1
|
Wei X, Gao J, Zhou D, Xu C, Chen P, Chen S, Zhang Y, Liu X, Li G, Zhu G, Liu H, Li J, Geng B, Gao L, Cheng Z, Lamont IL, Pletzer D, Jin Y, Jin S, Wu W. Murepavadin promotes the killing efficacies of aminoglycoside antibiotics against Pseudomonas aeruginosa by enhancing membrane potential. Antimicrob Agents Chemother 2024; 68:e0153923. [PMID: 38470195 PMCID: PMC10989017 DOI: 10.1128/aac.01539-23] [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: 11/22/2023] [Accepted: 02/19/2024] [Indexed: 03/13/2024] Open
Abstract
Murepavadin is a peptidomimetic that specifically targets the lipopolysaccharide transport protein LptD of Pseudomonas aeruginosa. Here, we found that murepavadin enhances the bactericidal efficacies of tobramycin and amikacin. We further demonstrated that murepavadin enhances bacterial respiration activity and subsequent membrane potential, which promotes intracellular uptake of aminoglycoside antibiotics. In addition, the murepavadin-amikacin combination displayed a synergistic bactericidal effect in a murine pneumonia model.
Collapse
Affiliation(s)
- Xiaoya Wei
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Jiacong Gao
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Dandan Zhou
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Congjuan Xu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Ping Chen
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Shuiping Chen
- Department of Laboratory Medicine, 5th Medical Center of PLA General Hospital, Beijing, China
| | - Yanhong Zhang
- Nankai University Affiliated Hospital (Tianjin Forth Hospital), Tianjin, China
| | - Xuehua Liu
- Tianjin Union Medical Center, Nankai University Affiliated Hospital, Tianjin, China
| | - Guanxian Li
- Tianjin Union Medical Center, Nankai University Affiliated Hospital, Tianjin, China
| | - Guangbo Zhu
- Tianjin Union Medical Center, Nankai University Affiliated Hospital, Tianjin, China
| | - Huimin Liu
- Tianjin Union Medical Center, Nankai University Affiliated Hospital, Tianjin, China
| | - Jinjin Li
- Tianjin Union Medical Center, Nankai University Affiliated Hospital, Tianjin, China
| | - Bin Geng
- Tianjin Union Medical Center, Nankai University Affiliated Hospital, Tianjin, China
| | - Linlin Gao
- Tianjin Union Medical Center, Nankai University Affiliated Hospital, Tianjin, China
| | - Zhihui Cheng
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Iain L. Lamont
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - Daniel Pletzer
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Yongxin Jin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Shouguang Jin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Weihui Wu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| |
Collapse
|
2
|
Lang M, Carvalho A, Baharoglu Z, Mazel D. Aminoglycoside uptake, stress, and potentiation in Gram-negative bacteria: new therapies with old molecules. Microbiol Mol Biol Rev 2023; 87:e0003622. [PMID: 38047635 PMCID: PMC10732077 DOI: 10.1128/mmbr.00036-22] [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] [Indexed: 12/05/2023] Open
Abstract
SUMMARYAminoglycosides (AGs) are long-known molecules successfully used against Gram-negative pathogens. While their use declined with the discovery of new antibiotics, they are now classified as critically important molecules because of their effectiveness against multidrug-resistant bacteria. While they can efficiently cross the Gram-negative envelope, the mechanism of AG entry is still incompletely understood, although this comprehension is essential for the development of new therapies in the face of the alarming increase in antibiotic resistance. Increasing antibiotic uptake in bacteria is one strategy to enhance effective treatments. This review aims, first, to consolidate old and recent knowledge about AG uptake; second, to explore the connection between AG-dependent bacterial stress and drug uptake; and finally, to present new strategies of potentiation of AG uptake for more efficient antibiotic therapies. In particular, we emphasize on the connection between sugar transport and AG potentiation.
Collapse
Affiliation(s)
- Manon Lang
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Unité Plasticité du Génome Bactérien, Paris, France
| | - André Carvalho
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Unité Plasticité du Génome Bactérien, Paris, France
| | - Zeynep Baharoglu
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Unité Plasticité du Génome Bactérien, Paris, France
| | - Didier Mazel
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Unité Plasticité du Génome Bactérien, Paris, France
| |
Collapse
|
3
|
Bie L, Zhang M, Wang J, Fang M, Li L, Xu H, Wang M. Comparative Analysis of Transcriptomic Response of Escherichia coli K-12 MG1655 to Nine Representative Classes of Antibiotics. Microbiol Spectr 2023; 11:e0031723. [PMID: 36853057 PMCID: PMC10100721 DOI: 10.1128/spectrum.00317-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 02/05/2023] [Indexed: 03/01/2023] Open
Abstract
The use of antibiotics leads to strong stresses to bacteria, leading to profound impact on cellular physiology. Elucidating how bacteria respond to antibiotic stresses not only helps us to decipher bacteria's strategies to resistant antibiotics but also assists in proposing targets for antibiotic development. In this work, a comprehensive comparative transcriptomic analysis on how Escherichia coli responds to nine representative classes of antibiotics (tetracycline, mitomycin C, imipenem, ceftazidime, kanamycin, ciprofloxacin, polymyxin E, erythromycin, and chloramphenicol) was performed, aimed at determining and comparing the responses of this model organism to antibiotics at the transcriptional level. On average, 39.71% of genes were differentially regulated by antibiotics at concentrations that inhibit 50% growth. Kanamycin leads to the strongest transcriptomic response (76.4% of genes regulated), whereas polymyxin E led to minimal transcriptomic response (4.7% of genes regulated). Further GO, KEGG, and EcoCyc enrichment analysis found significant transcriptomic changes in carbon metabolism, amino acid metabolism, nutrient assimilation, transport, stress response, nucleotide metabolism, protein biosynthesis, cell wall biosynthesis, energy conservation, mobility, and cell-environmental communications. Analysis of coregulated genes led to the finding of significant reduction of sulfur metabolism by all antibiotics, and analysis of transcription factor-coding genes suggested clustered regulatory patterns implying coregulation. In-depth analysis of regulated pathways revealed shared and unique strategies of E. coli resisting antibiotics, leading to the proposal of four different strategies (the pessimistic, the ignorant, the defensive, and the invasive). In conclusion, this work provides a comprehensive analysis of E. coli's transcriptomic response to antibiotics, which paves the road for further physiological investigation. IMPORTANCE Antibiotics are among the most important inventions in the history of humankind. They are the ultimate reason why bacterial infections are no longer the number one threat to people's lives. However, the wide application of antibiotics in the last half a century has led to aggravating antibiotic resistance, weakening the efficacy of antibiotics. To better comprehend the ways bacteria deal with antibiotics that may eventually turn into resistance mechanisms, and to identify good targets for potential antibiotics, knowledge on how bacteria regulate their physiology in response to different classes of antibiotics is needed. This work aimed to fill this knowledge gap by identifying changes of bacterial functions at the transcription level and suggesting strategies of bacteria to resist antibiotics.
Collapse
Affiliation(s)
- Luyao Bie
- State Key Laboratory of Microbial Technology, Microbial Technology Research Institute, Shandong University, Qingdao, China
- Tsinghua University-Peking University Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Mengge Zhang
- State Key Laboratory of Microbial Technology, Microbial Technology Research Institute, Shandong University, Qingdao, China
| | - Juan Wang
- State Key Laboratory of Microbial Technology, Microbial Technology Research Institute, Shandong University, Qingdao, China
- No.3 Middle School of Huimin, Binzhou, China
| | - Meng Fang
- State Key Laboratory of Microbial Technology, Microbial Technology Research Institute, Shandong University, Qingdao, China
| | - Ling Li
- State Key Laboratory of Microbial Technology, Microbial Technology Research Institute, Shandong University, Qingdao, China
| | - Hai Xu
- State Key Laboratory of Microbial Technology, Microbial Technology Research Institute, Shandong University, Qingdao, China
| | - Mingyu Wang
- State Key Laboratory of Microbial Technology, Microbial Technology Research Institute, Shandong University, Qingdao, China
| |
Collapse
|
4
|
The Pseudomonas aeruginosa RpoH (σ 32) Regulon and Its Role in Essential Cellular Functions, Starvation Survival, and Antibiotic Tolerance. Int J Mol Sci 2023; 24:ijms24021513. [PMID: 36675051 PMCID: PMC9866376 DOI: 10.3390/ijms24021513] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/23/2022] [Accepted: 01/10/2023] [Indexed: 01/15/2023] Open
Abstract
The bacterial heat-shock response is regulated by the alternative sigma factor, σ32 (RpoH), which responds to misfolded protein stress and directs the RNA polymerase to the promoters for genes required for protein refolding or degradation. In P. aeruginosa, RpoH is essential for viability under laboratory growth conditions. Here, we used a transcriptomics approach to identify the genes of the RpoH regulon, including RpoH-regulated genes that are essential for P. aeruginosa. We placed the rpoH gene under control of the arabinose-inducible PBAD promoter, then deleted the chromosomal rpoH allele. This allowed transcriptomic analysis of the RpoH (σ32) regulon following a short up-shift in the cellular concentration of RpoH by arabinose addition, in the absence of a sudden change in temperature. The P. aeruginosa ∆rpoH (PBAD-rpoH) strain grew in the absence of arabinose, indicating that some rpoH expression occurred without arabinose induction. When arabinose was added, the rpoH mRNA abundance of P. aeruginosa ∆rpoH (PBAD-rpoH) measured by RT-qPCR increased five-fold within 15 min of arabinose addition. Transcriptome results showed that P. aeruginosa genes required for protein repair or degradation are induced by increased RpoH levels, and that many genes essential for P. aeruginosa growth are induced by RpoH. Other stress response genes induced by RpoH are involved in damaged nucleic acid repair and in amino acid metabolism. Annotation of the hypothetical proteins under RpoH control included proteins that may play a role in antibiotic resistances and in non-ribosomal peptide synthesis. Phenotypic analysis of P. aeruginosa ∆rpoH (PBAD-rpoH) showed that it is impaired in its ability to survive during starvation compared to the wild-type strain. P. aeruginosa ∆rpoH (PBAD-rpoH) also had increased sensitivity to aminoglycoside antibiotics, but not to other classes of antibiotics, whether cultured planktonically or in biofilms. The enhanced aminoglycoside sensitivity of the mutant strain may be due to indirect effects, such as the build-up of toxic misfolded proteins, or to the direct effect of genes, such as aminoglycoside acetyl transferases, that are regulated by RpoH. Overall, the results demonstrate that RpoH regulates genes that are essential for viability of P. aeruginosa, that it protects P. aeruginosa from damage from aminoglycoside antibiotics, and that it is required for survival during nutrient-limiting conditions.
Collapse
|
5
|
Pseudomonas aeruginosa Phosphate Transporter PitA (PA4292) Controls Susceptibility to Aminoglycoside Antibiotics by Regulating the Proton Motive Force. Antimicrob Agents Chemother 2022; 66:e0099222. [PMID: 36346250 PMCID: PMC9765264 DOI: 10.1128/aac.00992-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic Gram-negative bacterium that causes nosocomial infections in immunocompromised patients. β-lactam and aminoglycoside antibiotics are commonly used in the treatment of P. aeruginosa infections. Previously, we found that mutation in a PA4292 gene increases bacterial resistance to β-lactam antibiotics. In this study, we demonstrated that mutation in PA4292 increases bacterial susceptibility to aminoglycoside antibiotics. We further found enhanced uptake of tobramycin by the ΔPA4292 mutant, which might be due to an increase of proton motive force (PMF). Sequence analysis revealed PA4292 is homologous to the Escherichia coli phosphate transporter PitA. Mutation of PA4292 indeed reduces intracellular phosphate concentration. We thus named PA4292 as pitA. Although the PMF is enhanced in the ΔpitA mutant, the intracellular ATP concentration is lower than that in the isogenic wild-type strain PA14, which might be due to lack of the ATP synthesis substrate phosphate. Overexpression of the phosphate transporter complex genes pstSCAB in the ΔpitA mutant restores the intracellular phosphate concentration, PMF, ATP synthesis, and aminoglycosides resistance. In addition, growth of wild-type PA14 in a low-phosphate medium resulted in higher PMF and aminoglycoside susceptibility compared to cells grown in a high-phosphate medium. Overall, our results demonstrate the roles of PitA in phosphate transportation and reveal the relationship between intracellular phosphate and aminoglycoside susceptibility.
