1
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Niu H, Gu J, Zhang Y. Bacterial persisters: molecular mechanisms and therapeutic development. Signal Transduct Target Ther 2024; 9:174. [PMID: 39013893 PMCID: PMC11252167 DOI: 10.1038/s41392-024-01866-5] [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: 11/04/2023] [Revised: 05/06/2024] [Accepted: 05/13/2024] [Indexed: 07/18/2024] Open
Abstract
Persisters refer to genetically drug susceptible quiescent (non-growing or slow growing) bacteria that survive in stress environments such as antibiotic exposure, acidic and starvation conditions. These cells can regrow after stress removal and remain susceptible to the same stress. Persisters are underlying the problems of treating chronic and persistent infections and relapse infections after treatment, drug resistance development, and biofilm infections, and pose significant challenges for effective treatments. Understanding the characteristics and the exact mechanisms of persister formation, especially the key molecules that affect the formation and survival of the persisters is critical to more effective treatment of chronic and persistent infections. Currently, genes related to persister formation and survival are being discovered and confirmed, but the mechanisms by which bacteria form persisters are very complex, and there are still many unanswered questions. This article comprehensively summarizes the historical background of bacterial persisters, details their complex characteristics and their relationship with antibiotic tolerant and resistant bacteria, systematically elucidates the interplay between various bacterial biological processes and the formation of persister cells, as well as consolidates the diverse anti-persister compounds and treatments. We hope to provide theoretical background for in-depth research on mechanisms of persisters and suggest new ideas for choosing strategies for more effective treatment of persistent infections.
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Affiliation(s)
- Hongxia Niu
- School of Basic Medical Science and Key Laboratory of Blood-stasis-toxin Syndrome of Zhejiang Province, Zhejiang Chinese Medical University, Hangzhou, 310053, Zhejiang, China
| | - Jiaying Gu
- School of Basic Medical Science and Key Laboratory of Blood-stasis-toxin Syndrome of Zhejiang Province, Zhejiang Chinese Medical University, Hangzhou, 310053, Zhejiang, China
| | - Ying Zhang
- State Key Laboratory for the Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, 310003, Zhejiang, China.
- Jinan Microecological Biomedicine Shandong Laboratory, Jinan, 250022, Shandong, China.
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2
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Sanchez-Torres V, Kirigo J, Wood TK. Implications of lytic phage infections inducing persistence. Curr Opin Microbiol 2024; 79:102482. [PMID: 38714140 DOI: 10.1016/j.mib.2024.102482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 04/03/2024] [Accepted: 04/15/2024] [Indexed: 05/09/2024]
Abstract
Phage therapy holds much promise as an alternative to antibiotics for fighting infection. However, this approach is no panacea as recent results show that a small fraction of cells survives lytic phage infection due to both dormancy (i.e. formation of persister cells) and resistance (genetic change). In this brief review, we summarize evidence suggesting phages induce the persister state. Therefore, it is predicted that phage cocktails should be combined with antipersister compounds to eradicate bacterial infections.
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Affiliation(s)
- Viviana Sanchez-Torres
- Escuela de Ingeniería Química, Universidad Industrial de Santander, Bucaramanga, Colombia
| | - Joy Kirigo
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA, USA
| | - Thomas K Wood
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA, USA.
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3
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Liu X, Wang P, Yuan N, Zhai Y, Yang Y, Hao M, Zhang M, Zhou D, Liu W, Jin Y, Wang A. The (p)ppGpp synthetase Rsh promotes rifampicin tolerant persister cell formation in Brucella abortus by regulating the type II toxin-antitoxin module mbcTA. Front Microbiol 2024; 15:1395504. [PMID: 38841069 PMCID: PMC11150624 DOI: 10.3389/fmicb.2024.1395504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Accepted: 05/01/2024] [Indexed: 06/07/2024] Open
Abstract
Persister cells are transiently tolerant to antibiotics and are associated with recalcitrant chronic infections due to recolonization of host cells after antibiotic removal. Brucella spp. are facultative pathogens that establish intracellular infection cycles in host cells which results in chronic persistent infections. Brucella abortus forms multi-drug persister cells which are promoted by the (p)ppGpp synthetase Rsh during rifampicin exposure. Here, we confirmed that Rsh promoted persister cells formation in B. abortus stationary phase treated with rifampicin and enrofloxacin. Deletion of the gene for Rsh decreased persister cells level in the presence of these drugs in different growth phases. However, persister cells formation by deletion strain varied in different growth phases in the presence of other antibiotics. Rsh also was involved in persister cells formation during rifampicin treatment under certain stress conditions, including acidic conditions, exposure to PBS, and heat stress. Moreover, Rsh impacted persister cell levels during rifampicin or enrofloxacin treatment in RAW264.7 macrophages. Certain typeIItoxin-antitoxin modules were upregulated under various stress conditions in B. abortus. We established that Rsh positively regulated the type II toxin-antitoxin mbcTA. Moreover, rifampicin-tolerant persister cells formation was elevated and ATP levels were decreased when mbcTA promoter was overexpressed in Rsh deletion background in stationary phase. Our results establish that (p)ppGpp synthetase Rsh plays a key role in B. abortus persistence and may serve as a potent novel target in combination with rifampicin in the development of new therapeutic approaches and prevention strategies to treat chronic infections of Brucella.
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Affiliation(s)
- Xiaofang Liu
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Xianyang, China
| | - Pingping Wang
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Xianyang, China
| | - Ningqiu Yuan
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Xianyang, China
| | - Yunyi Zhai
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Xianyang, China
| | - Yuanhao Yang
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Xianyang, China
| | - Mingyue Hao
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Xianyang, China
| | - Mingxing Zhang
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- College of Animal Science and Technology, Northwest A&F University, Xianyang, China
| | - Dong Zhou
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Xianyang, China
| | - Wei Liu
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Xianyang, China
| | - Yaping Jin
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Xianyang, China
| | - Aihua Wang
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Xianyang, China
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Shore SFH, Leinberger FH, Fozo EM, Berghoff BA. Type I toxin-antitoxin systems in bacteria: from regulation to biological functions. EcoSal Plus 2024:eesp00252022. [PMID: 38767346 DOI: 10.1128/ecosalplus.esp-0025-2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 04/11/2024] [Indexed: 05/22/2024]
Abstract
Toxin-antitoxin systems are ubiquitous in the prokaryotic world and widely distributed among chromosomes and mobile genetic elements. Several different toxin-antitoxin system types exist, but what they all have in common is that toxin activity is prevented by the cognate antitoxin. In type I toxin-antitoxin systems, toxin production is controlled by an RNA antitoxin and by structural features inherent to the toxin messenger RNA. Most type I toxins are small membrane proteins that display a variety of cellular effects. While originally discovered as modules that stabilize plasmids, chromosomal type I toxin-antitoxin systems may also stabilize prophages, or serve important functions upon certain stress conditions and contribute to population-wide survival strategies. Here, we will describe the intricate RNA-based regulation of type I toxin-antitoxin systems and discuss their potential biological functions.
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Affiliation(s)
- Selene F H Shore
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - Florian H Leinberger
- Institute for Microbiology and Molecular Biology, Justus-Liebig University, Giessen, Germany
| | - Elizabeth M Fozo
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - Bork A Berghoff
- Institute for Microbiology and Molecular Biology, Justus-Liebig University, Giessen, Germany
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5
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Pizzolato-Cezar LR, Spira B, Machini MT. Bacterial toxin-antitoxin systems: Novel insights on toxin activation across populations and experimental shortcomings. CURRENT RESEARCH IN MICROBIAL SCIENCES 2023; 5:100204. [PMID: 38024808 PMCID: PMC10643148 DOI: 10.1016/j.crmicr.2023.100204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2023] Open
Abstract
The alarming rise in hard-to-treat bacterial infections is of great concern to human health. Thus, the identification of molecular mechanisms that enable the survival and growth of pathogens is of utmost urgency for the development of more efficient antimicrobial therapies. In challenging environments, such as presence of antibiotics, or during host infection, metabolic adjustments are essential for microorganism survival and competitiveness. Toxin-antitoxin systems (TASs) consisting of a toxin with metabolic modulating activity and a cognate antitoxin that antagonizes that toxin are important elements in the arsenal of bacterial stress defense. However, the exact physiological function of TA systems is highly debatable and with the exception of stabilization of mobile genetic elements and phage inhibition, other proposed biological functions lack a broad consensus. This review aims at gaining new insights into the physiological effects of TASs in bacteria and exploring the experimental shortcomings that lead to discrepant results in TAS research. Distinct control mechanisms ensure that only subsets of cells within isogenic cultures transiently develop moderate levels of toxin activity. As a result, TASs cause phenotypic growth heterogeneity rather than cell stasis in the entire population. It is this feature that allows bacteria to thrive in diverse environments through the creation of subpopulations with different metabolic rates and stress tolerance programs.
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Affiliation(s)
- Luis R. Pizzolato-Cezar
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, Brazil
| | - Beny Spira
- Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - M. Teresa Machini
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, Brazil
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Wang X, Ma W, Shan J, Chen K, Xu W, Lu Z, Ju Z, Dong Z, Li B, Zhang Y. The phosphotransferase system gene ptsH affects persister formation in Klebsiella pneumoniae by regulating cyclic adenosine monophosphate levels. Int J Antimicrob Agents 2023; 62:106925. [PMID: 37451649 DOI: 10.1016/j.ijantimicag.2023.106925] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 06/30/2023] [Accepted: 07/09/2023] [Indexed: 07/18/2023]
Abstract
Klebsiella pneumoniae is one of the most common opportunistic pathogens causing hospital- and community-acquired infections. Antibiotic resistance in K. pneumoniae has emerged as a major clinical and public health threat. Persisters are specific antibiotic-tolerant bacterial cells. Studies on the mechanism underlying their formation mechanism and growth status are scarce. Therefore, it is urgent to explore the key genes and signalling pathways involved in the formation and recovery process of K. pneumoniae persisters to enhance the understanding and develop relevant treatment strategies. In this study, we treated K. pneumoniae with a lethal concentration of levofloxacin. It resulted in a distinct plateau of surviving levofloxacin-tolerant persisters. Subsequently, we obtained bacterial samples at five different time points during the formation and recovery of K. pneumoniae persisters to perform transcriptome analysis. ptsH gene was observed to be upregulated during the formation of persisters, and down-regulated during the recovery of the persisters. Further, we used CRISPR-Cas9 to construct ΔptsH, the ptsH-knockout K. pneumoniae strain, and to investigate the effect of ptsH on the persister formation. We observed that ptsH can promote the formation of persisters, reduce accumulation of reactive oxygen species, and enhance antioxidant capacity by reducing cyclic adenosine monophosphate (cAMP) levels. To the best of our knowledge, this is the first study to report that ptsH plays a vital role in forming K. pneumoniae persisters. This study provided important insights to further explore the mechanism underlying the formation of K. pneumoniae persisters and provided a potential target for treating infection with K. pneumoniae persisters.
