yoonjae Shin
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul, 02841, Republic of Korea
| | - Jungha Park
- Digital Appliances Business, Samsung Electronics, Suwon, 16677, Republic of Korea
| | - Woojun Park
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul, 02841, Republic of Korea.
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Human pleural fluid triggers global changes in the transcriptional landscape of Acinetobacter baumannii as an adaptive response to stress. Sci Rep 2019; 9:17251. [PMID: 31754169 PMCID: PMC6872806 DOI: 10.1038/s41598-019-53847-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 11/06/2019] [Indexed: 12/16/2022] Open
Abstract
Acinetobacter baumannii is a feared, drug-resistant pathogen, characterized by its ability to resist extreme environmental and nutrient-deprived conditions. Previously, we showed that human serum albumin (HSA) can increase foreign DNA acquisition specifically and alter the expression of genes associated with pathogenicity. Moreover, in a recent genome-wide transcriptomic study, we observed that pleural fluid (PF), an HSA-containing fluid, increases DNA acquisition, can modulate cytotoxicity, and control immune responses by eliciting changes in the A. baumannii metabolic profile. In the present work, using more stringent criteria and focusing on the analysis of genes related to pathogenicity and response to stress, we analyzed our previous RNA-seq data and performed phenotypic assays to further explore the impact of PF on A. baumannii's microbial behavior and the strategies used to overcome environmental stress. We observed that PF triggered differential expression of genes associated with motility, efflux pumps, antimicrobial resistance, biofilm formation, two-component systems (TCSs), capsule synthesis, osmotic stress, and DNA-damage response, among other categories. Phenotypic assays of A. baumannii A118 and two other clinical A. baumannii strains, revealed differences in their responses to PF in motility, biofilm formation, antibiotic susceptibility, osmotic stress, and outer membrane vesicle (OMV) production, suggesting that these changes are strain specific. We conclude that A. baumannii's pathoadaptive responses is induced by HSA-containing fluids and must be part of this bacterium armamentarium to persist in hostile environments.
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The Landscape of Phenotypic and Transcriptional Responses to Ciprofloxacin in Acinetobacter baumannii: Acquired Resistance Alleles Modulate Drug-Induced SOS Response and Prophage Replication. mBio 2019; 10:mBio.01127-19. [PMID: 31186328 PMCID: PMC6561030 DOI: 10.1128/mbio.01127-19] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The emergence of fluoroquinolone resistance in nosocomial pathogens has restricted the clinical efficacy of this antibiotic class. In Acinetobacter baumannii, the majority of clinical isolates now show high-level resistance due to mutations in gyrA (DNA gyrase) and parC (topoisomerase IV [topo IV]). To investigate the molecular basis for fluoroquinolone resistance, an exhaustive mutation analysis was performed in both drug-sensitive and -resistant strains to identify loci that alter ciprofloxacin sensitivity. To this end, parallel fitness tests of over 60,000 unique insertion mutations were performed in strains with various alleles in genes encoding the drug targets. The spectra of mutations that altered drug sensitivity were found to be similar in the drug-sensitive and gyrA parC double-mutant backgrounds, having resistance alleles in both genes. In contrast, the introduction of a single gyrA resistance allele, resulting in preferential poisoning of topo IV by ciprofloxacin, led to extreme alterations in the insertion mutation fitness landscape. The distinguishing feature of preferential topo IV poisoning was enhanced induction of DNA synthesis in the region of two endogenous prophages, with DNA synthesis associated with excision and circularization of the phages. Induction of the selective DNA synthesis in the gyrA background was also linked to heightened prophage gene transcription and enhanced activation of the mutagenic SOS response relative to that observed in either the wild-type (WT) or gyrA parC double mutant. Therefore, the accumulation of mutations that result in the stepwise evolution of high ciprofloxacin resistance is tightly connected to modulation of the SOS response and endogenous prophage DNA synthesis.IMPORTANCE Fluoroquinolones have been extremely successful antibiotics due to their ability to target multiple bacterial enzymes critical to DNA replication, the topoisomerases DNA gyrase and topo IV. Unfortunately, mutations lowering drug affinity for both enzymes are now widespread, rendering these drugs ineffective for many pathogens. To undermine this form of resistance, we examined how bacteria with target alterations differentially cope with fluoroquinolone exposures. We studied this problem in the nosocomial pathogen A. baumannii, which causes drug-resistant life-threatening infections. Employing genome-wide approaches, we uncovered numerous pathways that could be exploited to raise fluoroquinolone sensitivity independently of target alteration. Remarkably, fluoroquinolone targeting of topo IV in specific mutants caused dramatic hyperinduction of prophage replication and enhanced the mutagenic DNA damage response, but these responses were muted in strains with DNA gyrase as the primary target. This work demonstrates that resistance evolution via target modification can profoundly modulate the antibiotic stress response, revealing potential resistance-associated liabilities.