Collapse
|
6
|
Laborda P, Hernando-Amado S, Martínez JL, Sanz-García F. Antibiotic Resistance in Pseudomonas. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1386:117-143. [DOI: 10.1007/978-3-031-08491-1_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
7
|
Cell Envelope Stress Response in Pseudomonas aeruginosa. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1386:147-184. [DOI: 10.1007/978-3-031-08491-1_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
8
|
Adaptive responses of Pseudomonas aeruginosa to treatment with antibiotics. Antimicrob Agents Chemother 2021; 66:e0087821. [PMID: 34748386 DOI: 10.1128/aac.00878-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Pseudomonas aeruginosa is among the highest priority pathogens for drug development, because of its resistance to antibiotics, extraordinary adaptability, and persistence. Anti-pseudomonal research is strongly encouraged to address the acute scarcity of innovative antimicrobial lead structures. In an effort to understand the physiological response of P. aeruginosa to clinically relevant antibiotics, we investigated the proteome after exposure to ciprofloxacin, levofloxacin, rifampicin, gentamicin, tobramycin, azithromycin, tigecycline, polymyxin B, colistin, ceftazidime, meropenem, and piperacillin/tazobactam. We further investigated the response to CHIR-90, which represents a promising class of lipopolysaccharide biosynthesis inhibitors currently under evaluation. Radioactive pulse-labeling of newly synthesized proteins followed by 2D-PAGE was used to monitor the acute response of P. aeruginosa to antibiotic treatment. The proteomic profiles provide insights into the cellular defense strategies for each antibiotic. A mathematical comparison of these response profiles based on upregulated marker proteins revealed similarities of responses to antibiotics acting on the same target area. This study provides insights into the effects of commonly used antibiotics on P. aeruginosa and lays the foundation for the comparative analysis of the impact of novel compounds with precedented and unprecedented modes of action.
Collapse
|
9
|
Pepi M, Focardi S. Antibiotic-Resistant Bacteria in Aquaculture and Climate Change: A Challenge for Health in the Mediterranean Area. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:5723. [PMID: 34073520 PMCID: PMC8198758 DOI: 10.3390/ijerph18115723] [Citation(s) in RCA: 56] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 05/11/2021] [Accepted: 05/22/2021] [Indexed: 12/30/2022]
Abstract
Aquaculture is the productive activity that will play a crucial role in the challenges of the millennium, such as the need for proteins that support humans and the respect for the environment. Aquaculture is an important economic activity in the Mediterranean basin. A great impact is presented, however, by aquaculture practices as they involve the use of antibiotics for treatment and prophylaxis. As a consequence of the use of antibiotics in aquaculture, antibiotic resistance is induced in the surrounding bacteria in the column water, sediment, and fish-associated bacterial strains. Through horizontal gene transfer, bacteria can diffuse antibiotic-resistance genes and mobile resistance genes further spreading genetic determinants. Once triggered, antibiotic resistance easily spreads among aquatic microbial communities and, from there, can reach human pathogenic bacteria, making vain the use of antibiotics for human health. Climate change claims a significant role in this context, as rising temperatures can affect cell physiology in bacteria in the same way as antibiotics, causing antibiotic resistance to begin with. The Mediterranean Sea represents a 'hot spot' in terms of climate change and aspects of antibiotic resistance in aquaculture in this area can be significantly amplified, thus increasing threats to human health. Practices must be adopted to counteract negative impacts on human health, with a reduction in the use of antibiotics as a pivotal point. In the meantime, it is necessary to act against climate change by reducing anthropogenic impacts, for example by reducing CO2 emissions into the atmosphere. The One Health type approach, which involves the intervention of different skills, such as veterinary, ecology, and medicine in compliance with the principles of sustainability, is necessary and strongly recommended to face these important challenges for human and animal health, and for environmental safety in the Mediterranean area.
Collapse
Affiliation(s)
- Milva Pepi
- Stazione Zoologica Anton Dohrn, Fano Marine Centre, Viale Adriatico 1-N, 61032 Fano, Italy;
| | - Silvano Focardi
- Department of Environmental Sciences, Università di Siena, Via Mattioli, 4, 53100 Siena, Italy
| |
Collapse
|
10
|
Cianciulli Sesso A, Lilić B, Amman F, Wolfinger MT, Sonnleitner E, Bläsi U. Gene Expression Profiling of Pseudomonas aeruginosa Upon Exposure to Colistin and Tobramycin. Front Microbiol 2021; 12:626715. [PMID: 33995291 PMCID: PMC8120321 DOI: 10.3389/fmicb.2021.626715] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 03/31/2021] [Indexed: 11/22/2022] Open
Abstract
Pseudomonas aeruginosa (Pae) is notorious for its high-level resistance toward clinically used antibiotics. In fact, Pae has rendered most antimicrobials ineffective, leaving polymyxins and aminoglycosides as last resort antibiotics. Although several resistance mechanisms of Pae are known toward these drugs, a profounder knowledge of hitherto unidentified factors and pathways appears crucial to develop novel strategies to increase their efficacy. Here, we have performed for the first time transcriptome analyses and ribosome profiling in parallel with strain PA14 grown in synthetic cystic fibrosis medium upon exposure to polymyxin E (colistin) and tobramycin. This approach did not only confirm known mechanisms involved in colistin and tobramycin susceptibility but revealed also as yet unknown functions/pathways. Colistin treatment resulted primarily in an anti-oxidative stress response and in the de-regulation of the MexT and AlgU regulons, whereas exposure to tobramycin led predominantly to a rewiring of the expression of multiple amino acid catabolic genes, lower tricarboxylic acid (TCA) cycle genes, type II and VI secretion system genes and genes involved in bacterial motility and attachment, which could potentially lead to a decrease in drug uptake. Moreover, we report that the adverse effects of tobramycin on translation are countered with enhanced expression of genes involved in stalled ribosome rescue, tRNA methylation and type II toxin-antitoxin (TA) systems.
Collapse
Affiliation(s)
- Anastasia Cianciulli Sesso
- Max Perutz Labs, Vienna Biocenter (VBC), Department of Microbiology, Immunobiology and Genetics, University of Vienna, Vienna, Austria
| | - Branislav Lilić
- Max Perutz Labs, Vienna Biocenter (VBC), Department of Microbiology, Immunobiology and Genetics, University of Vienna, Vienna, Austria
| | - Fabian Amman
- Institute for Theoretical Chemistry, University of Vienna, Vienna, Austria
| | - Michael T Wolfinger
- Institute for Theoretical Chemistry, University of Vienna, Vienna, Austria.,Research Group Bioinformatics and Computational Biology, Faculty of Computer Science, University of Vienna, Vienna, Austria
| | - Elisabeth Sonnleitner
- Max Perutz Labs, Vienna Biocenter (VBC), Department of Microbiology, Immunobiology and Genetics, University of Vienna, Vienna, Austria
| | - Udo Bläsi
- Max Perutz Labs, Vienna Biocenter (VBC), Department of Microbiology, Immunobiology and Genetics, University of Vienna, Vienna, Austria
| |
Collapse
|
11
|
Bouffartigues E, Si Hadj Mohand I, Maillot O, Tortuel D, Omnes J, David A, Tahrioui A, Duchesne R, Azuama CO, Nusser M, Brenner-Weiss G, Bazire A, Connil N, Orange N, Feuilloley MGJ, Lesouhaitier O, Dufour A, Cornelis P, Chevalier S. The Temperature-Regulation of Pseudomonas aeruginosa cmaX-cfrX-cmpX Operon Reveals an Intriguing Molecular Network Involving the Sigma Factors AlgU and SigX. Front Microbiol 2020; 11:579495. [PMID: 33193206 PMCID: PMC7641640 DOI: 10.3389/fmicb.2020.579495] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 09/23/2020] [Indexed: 11/13/2022] Open
Abstract
Pseudomonas aeruginosa is a highly adaptable Gram-negative opportunistic pathogen, notably due to its large number of transcription regulators. The extracytoplasmic sigma factor (ECFσ) AlgU, responsible for alginate biosynthesis, is also involved in responses to cell wall stress and heat shock via the RpoH alternative σ factor. The SigX ECFσ emerged as a major regulator involved in the envelope stress response via membrane remodeling, virulence and biofilm formation. However, their functional interactions to coordinate the envelope homeostasis in response to environmental variations remain to be determined. The regulation of the putative cmaX-cfrX-cmpX operon located directly upstream sigX was investigated by applying sudden temperature shifts from 37°C. We identified a SigX- and an AlgU- dependent promoter region upstream of cfrX and cmaX, respectively. We show that cmaX expression is increased upon heat shock through an AlgU-dependent but RpoH independent mechanism. In addition, the ECFσ SigX is activated in response to valinomycin, an agent altering the membrane structure, and up-regulates cfrX-cmpX transcription in response to cold shock. Altogether, these data provide new insights into the regulation exerted by SigX and networks that are involved in maintaining envelope homeostasis.