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Affiliation(s)
- Xin Wang
- Department of Pathogenic Biology, Binzhou Medical University, Yantai, China
| | - Wenru Ma
- Department of Pathogenic Biology, Binzhou Medical University, Yantai, China
| | - Jiangfan Shan
- The Second School of Clinical Medicine, Binzhou Medical University, Yantai, China
| | - Kexu Chen
- Department of Pathogenic Biology, Binzhou Medical University, Yantai, China
| | - Weihao Xu
- Inspection Center of Yantai Yuhuangding Hospital, Yantai, China
| | - Zixuan Lu
- Department of Pathogenic Biology, Binzhou Medical University, Yantai, China
| | - Zhuofei Ju
- The First School of Clinical Medicine, Binzhou Medical University, Yantai, China
| | - Zhouyan Dong
- Department of Pathogenic Biology, Binzhou Medical University, Yantai, China
| | - Boqing Li
- Department of Pathogenic Biology, Binzhou Medical University, Yantai, China.
| | - Yumei Zhang
- Department of Pathogenic Biology, Binzhou Medical University, Yantai, China.
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Liu X, Wang P, Shi Y, Cui Y, Li S, Wu Dong G, Li J, Hao M, Zhai Y, Zhou D, Liu W, Wang A, Jin Y. (P)ppGpp synthetase Rsh participates in rifampicin tolerance of persister cells in Brucella abortus in vitro. Microb Pathog 2023; 183:106310. [PMID: 37604214 DOI: 10.1016/j.micpath.2023.106310] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 07/30/2023] [Accepted: 08/14/2023] [Indexed: 08/23/2023]
Abstract
Brucella abortus is facultative intracellular pathogen that causes chronic persistent infections and results in abortion and infertility in food animals. Recurrent infections can be one of the results of persister cells formation that transiently displays phenotypic tolerance to high dose of antibiotics treatment. We examined persister cells formation of B. abortus strain A19 in stationary phase and investigated a potential role for the (p)ppGpp synthetase Rsh in this process. We found that B. abortus stationary phase cells can produce higher levels of multi-drugs tolerant persister cells in vitro under high dose of antibiotics (20 × MIC) exposure than do exponential phase cells. Persister cell formation was also induced with environmental stressors pH 4.5, 0.01 M PBS (pH7.0), 2% NaCl and 25 °C, upon exposure to ampicillin, enrofloxacin and rifampicin. Persister cells were not formed following exposure to 1 mM H2O2. The numbers of persister cells were significantly increased following uptake of B. abortus stationary phase cells by RAW264.7 macrophages in contrast with cultures in TSB liquid medium. Environmental stressors to B. abortus significantly increased expression of rsh mRNA level. The rsh null mutant (Δrsh) formed significantly fewer persister cells than the complemented (CΔrsh) and wildtype (WT) strains under high dose of rifampicin in vitro. These data for the first time demonstrate that B. abortus can produce multi-drug tolerant persister cells in stationary phase. The (p)ppGpp synthetase Rsh is necessary for persister cell formation in B. abortus in the presence of rifampicin. On this basis, a new understanding of the recurrent infections of Brucella was advanced, thus provided a new basis for revelation of pathogenic mechanism of the chronic persistent infection in Brucella.
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Affiliation(s)
- Xiaofang Liu
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University; Yangling, Shaanxi 712100, China
| | - Pingping Wang
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University; Yangling, Shaanxi 712100, China
| | - Yong Shi
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University; Yangling, Shaanxi 712100, China
| | - Yimeng Cui
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University; Yangling, Shaanxi 712100, China
| | - Shengnan Li
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University; Yangling, Shaanxi 712100, China
| | - Gaowa Wu Dong
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University; Yangling, Shaanxi 712100, China
| | - Junmei Li
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University; Yangling, Shaanxi 712100, China
| | - Mingyue Hao
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University; Yangling, Shaanxi 712100, China
| | - Yunyi Zhai
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University; Yangling, Shaanxi 712100, China
| | - Dong Zhou
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University; Yangling, Shaanxi 712100, China
| | - Wei Liu
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University; Yangling, Shaanxi 712100, China
| | - Aihua Wang
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University; Yangling, Shaanxi 712100, China.
| | - Yaping Jin
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University; Yangling, Shaanxi 712100, China
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Pan X, Liu W, Du Q, Zhang H, Han D. Recent Advances in Bacterial Persistence Mechanisms. Int J Mol Sci 2023; 24:14311. [PMID: 37762613 PMCID: PMC10531727 DOI: 10.3390/ijms241814311] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 09/13/2023] [Accepted: 09/15/2023] [Indexed: 09/29/2023] Open
Abstract
The recurrence of bacterial infectious diseases is closely associated with bacterial persisters. This subpopulation of bacteria can escape antibiotic treatment by entering a metabolic status of low activity through various mechanisms, for example, biofilm, toxin-antitoxin modules, the stringent response, and the SOS response. Correspondingly, multiple new treatments are being developed. However, due to their spontaneous low abundance in populations and the lack of research on in vivo interactions between persisters and the host's immune system, microfluidics, high-throughput sequencing, and microscopy techniques are combined innovatively to explore the mechanisms of persister formation and maintenance at the single-cell level. Here, we outline the main mechanisms of persister formation, and describe the cutting-edge technology for further research. Despite the significant progress regarding study techniques, some challenges remain to be tackled.
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Affiliation(s)
- Xiaozhou Pan
- Department of Clinical Laboratory, Shanghai Children’s Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200062, China
- Institute of Pediatric Infection, Immunity, and Critical Care Medicine, School of Medicine, Shanghai Jiao Tong University, Shanghai 200062, China
| | - Wenxin Liu
- Department of Clinical Laboratory, Shanghai Children’s Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200062, China
- Institute of Pediatric Infection, Immunity, and Critical Care Medicine, School of Medicine, Shanghai Jiao Tong University, Shanghai 200062, China
| | - Qingqing Du
- Department of Clinical Laboratory, Shanghai Children’s Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200062, China
- Institute of Pediatric Infection, Immunity, and Critical Care Medicine, School of Medicine, Shanghai Jiao Tong University, Shanghai 200062, China
| | - Hong Zhang
- Department of Clinical Laboratory, Shanghai Children’s Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200062, China
- Institute of Pediatric Infection, Immunity, and Critical Care Medicine, School of Medicine, Shanghai Jiao Tong University, Shanghai 200062, China
| | - Dingding Han
- Department of Clinical Laboratory, Shanghai Children’s Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200062, China
- Institute of Pediatric Infection, Immunity, and Critical Care Medicine, School of Medicine, Shanghai Jiao Tong University, Shanghai 200062, China
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Mancini L, Pilizota T. Environmental conditions define the energetics of bacterial dormancy and its antibiotic susceptibility. Biophys J 2023; 122:3207-3218. [PMID: 37403359 PMCID: PMC10465703 DOI: 10.1016/j.bpj.2023.06.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 05/17/2023] [Accepted: 06/30/2023] [Indexed: 07/06/2023] Open
Abstract
Bacterial cells that stop growing but maintain viability and the capability to regrow are termed dormant and have been shown to transiently tolerate high concentrations of antimicrobials. Links between tolerance and cellular energetics as a possible explanation for the tolerance, have been investigated and have produced mixed and seemingly contradictory results. Because dormancy merely indicates growth arrest, which can be induced by various stimuli, we hypothesize that dormant cells may exist in a range of energetic states that depend on the environment. To energetically characterize different dormancies, we first induce them in a way that results in dormant populations and subsequently measure both of their main energy sources, the proton motive force magnitude and the concentration of ATP. We find that different types of dormancy exhibit characteristic energetic profiles that vary in level and dynamics. The energetic makeup was associated with survival to some antibiotics but not others. Our findings portray dormancy as a state that is rich in phenotypes with various stress survival capabilities. Because environmental conditions outside of the lab often halt or limit microbial growth, a typologization of dormant states may yield relevant insights on the survival and evolutionary strategies of these organisms.
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Affiliation(s)
- Leonardo Mancini
- School of Biological Sciences, Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Teuta Pilizota
- School of Biological Sciences, Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, United Kingdom.
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10
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Thorfinnsdottir LB, Bø GH, Booth JA, Bruheim P. Survival of Escherichia coli after high-antibiotic stress is dependent on both the pregrown physiological state and incubation conditions. Front Microbiol 2023; 14:1149978. [PMID: 36970700 PMCID: PMC10036391 DOI: 10.3389/fmicb.2023.1149978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 02/17/2023] [Indexed: 03/12/2023] Open
Abstract
IntroductionThe survival of bacterial cells exposed to antibiotics depends on the mode of action, the antibiotics concentration, and the duration of treatment. However, it also depends on the physiological state of the cells and the environmental conditions. In addition, bacterial cultures contain sub-populations that can survive high antibiotic concentrations, so-called persisters. Research on persisters is challenging due to multiple mechanisms for their formation and low fractions, down to and below one millionth of the total cell population. Here, we present an improved version of the persister assay used to enumerate the amount of persisters in a cell population.MethodsThe persister assay with high antibiotic stress exposure was performed at both growth supporting and non-supporting conditions. Escherichia coli cells were pregrown to various growth stages in shake flasks and bench-top bioreactors. In addition, the physiological state of E. coli before antibiotic treatment was determined by quantitative mass spectrometry-based metabolite profiling.ResultsSurvival of E. coli strongly depended on whether the persister assay medium supported growth or not. The results were also highly dependent on the type of antibiotic and pregrown physiological state of the cells. Therefore, applying the same conditions is critical for consistent and comparable results. No direct connection was observed between antibiotic efficacy to the metabolic state. This also includes the energetic state (i.e., the intracellular concentration of ATP and the adenylate energy charge), which has earlier been hypothesized to be decisive for persister formation.DiscussionThe study provides guides and suggestions for the design of future experimentation in the research fields of persisters and antibiotic tolerance.
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Affiliation(s)
| | - Gaute Hovde Bø
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, Trondheim, Norway
| | - James Alexander Booth
- Department of Microbiology, Oslo University Hospital, University of Oslo, Oslo, Norway
| | - Per Bruheim
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, Trondheim, Norway
- *Correspondence: Per Bruheim,
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Sonika S, Singh S, Mishra S, Verma S. Toxin-antitoxin systems in bacterial pathogenesis. Heliyon 2023; 9:e14220. [PMID: 37101643 PMCID: PMC10123168 DOI: 10.1016/j.heliyon.2023.e14220] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 02/27/2023] [Indexed: 03/06/2023] Open
Abstract
Toxin-Antitoxin (TA) systems are abundant in prokaryotes and play an important role in various biological processes such as plasmid maintenance, phage inhibition, stress response, biofilm formation, and dormant persister cell generation. TA loci are abundant in pathogenic intracellular micro-organisms and help in their adaptation to the harsh host environment such as nutrient deprivation, oxidation, immune response, and antimicrobials. Several studies have reported the involvement of TA loci in establishing successful infection, intracellular survival, better colonization, adaptation to host stresses, and chronic infection. Overall, the TA loci play a crucial role in bacterial virulence and pathogenesis. Nonetheless, there are some controversies about the role of TA system in stress response, biofilm and persister formation. In this review, we describe the role of the TA systems in bacterial virulence. We discuss the important features of each type of TA system and the recent discoveries identifying key contributions of TA loci in bacterial pathogenesis.