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Bacterial Cytological Profiling as a Tool To Study Mechanisms of Action of Antibiotics That Are Active against Acinetobacter baumannii. Antimicrob Agents Chemother 2019; 63:AAC.02310-18. [PMID: 30745382 DOI: 10.1128/aac.02310-18] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 01/30/2019] [Indexed: 01/09/2023] Open
Abstract
An increasing number of multidrug-resistant Acinetobacter baumannii (MDR-AB) infections have been reported worldwide, posing a threat to public health. The establishment of methods to elucidate the mechanism of action (MOA) of A. baumannii-specific antibiotics is needed to develop novel antimicrobial therapeutics with activity against MDR-AB We previously developed bacterial cytological profiling (BCP) to understand the MOA of compounds in Escherichia coli and Bacillus subtilis Given how distantly related A. baumannii is to these species, it was unclear to what extent it could be applied. Here, we implemented BCP as an antibiotic MOA discovery platform for A. baumannii We found that the BCP platform can distinguish among six major antibiotic classes and can also subclassify antibiotics that inhibit the same cellular pathway but have different molecular targets. We used BCP to show that the compound NSC145612 inhibits the growth of A. baumannii via targeting RNA transcription. We confirmed this result by isolating and characterizing resistant mutants with mutations in the rpoB gene. Altogether, we conclude that BCP provides a useful tool for MOA studies of antibacterial compounds that are active against A. baumannii.
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Ajiboye TO, Aliyu NO, Ajala-Lawal RA. Lophirones B and C induce oxidative cellular death pathway in Acinetobacter baumannii by inhibiting DNA gyrase. Microb Pathog 2019; 130:226-231. [PMID: 30872146 DOI: 10.1016/j.micpath.2019.03.011] [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: 01/11/2019] [Revised: 03/02/2019] [Accepted: 03/07/2019] [Indexed: 10/27/2022]
Abstract
We evaluated the inactivation of DNA gyrase on the oxidative stress response and sensitivity of A. baumannii to lophirones B and C. The sensitivity of parental and the mutant strains of A. baumannii to lophirones B and C was determined using minimum inhibitory concentration (MIC) and time-kill sensitivity. Inactivation of sodB, katG, recA enhanced the sensitivity of A. baumannii to lophirones B and C. Furthermore, this inactivation increased the accumulation of superoxide anion radical and hydrogen peroxide in lophirones B and C-treated A. baumannii, which was reversed in the presence of thiourea. Inactivation of gyrA stalled lophirones B and C-mediated ROS accumulation in A. baumannii. In addition, lophirones B and C raised the Fe2+ contents of A. baumannii. Dipyridyl (Fe chelator) reversed the sensitivity of A. baumannii to lophirones B and C. Lophirones significantly lowered the NAD+/NADH ratio of A. baumannii. The results of this study revealed that the impact of DNA gyrase in lophirones B and C-mediated ROS accumulation, Fe2+ release and cell death.