Collapse
Affiliation(s)
- Emeline Bouffartigues
- Laboratoire de Microbiologie Signaux et Microenvironnement (LMSM) EA 4312, Normandie Université, Université de Rouen Normandie, Centre de Sécurité Sanitaire de Normandie, Evreux, France
| | - Ishac Si Hadj Mohand
- Laboratoire de Microbiologie Signaux et Microenvironnement (LMSM) EA 4312, Normandie Université, Université de Rouen Normandie, Centre de Sécurité Sanitaire de Normandie, Evreux, France
| | - Olivier Maillot
- Laboratoire de Microbiologie Signaux et Microenvironnement (LMSM) EA 4312, Normandie Université, Université de Rouen Normandie, Centre de Sécurité Sanitaire de Normandie, Evreux, France
| | - Damien Tortuel
- Laboratoire de Microbiologie Signaux et Microenvironnement (LMSM) EA 4312, Normandie Université, Université de Rouen Normandie, Centre de Sécurité Sanitaire de Normandie, Evreux, France
| | - Jordane Omnes
- Laboratoire de Microbiologie Signaux et Microenvironnement (LMSM) EA 4312, Normandie Université, Université de Rouen Normandie, Centre de Sécurité Sanitaire de Normandie, Evreux, France
| | - Audrey David
- Laboratoire de Microbiologie Signaux et Microenvironnement (LMSM) EA 4312, Normandie Université, Université de Rouen Normandie, Centre de Sécurité Sanitaire de Normandie, Evreux, France
| | - Ali Tahrioui
- Laboratoire de Microbiologie Signaux et Microenvironnement (LMSM) EA 4312, Normandie Université, Université de Rouen Normandie, Centre de Sécurité Sanitaire de Normandie, Evreux, France
| | - Rachel Duchesne
- Laboratoire de Microbiologie Signaux et Microenvironnement (LMSM) EA 4312, Normandie Université, Université de Rouen Normandie, Centre de Sécurité Sanitaire de Normandie, Evreux, France
| | - Cecil Onyedikachi Azuama
- Laboratoire de Microbiologie Signaux et Microenvironnement (LMSM) EA 4312, Normandie Université, Université de Rouen Normandie, Centre de Sécurité Sanitaire de Normandie, Evreux, France
| | - Michael Nusser
- Institute of Functional Interfaces, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Gerald Brenner-Weiss
- Institute of Functional Interfaces, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Alexis Bazire
- Laboratoire de Biotechnologie et Chimie Marines (LBCM) EA3884, IUEM, Université de Bretagne-Sud, Lorient, France
| | - Nathalie Connil
- Laboratoire de Microbiologie Signaux et Microenvironnement (LMSM) EA 4312, Normandie Université, Université de Rouen Normandie, Centre de Sécurité Sanitaire de Normandie, Evreux, France
| | - Nicole Orange
- Laboratoire de Microbiologie Signaux et Microenvironnement (LMSM) EA 4312, Normandie Université, Université de Rouen Normandie, Centre de Sécurité Sanitaire de Normandie, Evreux, France
| | - Marc G J Feuilloley
- Laboratoire de Microbiologie Signaux et Microenvironnement (LMSM) EA 4312, Normandie Université, Université de Rouen Normandie, Centre de Sécurité Sanitaire de Normandie, Evreux, France
| | - Olivier Lesouhaitier
- Laboratoire de Microbiologie Signaux et Microenvironnement (LMSM) EA 4312, Normandie Université, Université de Rouen Normandie, Centre de Sécurité Sanitaire de Normandie, Evreux, France
| | - Alain Dufour
- Laboratoire de Biotechnologie et Chimie Marines (LBCM) EA3884, IUEM, Université de Bretagne-Sud, Lorient, France
| | - Pierre Cornelis
- Laboratoire de Microbiologie Signaux et Microenvironnement (LMSM) EA 4312, Normandie Université, Université de Rouen Normandie, Centre de Sécurité Sanitaire de Normandie, Evreux, France
| | - Sylvie Chevalier
- Laboratoire de Microbiologie Signaux et Microenvironnement (LMSM) EA 4312, Normandie Université, Université de Rouen Normandie, Centre de Sécurité Sanitaire de Normandie, Evreux, France
| |
Collapse
|
12
|
Yang N, Cao Q, Hu S, Xu C, Fan K, Chen F, Yang C, Liang H, Wu M, Bae T, Lan L. Alteration of protein homeostasis mediates the interaction of
Pseudomonas aeruginosa
with
Staphylococcus aureus. Mol Microbiol 2020; 114:423-442. [DOI: 10.1111/mmi.14519] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 04/09/2020] [Accepted: 04/15/2020] [Indexed: 12/29/2022]
Affiliation(s)
- Nana Yang
- University of Chinese Academy of Sciences Beijing China
- State Key Laboratory of Drug Research Shanghai Institute of Materia Medica Chinese Academy of Sciences Shanghai China
| | - Qiao Cao
- State Key Laboratory of Drug Research Shanghai Institute of Materia Medica Chinese Academy of Sciences Shanghai China
- College of Life Science Northwest University Xi'an China
| | - Shuyang Hu
- University of Chinese Academy of Sciences Beijing China
- State Key Laboratory of Drug Research Shanghai Institute of Materia Medica Chinese Academy of Sciences Shanghai China
| | - Chenchen Xu
- University of Chinese Academy of Sciences Beijing China
- State Key Laboratory of Drug Research Shanghai Institute of Materia Medica Chinese Academy of Sciences Shanghai China
| | - Ke Fan
- University of Chinese Academy of Sciences Beijing China
- State Key Laboratory of Drug Research Shanghai Institute of Materia Medica Chinese Academy of Sciences Shanghai China
| | - Feifei Chen
- State Key Laboratory of Drug Research Shanghai Institute of Materia Medica Chinese Academy of Sciences Shanghai China
- College of Life Science Northwest University Xi'an China
| | - Cai‐Guang Yang
- University of Chinese Academy of Sciences Beijing China
- State Key Laboratory of Drug Research Shanghai Institute of Materia Medica Chinese Academy of Sciences Shanghai China
| | - Haihua Liang
- College of Life Science Northwest University Xi'an China
| | - Min Wu
- Department of Biomedical Sciences University of North Dakota Grand Forks ND USA
| | - Taeok Bae
- Department of Microbiology and Immunology Indiana University School of Medicine‐Northwest Gary IN USA
| | - Lefu Lan
- University of Chinese Academy of Sciences Beijing China
- State Key Laboratory of Drug Research Shanghai Institute of Materia Medica Chinese Academy of Sciences Shanghai China
- College of Life Science Northwest University Xi'an China
- NMPA Key Laboratory for Testing Technology of Pharmaceutical Microbiology Shanghai Institute for Food and Drug Control Shanghai China
| |
Collapse
|
13
|
Woode BK, Daliri F, Daliri EBM. Correlation Between food Processing-Associated Stress Tolerance and Antimicrobial Resistance in Food Pathogens. ACTA ACUST UNITED AC 2020. [DOI: 10.13103/jfhs.2020.35.2.103] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
14
|
Muselius B, Sukumaran A, Yeung J, Geddes-McAlister J. Iron Limitation in Klebsiella pneumoniae Defines New Roles for Lon Protease in Homeostasis and Degradation by Quantitative Proteomics. Front Microbiol 2020; 11:546. [PMID: 32390954 PMCID: PMC7194016 DOI: 10.3389/fmicb.2020.00546] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Accepted: 03/12/2020] [Indexed: 01/24/2023] Open
Abstract
Nutrient adaptation is key in limiting environments for the promotion of microbial growth and survival. In microbial systems, iron is an essential component for many cellular processes, and bioavailability varies greatly among different conditions. In the bacterium, Klebsiella pneumoniae, the impact of iron limitation is known to alter transcriptional expression of iron-acquisition pathways and influence secretion of iron-binding siderophores, however, a comprehensive view of iron limitation at the protein level remains to be defined. Here, we apply a mass-spectrometry-based quantitative proteomics strategy to profile the global impact of iron limitation on the cellular proteome and extracellular environment (secretome) of K. pneumoniae. Our data define the impact of iron on proteins involved in transcriptional regulation and emphasize the modulation of a vast array of proteins associated with iron acquisition, transport, and binding. We also identify proteins in the extracellular environment associated with conventional and non-conventional modes of secretion, as well as vesicle release. In particular, we demonstrate a new role for Lon protease in promoting iron homeostasis outside of the cell. Characterization of a Lon protease mutant in K. pneumoniae validates roles in bacterial growth, cell division, and virulence, and uncovers novel degradation candidates of Lon protease associated with improved iron utilization strategies in the absence of the enzyme. Overall, we provide evidence of unique connections between Lon and iron in a bacterial system and suggest a new role for Lon protease in the extracellular environment during nutrient limitation.
Collapse
|
15
|
Palma E, Tilocca B, Roncada P. Antimicrobial Resistance in Veterinary Medicine: An Overview. Int J Mol Sci 2020; 21:E1914. [PMID: 32168903 PMCID: PMC7139321 DOI: 10.3390/ijms21061914] [Citation(s) in RCA: 105] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 03/03/2020] [Accepted: 03/10/2020] [Indexed: 02/07/2023] Open
Abstract
Antimicrobial resistance (AMR) represents one of the most important human- and animal health-threatening issues worldwide. Bacterial capability to face antimicrobial compounds is an ancient feature, enabling bacterial survival over time and the dynamic surrounding. Moreover, bacteria make use of their evolutionary machinery to adapt to the selective pressure exerted by antibiotic treatments, resulting in reduced efficacy of the therapeutic intervention against human and animal infections. The mechanisms responsible for both innate and acquired AMR are thoroughly investigated. Commonly, AMR traits are included in mobilizable genetic elements enabling the homogeneous diffusion of the AMR traits pool between the ecosystems of diverse sectors, such as human medicine, veterinary medicine, and the environment. Thus, a coordinated multisectoral approach, such as One-Health, provides a detailed comprehensive picture of the AMR onset and diffusion. Following a general revision of the molecular mechanisms responsible for both innate and acquired AMR, the present manuscript focuses on reviewing the contribution of veterinary medicine to the overall issue of AMR. The main sources of AMR amenable to veterinary medicine are described, driving the attention towards the indissoluble cross-talk existing between the diverse ecosystems and sectors and their cumulative cooperation to this warning phenomenon.
Collapse
Affiliation(s)
| | | | - Paola Roncada
- Department of Health Science, University “Magna Graecia” of Catanzaro, Viale Europa, 88100 Catanzaro, Italy; (E.P.); (B.T.)
| |
Collapse
|
16
|
TpiA is a Key Metabolic Enzyme That Affects Virulence and Resistance to Aminoglycoside Antibiotics through CrcZ in Pseudomonas aeruginosa. mBio 2020; 11:mBio.02079-19. [PMID: 31911486 PMCID: PMC6946797 DOI: 10.1128/mbio.02079-19] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The increase in bacterial resistance against antibiotics imposes a severe threat to public health. It is urgent to identify new drug targets and develop novel antimicrobials. Metabolic homeostasis of bacteria plays an essential role in their virulence and resistance to antibiotics. Recent studies demonstrated that antibiotic efficacies can be improved by modulating the bacterial metabolism. Pseudomonas aeruginosa is an important opportunistic human pathogen that causes various infections. The bacterium is intrinsically resistant to antibiotics. In this study, we provide clear evidence that TpiA (triosephosphate isomerase) plays an essential role in the metabolism of P. aeruginosa and influences bacterial virulence and antibiotic resistance. The significance of this work is in identifying a key enzyme in the metabolic network, which will provide clues as to the development of novel treatment strategies against infections caused by P. aeruginosa. Carbon metabolism plays an essential role in bacterial pathogenesis and susceptibility to antibiotics. In Pseudomonas aeruginosa, Crc, Hfq, and a small RNA, CrcZ, are central regulators of carbon metabolism. By screening mutants of genes involved in carbon metabolism, we found that mutation of the tpiA gene reduces the expression of the type III secretion system (T3SS) and bacterial resistance to aminoglycoside antibiotics. TpiA is a triosephosphate isomerase that reversibly converts glyceraldehyde 3-phosphate to dihydroxyacetone phosphate, a key step connecting glucose metabolism with glycerol and phospholipid metabolisms. We found that mutation of the tpiA gene enhances the bacterial carbon metabolism, respiration, and oxidative phosphorylation, which increases the membrane potential and promotes the uptake of aminoglycoside antibiotics. Further studies revealed that the level of CrcZ is increased in the tpiA mutant due to enhanced stability. Mutation of the crcZ gene in the tpiA mutant background restored the expression of the T3SS genes and the bacterial resistance to aminoglycoside antibiotics. Overall, this study reveals an essential role of TpiA in the metabolism, virulence, and antibiotic resistance in P. aeruginosa.