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12
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Tetz V, Tetz G. Novel prokaryotic system employing previously unknown nucleic acids-based receptors. Microb Cell Fact 2022; 21:202. [PMID: 36195904 PMCID: PMC9531389 DOI: 10.1186/s12934-022-01923-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 09/16/2022] [Indexed: 12/26/2022] Open
Abstract
The present study describes a previously unknown universal system that orchestrates the interaction of bacteria with the environment, named the Teazeled receptor system (TR-system). The identical system was recently discovered within eukaryotes. The system includes DNA- and RNA-based molecules named "TezRs", that form receptor's network located outside the membrane, as well as reverse transcriptases and integrases. TR-system takes part in the control of all major aspects of bacterial behavior, such as intra cellular communication, growth, biofilm formation and dispersal, utilization of nutrients including xenobiotics, virulence, chemo- and magnetoreception, response to external factors (e.g., temperature, UV, light and gas content), mutation events, phage-host interaction, and DNA recombination activity. Additionally, it supervises the function of other receptor-mediated signaling pathways. Importantly, the TR-system is responsible for the formation and maintenance of cell memory to preceding cellular events, as well the ability to "forget" preceding events. Transcriptome and biochemical analysis revealed that the loss of different TezRs instigates significant alterations in gene expression and proteins synthesis.
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Affiliation(s)
- Victor Tetz
- Human Microbiology Institute, New York, NY, 10013, USA
| | - George Tetz
- Human Microbiology Institute, New York, NY, 10013, USA.
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13
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Fernández-García L, Muthami JM, Tomas M, Wood TK. What are the options for treating infections by persister-forming pathogens? Environ Microbiol 2022; 24:4500-4504. [PMID: 35912818 DOI: 10.1111/1462-2920.16117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 06/21/2022] [Indexed: 11/30/2022]
Affiliation(s)
- Laura Fernández-García
- Department of Chemical Engineering, Pennsylvania State University, University Park, Pennsylvania, USA.,Microbiology Translational and Multidisciplinary (MicroTM)-Research Institute Biomedical A Coruña (INIBIC) and Microbiology Department of Hospital A Coruña (CHUAC), University of A Coruña (UDC), A Coruña, Spain
| | - Joy M Muthami
- Department of Chemical Engineering, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Maria Tomas
- Microbiology Translational and Multidisciplinary (MicroTM)-Research Institute Biomedical A Coruña (INIBIC) and Microbiology Department of Hospital A Coruña (CHUAC), University of A Coruña (UDC), A Coruña, Spain
| | - Thomas K Wood
- Department of Chemical Engineering, Pennsylvania State University, University Park, Pennsylvania, USA
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14
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Manandhar S, Singh A, Varma A, Pandey S, Shrivastava N. High level of persister frequency in clinical staphylococcal isolates. BMC Microbiol 2022; 22:109. [PMID: 35448965 PMCID: PMC10124895 DOI: 10.1186/s12866-022-02529-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 04/12/2022] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Staphylococcus aureus is a notorious human pathogen that causes often lethal systemic conditions that are mostly medical device associated biofilm infections. Similarly, coagulase negative staphylococci are emerging as leading pathogen for nosocomial infections owing to their ability to form biofilm on implanted medical equipment. Chronic in nature, these infections are difficult to treat. Such recalcitrance of these infections is caused mainly due to the presence of persister cells, which exhibit transient yet extreme tolerance to antibiotics. Despite tremendous clinical significance, there is lack of studies on persister cells formation among clinical bacterial isolates. Considering the importance of factors influencing persister formation, in this study, we evaluate the association of antibiotic tolerance with biofilm production, antibiotic stress, growth phase, specimen type, and dependency on staphylococcal species. Biofilm formation was detected among 375 clinical staphylococcal isolates by quantitative tissue culture plate method (TCP) and icaAD genes by genotypic method. The antibiotic susceptibility was determined by Kirby Bauer disc diffusion method while minimum inhibitory concentration values were obtained by agar dilution method. Persister cells were measured in the susceptible staphylococcal isolates in the presence of clinically relevant antibiotics. RESULTS In the study, 161 (43%) S. aureus and 214 (57%) coagulase negative staphylococci (CNS) were isolated from different clinical samples. TCP method detected biofilm production in 84 (52.2%) S. aureus and 90 (42.1%) CNS isolates. The genotypic method detected icaAD genes in 86 (22.9%) isolates. Majority (> 90%) of both the biofilm producers and non-producers were sensitive to chloramphenicol and tetracycline but were resistant to penicillin. Interestingly, all isolates were sensitive to vancomycin irrespective of biofilm production. While high persister frequency was observed among all staphylococci isolates in the stationary growth phase, the persister frequency in exponential growth phase was statistically high among isolates possessing icaAD genes compared to icaAD negative isolates. CONCLUSION The research findings provide strong evidence that the clinical staphylococcal isolates exhibit extreme antibiotic tolerance suggesting their causal link with treatment failures. Understanding the factors influencing the formation and maintenance of persister cells are of utmost important aspect to design therapeutics and control recalcitrant bacterial infections.
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Affiliation(s)
- Sarita Manandhar
- Tri-Chandra Multiple College, Tribhuvan University, Kathmandu, Nepal.
| | - Anjana Singh
- Central Department of Microbiology, Tribhuvan University, Kathmandu, Nepal
| | - Ajit Varma
- Amity Institute of Microbial Technology, Amity University, Uttar Pradesh, Noida, UP, 201303, India
| | - Shanti Pandey
- The University of Southern Mississippi, Hattiesburg, MS-39406, USA
| | - Neeraj Shrivastava
- Amity Institute of Microbial Technology, Amity University, Uttar Pradesh, Noida, UP, 201303, India
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15
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Edelmann D, Berghoff BA. A Shift in Perspective: A Role for the Type I Toxin TisB as Persistence-Stabilizing Factor. Front Microbiol 2022; 13:871699. [PMID: 35369430 PMCID: PMC8969498 DOI: 10.3389/fmicb.2022.871699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 02/28/2022] [Indexed: 11/13/2022] Open
Abstract
Bacterial persistence is a phenomenon that is founded by the existence of a subpopulation of multidrug-tolerant cells. These so-called persister cells endure otherwise lethal stress situations and enable restoration of bacterial populations upon return to favorable conditions. Persisters are especially notorious for their ability to survive antibiotic treatments without conventional resistance genes and to cause infection relapse. The persister state is typically correlated with reduction or inhibition of cellular activity. Early on, chromosomal toxin-antitoxin (TA) systems were suspected to induce the persister state in response to environmental stress. However, this idea has been challenged during the last years. Especially the involvement of toxins from type II TA systems in persister formation is put into question. For toxins from type I TA systems the debate has just started. Here, we would like to summarize recent knowledge gained for the type I TA system tisB/istR-1 from Escherichia coli. TisB is a small, membrane-targeting toxin, which disrupts the proton motive force (PMF), leading to membrane depolarization. Based on experimental data, we hypothesize that TisB primarily stabilizes the persister state through depolarization and further, secondary effects. We will present a simple model that will provide a framework for future directions.
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16
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Hartline CJ, Zhang R, Zhang F. Transient Antibiotic Tolerance Triggered by Nutrient Shifts From Gluconeogenic Carbon Sources to Fatty Acid. Front Microbiol 2022; 13:854272. [PMID: 35359720 PMCID: PMC8963472 DOI: 10.3389/fmicb.2022.854272] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 02/22/2022] [Indexed: 12/04/2022] Open
Abstract
Nutrient shifts from glycolytic-to-gluconeogenic carbon sources can create large sub-populations of extremely antibiotic tolerant bacteria, called persisters. Positive feedback in Escherichia coli central metabolism was believed to play a key role in the formation of persister cells. To examine whether positive feedback in nutrient transport can also support high persistence to β-lactams, we performed nutrient shifts for E. coli from gluconeogenic carbon sources to fatty acid (FA). We observed tri-phasic antibiotic killing kinetics characterized by a transient period of high antibiotic tolerance, followed by rapid killing then a slower persister-killing phase. The duration of transient tolerance (3-44 h) varies with pre-shift carbon source and correlates strongly with the time needed to accumulate the FA degradation enzyme FadD after the shift. Additionally, FadD accumulation time and thus transient tolerance time can be reduced by induction of the glyoxylate bypass prior to switching, highlighting that two interacting feedback loops simultaneously control the length of transient tolerance. Our results demonstrate that nutrient switches along with positive feedback are not sufficient to trigger persistence in a majority of the population but instead triggers only a temporary tolerance. Additionally, our results demonstrate that the pre-shift metabolic state determines the duration of transient tolerance and that supplying glyoxylate can facilitate antibiotic killing of bacteria.
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Affiliation(s)
- Christopher J. Hartline
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, Saint Louis, MO, United States
| | - Ruixue Zhang
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, Saint Louis, MO, United States
| | - Fuzhong Zhang
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, Saint Louis, MO, United States
- Division of Biology and Biomedical Sciences, Washington University in St. Louis, Saint Louis, MO, United States
- Institute of Materials Science and Engineering, Washington University in St. Louis, Saint Louis, MO, United States
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17
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Hemeg HA. Combatting persisted and biofilm antimicrobial resistant bacterial by using nanoparticles. Z NATURFORSCH C 2022; 77:365-378. [PMID: 35234019 DOI: 10.1515/znc-2021-0296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 02/04/2022] [Indexed: 11/15/2022]
Abstract
Some bacteria can withstand the existence of an antibiotic without undergoing any genetic changes. They are neither cysts nor spores and are one of the causes of disease recurrence, accounting for about 1% of the biofilm. There are numerous approaches to eradication and combating biofilm-forming organisms. Nanotechnology is one of them, and it has shown promising results against persister cells. In the review, we go over the persister cell and biofilm in extensive detail. This includes the biofilm formation cycle, antibiotic resistance, and treatment with various nanoparticles. Furthermore, the gene-level mechanism of persister cell formation and its therapeutic interventions with nanoparticles were discussed.
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Affiliation(s)
- Hassan A Hemeg
- Department of Medical Laboratory Technology, College of Applied Medical Sciences, Taibah University, P.O. Box 344, Al-Madinah Al-Monawra 41411, Saudi Arabia
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18
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Mohiuddin SG, Massahi A, Orman MA. High-Throughput Screening of a Promoter Library Reveals New Persister Mechanisms in Escherichia Coli. Microbiol Spectr 2022; 10:e0225321. [PMID: 35196813 PMCID: PMC8865558 DOI: 10.1128/spectrum.02253-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Accepted: 01/31/2022] [Indexed: 11/23/2022] Open
Abstract
Persister cells are a small subpopulation of phenotypic variants that survive high concentrations of bactericidal antibiotics. Their survival mechanisms are not heritable and can be formed stochastically or triggered by environmental stresses such as antibiotic treatment. In this study, high-throughput screening of an Escherichia coli promoter library and subsequent validation experiments identified several genes whose expression was upregulated by antibiotic treatment. Among the identified genes, waaG, guaA, and guaB were found to be important in persister cell formation in E. coli as their deletion significantly enhanced the sensitivity of cells to various antibiotics. The GuaA and GuaB enzymes form the upstream reactions of ppGpp (a global persister molecule) biosynthesis, and the deletion of guaA and guaB drastically perturbs the ppGpp regulon in E. coli. WaaG, a lipopolysaccharide glucosyltransferase, plays an important role in shaping the outer membrane structure, and the deletion of waaG dissipates the proton gradient (ΔpH) component of cellular proton motive force (PMF), perturbs cellular ATP production, and reduces type I persister formation in stationary phase. Active respiration in the stationary phase, which drives the PMF, was previously shown to play a critical role in type I persister formation, and our results associated with the waaG deficient strain further corroborate these findings. IMPORTANCE Persistence is a nonheritable trait by which normal growing cells switch phenotypically to antibiotic tolerant persister cells. This transient state enables persister cells to recover and grow into an antibiotic-sensitive population. Persister cells have been observed in many pathogenic and nonpathogenic bacteria. Previous studies highlight the complexity and diversity of bacterial persister-cell mechanisms, many of which still remain to be elucidated. Here, using promoter and knockout cell libraries in Escherichia coli, we have identified genes that reveal novel persister mechanisms. As persistence is a critical survival strategy that evolved in many bacteria, our study will enhance the current molecular-level understanding of this conserved mechanism.