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Affiliation(s)
- T O Ajiboye
- Antioxidants, Redox Biology and Toxicology Research Group, Department of Medical Biochemistry, College of Health Sciences, Nile University of Nigeria, FCT-Abuja, Nigeria.
| | - N O Aliyu
- Antioxidants, Redox Biology and Toxicology Research Group, Department of Medical Biochemistry, College of Health Sciences, Nile University of Nigeria, FCT-Abuja, Nigeria
| | - R A Ajala-Lawal
- Antioxidants, Redox Biology and Toxicology Research Group, Department of Medical Biochemistry, College of Health Sciences, Nile University of Nigeria, FCT-Abuja, Nigeria
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Zeidler S, Müller V. Coping with low water activities and osmotic stress in Acinetobacter baumannii: significance, current status and perspectives. Environ Microbiol 2019; 21:2212-2230. [PMID: 30773801 DOI: 10.1111/1462-2920.14565] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 02/11/2019] [Accepted: 02/13/2019] [Indexed: 01/26/2023]
Abstract
Multidrug resistant (MDR) pathogens are one of the most pressing challenges of contemporary health care. Acinetobacter baumannii takes a predominant position, emphasized in 2017 by the World Health Organization. The increasing emergence of MDR strains strengthens the demand for new antimicrobials. Possible targets for such compounds might be proteins involved in resistance against low water activity environments, since A. baumannii is known for its pronounced resistance against desiccation stress. Despite the importance of desiccation resistance for persistence of this pathogen in hospitals, comparable studies and precise data on this topic are rare and the mechanisms involved are largely unknown. This review aims to give an overview of the studies performed so far and the current knowledge on genes and proteins important for desiccation survival. 'Osmotic stress' is not identical to 'desiccation stress', but the two share the response of bacteria to low water activities. Osmotic stress resistance is in general studied much better, and in recent years it turned out that accumulation of compatible solutes in A. baumannii comprises some special features such as the bifunctional enzyme MtlD synthesizing the unusual solute mannitol. Furthermore, the regulatory pathways, as understood today, will be discussed.
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Affiliation(s)
- Sabine Zeidler
- Department of Molecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Goethe-University Frankfurt am Main, Frankfurt am Main, Germany
| | - Volker Müller
- Department of Molecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Goethe-University Frankfurt am Main, Frankfurt am Main, Germany
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Ajiboye TO. Contributions of reactive oxygen species, oxidative DNA damage and glutathione depletion to the sensitivity of Acinetobacter baumannii to 2-(2-nitrovinyl) furan. Microb Pathog 2019; 128:342-346. [PMID: 30682524 DOI: 10.1016/j.micpath.2019.01.034] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Revised: 01/16/2019] [Accepted: 01/22/2019] [Indexed: 12/28/2022]
Abstract
2-(2-nitrovinyl) furan is a broad-spectrum antibacterial agent with activity against Gram-positive and Gram-negative bacteria. In this study, the contributions of reactive oxygen species, oxidative DNA damage and glutathione depletion to its activity against Acinetobacter baumannii was investigated. Inactivation of sodB, katG and recA lowered the minimum inhibitory concentration of 2-(2-nitrovinyl) furan. Furthermore, the inactivation increased the superoxide anion radical and hydrogen peroxide contents of 2-(2-nitrovinyl) furan-treated A. baumannii. Antioxidant (thiourea) reversed the elevated levels of superoxide anion radical and hydrogen peroxide. In addition, thiourea lowered the susceptibility of A. baumannii to 2-(2-nitrovinyl) furan. 2-(2-nitrovinyl) furan depleted reduced glutathione (GSH) contents of parental, sodB, katG and recA strains of A. baumannii. NAD+/NADH ratio parental, sodB, katG and recA strains of A. baumannii exposed to 2-(2-nitrovinyl) furan increased significantly. Inactivation of type-I NADH dehydrogenase lowered the reactive oxygen species generation in 2-(2-nitrovinyl) furan-treated A. baumannii. It is evident from this study that 2-(2-nitrovinyl) furan stimulates respiratory chain activity of A. baumannii leading to enhanced ROS generation, which depletes GSH and reacts with Fe2+ to produce hydroxyl radical that damage DNA.
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Affiliation(s)
- T O Ajiboye
- Antioxidants, Redox Biology and Toxicology Research Group, Department of Medical Biochemistry, College of Health Sciences, Nile University of Nigeria, FCT-Abuja, Nigeria.
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