Collapse
|
17
|
Interplay of antibiotic resistance and food-associated stress tolerance in foodborne pathogens. Trends Food Sci Technol 2020. [DOI: 10.1016/j.tifs.2019.11.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
|
18
|
Ciofu O, Tolker-Nielsen T. Tolerance and Resistance of Pseudomonas aeruginosa Biofilms to Antimicrobial Agents-How P. aeruginosa Can Escape Antibiotics. Front Microbiol 2019; 10:913. [PMID: 31130925 PMCID: PMC6509751 DOI: 10.3389/fmicb.2019.00913] [Citation(s) in RCA: 371] [Impact Index Per Article: 74.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 04/10/2019] [Indexed: 11/24/2022] Open
Abstract
Pseudomonas aeruginosa is one of the six bacterial pathogens, Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp., which are commonly associated with antimicrobial resistance, and denoted by their acronym ESKAPE. P. aeruginosa is also recognized as an important cause of chronic infections due to its ability to form biofilms, where the bacteria are present in aggregates encased in a self-produced extracellular matrix and are difficult or impossible to eradicate with antibiotic treatment. P. aeruginosa causes chronic infections in the lungs of patients with cystic fibrosis and chronic obstructive lung disease, as well as chronic urinary tract infections in patients with permanent bladder catheter, and ventilator-associated pneumonia in intubated patients, and is also an important pathogen in chronic wounds. Antibiotic treatment cannot eradicate these biofilm infections due to their intrinsic antibiotic tolerance and the development of mutational antibiotic resistance. The tolerance of biofilms to antibiotics is multifactorial involving physical, physiological, and genetic determinants, whereas the antibiotic resistance of bacteria in biofilms is caused by mutations and driven by the repeated exposure of the bacteria to high levels of antibiotics. In this review, both the antimicrobial tolerance and the development of resistance to antibiotics in P. aeruginosa biofilms are discussed. Possible therapeutic approaches based on the understanding of the mechanisms involved in the tolerance and resistances of biofilms to antibiotics are also addressed.
Collapse
Affiliation(s)
- Oana Ciofu
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark
| | - Tim Tolker-Nielsen
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark
| |
Collapse
|
19
|
Reichhardt C, Parsek MR. Confocal Laser Scanning Microscopy for Analysis of Pseudomonas aeruginosa Biofilm Architecture and Matrix Localization. Front Microbiol 2019; 10:677. [PMID: 31001240 PMCID: PMC6454187 DOI: 10.3389/fmicb.2019.00677] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Accepted: 03/18/2019] [Indexed: 11/24/2022] Open
Abstract
Most microbes can produce surface-associated or suspended aggregates called biofilms, which are encased within a biopolymer-rich matrix. The biofilm matrix provides structural integrity to the aggregates and shields the resident cells against environmental stressors, including antibiotic treatment. Microscopy permits examination of biofilm structure in relation to the spatial localization of important biofilm matrix components. This review highlights microscopic approaches to investigate bacterial biofilm assembly, matrix composition, and localization using Pseudomonas aeruginosa as a model organism. Initial microscopic investigations provided information about the role key matrix components play in elaborating biofilm aggregate structures. Additionally, staining of matrix components using specific labels revealed distinct positioning of matrix components within the aggregates relative to the resident cells. In some cases, it was found that individual matrix components co-localize within aggregates. The methodologies for studying the biofilm matrix are continuing to develop as our studies reveal novel aspects of its composition and function. We additionally describe some outstanding questions and how microscopy might be used to identify the functional aspects of biofilm matrix components.
Collapse
Affiliation(s)
| | - Matthew R. Parsek
- Department of Microbiology, University of Washington, Seattle, WA, United States
| |
Collapse
|
20
|
Hwang W, Yoon SS. Virulence Characteristics and an Action Mode of Antibiotic Resistance in Multidrug-Resistant Pseudomonas aeruginosa. Sci Rep 2019; 9:487. [PMID: 30679735 PMCID: PMC6345838 DOI: 10.1038/s41598-018-37422-9] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 11/28/2018] [Indexed: 12/15/2022] Open
Abstract
Pseudomonas aeruginosa displays intrinsic resistance to many antibiotics and known to acquire actively genetic mutations for further resistance. In this study, we attempted to understand genomic and transcriptomic landscapes of P. aeruginosa clinical isolates that are highly resistant to multiple antibiotics. We also aimed to reveal a mode of antibiotic resistance by elucidating transcriptional response of genes conferring antibiotic resistance. To this end, we sequenced the whole genomes and profiled genome-wide RNA transcripts of three different multi-drug resistant (MDR) clinical isolates that are phylogenetically distant from one another. Multi-layered genome comparisons with genomes of antibiotic-susceptible P. aeruginosa strains and 70 other antibiotic-resistance strains revealed both well-characterized conserved gene mutations and distinct distribution of antibiotic-resistant genes (ARGs) among strains. Transcriptions of genes involved in quorum sensing and type VI secretion systems were invariably downregulated in the MDR strains. Virulence-associated phenotypes were further examined and results indicate that our MDR strains are clearly avirulent. Transcriptions of 64 genes, logically selected to be related with antibiotic resistance in MDR strains, were active under normal growth conditions and remained unchanged during antibiotic treatment. These results propose that antibiotic resistance is achieved by a "constitutive" response scheme, where ARGs are actively expressed even in the absence of antibiotic stress, rather than a "reactive" response. Bacterial responses explored at the transcriptomic level in conjunction with their genome repertoires provided novel insights into (i) the virulence-associated phenotypes and (ii) a mode of antibiotic resistance in MDR P. aeruginosa strains.
Collapse
Affiliation(s)
- Wontae Hwang
- Department of Microbiology and Immunology, Brain Korea 21 PLUS Project for Medical Sciences, Seoul, Korea
- Institute for Immunology and Immunological Diseases, Yonsei University College of Medicine, Seoul, 03722, Korea
| | - Sang Sun Yoon
- Department of Microbiology and Immunology, Brain Korea 21 PLUS Project for Medical Sciences, Seoul, Korea.
- Institute for Immunology and Immunological Diseases, Yonsei University College of Medicine, Seoul, 03722, Korea.
| |
Collapse
|
21
|
Triclosan Is an Aminoglycoside Adjuvant for Eradication of Pseudomonas aeruginosa Biofilms. Antimicrob Agents Chemother 2018; 62:AAC.00146-18. [PMID: 29661867 DOI: 10.1128/aac.00146-18] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 03/31/2018] [Indexed: 02/06/2023] Open
Abstract
One of the most important clinical obstacles in cystic fibrosis (CF) treatment is antibiotic treatment failure due to biofilms produced by Pseudomonas aeruginosa The ability of this pathogen to survive eradication by tobramycin and pathoadapt into a hyperbiofilm state leading to chronic infections is key to its success. Retrospective studies have demonstrated that preventing this pathoadaptation by improving eradication is essential to extend the lives of CF patients. To identify adjuvants that enhance tobramycin eradication of P. aeruginosa, we performed a high-throughput screen of 6,080 compounds from four drug-repurposing libraries. We identified that the Food and Drug Administration (FDA)-approved compound triclosan, in combination with tobramycin, resulted in a 100-fold reduction of viable cells within biofilms at 6 h, but neither compound alone had significant antimicrobial activity against biofilms. This synergistic treatment significantly accelerated the killing of biofilms compared to that with tobramycin treatment alone, and the combination was effective against 6/7 CF clinical isolates compared to tobramycin treatment alone, including a tobramycin-resistant strain. Further, triclosan and tobramycin killed persister cells, causing a 100-fold reduction by 8 h and complete eradication by 24 h. Triclosan also enhances tobramycin killing of multiple Burkholderia cenocepacia and Staphylococcus aureus clinical isolates grown as biofilms. Additionally, triclosan showed synergy with other aminoglycosides, such as gentamicin or streptomycin. Triclosan is a well-tolerated aminoglycoside adjuvant shown to be safe for human use that could improve the treatment of biofilm-based infections.
Collapse
|
22
|
Tkachenko AG. Stress Responses of Bacterial Cells as Mechanism of Development of Antibiotic Tolerance (Review). APPL BIOCHEM MICRO+ 2018. [DOI: 10.1134/s0003683818020114] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
23
|
Sub-inhibitory concentrations of gentamicin triggers the expression of aac(6')Ie-aph(2″)Ia, chaperons and biofilm related genes in Lactobacillus plantarum MCC 3011. Res Microbiol 2017; 168:722-731. [PMID: 28684253 DOI: 10.1016/j.resmic.2017.06.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 06/10/2017] [Accepted: 06/18/2017] [Indexed: 12/23/2022]
Abstract
The study aimed to analyze the effects of sub-inhibitory concentrations of gentamicin on the expressions of high level aminoglycoside resistant (HLAR) bifunctional aac(6')Ie-aph(2″)Ia, biofilm and chaperone genes in Lactobacillus plantarum. The analysis of the biofilm formation in five isolates obtained from chicken sausages indicated their role in exhibiting phenotypic resistance based on the varied MIC values despite carrying the bifunctional gene. The biofilm formation significantly increased when L. plantarum MCC 3011 was grown in sub-inhibitory concentrations of gentamicin (4 μg/ml), kanamycin (8 μg/ml) and streptomycin (2 μg/ml). Thirty day gentamicin selection increased minimum inhibitory concentration (MIC) values from 4 to 64 and 2 to 256 fold for gentamicin and kanamycin, respectively when compared to the parental cultures. Expression studies revealed that constant exposure to gentamicin had induced chaperon [groEL] and the bifunctional gene, aac(6')Ie-aph(2″)Ia upto nine fold. Induction of groEL, groES and lamC genes in gentamicin (4 μg/ml) preincubated MCC 3011 indicated their significant role in aminoglycoside mediated response. Our study indicates that constant exposure to sub inhibitory concentrations of gentamicin allows L. plantarum to adapt against higher doses of aminoglycosides. This highlights the risks and food safety issues associated with the use of aminoglycosides in livestock and consumption of farm oriented fermented food products.
Collapse
|
24
|
Pan X, Dong Y, Fan Z, Liu C, Xia B, Shi J, Bai F, Jin Y, Cheng Z, Jin S, Wu W. In vivo Host Environment Alters Pseudomonas aeruginosa Susceptibility to Aminoglycoside Antibiotics. Front Cell Infect Microbiol 2017; 7:83. [PMID: 28352614 PMCID: PMC5348532 DOI: 10.3389/fcimb.2017.00083] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Accepted: 03/02/2017] [Indexed: 01/06/2023] Open
Abstract
During host infection, Pseudomonas aeruginosa coordinately regulates the expression of numerous genes to adapt to the host environment while counteracting host clearance mechanisms. As infected patients take antibiotics, the invading bacteria encounter antibiotics in the host milieu. P. aeruginosa is highly resistant to antibiotics due to multiple chromosomally encoded resistant determinants. And numerous in vitro studies have demonstrated the regulatory mechanisms of antibiotic resistance related genes in response to antibiotics. However, it is not well-known how host environment affects bacterial response to antibiotics. In this study, we found that P. aeruginosa cells directly isolated from mice lungs displayed higher susceptibility to tobramycin than in vitro cultured bacteria. In vitro experiments demonstrated that incubation with A549 and differentiated HL60 (dHL60) cells sensitized P. aeruginosa to tobramycin. Further studies revealed that reactive oxygen species produced by the host cells contributed to the increased bacterial susceptibility. At the same concentration of tobramycin, presence of A549 and dHL60 cells resulted in higher expression of heat shock proteins, which are known inducible by tobramycin. Further analyses revealed decreased membrane potential upon incubation with the host cells and modification of lipopolysaccharide, which contributed to the increased susceptibility to tobramycin. Therefore, our results demonstrate that contact with host cells increased bacterial susceptibility to tobramycin.