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Affiliation(s)
- Sayed Golam Mohiuddin
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas, USA
| | - Aslan Massahi
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas, USA
| | - Mehmet A. Orman
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas, USA
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19
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Abstract
Bacterial persisters are nongrowing cells highly tolerant to bactericidal antibiotics. However, this tolerance is reversible and not mediated by heritable genetic changes. Lon, an ATP-dependent protease, has repeatedly been shown to play a critical role in fluoroquinolone persistence in Escherichia coli. Although lon deletion (Δlon) is thought to eliminate persister cells via accumulation of the cell division inhibitor protein SulA, the exact mechanism underlying this phenomenon is not yet elucidated. Here, we show that Lon is an important regulatory protein for the resuscitation of the fluoroquinolone persisters in E. coli, and lon deletion impairs the ability of persister cells to form colonies during recovery through a sulA- and ftsZ-dependent mechanism. Notably, this observed "viable but nonculturable" state of antibiotic-tolerant Δlon cells is transient, as environmental conditions, such as starvation, can restore their culturability. Our data further indicate that starvation-induced SulA degradation or expression of Lon during recovery facilitates Z-ring formation in Δlon persisters, and Z-ring architecture is important for persister resuscitation in both wild-type and Δlon strains. Our in-depth image analysis clearly shows that the ratio of cell length to number of FtsZ rings for each intact ofloxacin-treated cell predicts the probability of resuscitation and, hence, can be used as a potential biomarker for persisters. IMPORTANCE The ATP-dependent Lon protease is one of the most studied bacterial proteases. Although deletion of lon has been frequently shown to reduce fluoroquinolone persistence, the proposed mechanisms underlying this phenomenon are highly controversial. Here, we have shown that lon deletion in Escherichia coli impairs the ability of persister cells to form colonies during recovery and that this reduction of persister levels in lon-deficient cells can be transient. We also found that altered Z-ring architecture is a key biomarker in both wild-type and lon-deficient persister cells transitioning to a normal cell state. Collectively, our findings highlight the importance of differentiating persister formation mechanisms from resuscitation mechanisms and underscore the critical role of the nonculturable cell state in antibiotic tolerance.
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20
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Zou J, Peng B, Qu J, Zheng J. Are Bacterial Persisters Dormant Cells Only? Front Microbiol 2022; 12:708580. [PMID: 35185807 PMCID: PMC8847742 DOI: 10.3389/fmicb.2021.708580] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 12/15/2021] [Indexed: 11/13/2022] Open
Abstract
Bacterial persisters are a sub-population of phenotypic variants that tolerate high concentrations of antibiotics within the genetically homogeneous cells. They resume division upon the removal of drugs. Bacterial persistence is one of major causes of antibiotic treatment failure and recurrent infection. Cell dormancy, triggered by toxin/antitoxin pair, (p)ppGpp, SOS response and ATP levels, is known to be the mechanistic basis for persistence. However, recent studies have demonstrated that bacteria with active metabolism can maintain persistence by lowering intracellular antibiotic concentration via an efflux pump. Additionally, others and our work have showed that cell wall deficient bacteria (CWDB), including both L-form and spheroplasts that produced by β-lactam antibiotics, are associated with antibiotic persistence. They are not dormant cells as their cell walls have been completely damaged. In this review, we discuss the various types of persisters and highlight the contribution of non-walled bacteria on bacterial persistence.
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Affiliation(s)
- Jin Zou
- Department of Clinical Laboratory, The Third People's Hospital of Shenzhen, Southern University of Science and Technology, National Clinical Research Center for Infectious Diseases, Shenzhen, China.,Faculty of Health Sciences, University of Macau, Zhuhai, Macau SAR, China
| | - Bo Peng
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Jiuxin Qu
- Department of Clinical Laboratory, The Third People's Hospital of Shenzhen, Southern University of Science and Technology, National Clinical Research Center for Infectious Diseases, Shenzhen, China
| | - Jun Zheng
- Faculty of Health Sciences, University of Macau, Zhuhai, Macau SAR, China.,Institute of Translational Medicine, University of Macau, Zhuhai, Macau SAR, China
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21
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Svenningsen MS, Svenningsen SL, Sørensen MA, Mitarai N. Existence of log-phase Escherichia coli persisters and lasting memory of a starvation pulse. Life Sci Alliance 2021; 5:5/2/e202101076. [PMID: 34795016 PMCID: PMC8605324 DOI: 10.26508/lsa.202101076] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 11/04/2021] [Accepted: 11/04/2021] [Indexed: 11/24/2022] Open
Abstract
The authors characterize the growth condition dependence of survival of bacteria exposed to lethal antibiotics for a week. 1-h starvation pulse is shown to cause an increase in survival for days. The vast majority of a bacterial population is killed when treated with a lethal concentration of antibiotics. The time scale of this killing is often comparable with the bacterial generation time before the addition of antibiotics. Yet, a small subpopulation typically survives for an extended period. However, the long-term killing dynamics of bacterial cells has not been fully quantified even in well-controlled laboratory conditions. We constructed a week-long killing assay and followed the survival fraction of Escherichia coli K12 exposed to a high concentration of ciprofloxacin. We found that long-term survivors were formed during exponential growth, with some cells surviving at least 7 d. The long-term dynamics contained at least three time scales, which greatly enhances predictions of the population survival time compared with the biphasic extrapolation from the short-term behavior. Furthermore, we observed a long memory effect of a brief starvation pulse, which was dependent on the (p)ppGpp synthase relA. Specifically, 1 h of carbon starvation before antibiotics exposure increased the surviving fraction by nearly 100-fold even after 4 d of ciprofloxacin treatment.
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Affiliation(s)
| | | | | | - Namiko Mitarai
- The Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
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22
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Wainwright J, Hobbs G, Nakouti I. Persister cells: formation, resuscitation and combative therapies. Arch Microbiol 2021; 203:5899-5906. [PMID: 34739553 PMCID: PMC8590677 DOI: 10.1007/s00203-021-02585-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 09/06/2021] [Accepted: 09/16/2021] [Indexed: 12/14/2022]
Abstract
Persister cells, or superfits, have been strongly implicated in the recalcitrance and recurrence of chronic bacterial infection through the dormant (metabolically reduced) phenotype they display and the tolerance to antimicrobial agents this dormancy grants them. The complex biochemical events that lead to the formation of persister cells are not completely understood, though much research has linked the degradation of type II toxin/antitoxin systems and reduced cellular ATP levels to the rise in stress response molecules (where (p)ppGpp is of particular interest), which induce this dormant state. The equally complex mechanism of resuscitation is initiated by the cells’ ability to sense nutrient availability via chemotaxis systems. Levels of secondary messenger proteins (i.e., cAMP) within the cell are reduced to allow the resuscitation of ribosomes, by ribosomal resuscitation factor HflX, to reinstate protein synthesis and, therefore, growth to re-populate. Techniques of superfit eradication utilise one, or more, of three approaches (i) direct killing, (ii) re-sensitising persister cells to conventional antimicrobials, or (iii) prevention of persister formation though few laboratory findings have been translated to clinical practice. This work will outline current findings in the field with a critical approach, where possible.
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Affiliation(s)
- Jack Wainwright
- Centre for Natural Products Discovery (CNPD), School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, UK
| | - Glyn Hobbs
- Centre for Natural Products Discovery (CNPD), School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, UK
| | - Ismini Nakouti
- Centre for Natural Products Discovery (CNPD), School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, UK.
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23
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Song S, Kim JS, Yamasaki R, Oh S, Benedik MJ, Wood TK. Escherichia coli cryptic prophages sense nutrients to influence persister cell resuscitation. Environ Microbiol 2021; 23:7245-7254. [PMID: 34668292 DOI: 10.1111/1462-2920.15816] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 10/07/2021] [Indexed: 11/28/2022]
Abstract
Cryptic prophages are not genomic junk but instead enable cells to combat myriad stresses as an active stress response. How these phage fossils affect persister cell resuscitation has, however, not been explored. Persister cells form as a result of stresses such as starvation, antibiotics and oxidative conditions, and resuscitation of these persister cells likely causes recurring infections such as those associated with tuberculosis, cystic fibrosis and Lyme disease. Deletion of each of the nine Escherichia coli cryptic prophages has no effect on persister cell formation. Strikingly, elimination of each cryptic prophage results in an increase in persister cell resuscitation with a dramatic increase in resuscitation upon deleting all nine prophages. This increased resuscitation includes eliminating the need for a carbon source and is due to activation of the phosphate import system resulting from inactivating the transcriptional regulator AlpA of the CP4-57 cryptic prophage. Deletion of alpA increases persister resuscitation, and AlpA represses phosphate regulator PhoR. Both phosphate regulators PhoP and PhoB stimulate resuscitation. This suggests a novel cellular stress mechanism controlled by cryptic prophages: regulation of phosphate uptake which controls the exit of the cell from dormancy and prevents premature resuscitation in the absence of nutrients.
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Affiliation(s)
- Sooyeon Song
- Department of Chemical Engineering, Pennsylvania State University, University Park, Pennsylvania, 16802-4400, USA.,Department of Animal Science, Jeonbuk National University, 587 Baekje-Daero, Deokjin-Gu, Jeonju-Si, Jeollabuk-Do, 54896, South Korea.,Department of Agricultural Convergence Technology, Jeonbuk National University, 587 Baekje-Daero, Deokjin-Gu, Jeonju-Si, Jeollabuk-Do, 54896, South Korea
| | - Jun-Seob Kim
- Department of Nano-Bioengineering, Incheon National University, 119 Academy-ro, Incheon, 22012, South Korea
| | - Ryota Yamasaki
- Department of Health Promotion, Kyushu Dental University, Kitakyushu, Fukuoka, 803-8580, Japan
| | - Sejong Oh
- Division of Animal Science, Chonnam National University, 77 Yongbong-Ro, Buk-Gu, Gwangju, 61186, South Korea
| | - Michael J Benedik
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA
| | - Thomas K Wood
- Department of Chemical Engineering, Pennsylvania State University, University Park, Pennsylvania, 16802-4400, USA
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24
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Identification and Characterization of Pleiotropic High-Persistence Mutations in the Beta Subunit of the Bacterial RNA Polymerase. Antimicrob Agents Chemother 2021; 65:e0052221. [PMID: 34424038 DOI: 10.1128/aac.00522-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mutations conferring resistance to bactericidal antibiotics reduce the average susceptibility of mutant populations. It is unknown, however, how those mutations affect the survival of individual bacteria. Since surviving bacteria can be a reservoir for recurring infections, it is important to know how survival rates may be affected by resistance mutations and by the choice of antibiotics. Here, we present evidence that (i) Escherichia coli mutants with 100 to 1,000 times increased frequency of survival in ciprofloxacin, an archetypal fluoroquinolone antibiotic, can be readily obtained in a stepwise selection; (ii) the high survival frequency is conferred by mutations in the switch region of the beta subunit of the RNA polymerase; (iii) the switch-region mutations are (p)ppGpp mimics, partially analogous to rpoB stringent mutations; (iv) the stringent and switch region rpoB mutations frequently occur in clinical isolates of E. coli, Acinetobacter baumannii, Mycobacterium tuberculosis, and Staphylococcus aureus, and at least one of them, RpoB S488L, which is a common rifampicin resistance mutations, dramatically increases the survival of a clinical methicillin-resistant S. aureus (MRSA) strain in ampicillin; and (v) the RpoB-associated high-survival phenotype can be reversed by subinhibitory concentrations of chloramphenicol.
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25
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Persister Escherichia coli Cells Have a Lower Intracellular pH than Susceptible Cells but Maintain Their pH in Response to Antibiotic Treatment. mBio 2021; 12:e0090921. [PMID: 34281389 PMCID: PMC8406257 DOI: 10.1128/mbio.00909-21] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Persister and viable but non-culturable (VBNC) cells are two clonal subpopulations that can survive multidrug exposure via a plethora of putative molecular mechanisms. Here, we combine microfluidics, time-lapse microscopy, and a plasmid-encoded fluorescent pH reporter to measure the dynamics of the intracellular pH of individual persister, VBNC, and susceptible Escherichia coli cells in response to ampicillin treatment. We found that even before antibiotic exposure, persisters have a lower intracellular pH than those of VBNC and susceptible cells. We then investigated the molecular mechanisms underlying the observed differential pH regulation in persister E. coli cells and found that this is linked to the activity of the enzyme tryptophanase, which is encoded by tnaA. In fact, in a ΔtnaA strain, we found no difference in intracellular pH between persister, VBNC, and susceptible E. coli cells. Whole-genome transcriptomic analysis revealed that, besides downregulating tryptophan metabolism, the ΔtnaA strain downregulated key pH homeostasis pathways, including the response to pH, oxidation reduction, and several carboxylic acid catabolism processes, compared to levels of expression in the parental strain. Our study sheds light on pH homeostasis, proving that the regulation of intracellular pH is not homogeneous within a clonal population, with a subset of cells displaying a differential pH regulation to perform dedicated functions, including survival after antibiotic treatment. IMPORTANCE Persister and VBNC cells can phenotypically survive environmental stressors, such as antibiotic treatment, limitation of nutrients, and acid stress, and have been linked to chronic infections and antimicrobial resistance. It has recently been suggested that pH regulation might play a role in an organism's phenotypic survival to antibiotics; however, this hypothesis remains to be tested. Here, we demonstrate that even before antibiotic treatment, cells that will become persisters have a more acidic intracellular pH than clonal cells that will be either susceptible or VBNC upon antibiotic treatment. Moreover, after antibiotic treatment, persisters become more alkaline than VBNC and susceptible E. coli cells. This newly found phenotypic feature is remarkable because it distinguishes persister and VBNC cells that have often been thought to display the same dormant phenotype. We then show that this differential pH regulation is abolished in the absence of the enzyme tryptophanase via a major remodeling of bacterial metabolism and pH homeostasis. These new whole-genome transcriptome data should be taken into account when modeling bacterial metabolism at the crucial transition from exponential to stationary phase. Overall, our findings indicate that the manipulation of the intracellular pH represents a bacterial strategy for surviving antibiotic treatment. In turn, this suggests a strategy for developing persister-targeting antibiotics by interfering with cellular components, such as tryptophanase, that play a major role in pH homeostasis.
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26
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Wang Y, Li Q, Tian P, Tan T. Charting the landscape of RNA polymerases to unleash their potential in strain improvement. Biotechnol Adv 2021; 54:107792. [PMID: 34216775 DOI: 10.1016/j.biotechadv.2021.107792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 05/28/2021] [Accepted: 06/26/2021] [Indexed: 11/19/2022]
Abstract
One major mission of microbial cell factory is overproduction of desired chemicals. To this end, it is necessary to orchestrate enzymes that affect metabolic fluxes. However, only modification of a small number of enzymes in most cases cannot maximize desired metabolites, and global regulation is required. Of myriad enzymes influencing global regulation, RNA polymerase (RNAP) may be the most versatile enzyme in biological realm because it not only serves as the workhorse of central dogma but also participates in a plethora of biochemical events. In fact, recent years have witnessed extensive exploitation of RNAPs for phenotypic engineering. While a few impressive reviews showcase the structures and functionalities of RNAPs, this review not only summarizes the state-of-the-art advance in the structures of RNAPs but also points out their enormous potentials in metabolic engineering and synthetic biology. This review aims to provide valuable insights for strain improvement.
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Affiliation(s)
- Ye Wang
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, PR China
| | - Qingyang Li
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510641, PR China
| | - Pingfang Tian
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, PR China.
| | - Tianwei Tan
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, PR China
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The RNA Chaperone Hfq Participates in Persistence to Multiple Antibiotics in the Fish Pathogen Yersinia ruckeri. Microorganisms 2021; 9:microorganisms9071404. [PMID: 34209738 PMCID: PMC8308036 DOI: 10.3390/microorganisms9071404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 06/11/2021] [Accepted: 06/25/2021] [Indexed: 11/16/2022] Open
Abstract
Yersinia ruckeri causes outbreaks of enteric redmouth disease in salmon aquaculture all over the world. The transient antibiotic tolerance exhibited by bacterial persisters is commonly thought to be responsible for outbreaks; however, the molecular factors underlying this behavior have not been explored in Y. ruckeri. In this study, we investigated the participation of the RNA chaperone Hfq from Y. ruckeri in antibiotic persistence. Cultures of the hfq-knockout mutant (Δhfq) exhibited faster replication, increased ATP levels and a more reductive environment than the wild type. The growth curves of bacteria exposed to sublethal concentrations of ampicillin, oxolinic acid, ciprofloxacin and polymyxin B revealed a greater susceptibility for the Δhfq strain. The time-kill curves of bacteria treated with the antibiotics mentioned above and florfenicol, using inoculums from exponential, stationary and biofilm cultures, demonstrated that the Δhfq strain has significant defects in persister cells production. To shed more light on the role of Hfq in antibiotic persistence, we analyzed its dependence on the (p)ppGpp synthetase RelA by determining the persister cells production in the absence of the relA gene. The ΔrelA and ΔrelAΔhfq strains displayed similar defects in persister cells formation, but higher than Δhfq strain. Similarly, stationary cultures of the ΔrelA and ΔrelAΔhfq strains exhibited comparable levels of ATP but higher than that of the Δhfq strain, indicating that relA is epistatic over hfq. Taken together, our findings provide valuable information on antibiotic persistence in Y. ruckeri, shedding light on the participation of Hfq in the persistence phenomenon.
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Lauxen AI, Kobauri P, Wegener M, Hansen MJ, Galenkamp NS, Maglia G, Szymanski W, Feringa BL, Kuipers OP. Mechanism of Resistance Development in E. coli against TCAT, a Trimethoprim-Based Photoswitchable Antibiotic. Pharmaceuticals (Basel) 2021; 14:ph14050392. [PMID: 33919397 PMCID: PMC8143356 DOI: 10.3390/ph14050392] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 04/17/2021] [Accepted: 04/19/2021] [Indexed: 11/16/2022] Open
Abstract
During the last decades, a continuous rise of multi-drug resistant pathogens has threatened antibiotic efficacy. To tackle this key challenge, novel antimicrobial therapies are needed with increased specificity for the site of infection. Photopharmacology could enable such specificity by allowing for the control of antibiotic activity with light, as exemplified by trans/cis-tetra-ortho-chloroazobenzene-trimethoprim (TCAT) conjugates. Resistance development against the on (irradiated, TCATa) and off (thermally adapted, TCATd) states of TCAT were compared to that of trimethoprim (TMP) in Escherichia coli mutant strain CS1562. Genomics and transcriptomics were used to explore the acquired resistance. Although TCAT shows TMP-like dihydrofolate reductase (DHFR) inhibition in vitro, transcriptome analyses show different responses in acquired resistance. Resistance against TCATa (on) relies on the production of exopolysaccharides and overexpression of TolC. While resistance against TCATd (off) follows a slightly different gene expression profile, both indicate hampering the entrance of the molecule into the cell. Conversely, resistance against TMP is based on alterations in cell metabolism towards a more persister-like phenotype, as well as alteration of expression levels of enzymes involved in the folate biosynthesis. This study provides a deeper understanding of the development of new therapeutic strategies and the consequences on resistance development against photopharmacological drugs.
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Affiliation(s)
- Anna I. Lauxen
- Department of Molecular Genetics, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands;
| | - Piermichele Kobauri
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands; (P.K.); (M.W.); (M.J.H.)
| | - Michael Wegener
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands; (P.K.); (M.W.); (M.J.H.)
| | - Mickel J. Hansen
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands; (P.K.); (M.W.); (M.J.H.)
| | - Nicole S. Galenkamp
- Groningen Biomolecular Science & Biotechnology Institute, University of Groningen, Nijenborg 4, 9747 AG Groningen, The Netherlands; (N.S.G.); (G.M.)
| | - Giovanni Maglia
- Groningen Biomolecular Science & Biotechnology Institute, University of Groningen, Nijenborg 4, 9747 AG Groningen, The Netherlands; (N.S.G.); (G.M.)
| | - Wiktor Szymanski
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands; (P.K.); (M.W.); (M.J.H.)
- Medical Imaging Center, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands
- Correspondence: (W.S.); (B.L.F.); (O.P.K.)
| | - Ben L. Feringa
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands; (P.K.); (M.W.); (M.J.H.)
- Correspondence: (W.S.); (B.L.F.); (O.P.K.)
| | - Oscar P. Kuipers
- Department of Molecular Genetics, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands;
- Correspondence: (W.S.); (B.L.F.); (O.P.K.)
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29
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Identification of a Toxin-Antitoxin System That Contributes to Persister Formation by Reducing NAD in Pseudomonas aeruginosa. Microorganisms 2021; 9:microorganisms9040753. [PMID: 33918483 PMCID: PMC8065639 DOI: 10.3390/microorganisms9040753] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 03/31/2021] [Accepted: 03/31/2021] [Indexed: 12/14/2022] Open
Abstract
Bacterial persisters are slow-growing or dormant cells that are highly tolerant to bactericidal antibiotics and contribute to recalcitrant and chronic infections. Toxin/antitoxin (TA) systems play important roles in controlling persister formation. Here, we examined the roles of seven predicted type II TA systems in the persister formation of a Pseudomonas aeruginosa wild-type strain PA14. Overexpression of a toxin gene PA14_51010 or deletion of the cognate antitoxin gene PA14_51020 increased the bacterial tolerance to antibiotics. Co-overexpression of PA14_51010 and PA14_51020 or simultaneous deletion of the two genes resulted in a wild-type level survival rate following antibiotic treatment. The two genes were located in the same operon that was repressed by PA14_51020. We further demonstrated the interaction between PA14_51010 and PA14_51020. Sequence analysis revealed that PA14_51010 contained a conserved RES domain. Overexpression of PA14_51010 reduced the intracellular level of nicotinamide adenine dinucleotide (NAD+). Mutation of the RES domain abolished the abilities of PA14_51010 in reducing NAD+ level and promoting persister formation. In addition, overproduction of NAD+ by mutation in an nrtR gene counteracted the effect of PA14_51010 overexpression in promoting persister formation. In combination, our results reveal a novel TA system that contributes to persister formation through reducing the intracellular NAD+ level in P. aeruginosa.