Collapse
Affiliation(s)
- Xiaolei Pan
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Yuanyuan Dong
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Zheng Fan
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Chang Liu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Bin Xia
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Jing Shi
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Fang Bai
- State Key Laboratory of Medicinal Chemical Biology and College of Pharmacy and Life Sciences, Nankai University Tianjin, China
| | - Yongxin Jin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Zhihui Cheng
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Shouguang Jin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai UniversityTianjin, China; Department of Molecular Genetics and Microbiology, College of Medicine, University of FloridaGainesville, FL, USA
| | - Weihui Wu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| |
Collapse
|
25
|
Trimble MJ, Mlynárčik P, Kolář M, Hancock REW. Polymyxin: Alternative Mechanisms of Action and Resistance. Cold Spring Harb Perspect Med 2016; 6:cshperspect.a025288. [PMID: 27503996 DOI: 10.1101/cshperspect.a025288] [Citation(s) in RCA: 243] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Antibiotic resistance among pathogenic bacteria is an ever-increasing issue worldwide. Unfortunately, very little has been achieved in the pharmaceutical industry to combat this problem. This has led researchers and the medical field to revisit past drugs that were deemed too toxic for clinical use. In particular, the cyclic cationic peptides polymyxin B and colistin, which are specific for Gram-negative bacteria, have been used as "last resort" antimicrobials. Before the 1980s, these drugs were known for their renal and neural toxicities; however, new clinical practices and possibly improved manufacturing have made them safer to use. Previously suggested to primarily attack the membranes of Gram-negative bacteria and to not easily select for resistant mutants, recent research exploring resistance and mechanisms of action has provided new perspectives. This review focuses primarily on the proposed alternative mechanisms of action, known resistance mechanisms, and how these support the alternative mechanisms of action.
Collapse
Affiliation(s)
- Michael J Trimble
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Patrik Mlynárčik
- Department of Microbiology, Faculty of Medicine and Dentistry, Palacký University, 771 47 Olomouc, Czech Republic
| | - Milan Kolář
- Department of Microbiology, Faculty of Medicine and Dentistry, Palacký University, 771 47 Olomouc, Czech Republic
| | - Robert E W Hancock
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| |
Collapse
|
26
|
Chan KG, Priya K, Chang CY, Abdul Rahman AY, Tee KK, Yin WF. Transcriptome analysis of Pseudomonas aeruginosa PAO1 grown at both body and elevated temperatures. PeerJ 2016; 4:e2223. [PMID: 27547539 PMCID: PMC4957987 DOI: 10.7717/peerj.2223] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 06/15/2016] [Indexed: 01/15/2023] Open
Abstract
Functional genomics research can give us valuable insights into bacterial gene function. RNA Sequencing (RNA-seq) can generate information on transcript abundance in bacteria following abiotic stress treatments. In this study, we used the RNA-seq technique to study the transcriptomes of the opportunistic nosocomial pathogen Pseudomonas aeruginosa PAO1 following heat shock. Samples were grown at both the human body temperature (37 °C) and an arbitrarily-selected temperature of 46 °C. In this work using RNA-seq, we identified 133 genes that are differentially expressed at 46 °C compared to the human body temperature. Our work identifies some key P. aeruginosa PAO1 genes whose products have importance in both environmental adaptation as well as in vivo infection in febrile hosts. More importantly, our transcriptomic results show that many genes are only expressed when subjected to heat shock. Because the RNA-seq can generate high throughput gene expression profiles, our work reveals many unanticipated genes with further work to be done exploring such genes products.
Collapse
Affiliation(s)
- Kok-Gan Chan
- ISB (Genetics & Molecular Biology), Faculty of Science, University of Malaya , Kuala Lumpur , Malaysia
| | - Kumutha Priya
- ISB (Genetics & Molecular Biology), Faculty of Science, University of Malaya , Kuala Lumpur , Malaysia
| | - Chien-Yi Chang
- School of Life Sciences, Heriot-Watt University , Edinburgh , United Kingdom
| | | | - Kok Keng Tee
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya , Kuala Lumpur , Malaysia
| | - Wai-Fong Yin
- ISB (Genetics & Molecular Biology), Faculty of Science, University of Malaya , Kuala Lumpur , Malaysia
| |
Collapse
|
27
|
Interconnection of post-transcriptional regulation: The RNA-binding protein Hfq is a novel target of the Lon protease in Pseudomonas aeruginosa. Sci Rep 2016; 6:26811. [PMID: 27229357 PMCID: PMC4882532 DOI: 10.1038/srep26811] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 05/09/2016] [Indexed: 01/22/2023] Open
Abstract
Besides being a major opportunistic human pathogen, Pseudomonas aeruginosa can be found in a wide range of environments. This versatility is linked to complex regulation, which is achieved through the action of transcriptional regulators, and post-transcriptional regulation by intracellular proteases including Lon. Indeed, lon mutants in this species show defects in motility, biofilm formation, pathogenicity and fluoroquinolone resistance. Here, the proteomic approach stable isotope labeling by amino acids in cell culture (SILAC) was used to search for novel proteolytic targets. One of the proteins that accumulated in the lon mutant was the RNA-binding protein Hfq. Further experiments demonstrated the ability of Lon to degrade Hfq in vitro. Also, overexpression of the hfq gene in the wild-type strain led to partial inhibition of swarming, swimming and twitching motilities, indicating that Hfq accumulation could contribute to the phenotypes displayed by Lon mutants. Hfq overexpression also led to the upregulation of the small regulatory RNA PhrS. Analysis of the phenotypes of strains lacking or overexpressing this sRNA indicated that the Lon protease might be indirectly regulating the levels and activity of sRNAs via Hfq. Overall, this study revealed new links in the complex regulatory chain that controls multicellular behaviours in P. aeruginosa.
Collapse
|
28
|
Rybtke M, Hultqvist LD, Givskov M, Tolker-Nielsen T. Pseudomonas aeruginosa Biofilm Infections: Community Structure, Antimicrobial Tolerance and Immune Response. J Mol Biol 2015; 427:3628-45. [DOI: 10.1016/j.jmb.2015.08.016] [Citation(s) in RCA: 132] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 08/18/2015] [Accepted: 08/20/2015] [Indexed: 02/07/2023]
|
29
|
Abstract
Antimicrobial-resistant bacteria pose a serious threat in the clinic. This is particularly true for opportunistic pathogens that possess high intrinsic resistance. Though many studies have focused on understanding the acquisition of bacterial resistance upon exposure to antimicrobials, the mechanisms controlling intrinsic resistance are not well understood. In this study, we subjected the model opportunistic superbug Pseudomonas aeruginosa to 14 antimicrobials under highly controlled conditions and assessed its response using expression- and fitness-based genomic approaches. Our results reveal that gene expression changes and mutant fitness in response to sub-MIC antimicrobials do not correlate on a genomewide scale, indicating that gene expression is not a good predictor of fitness determinants. In general, fewer fitness determinants were identified for antiseptics and disinfectants than for antibiotics. Analysis of gene expression and fitness data together allowed the prediction of antagonistic interactions between antimicrobials and insight into the molecular mechanisms controlling these interactions. Infections involving multidrug-resistant pathogens are difficult to treat because the therapeutic options are limited. These infections impose a significant financial burden on infected patients and on health care systems. Despite years of antimicrobial resistance research, we lack a comprehensive understanding of the intrinsic mechanisms controlling antimicrobial resistance. This work uses two fine-scale genomic approaches to identify genetic loci important for antimicrobial resistance of the opportunistic pathogen Pseudomonas aeruginosa. Our results reveal that antibiotics have more resistance determinants than antiseptics/disinfectants and that gene expression upon exposure to antimicrobials is not a good predictor of these resistance determinants. In addition, we show that when used together, genomewide gene expression and fitness profiling can provide mechanistic insights into multidrug resistance mechanisms.
Collapse
|
30
|
Bernardini A, Corona F, Dias R, Sánchez MB, Martínez JL. The inactivation of RNase G reduces the Stenotrophomonas maltophilia susceptibility to quinolones by triggering the heat shock response. Front Microbiol 2015; 6:1068. [PMID: 26539164 PMCID: PMC4609926 DOI: 10.3389/fmicb.2015.01068] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 09/17/2015] [Indexed: 01/11/2023] Open
Abstract
Quinolone resistance is usually due to mutations in the genes encoding bacterial topoisomerases. However, different reports have shown that neither clinical quinolone resistant isolates nor in vitro obtained Stenotrophomonas maltophilia mutants present mutations in such genes. The mechanisms so far described consist on efflux pumps' overexpression. Our objective is to get information on novel mechanisms of S. maltophilia quinolone resistance. For this purpose, a transposon-insertion mutant library was obtained in S. maltophilia D457. One mutant presenting reduced susceptibility to nalidixic acid was selected. Inverse PCR showed that the inactivated gene encodes RNase G. Complementation of the mutant with wild-type RNase G allele restored the susceptibility to quinolones. Transcriptomic and real-time RT-PCR analyses showed that several genes encoding heat-shock response proteins were expressed at higher levels in the RNase defective mutant than in the wild-type strain. In agreement with this situation, heat-shock reduces the S. maltophilia susceptibility to quinolone. We can then conclude that the inactivation of the RNase G reduces the susceptibility of S. maltophilia to quinolones, most likely by regulating the expression of heat-shock response genes. Heat-shock induces a transient phenotype of quinolone resistance in S. maltophilia.
Collapse
Affiliation(s)
- Alejandra Bernardini
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas Madrid, Spain
| | - Fernando Corona
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas Madrid, Spain
| | - Ricardo Dias
- Biosystems and Integrative Sciences Institute, Faculty of Sciences, University of Lisbon Lisbon, Portugal
| | - Maria B Sánchez
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas Madrid, Spain
| | - Jose L Martínez
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas Madrid, Spain
| |
Collapse
|
31
|
Tobramycin-Treated Pseudomonas aeruginosa PA14 Enhances Streptococcus constellatus 7155 Biofilm Formation in a Cystic Fibrosis Model System. J Bacteriol 2015; 198:237-47. [PMID: 26483523 DOI: 10.1128/jb.00705-15] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 10/12/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Cystic fibrosis (CF) is a human genetic disorder which results in a lung environment that is highly conducive to chronic microbial infection. Over the past decade, deep-sequencing studies have demonstrated that the CF lung can harbor a highly diverse polymicrobial community. We expanded our existing in vitro model of Pseudomonas aeruginosa biofilm formation on CF-derived airway cells to include this broader set of CF airway colonizers to investigate their contributions to CF lung disease, particularly as they relate to the antibiotic response of the population. Using this system, we identified an interspecies interaction between P. aeruginosa, a bacterium associated with declining lung function and worsening disease, and Streptococcus constellatus, a bacterium correlated with the onset of pulmonary exacerbations in CF patients. The growth rate and cytotoxicity of S. constellatus 7155 and P. aeruginosa PA14 were unchanged when grown together as mixed biofilms in the absence of antibiotics. However, the addition of tobramycin, the frontline maintenance therapy antibiotic for individuals with CF, to a mixed biofilm of S. constellatus 7155 and P. aeruginosa PA14 resulted in enhanced S. constellatus biofilm formation. Through a candidate genetic approach, we showed that P. aeruginosa rhamnolipids were reduced upon tobramycin exposure, allowing for S. constellatus 7155 biofilm enhancement, and monorhamnolipids were sufficient to reduce S. constellatus 7155 biofilm viability in the absence of tobramycin. While the findings presented here are specific to a biofilm of S. constellatus 7155 and P. aeruginosa PA14, they highlight the potential of polymicrobial interactions to impact antibiotic tolerance in unanticipated ways. IMPORTANCE Deep-sequencing studies have demonstrated that the CF lung can harbor a diverse polymicrobial community. By recapitulating the polymicrobial communities observed in the CF lung and identifying mechanisms of interspecies interactions, we have the potential to select the best therapy for a given bacterial community and reveal potential opportunities for novel therapeutic interventions. Using an in vitro model of bacterial infection on CF airway cells, we tested how a particular polymicrobial community grows, damages human cells, and responds to antibiotics in single and mixed infections. We describe here the mechanism of an interspecies interaction between two pathogens in the CF lung, P. aeruginosa and S. constellatus, which is potentiated by a commonly prescribed antibiotic, tobramycin.