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30
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Manuse S, Shan Y, Canas-Duarte SJ, Bakshi S, Sun WS, Mori H, Paulsson J, Lewis K. Bacterial persisters are a stochastically formed subpopulation of low-energy cells. PLoS Biol 2021; 19:e3001194. [PMID: 33872303 PMCID: PMC8084331 DOI: 10.1371/journal.pbio.3001194] [Citation(s) in RCA: 65] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 04/29/2021] [Accepted: 03/18/2021] [Indexed: 11/19/2022] Open
Abstract
Persisters represent a small subpopulation of non- or slow-growing bacterial cells that are tolerant to killing by antibiotics. Despite their prominent role in the recalcitrance of chronic infections to antibiotic therapy, the mechanism of their formation has remained elusive. We show that sorted cells of Escherichia coli with low levels of energy-generating enzymes are better able to survive antibiotic killing. Using microfluidics time-lapse microscopy and a fluorescent reporter for in vivo ATP measurements, we find that a subpopulation of cells with a low level of ATP survives killing by ampicillin. We propose that these low ATP cells are formed stochastically as a result of fluctuations in the abundance of energy-generating components. These findings point to a general "low energy" mechanism of persister formation.
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Affiliation(s)
- Sylvie Manuse
- Antimicrobial Discovery Center, Department of Biology, Northeastern University, Boston, Massachusetts, United States of America
| | - Yue Shan
- Antimicrobial Discovery Center, Department of Biology, Northeastern University, Boston, Massachusetts, United States of America
| | - Silvia J. Canas-Duarte
- Department of Systems Biology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Somenath Bakshi
- Department of Systems Biology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Wei-Sheng Sun
- Antimicrobial Discovery Center, Department of Biology, Northeastern University, Boston, Massachusetts, United States of America
| | - Hirotada Mori
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Nara, Japan
| | - Johan Paulsson
- Department of Systems Biology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Kim Lewis
- Antimicrobial Discovery Center, Department of Biology, Northeastern University, Boston, Massachusetts, United States of America
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31
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Nowicki D, Krause K, Szamborska P, Żukowska A, Cech GM, Szalewska-Pałasz A. Induction of the Stringent Response Underlies the Antimicrobial Action of Aliphatic Isothiocyanates. Front Microbiol 2021; 11:591802. [PMID: 33584562 PMCID: PMC7874123 DOI: 10.3389/fmicb.2020.591802] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 12/15/2020] [Indexed: 11/24/2022] Open
Abstract
Bacterial resistance to known antibiotics comprises a serious threat to public health. Propagation of multidrug-resistant pathogenic strains is a reason for undertaking a search for new therapeutic strategies, based on newly developed chemical compounds and the agents present in nature. Moreover, antibiotic treatment of infections caused by enterotoxin toxin-bearing strain—enterohemorrhagic Escherichia coli (EHEC) is considered hazardous and controversial due to the possibility of induction of bacteriophage-encoded toxin production by the antibiotic-mediated stress. The important source of potentially beneficial compounds are secondary plant metabolites, isothiocyanates (ITC), and phytoncides from the Brassicaceae family. We reported previously that sulforaphane and phenethyl isothiocyanate, already known for their chemopreventive and anticancer features, exhibit significant antibacterial effects against various pathogenic bacteria. The mechanism of their action is based on the induction of the stringent response and accumulation of its alarmones, the guanosine penta- and tetraphosphate. In this process, the amino acid starvation path is employed via the RelA protein, however, the precise mechanism of amino acid limitation in the presence of ITCs is yet unknown. In this work, we asked whether ITCs could act synergistically with each other to increase the antibacterial effect. A set of aliphatic ITCs, such as iberin, iberverin, alyssin, erucin, sulforaphen, erysolin, and cheirolin was tested in combination with sulforaphane against E. coli. Our experiments show that all tested ITCs exhibit strong antimicrobial effect individually, and this effect involves the stringent response caused by induction of the amino acid starvation. Interestingly, excess of specific amino acids reversed the antimicrobial effects of ITCs, where the common amino acid for all tested compounds was glycine. The synergistic action observed for iberin, iberverin, and alyssin also led to accumulation of (p)ppGpp, and the minimal inhibitory concentration necessary for the antibacterial effect was four- to eightfold lower than for individual ITCs. Moreover, the unique mode of ITC action is responsible for inhibition of prophage induction and toxin production, in addition to growth inhibition of EHEC strains. Thus, the antimicrobial effect of plant secondary metabolites by the stringent response induction could be employed in potential therapeutic strategies.
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Affiliation(s)
- Dariusz Nowicki
- Department of Bacterial Molecular Genetics, Faculty of Biology, University of Gdańsk, Gdańsk, Poland
| | - Klaudyna Krause
- Department of Bacterial Molecular Genetics, Faculty of Biology, University of Gdańsk, Gdańsk, Poland
| | - Patrycja Szamborska
- Department of Bacterial Molecular Genetics, Faculty of Biology, University of Gdańsk, Gdańsk, Poland
| | - Adrianna Żukowska
- Department of Bacterial Molecular Genetics, Faculty of Biology, University of Gdańsk, Gdańsk, Poland
| | - Grzegorz M Cech
- Department of Bacterial Molecular Genetics, Faculty of Biology, University of Gdańsk, Gdańsk, Poland
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32
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Song S, Wood TK. Are we really studying persister cells? ENVIRONMENTAL MICROBIOLOGY REPORTS 2021; 13:3-7. [PMID: 32363793 DOI: 10.1111/1758-2229.12849] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Affiliation(s)
- Sooyeon Song
- Department of Animal Science, JeonBuk National University, Jeonju-si, Jeollabuk-do, 54896, Republic of Korea
| | - Thomas K Wood
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA, 16802-4400, USA
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33
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Abstract
Persister cells are defined as a small fraction of phenotypic variants in a cell population that are temporarily tolerant to bactericidal antibiotics. Persisters are not mutant cells; they generally survive lethal concentrations of antibiotics due to their transient nongrowing state. Persister cells have the ability to resuscitate after the end of antibiotic treatment. Despite significant advancements in the understanding of the molecular mechanisms underlying persister formation, we still have little information about their resuscitation mechanisms. In this chapter, we describe a method to detect and monitor persister resuscitation at the single-cell level using flow cytometry analysis. This method enables us to not only assess the resuscitation characteristics of persisters but also determine and quantify various subpopulations in antibiotic-treated cultures, including viable but nonculturable (VBNC) and dead cells.
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Affiliation(s)
- Sayed Golam Mohiuddin
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX, USA
| | - Mehmet A Orman
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX, USA.
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34
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Wood TK, Song S. Forming and waking dormant cells: The ppGpp ribosome dimerization persister model. Biofilm 2020; 2:100018. [PMID: 33447804 PMCID: PMC7798447 DOI: 10.1016/j.bioflm.2019.100018] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Revised: 12/20/2019] [Accepted: 12/23/2019] [Indexed: 02/07/2023] Open
Abstract
Procaryotes starve and face myriad stresses. The bulk population actively resists the stress, but a small population weathers the stress by entering a resting stage known as persistence. No mutations occur, and so persisters behave like wild-type cells upon removal of the stress and regrowth; hence, persisters are phenotypic variants. In contrast, resistant bacteria have mutations that allow cells to grow in the presence of antibiotics, and tolerant cells survive antibiotics better than actively-growing cells due to their slow growth (such as that of the stationary phase). In this review, we focus on the latest developments in studies related to the formation and resuscitation of persister cells and propose the guanosine pentaphosphate/tetraphosphate (henceforth ppGpp) ribosome dimerization persister (PRDP) model for entering and exiting the persister state.
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Affiliation(s)
- Thomas K. Wood
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA, 16802-4400, USA
| | - Sooyeon Song
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA, 16802-4400, USA
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35
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Liu S, Brul S, Zaat SAJ. Bacterial Persister-Cells and Spores in the Food Chain: Their Potential Inactivation by Antimicrobial Peptides (AMPs). Int J Mol Sci 2020; 21:E8967. [PMID: 33260797 PMCID: PMC7731242 DOI: 10.3390/ijms21238967] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 11/23/2020] [Accepted: 11/24/2020] [Indexed: 12/15/2022] Open
Abstract
The occurrence of bacterial pathogens in the food chain has caused a severe impact on public health and welfare in both developing and developed countries. Moreover, the existence of antimicrobial-tolerant persisting morphotypes of these pathogens including both persister-cells as well as bacterial spores contributes to difficulty in elimination and in recurrent infection. Therefore, comprehensive understanding of the behavior of these persisting bacterial forms in their environmental niche and upon infection of humans is necessary. Since traditional antimicrobials fail to kill persisters and spores due to their (extremely) low metabolic activities, antimicrobial peptides (AMPs) have been intensively investigated as one of the most promising strategies against these persisting bacterial forms, showing high efficacy of inactivation. In addition, AMP-based foodborne pathogen detection and prevention of infection has made significant progress. This review focuses on recent research on common bacterial pathogens in the food chain, their persisting morphotypes, and on AMP-based solutions. Challenges in research and application of AMPs are described.
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Affiliation(s)
- Shiqi Liu
- Swammerdam Institute for Life Sciences, Department of Molecular Biology and Microbial Food Safety, University of Amsterdam, 1098 XH Amsterdam, The Netherlands;
| | - Stanley Brul
- Swammerdam Institute for Life Sciences, Department of Molecular Biology and Microbial Food Safety, University of Amsterdam, 1098 XH Amsterdam, The Netherlands;
| | - Sebastian A. J. Zaat
- Department of Medical Microbiology, Centre for Infection and Immunity Amsterdam (CINIMA), Academic Medical Centre, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands;
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36
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Yan D, Zhang Q, Fu Q, Sun M, Huang X. Disruption of Fis reduces bacterial persister formation by regulating glutamate metabolism in Salmonella. Microb Pathog 2020; 152:104651. [PMID: 33249164 DOI: 10.1016/j.micpath.2020.104651] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 08/21/2020] [Accepted: 11/19/2020] [Indexed: 10/22/2022]
Abstract
The presence of persisters causes recalcitrance to antibiotic treatment, and can be attributed to a fairly large number of clinically refractory infections in several species of bacteria. Many studies have explored this phenomenon, but the mechanisms remain poorly understood. In this study, we found that the deletion of fis, which encodes a key DNA-binding protein mediating various biological processes, significantly reduced persister formation in S. Typhi. Persister assays and glutamate determination analysis showed that Fis mediated Salmonella persistence through regulating glutamate metabolism. Additionally, glutamate incubation altered the expression of the stringent response regulatory genes, demonstrating that the stringent response was related to glutamate regulation by Fis. The findings revealed that glutamate metabolism regulated by Fis serves as a mechanism for persister formation in S. Typhi.