Collapse
|
32
|
Garneau-Tsodikova S, Labby KJ. Mechanisms of Resistance to Aminoglycoside Antibiotics: Overview and Perspectives. MEDCHEMCOMM 2015; 7:11-27. [PMID: 26877861 DOI: 10.1039/c5md00344j] [Citation(s) in RCA: 267] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Aminoglycoside (AG) antibiotics are used to treat many Gram-negative and some Gram-positive infections and, importantly, multidrug-resistant tuberculosis. Among various bacterial species, resistance to AGs arises through a variety of intrinsic and acquired mechanisms. The bacterial cell wall serves as a natural barrier for small molecules such as AGs and may be further fortified via acquired mutations. Efflux pumps work to expel AGs from bacterial cells, and modifications here too may cause further resistance to AGs. Mutations in the ribosomal target of AGs, while rare, also contribute to resistance. Of growing clinical prominence is resistance caused by ribosome methyltransferases. By far the most widespread mechanism of resistance to AGs is the inactivation of these antibiotics by AG-modifying enzymes. We provide here an overview of these mechanisms by which bacteria become resistant to AGs and discuss their prevalence and potential for clinical relevance.
Collapse
Affiliation(s)
- Sylvie Garneau-Tsodikova
- University of Kentucky, Department of Pharmaceutical Sciences, 789 South Limestone Street, Lexington, KY, USA. ; Tel: 859-218-1686
| | - Kristin J Labby
- Beloit College, Department of Chemistry, 700 College Street, Beloit, WI, USA. ; Tel: 608-363-2273
| |
Collapse
|
33
|
Wu X, Held K, Zheng C, Staudinger BJ, Chavez JD, Weisbrod CR, Eng JK, Singh PK, Manoil C, Bruce JE. Dynamic Proteome Response of Pseudomonas aeruginosa to Tobramycin Antibiotic Treatment. Mol Cell Proteomics 2015; 14:2126-37. [PMID: 26018413 DOI: 10.1074/mcp.m115.050161] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Indexed: 11/06/2022] Open
Abstract
Genetically susceptible bacteria become antibiotic tolerant during chronic infections, and the mechanisms responsible are poorly understood. One factor that may contribute to differential sensitivity in vitro and in vivo is differences in the time-dependent tobramycin concentration profile experienced by the bacteria. Here, we examine the proteome response induced by subinhibitory concentrations of tobramycin in Pseudomonas aeruginosa cells grown under planktonic conditions. These efforts revealed increased levels of heat shock proteins and proteases were present at higher dosage treatments (0.5 and 1 μg/ml), while less dramatic at 0.1 μg/ml dosage. In contrast, many metabolic enzymes were significantly induced by lower dosages (0.1 and 0.5 μg/ml) but not at 1 μg/ml dosage. Time course proteome analysis further revealed that the increase of heat shock proteins and proteases was most rapid from 15 min to 60 min, and the increased levels sustained till 6 h (last time point tested). Heat shock protein IbpA exhibited the greatest induction by tobramycin, up to 90-fold. Nevertheless, deletion of ibpA did not enhance sensitivity to tobramycin. It seemed possible that the absence of sensitization could be due to redundant functioning of IbpA with other proteins that protect cells from tobramycin. Indeed, inactivation of two heat shock chaperones/proteases in addition to ibpA in double mutants (ibpA/clpB, ibpA/PA0779 and ibpA/hslV) did increase tobramycin sensitivity. Collectively, these results demonstrate the time- and concentration-dependent nature of the P. aeruginosa proteome response to tobramycin and that proteome modulation and protein redundancy are protective mechanisms to help bacteria resist antibiotic treatments.
Collapse
Affiliation(s)
- Xia Wu
- From the ‡Department of Genome Sciences
| | | | | | - Benjamin J Staudinger
- ¶Department of Medicine and Microbiology, University of Washington, Seattle, WA 98195
| | | | | | | | - Pradeep K Singh
- ¶Department of Medicine and Microbiology, University of Washington, Seattle, WA 98195
| | | | - James E Bruce
- From the ‡Department of Genome Sciences, §Department of Chemistry,
| |
Collapse
|
34
|
Contribution of stress responses to antibiotic tolerance in Pseudomonas aeruginosa biofilms. Antimicrob Agents Chemother 2015; 59:3838-47. [PMID: 25870065 DOI: 10.1128/aac.00433-15] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 04/07/2015] [Indexed: 11/20/2022] Open
Abstract
Enhanced tolerance of biofilm-associated bacteria to antibiotic treatments is likely due to a combination of factors, including changes in cell physiology as bacteria adapt to biofilm growth and the inherent physiological heterogeneity of biofilm bacteria. In this study, a transcriptomics approach was used to identify genes differentially expressed during biofilm growth of Pseudomonas aeruginosa. These genes were tested for statistically significant overlap, with independently compiled gene lists corresponding to stress responses and other putative antibiotic-protective mechanisms. Among the gene groups tested were those associated with biofilm response to tobramycin or ciprofloxacin, drug efflux pumps, acyl homoserine lactone quorum sensing, osmotic shock, heat shock, hypoxia stress, and stationary-phase growth. Regulons associated with Anr-mediated hypoxia stress, RpoS-regulated stationary-phase growth, and osmotic stress were significantly enriched in the set of genes induced in the biofilm. Mutant strains deficient in rpoS, relA and spoT, or anr were cultured in biofilms and challenged with ciprofloxacin and tobramycin. When challenged with ciprofloxacin, the mutant strain biofilms had 2.4- to 2.9-log reductions in viable cells compared to a 0.9-log reduction of the wild-type strain. Interestingly, none of the mutants exhibited a statistically significant alteration in tobramycin susceptibility compared to that with the wild-type biofilm. These results are consistent with a model in which multiple genes controlled by overlapping starvation or stress responses contribute to the protection of a P. aeruginosa biofilm from ciprofloxacin. A distinct and as yet undiscovered mechanism protects the biofilm bacteria from tobramycin.
Collapse
|
35
|
Poole K. Stress responses as determinants of antimicrobial resistance in Pseudomonas aeruginosa: multidrug efflux and more. Can J Microbiol 2015; 60:783-91. [PMID: 25388098 DOI: 10.1139/cjm-2014-0666] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Pseudomonas aeruginosa is a notoriously antimicrobial-resistant organism that is increasingly refractory to antimicrobial chemotherapy. While the usual array of acquired resistance mechanisms contribute to resistance development in this organism a multitude of endogenous genes also play a role. These include a variety of multidrug efflux loci that contribute to both intrinsic and acquired antimicrobial resistance. Despite their roles in resistance, however, it is clear that these efflux systems function in more than just antimicrobial efflux. Indeed, recent data indicate that they are recruited in response to environmental stress and, therefore, function as components of the organism's stress responses. In fact, a number of endogenous resistance-promoting genes are linked to environmental stress, functioning as part of known stress responses or recruited in response to a variety of environmental stress stimuli. Stress responses are, thus, important determinants of antimicrobial resistance in P. aeruginosa. As such, they represent possible therapeutic targets in countering antimicrobial resistance in this organism.
Collapse
Affiliation(s)
- Keith Poole
- Department of Biomedical and Molecular Sciences, Botterell Hall, Queen's University, Kingston, ON K7L 3N6, Canada
| |
Collapse
|
36
|
Heo A, Jang HJ, Sung JS, Park W. Global transcriptome and physiological responses of Acinetobacter oleivorans DR1 exposed to distinct classes of antibiotics. PLoS One 2014; 9:e110215. [PMID: 25330344 PMCID: PMC4201530 DOI: 10.1371/journal.pone.0110215] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 09/09/2014] [Indexed: 11/18/2022] Open
Abstract
The effects of antibiotics on environment-originated nonpathogenic Acinetobacter species have been poorly explored. To understand the antibiotic-resistance mechanisms that function in nonpathogenic Acinetobacter species, we used an RNA-sequencing (RNA-seq) technique to perform global gene-expression profiling of soil-borne Acinetobacter oleivorans DR1 after exposing the bacteria to 4 classes of antibiotics (ampicillin, Amp; kanamycin, Km; tetracycline, Tc; norfloxacin, Nor). Interestingly, the well-known two global regulators, the soxR and the rpoE genes are present among 41 commonly upregulated genes under all 4 antibiotic-treatment conditions. We speculate that these common genes are essential for antibiotic resistance in DR1. Treatment with the 4 antibiotics produced diverse physiological and phenotypic changes. Km treatment induced the most dramatic phenotypic changes. Examination of mutation frequency and DNA-repair capability demonstrated the induction of the SOS response in Acinetobacter especially under Nor treatment. Based on the RNA-seq analysis, the glyoxylate-bypass genes of the citrate cycle were specifically upregulated under Amp treatment. We also identified newly recognized non-coding small RNAs of the DR1 strain, which were also confirmed by Northern blot analysis. These results reveal that treatment with antibiotics of distinct classes differentially affected the gene expression and physiology of DR1 cells. This study expands our understanding of the molecular mechanisms of antibiotic-stress response of environment-originated bacteria and provides a basis for future investigations.
Collapse
Affiliation(s)
- Aram Heo
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul, Republic of Korea
| | - Hyun-Jin Jang
- Department of Life Science, Dongguk University, Seoul, Republic of Korea
| | - Jung-Suk Sung
- Department of Life Science, Dongguk University, Seoul, Republic of Korea
| | - Woojun Park
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul, Republic of Korea
- * E-mail:
| |
Collapse
|
37
|
Taylor PK, Yeung ATY, Hancock REW. Antibiotic resistance in Pseudomonas aeruginosa biofilms: towards the development of novel anti-biofilm therapies. J Biotechnol 2014; 191:121-30. [PMID: 25240440 DOI: 10.1016/j.jbiotec.2014.09.003] [Citation(s) in RCA: 213] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 09/03/2014] [Accepted: 09/04/2014] [Indexed: 12/23/2022]
Abstract
The growth of bacteria as structured aggregates termed biofilms leads to their protection from harsh environmental conditions such as physical and chemical stresses, shearing forces, and limited nutrient availability. Because of this highly adapted ability to survive adverse environmental conditions, bacterial biofilms are recalcitrant to antibiotic therapies and immune clearance. This is particularly problematic in hospital settings where biofilms are a frequent cause of chronic and device-related infections and constitute a significant burden on the health-care system. The major therapeutic strategy against infections is the use of antibiotics, which, due to adaptive resistance, are often insufficient to clear biofilm infections. Thus, novel biofilm-specific therapies are required. Specific features of biofilm development, such as surface adherence, extracellular matrix formation, quorum sensing, and highly regulated biofilm maturation and dispersal are currently being studied as targets to be exploited in the development of novel biofilm-specific treatments. Using Pseudomonas aeruginosa for illustrative purposes, this review highlights the antibiotic resistance mechanisms of biofilms, and discusses current research into novel biofilm-specific therapies.