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Affiliation(s)
- Dongmei Yan
- Department of Clinical Laboratory, Affiliated Yancheng Hospital, School of Medicine, Southeast University, Yancheng, Jiangsu, China.
| | - Qisi Zhang
- Department of Clinical Laboratory, Henan Provincial People's Hospital, Department of Clinical Laboratory of Central China Fuwai Hospital, Central China Fuwai Hospital of Zhengzhou University, Zhengzhou, Henan, 450003, China.
| | - Qingping Fu
- Department of Clinical Laboratory, Affiliated Yancheng Hospital, School of Medicine, Southeast University, Yancheng, Jiangsu, China
| | - Mingzhong Sun
- Department of Clinical Laboratory, Affiliated Yancheng Hospital, School of Medicine, Southeast University, Yancheng, Jiangsu, China.
| | - Xinxiang Huang
- School of Medicine, Jiangsu University, Zhenjiang, Jiangsu, 212013, China.
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37
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Abstract
Many bacterial pathogens can permanently colonize their host and establish either chronic or recurrent infections that the immune system and antimicrobial therapies fail to eradicate. Antibiotic persisters (persister cells) are believed to be among the factors that make these infections challenging. Persisters are subpopulations of bacteria which survive treatment with bactericidal antibiotics in otherwise antibiotic-sensitive cultures and were extensively studied in a hope to discover the mechanisms that cause treatment failures in chronically infected patients; however, most of these studies were conducted in the test tube. Research into antibiotic persistence has uncovered large intrapopulation heterogeneity of bacterial growth and regrowth but has not identified essential, dedicated molecular mechanisms of antibiotic persistence. Diverse factors and stresses that inhibit bacterial growth reduce killing of the bulk population and may also increase the persister subpopulation, implying that an array of mechanisms are present. Hopefully, further studies under conditions that simulate the key aspects of persistent infections will lead to identifying target mechanisms for effective therapeutic solutions.
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38
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Fernández-Coll L, Cashel M. Possible Roles for Basal Levels of (p)ppGpp: Growth Efficiency Vs. Surviving Stress. Front Microbiol 2020; 11:592718. [PMID: 33162969 PMCID: PMC7581894 DOI: 10.3389/fmicb.2020.592718] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 09/16/2020] [Indexed: 11/18/2022] Open
Abstract
Two (p)ppGpp nucleotide analogs, sometimes abbreviated simply as ppGpp, are widespread in bacteria and plants. Their name alarmone reflects a view of their function as intracellular hormone-like protective alarms that can increase a 100-fold when sensing any of an array of physical or nutritional dangers, such as abrupt starvation, that trigger lifesaving adjustments of global gene expression and physiology. The diversity of mechanisms for stress-specific adjustments of this sort is large and further compounded by almost infinite microbial diversity. The central question raised by this review is whether the small basal levels of (p)ppGpp functioning during balanced growth serve very different roles than alarmone-like functions. Recent discoveries that abrupt amino acid starvation of Escherichia coli, accompanied by very high levels of ppGpp, occasion surprising instabilities of transfer RNA (tRNA), ribosomal RNA (rRNA), and ribosomes raises new questions. Is this destabilization, a mode of regulation linearly related to (p)ppGpp over the entire continuum of (p)ppGpp levels, including balanced growth? Are regulatory mechanisms exerted by basal (p)ppGpp levels fundamentally different than for high levels? There is evidence from studies of other organisms suggesting special regulatory features of basal levels compared to burst of (p)ppGpp. Those differences seem to be important even during bacterial infection, suggesting that unbalancing the basal levels of (p)ppGpp may become a future antibacterial treatment. A simile for this possible functional duality is that (p)ppGpp acts like a car’s brake, able to stop to avoid crashes as well as to slow down to drive safely.
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Affiliation(s)
- Llorenç Fernández-Coll
- Intramural Research Program, Eunice Kennedy Shriver NICHD, NIH, Bethesda, MD, United States
| | - Michael Cashel
- Intramural Research Program, Eunice Kennedy Shriver NICHD, NIH, Bethesda, MD, United States
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39
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(p)ppGpp and Its Role in Bacterial Persistence: New Challenges. Antimicrob Agents Chemother 2020; 64:AAC.01283-20. [PMID: 32718971 DOI: 10.1128/aac.01283-20] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Antibiotic failure not only is due to the development of resistance by pathogens but can also often be explained by persistence and tolerance. Persistence and tolerance can be included in the "persistent phenotype," with high relevance for clinics. Two of the most important molecular mechanisms involved in tolerance and persistence are toxin-antitoxin (TA) modules and signaling via guanosine pentaphosphate/tetraphosphate [(p)ppGpp], also known as "magic spot." (p)ppGpp is a very important stress alarmone which orchestrates the stringent response in bacteria; hence, (p)ppGpp is produced during amino acid or fatty acid starvation by proteins belonging to the RelA/SpoT homolog family (RSH). However, (p)ppGpp levels can also accumulate in response to a wide range of signals, including oxygen variation, pH downshift, osmotic shock, temperature shift, or even exposure to darkness. Furthermore, the stringent response is not only involved in responses to environmental stresses (starvation for carbon sources, fatty acids, and phosphates or heat shock), but it is also used in bacterial pathogenesis, host invasion, and antibiotic tolerance and persistence. Given the exhaustive and contradictory literature surrounding the role of (p)ppGpp in bacterial persistence, and with the aim of summarizing what is known so far about the magic spot in this bacterial stage, this review provides new insights into the link between the stringent response and persistence. Moreover, we review some of the innovative treatments that have (p)ppGpp as a target, which are in the spotlight of the scientific community as candidates for effective antipersistence agents.
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40
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Salcedo-Sora JE, Kell DB. A Quantitative Survey of Bacterial Persistence in the Presence of Antibiotics: Towards Antipersister Antimicrobial Discovery. Antibiotics (Basel) 2020; 9:E508. [PMID: 32823501 PMCID: PMC7460088 DOI: 10.3390/antibiotics9080508] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 08/08/2020] [Accepted: 08/11/2020] [Indexed: 12/17/2022] Open
Abstract
Background: Bacterial persistence to antibiotics relates to the phenotypic ability to survive lethal concentrations of otherwise bactericidal antibiotics. The quantitative nature of the time-kill assay, which is the sector's standard for the study of antibiotic bacterial persistence, is an invaluable asset for global, unbiased, and cross-species analyses. Methods: We compiled the results of antibiotic persistence from antibiotic-sensitive bacteria during planktonic growth. The data were extracted from a sample of 187 publications over the last 50 years. The antibiotics used in this compilation were also compared in terms of structural similarity to fluorescent molecules known to accumulate in Escherichia coli. Results: We reviewed in detail data from 54 antibiotics and 36 bacterial species. Persistence varies widely as a function of the type of antibiotic (membrane-active antibiotics admit the fewest), the nature of the growth phase and medium (persistence is less common in exponential phase and rich media), and the Gram staining of the target organism (persistence is more common in Gram positives). Some antibiotics bear strong structural similarity to fluorophores known to be taken up by E. coli, potentially allowing competitive assays. Some antibiotics also, paradoxically, seem to allow more persisters at higher antibiotic concentrations. Conclusions: We consolidated an actionable knowledge base to support a rational development of antipersister antimicrobials. Persistence is seen as a step on the pathway to antimicrobial resistance, and we found no organisms that failed to exhibit it. Novel antibiotics need to have antipersister activity. Discovery strategies should include persister-specific approaches that could find antibiotics that preferably target the membrane structure and permeability of slow-growing cells.
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Affiliation(s)
- Jesus Enrique Salcedo-Sora
- Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative Biology, Biosciences Building, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK;
| | - Douglas B. Kell
- Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative Biology, Biosciences Building, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK;
- Novo Nordisk Foundation Centre for Biosustainability, Technical University of Denmark, Building 220, Kemitorvet, 2800 Kgs. Lyngby, Denmark
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41
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Song S, Wood TK. A Primary Physiological Role of Toxin/Antitoxin Systems Is Phage Inhibition. Front Microbiol 2020; 11:1895. [PMID: 32903830 PMCID: PMC7438911 DOI: 10.3389/fmicb.2020.01895] [Citation(s) in RCA: 91] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 07/20/2020] [Indexed: 12/20/2022] Open
Abstract
Toxin/antitoxin (TA) systems are present in most prokaryote genomes. Toxins are almost exclusively proteins that reduce metabolism (but do not cause cell death), and antitoxins are either RNA or proteins that counteract the toxin or the RNA that encodes it. Although TA systems clearly stabilize mobile genetic elements, after four decades of research, the physiological roles of chromosomal TA systems are less clear. For example, recent reports have challenged the notion of TA systems as stress-response elements, including a role in creating the dormant state known as persistence. Here, we present evidence that a primary physiological role of chromosomally encoded TA systems is phage inhibition, a role that is also played by some plasmid-based TA systems. This includes results that show some CRISPR-Cas system elements are derived from TA systems and that some CRISPR-Cas systems mimic the host growth inhibition invoked by TA systems to inhibit phage propagation.
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Affiliation(s)
- Sooyeon Song
- Department of Animal Science, Jeonbuk National University, Jeonju-si, South Korea
| | - Thomas K Wood
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA, United States
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Song S, Wood TK. Combatting Persister Cells With Substituted Indoles. Front Microbiol 2020; 11:1565. [PMID: 32733426 PMCID: PMC7358577 DOI: 10.3389/fmicb.2020.01565] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 06/16/2020] [Indexed: 12/14/2022] Open
Abstract
Given that a subpopulation of most bacterial cells becomes dormant due to stress, and that the resting cells of pathogens can revive and reconstitute infections, it is imperative to find methods to treat dormant cells to eradicate infections. The dormant bacteria that are not spores or cysts are known as persister cells. Remarkably, in contrast to the original report that incorrectly indicated indole increases persistence, a large number of indole-related compounds have been found in the last few years that kill persister cells. Hence, in this review, along with a summary of recent results related to persister cell formation and resuscitation, we focus on the ability of indole and substituted indoles to combat the persister cells of both pathogens and non-pathogens.
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Affiliation(s)
- Sooyeon Song
- Department of Animal Science, Jeonbuk National University, Jeonju, South Korea
| | - Thomas K. Wood
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA, United States
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Zhang D, Hu Y, Zhu Q, Huang J, Chen Y. Proteomic interrogation of antibiotic resistance and persistence in Escherichia coli - progress and potential for medical research. Expert Rev Proteomics 2020; 17:393-409. [PMID: 32567419 DOI: 10.1080/14789450.2020.1784731] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Introduction Escherichia coli strains possess two survival strategies to endure lethal antibiotic exposure including antibiotic resistance and persistence, in which persistence can contribute to the emergence of antibiotic resistance and increasing the risk of multidrug resistance. Using high-throughput proteomics for the comprehensive understanding of mechanisms of antibiotic resistance and persistence is an effective strategy for development of target-based anti-bacterial therapies. Areas covered In this review, we summarize a comprehensive proteomic perspective of antibiotic resistance and persistence in E. coli, and overview of anti-antibiotic resistance and anti-persister molecules and strategies for the development of potential therapies. Expert opinion Proteomics allows us to globally identify the critical proteins and pathways involved in antibiotic resistance and persistence. Advancements in methodologies of proteomics and multi-omic strategies are required to overcome the limitations of proteomics and better understand mechanisms of antibiotic resistance and persistence in E. coli, and to open the possibility for identification of new targets for alternative strategies in therapeutics.