Collapse
Affiliation(s)
- Patrick K Taylor
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, 2259 Lower Mall, Vancouver, British Columbia V6T 1Z4, Canada
| | - Amy T Y Yeung
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, 2259 Lower Mall, Vancouver, British Columbia V6T 1Z4, Canada
| | - Robert E W Hancock
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, 2259 Lower Mall, Vancouver, British Columbia V6T 1Z4, Canada.
| |
Collapse
|
38
|
Morita Y, Tomida J, Kawamura Y. Responses of Pseudomonas aeruginosa to antimicrobials. Front Microbiol 2014; 4:422. [PMID: 24409175 PMCID: PMC3884212 DOI: 10.3389/fmicb.2013.00422] [Citation(s) in RCA: 207] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Accepted: 12/24/2013] [Indexed: 11/29/2022] Open
Abstract
Infections caused by Pseudomonas aeruginosa often are hard to treat; inappropriate chemotherapy readily selects multidrug-resistant P. aeruginosa. This organism can be exposed to a wide range of concentrations of antimicrobials during treatment; learning more about the responses of P. aeruginosa to antimicrobials is therefore important. We review here responses of the bacterium P. aeruginosa upon exposure to antimicrobials at levels below the inhibitory concentration. Carbapenems (e.g., imipenem) have been shown to induce the formation of thicker and more robust biofilms, while fluoroquinolones (e.g., ciprofloxacin) and aminoglycosides (e.g., tobramycin) have been shown to induce biofilm formation. Ciprofloxacin also has been demonstrated to enhance the frequency of mutation to carbapenem resistance. Conversely, although macrolides (e.g., azithromycin) typically are not effective against P. aeruginosa because of the pseudomonal outer-membrane impermeability and efflux, macrolides do lead to a reduction in virulence factor production. Similarly, tetracycline is not very effective against this organism, but is known to induce the type-III secretion system and consequently enhance cytotoxicity of P. aeruginosain vivo. Of special note are the effects of antibacterials and disinfectants on pseudomonal efflux systems. Sub-inhibitory concentrations of protein synthesis inhibitors (aminoglycosides, tetracycline, chloramphenicol, etc.) induce the MexXY multidrug efflux system. This response is known to be mediated by interference with the translation of the leader peptide PA5471.1, with consequent effects on expression of the PA5471 gene product. Additionally, induction of the MexCD-OprJ multidrug efflux system is observed upon exposure to sub-inhibitory concentrations of disinfectants such as chlorhexidine and benzalkonium. This response is known to be dependent upon the AlgU stress response factor. Altogether, these biological responses of P. aeruginosa provide useful clues for the improvement and optimization of chemotherapy in order to appropriately treat pseudomonal infections while minimizing the emergence of resistance.
Collapse
Affiliation(s)
- Yuji Morita
- Department of Microbiology, School of Pharmacy, Aichi Gakuin University, Nagoya Japan
| | - Junko Tomida
- Department of Microbiology, School of Pharmacy, Aichi Gakuin University, Nagoya Japan
| | - Yoshiaki Kawamura
- Department of Microbiology, School of Pharmacy, Aichi Gakuin University, Nagoya Japan
| |
Collapse
|
39
|
Gicquel G, Bouffartigues E, Bains M, Oxaran V, Rosay T, Lesouhaitier O, Connil N, Bazire A, Maillot O, Bénard M, Cornelis P, Hancock REW, Dufour A, Feuilloley MGJ, Orange N, Déziel E, Chevalier S. The extra-cytoplasmic function sigma factor sigX modulates biofilm and virulence-related properties in Pseudomonas aeruginosa. PLoS One 2013; 8:e80407. [PMID: 24260387 PMCID: PMC3832394 DOI: 10.1371/journal.pone.0080407] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2013] [Accepted: 10/02/2013] [Indexed: 11/23/2022] Open
Abstract
SigX, one of the 19 extra-cytoplasmic function sigma factors of P. aeruginosa, was only known to be involved in transcription of the gene encoding the major outer membrane protein OprF. We conducted a comparative transcriptomic study between the wildtype H103 strain and its sigX mutant PAOSX, which revealed a total of 307 differentially expressed genes that differed by more than 2 fold. Most dysregulated genes belonged to six functional classes, including the “chaperones and heat shock proteins”, “antibiotic resistance and susceptibility”, “energy metabolism”, “protein secretion/export apparatus”, and “secreted factors”, and “motility and attachment” classes. In this latter class, the large majority of the affected genes were down-regulated in the sigX mutant. In agreement with the array data, the sigX mutant was shown to demonstrate substantially reduced motility, attachment to biotic and abiotic surfaces, and biofilm formation. In addition, virulence towards the nematode Caenorhabditis elegans was reduced in the sigX mutant, suggesting that SigX is involved in virulence-related phenotypes.
Collapse
Affiliation(s)
- Gwendoline Gicquel
- Normandie Université, Université de Rouen, Laboratoire de Microbiologie Signaux et Micro-environnement EA 4312, Evreux, France
| | - Emeline Bouffartigues
- Normandie Université, Université de Rouen, Laboratoire de Microbiologie Signaux et Micro-environnement EA 4312, Evreux, France
| | - Manjeet Bains
- Centre for Microbal Diseases and Immunity Research, University of British Columbia, Vancouver, Canada
| | - Virginie Oxaran
- Normandie Université, Université de Rouen, Laboratoire de Microbiologie Signaux et Micro-environnement EA 4312, Evreux, France
| | - Thibaut Rosay
- Normandie Université, Université de Rouen, Laboratoire de Microbiologie Signaux et Micro-environnement EA 4312, Evreux, France
| | - Olivier Lesouhaitier
- Normandie Université, Université de Rouen, Laboratoire de Microbiologie Signaux et Micro-environnement EA 4312, Evreux, France
| | - Nathalie Connil
- Normandie Université, Université de Rouen, Laboratoire de Microbiologie Signaux et Micro-environnement EA 4312, Evreux, France
| | - Alexis Bazire
- IUEM, Université de Bretagne-Sud (UEB), Laboratoire de Biotechnologie et Chimie Marines EA 3884, Lorient, France
| | - Olivier Maillot
- Normandie Université, Université de Rouen, Laboratoire de Microbiologie Signaux et Micro-environnement EA 4312, Evreux, France
| | - Magalie Bénard
- Cell Imaging Platform of Normandy (PRIMACEN), IRIB, Faculty of Sciences, University of Rouen, Mont-Saint-Aignan, France
| | - Pierre Cornelis
- Department of Bioengineering Sciences, Research group Microbiology, VIB Department of Structural Biology, Vrije Universiteit Brussel, Brussels, Belgium
| | - Robert E. W. Hancock
- Centre for Microbal Diseases and Immunity Research, University of British Columbia, Vancouver, Canada
| | - Alain Dufour
- IUEM, Université de Bretagne-Sud (UEB), Laboratoire de Biotechnologie et Chimie Marines EA 3884, Lorient, France
| | - Marc G. J. Feuilloley
- Normandie Université, Université de Rouen, Laboratoire de Microbiologie Signaux et Micro-environnement EA 4312, Evreux, France
| | - Nicole Orange
- Normandie Université, Université de Rouen, Laboratoire de Microbiologie Signaux et Micro-environnement EA 4312, Evreux, France
| | - Eric Déziel
- INRS-Institut Armand-Frappier, Laval, Québec, Canada
| | - Sylvie Chevalier
- Normandie Université, Université de Rouen, Laboratoire de Microbiologie Signaux et Micro-environnement EA 4312, Evreux, France
- * E-mail:
| |
Collapse
|
40
|
de la Fuente-Núñez C, Reffuveille F, Fernández L, Hancock REW. Bacterial biofilm development as a multicellular adaptation: antibiotic resistance and new therapeutic strategies. Curr Opin Microbiol 2013; 16:580-9. [PMID: 23880136 DOI: 10.1016/j.mib.2013.06.013] [Citation(s) in RCA: 495] [Impact Index Per Article: 45.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 06/27/2013] [Accepted: 06/28/2013] [Indexed: 12/20/2022]
Abstract
Bacteria have evolved the ability to form multicellular, surface-adherent communities called biofilms that allow survival in hostile environments. In clinical settings, bacteria are exposed to various sources of stress, including antibiotics, nutrient limitation, anaerobiosis, heat shock, etc., which in turn trigger adaptive responses in bacterial cells. The combination of this and other defense mechanisms results in the formation of highly (adaptively) resistant multicellular structures that are recalcitrant to host immune clearance mechanisms and very difficult to eradicate with the currently available antimicrobial agents, which are generally developed for the eradication of free-swimming (planktonic) bacteria. However, novel strategies that specifically target the biofilm mode of growth have been recently described, thus providing the basis for future anti-biofilm therapy.
Collapse
Affiliation(s)
- César de la Fuente-Núñez
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | | | | | | |
Collapse
|
41
|
Tseng BS, Zhang W, Harrison JJ, Quach TP, Song JL, Penterman J, Singh PK, Chopp DL, Packman AI, Parsek MR. The extracellular matrix protects Pseudomonas aeruginosa biofilms by limiting the penetration of tobramycin. Environ Microbiol 2013; 15:2865-78. [PMID: 23751003 DOI: 10.1111/1462-2920.12155] [Citation(s) in RCA: 237] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Revised: 05/03/2013] [Accepted: 05/07/2013] [Indexed: 01/20/2023]
Abstract
Biofilm cells are less susceptible to antimicrobials than their planktonic counterparts. While this phenomenon is multifactorial, the ability of the matrix to reduce antibiotic penetration into the biofilm is thought to be of limited importance studies suggest that antibiotics move fairly rapidly through biofilms. In this study, we monitored the transport of two clinically relevant antibiotics, tobramycin and ciprofloxacin, into non-mucoid Pseudomonas aeruginosa biofilms. To our surprise, we found that the positively charged antibiotic tobramycin is sequestered to the biofilm periphery, while the neutral antibiotic ciprofloxacin readily penetrated. We provide evidence that tobramycin in the biofilm periphery both stimulated a localized stress response and killed bacteria in these regions but not in the underlying biofilm. Although it is unclear which matrix component binds tobramycin, its penetration was increased by the addition of cations in a dose-dependent manner, which led to increased biofilm death. These data suggest that ionic interactions of tobramycin with the biofilm matrix limit its penetration. We propose that tobramycin sequestration at the biofilm periphery is an important mechanism in protecting metabolically active cells that lie just below the zone of sequestration.
Collapse
Affiliation(s)
- Boo Shan Tseng
- Department of Microbiology, University of Washington, Seattle, WA, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
42
|
Olivares J, Bernardini A, Garcia-Leon G, Corona F, B Sanchez M, Martinez JL. The intrinsic resistome of bacterial pathogens. Front Microbiol 2013; 4:103. [PMID: 23641241 PMCID: PMC3639378 DOI: 10.3389/fmicb.2013.00103] [Citation(s) in RCA: 105] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Accepted: 04/11/2013] [Indexed: 11/13/2022] Open
Abstract
Intrinsically resistant bacteria have emerged as a relevant health problem in the last years. Those bacterial species, several of them with an environmental origin, present naturally low-level susceptibility to several drugs. It has been proposed that intrinsic resistance is mainly the consequence of the impermeability of cellular envelopes, the activity of multidrug efflux pumps or the lack of appropriate targets for a given family of drugs. However, recently published articles indicate that the characteristic phenotype of susceptibility to antibiotics of a given bacterial species depends on the concerted activity of several elements, what has been named as intrinsic resistome. These determinants comprise not just classical resistance genes. Other elements, several of them involved in basic bacterial metabolic processes, are of relevance for the intrinsic resistance of bacterial pathogens. In the present review we analyze recent publications on the intrinsic resistomes of Escherichia coli and Pseudomonas aeruginosa. We present as well information on the role that global regulators of bacterial metabolism, as Crc from P. aeruginosa, may have on modulating bacterial susceptibility to antibiotics. Finally, we discuss the possibility of searching inhibitors of the intrinsic resistome in the aim of improving the activity of drugs currently in use for clinical practice.
Collapse
Affiliation(s)
- Jorge Olivares
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas Madrid, Spain
| | | | | | | | | | | |
Collapse
|
43
|
Goltermann L, Good L, Bentin T. Chaperonins fight aminoglycoside-induced protein misfolding and promote short-term tolerance in Escherichia coli. J Biol Chem 2013; 288:10483-9. [PMID: 23447537 DOI: 10.1074/jbc.m112.420380] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
For almost half of a century, we have known that aminoglycoside antibiotics corrupt ribosomes, causing translational misreading, yet it remains unclear whether or not misreading triggers protein misfolding, and possible effects of chaperone action on drug susceptibilities are poorly understood. Here, we show that aminoglycosides cause cytosolic protein misfolding and that chaperonin GroEL/GroES overexpression counters this defect. During aminoglycoside exposure to exponential cultures, chaperonin overexpression protected the bacterial membrane potential, rescued cell growth, and facilitated survival, whereas inhibition of chaperonin expression sensitized bacteria. Overexpression of the DnaK/DnaJ/GrpE chaperone system similarly facilitated survival but did not promote growth of aminoglycoside-treated bacteria. Inhibition of chaperonin expression sensitized bacteria to aminoglycosides as measured by reduced minimum inhibitory concentrations, whereas GroEL/GroES overexpression did not increase minimum inhibitory concentrations. Our observations establish misfolding of cytosolic proteins as an effect of aminoglycoside action and reveal that chaperones, chaperonins in particular, help bacteria cope during early exposure to these drugs.
Collapse
Affiliation(s)
- Lise Goltermann
- Department of Cellular and Molecular Medicine, The Panum Institute, University of Copenhagen, 200 Copenhagen, Denmark
| | | | | |
Collapse
|
44
|
Morita Y, Tomida J, Kawamura Y. MexXY multidrug efflux system of Pseudomonas aeruginosa. Front Microbiol 2012; 3:408. [PMID: 23233851 PMCID: PMC3516279 DOI: 10.3389/fmicb.2012.00408] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Accepted: 11/13/2012] [Indexed: 01/01/2023] Open
Abstract
Anti-pseudomonas aminoglycosides, such as amikacin and tobramycin, are used in the treatment of Pseudomonas aeruginosa infections. However, their use is linked to the development of resistance. During the last decade, the MexXY multidrug efflux system has been comprehensively studied, and numerous reports of laboratory and clinical isolates have been published. This system has been increasingly recognized as one of the primary determinants of aminoglycoside resistance in P. aeruginosa. In P. aeruginosa cystic fibrosis isolates, upregulation of the pump is considered the most common mechanism of aminoglycoside resistance. Non-fermentative Gram-negative pathogens possessing very close MexXY orthologs such as Achromobacter xylosoxidans and various Burkholderia species (e.g., Burkholderia pseudomallei and B. cepacia complexes), but not B. gladioli, are intrinsically resistant to aminoglycosides. Here, we summarize the properties (e.g., discovery, mechanism, gene expression, clinical significance) of the P. aeruginosa MexXY pump and other aminoglycoside efflux pumps such as AcrD of Escherichia coli, AmrAB-OprA of B. pseudomallei, and AdeABC of Acinetobacter baumannii. MexXY inducibility of the PA5471 gene product, which is dependent on ribosome inhibition or oxidative stress, is noteworthy. Moreover, the discovery of the cognate outer membrane component (OprA) of MexXY in the multidrug-resistant clinical isolate PA7, serotype O12 deserves special attention.
Collapse
Affiliation(s)
- Yuji Morita
- Department of Microbiology, School of Pharmacy, Aichi Gakuin University Nagoya, Japan
| | | | | |
Collapse
|
45
|
Breidenstein EBM, Hancock REW. Armand-Frappier outstanding student award -- role of ATP-dependent proteases in antibiotic resistance and virulence. Can J Microbiol 2012; 59:1-8. [PMID: 23391222 DOI: 10.1139/cjm-2012-0681] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
ATP-dependent proteases are found in nearly all living organisms and are known to play important roles in protein quality control, including protein degradation and protein refolding. ATP-dependent proteases have been well characterized in Escherichia coli. However, in the opportunistic human pathogen Pseudomonas aeruginosa, the role of these proteases is only starting to be understood. This review will discuss the most recent research regarding the role of ATP-dependent proteases, particularly Lon and ClpP, in P. aeruginosa. These studies have revealed that despite the fact that they are not traditional regulators, these proteases are involved in regulating a multitude of processes, including antibiotic resistance and virulence, implicating a broad array of functions that these intracellular proteases have in Pseudomonas. These results are also relevant in the context of drug therapy, since ClpP and Lon are good candidates to become novel therapeutic targets to combat Pseudomonas infections.
Collapse
Affiliation(s)
- Elena B M Breidenstein
- Department of Microbiology and Immunology, Centre for Microbial Diseases & Immunity Research, University of British Columbia, No. 232 2259 Lower Mall, Lower Mall Research Station, Vancouver, BC V6T 1Z4, Canada
| | | |
Collapse
|
46
|
Knudsen G, Holch A, Gram L. Subinhibitory concentrations of antibiotics affect stress and virulence gene expression inListeria monocytogenesand cause enhanced stress sensitivity but do not affect Caco-2 cell invasion. J Appl Microbiol 2012; 113:1273-86. [DOI: 10.1111/j.1365-2672.2012.05435.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Revised: 08/14/2012] [Accepted: 08/15/2012] [Indexed: 11/29/2022]
Affiliation(s)
- G.M. Knudsen
- National Food Institute; Technical University of Denmark; Kongens Lyngby; Denmark
| | - A. Holch
- National Food Institute; Technical University of Denmark; Kongens Lyngby; Denmark
| | - L. Gram
- National Food Institute; Technical University of Denmark; Kongens Lyngby; Denmark
| |
Collapse
|
47
|
Poole K. Bacterial stress responses as determinants of antimicrobial resistance. J Antimicrob Chemother 2012; 67:2069-89. [PMID: 22618862 DOI: 10.1093/jac/dks196] [Citation(s) in RCA: 305] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Bacteria encounter a myriad of stresses in their natural environments, including, for pathogens, their hosts. These stresses elicit a variety of specific and highly regulated adaptive responses that not only protect bacteria from the offending stress, but also manifest changes in the cell that impact innate antimicrobial susceptibility. Thus exposure to nutrient starvation/limitation (nutrient stress), reactive oxygen and nitrogen species (oxidative/nitrosative stress), membrane damage (envelope stress), elevated temperature (heat stress) and ribosome disruption (ribosomal stress) all impact bacterial susceptibility to a variety of antimicrobials through their initiation of stress responses that positively impact recruitment of resistance determinants or promote physiological changes that compromise antimicrobial activity. As de facto determinants of antimicrobial, even multidrug, resistance, stress responses may be worthy of consideration as therapeutic targets.
Collapse
Affiliation(s)
- Keith Poole
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada K7L 3N6.
| |
Collapse
|
48
|
Involvement of the lon protease in the SOS response triggered by ciprofloxacin in Pseudomonas aeruginosa PAO1. Antimicrob Agents Chemother 2012; 56:2879-87. [PMID: 22450976 DOI: 10.1128/aac.06014-11] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Pseudomonas aeruginosa PAO1 lon mutants have phenotypes of deficiencies in cell division, swarming, twitching, and biofilm formation as well as a phenotype of ciprofloxacin supersusceptibility. In this study, we demonstrated that a lon mutant was also supersensitive to the DNA-damaging agent UV light. To understand the influence of lon in causing these phenotypes, global gene expression was characterized by performing microarrays on the lon mutant and the PAO1 wild type grown in the presence of subinhibitory concentrations of ciprofloxacin. This revealed major differences in the expression of genes involved in the SOS response and DNA repair. Real-time quantitative PCR confirmed that these genes were highly upregulated upon ciprofloxacin exposure in the wild type but were significantly less induced in the lon mutant, indicating that Lon modulates the SOS response and consequentially ciprofloxacin susceptibility. As the known Lon target SulA is a member of the SOS response regulon, the influence of mutating or overexpressing this gene, and the negative regulator of the SOS response, LexA, was examined. Overexpression of lexA had no effect on the Lon-related phenotypes, but sulA overexpression recapitulated certain lon mutant phenotypes, including altered motility and cell division, indicating that Lon regulates these phenotypes through SulA. However, sulA overexpression did not affect ciprofloxacin susceptibility or biofilm formation, indicating that these properties were independently determined. Lon protease was also demonstrated to strongly influence RecA protein accumulation in the presence of ciprofloxacin. A model of DNA repair involving the Lon protease is proposed.
Collapse
|
49
|
Poole K. Stress responses as determinants of antimicrobial resistance in Gram-negative bacteria. Trends Microbiol 2012; 20:227-34. [PMID: 22424589 DOI: 10.1016/j.tim.2012.02.004] [Citation(s) in RCA: 126] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Revised: 01/25/2012] [Accepted: 02/08/2012] [Indexed: 10/28/2022]
Abstract
Bacteria encounter a myriad of potentially growth-compromising conditions in nature and in hosts of pathogenic bacteria. These 'stresses' typically elicit protective and/or adaptive responses that serve to enhance bacterial survivability. Because they impact upon many of the same cellular components and processes that are targeted by antimicrobials, adaptive stress responses can influence antimicrobial susceptibility. In targeting and interfering with key cellular processes, antimicrobials themselves are 'stressors' to which protective stress responses have also evolved. Cellular responses to nutrient limitation (nutrient stress), oxidative and nitrosative stress, cell envelope damage (envelope stress), antimicrobial exposure and other growth-compromising stresses, have all been linked to the development of antimicrobial resistance in Gram-negative bacteria - resulting from the stimulation of protective changes to cell physiology, activation of resistance mechanisms, promotion of resistant lifestyles (biofilms), and induction of resistance mutations.
Collapse
Affiliation(s)
- Keith Poole
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario K7L 3N6, Canada.
| |
Collapse
|
50
|
Morita Y, Tomida J, Kawamura Y. Primary mechanisms mediating aminoglycoside resistance in the multidrug-resistant Pseudomonas aeruginosa clinical isolate PA7. MICROBIOLOGY-SGM 2012; 158:1071-1083. [PMID: 22282519 DOI: 10.1099/mic.0.054320-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The multiresistant taxonomic outlier Pseudomonas aeruginosa PA7 possesses the conserved efflux genes, mexXY; however these are linked to a unique gene encoding an outer membrane channel, dubbed oprA, that is absent in most P. aeruginosa strains. Using genetic knockouts and single copy chromosomal complementation, we showed that aminoglycoside resistance in PA7 is mediated in part by the MexXY-OprA pump, and intriguingly that MexXY in this strain can utilize either the OprA or OprM outer membrane channel, linked to the mexAB efflux genes. We also identified a small portion of the oprA gene immediately downstream of the mexY gene in PAO1, suggesting that non-PA7 P. aeruginosa strains might have possessed, but lost, the intact mexXY-oprA efflux pump locus. Consistent with this, most of a panel of serotype strains possessed the truncated oprA but the serotype O12 isolate had an intact mexXY-oprA locus, similar to PA7 and the related strain DSM 1128. We also showed that the mexZ repressor gene upstream of mexXY-oprA in PA7 is mutated, leading to overexpression of mexXY-oprA, using sequencing, homologous replacement and real-time quantitative reverse transcriptase PCR. Finally we assessed the contribution of MexXY and aminoglycoside modifying enzymes AAC together to resistance in PA7 and the AAC(6')-Iae-mediated amikacin-resistant clinical isolate IMCJ2.S1, concluding that the effect of the modifying enzymes is enhanced by functional efflux, especially in the presence of divalent cations, to develop high-level aminoglycoside resistance in P. aeruginosa.
Collapse
Affiliation(s)
- Yuji Morita
- Department of Microbiology, School of Pharmacy, Aichi Gakuin University, Nagoya, Aichi 464-8650, Japan
| | - Junko Tomida
- Department of Microbiology, School of Pharmacy, Aichi Gakuin University, Nagoya, Aichi 464-8650, Japan
| | - Yoshiaki Kawamura
- Department of Microbiology, School of Pharmacy, Aichi Gakuin University, Nagoya, Aichi 464-8650, Japan
| |
Collapse
|