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Affiliation(s)
- Danfeng Zhang
- School of Biological Science and Biotechnology, Minnan Normal University , Zhangzhou, China
| | - Yuanqing Hu
- School of Biological Science and Biotechnology, Minnan Normal University , Zhangzhou, China
| | - Qiuqiang Zhu
- School of Biological Science and Biotechnology, Minnan Normal University , Zhangzhou, China
| | - Jiafu Huang
- School of Biological Science and Biotechnology, Minnan Normal University , Zhangzhou, China.,Engineering Technological Center of Mushroom Industry , Zhangzhou, China
| | - Yiyun Chen
- School of Biological Science and Biotechnology, Minnan Normal University , Zhangzhou, China
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Intracellular Staphylococcus aureus persisters upon antibiotic exposure. Nat Commun 2020; 11:2200. [PMID: 32366839 PMCID: PMC7198484 DOI: 10.1038/s41467-020-15966-7] [Citation(s) in RCA: 172] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 04/02/2020] [Indexed: 01/31/2023] Open
Abstract
Bacterial persister cells are phenotypic variants that exhibit a transient non-growing state and antibiotic tolerance. Here, we provide in vitro evidence of Staphylococcus aureus persisters within infected host cells. We show that the bacteria surviving antibiotic treatment within host cells are persisters, displaying biphasic killing and reaching a uniformly non-responsive, non-dividing state when followed at the single-cell level. This phenotype is stable but reversible upon antibiotic removal. Intracellular S. aureus persisters remain metabolically active but display an altered transcriptomic profile consistent with activation of stress responses, including the stringent response as well as cell wall stress, SOS and heat shock responses. These changes are associated with multidrug tolerance after exposure to a single antibiotic. We hypothesize that intracellular S. aureus persisters may constitute a reservoir for relapsing infection and could contribute to therapeutic failures. Bacterial persister cells exhibit a transient non-growing state and antibiotic tolerance. Here, Peyrusson et al. provide evidence of metabolically active Staphylococcus aureus persisters within infected host cells exposed to antibiotics and analyse transcriptomic alterations associated with persistence.
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Song S, Wood TK. Toxin/Antitoxin System Paradigms: Toxins Bound to Antitoxins Are Not Likely Activated by Preferential Antitoxin Degradation. ACTA ACUST UNITED AC 2020; 4:e1900290. [PMID: 32293143 DOI: 10.1002/adbi.201900290] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 01/27/2020] [Indexed: 12/28/2022]
Abstract
Periodically, a scientific field should examine its early premises. For ubiquitous toxin/antitoxin (TA) systems, several initial paradigms require adjustment based on accumulated data. For example, it is now clear that under physiological conditions, there is little evidence that toxins of TA systems cause cell death and little evidence that TA systems cause persistence. Instead, TA systems are utilized to reduce metabolism during stress, inhibit phages, stabilize genetic elements, and influence biofilm formation (bacterial cells attached via an extracellular matrix). In this essay, it is argued that toxins bound to antitoxins are not likely to become activated by preferential antitoxin degradation but instead, de novo toxin synthesis in the absence of stoichiometric amounts of antitoxin activates toxins.
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Affiliation(s)
- Sooyeon Song
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA, 16802-4400, USA
| | - Thomas K Wood
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA, 16802-4400, USA
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Huang CY, Gonzalez-Lopez C, Henry C, Mijakovic I, Ryan KR. hipBA toxin-antitoxin systems mediate persistence in Caulobacter crescentus. Sci Rep 2020; 10:2865. [PMID: 32071324 PMCID: PMC7029023 DOI: 10.1038/s41598-020-59283-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 01/27/2020] [Indexed: 11/09/2022] Open
Abstract
Antibiotic persistence is a transient phenotypic state during which a bacterium can withstand otherwise lethal antibiotic exposure or environmental stresses. In Escherichia coli, persistence is promoted by the HipBA toxin-antitoxin system. The HipA toxin functions as a serine/threonine kinase that inhibits cell growth, while the HipB antitoxin neutralizes the toxin. E. coli HipA inactivates the glutamyl-tRNA synthetase GltX, which inhibits translation and triggers the highly conserved stringent response. Although hipBA operons are widespread in bacterial genomes, it is unknown if this mechanism is conserved in other species. Here we describe the functions of three hipBA modules in the alpha-proteobacterium Caulobacter crescentus. The HipA toxins have different effects on growth and macromolecular syntheses, and they phosphorylate distinct substrates. HipA1 and HipA2 contribute to antibiotic persistence during stationary phase by phosphorylating the aminoacyl-tRNA synthetases GltX and TrpS. The stringent response regulator SpoT is required for HipA-mediated antibiotic persistence, but persister cells can form in the absence of all hipBA operons or spoT, indicating that multiple pathways lead to persister cell formation in C. crescentus.
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Affiliation(s)
- Charlie Y Huang
- Department of Plant & Microbial Biology, University of California, Berkeley, USA
| | | | - Céline Henry
- Université Paris-Saclay, AgroParisTech, Micalis Institute, PAPPSO, INRAE, 78350, Jouy-en-Josas, France
| | - Ivan Mijakovic
- Division of Systems and Synthetic Biology, Department of Chemical and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden.,Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Kathleen R Ryan
- Department of Plant & Microbial Biology, University of California, Berkeley, USA.
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Song S, Wood TK. ppGpp ribosome dimerization model for bacterial persister formation and resuscitation. Biochem Biophys Res Commun 2020; 523:281-286. [PMID: 32007277 DOI: 10.1016/j.bbrc.2020.01.102] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 01/17/2020] [Indexed: 12/21/2022]
Abstract
Stress is ubiquitous for bacteria and can convert a subpopulation of cells into a dormant state known as persistence, in which cells are tolerant to antimicrobials. These cells revive rapidly when the stress is removed and are likely the cause of many recurring infections such as those associated with tuberculosis, cystic fibrosis, and Lyme disease. However, how persister cells are formed is not understood well. Here we propose the ppGpp ribosome dimerization persister (PRDP) model in which the alarmone guanosine pentaphosphate/tetraphosphate (henceforth ppGpp) generates persister cells directly by inactivating ribosomes via the ribosome modulation factor (RMF), the hibernation promoting factor (Hpf), and the ribosome-associated inhibitor (RaiA). We demonstrate that persister cells contain a large fraction of 100S ribosomes, that inactivation of RMF, HpF, and RaiA reduces persistence and increases single-cell persister resuscitation and that ppGpp has no effect on single-cell persister resuscitation. Hence, a direct connection between ppGpp and persistence is shown along with evidence of the importance of ribosome dimerization in persistence and for active ribosomes during resuscitation.
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Affiliation(s)
- Sooyeon Song
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA, 16802-4400, USA
| | - Thomas K Wood
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA, 16802-4400, USA.
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Yamasaki R, Song S, Benedik MJ, Wood TK. Persister Cells Resuscitate Using Membrane Sensors that Activate Chemotaxis, Lower cAMP Levels, and Revive Ribosomes. iScience 2020; 23:100792. [PMID: 31926430 PMCID: PMC6957856 DOI: 10.1016/j.isci.2019.100792] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 10/03/2019] [Accepted: 12/17/2019] [Indexed: 12/20/2022] Open
Abstract
Persistence, the stress-tolerant state, is arguably the most vital phenotype since nearly all cells experience nutrient stress, which causes a sub-population to become dormant. However, how persister cells wake to reconstitute infections is not understood well. Here, using single-cell observations, we determined that Escherichia coli persister cells resuscitate primarily when presented with specific carbon sources, rather than spontaneously. In addition, we found that the mechanism of persister cell waking is through sensing nutrients by chemotaxis and phosphotransferase membrane proteins. Furthermore, nutrient transport reduces the level of secondary messenger cAMP through enzyme IIA; this reduction in cAMP levels leads to ribosome resuscitation and rescue. Resuscitating cells also immediately commence chemotaxis toward nutrients, although flagellar motion is not required for waking. Hence, persister cells wake by perceiving nutrients via membrane receptors that relay the signal to ribosomes via the secondary messenger cAMP, and persisters wake and utilize chemotaxis to acquire nutrients.
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Affiliation(s)
- Ryota Yamasaki
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA 16802-4400, USA
| | - Sooyeon Song
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA 16802-4400, USA
| | - Michael J Benedik
- Department of Biology, Texas A & M University, College Station, TX 77843-3122, USA
| | - Thomas K Wood
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA 16802-4400, USA; The Huck Institute of the Life Sciences, Pennsylvania State University, University Park, PA 16802-4400, USA.
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Turnbull KJ, Dzhygyr I, Lindemose S, Hauryliuk V, Roghanian M. Intramolecular Interactions Dominate the Autoregulation of Escherichia coli Stringent Factor RelA. Front Microbiol 2019; 10:1966. [PMID: 31507571 PMCID: PMC6719525 DOI: 10.3389/fmicb.2019.01966] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Accepted: 08/09/2019] [Indexed: 01/08/2023] Open
Abstract
Amino acid starvation in Escherichia coli activates the enzymatic activity of the stringent factor RelA, leading to accumulation of the alarmone nucleotide (p)ppGpp. The alarmone acts as an intercellular messenger to regulate transcription, translation and metabolism to mediate bacterial stress adaptation. The enzymatic activity of RelA is subject to multi-layered allosteric control executed both by ligands - such as "starved" ribosomal complexes, deacylated tRNA and pppGpp - and by individual RelA domains. The auto-regulation of RelA is proposed to act either in cis (inhibition of the enzymatic activity of the N-terminal region, NTD, by regulatory C-terminal region, CTD) or in trans (CTD-mediated dimerization leading to enzyme inhibition). In this report, we probed the regulatory roles of the individual domains of E. coli RelA and our results are not indicative of RelA dimerization being the key regulatory mechanism. First, at growth-permitting levels, ectopic expression of RelA CTD does not interfere with activation of native RelA, indicating lack of regulation via inhibitory complex formation in the cell. Second, in our biochemical assays, increasing RelA concentration does not decrease the enzyme activity, as would be expected in the case of efficient auto-inhibition via dimerization. Third, while high-level CTD expression efficiently inhibits the growth, the effect is independent of native RelA and is mediated by direct inhibition of protein synthesis, likely via direct interaction with the ribosomal A-site. Finally, deletion of the RRM domain of the CTD region leads to growth inhibition mediated by accumulation of (p)ppGpp, suggesting de-regulation of the synthetic activity in this mutant.
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Affiliation(s)
- Kathryn Jane Turnbull
- Centre for Bacterial Stress Response and Persistence, Department of Biology, University of Copenhagen, Copenhagen, Denmark
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
| | - Ievgen Dzhygyr
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
| | - Søren Lindemose
- Centre for Bacterial Stress Response and Persistence, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Vasili Hauryliuk
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Mohammad Roghanian
- Centre for Bacterial Stress Response and Persistence, Department of Biology, University of Copenhagen, Copenhagen, Denmark
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
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