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Singh H, Wiscovitch-Russo R, Kuelbs C, Espinoza J, Appel AE, Lyons RJ, Vashee S, Förtsch HEA, Foster JE, Ramdath D, Hayes VM, Nelson KE, Gonzalez-Juarbe N. Multiomic Insights into Human Health: Gut Microbiomes of Hunter-Gatherer, Agropastoral, and Western Urban Populations. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.09.03.611095. [PMID: 39282340 PMCID: PMC11398329 DOI: 10.1101/2024.09.03.611095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 09/22/2024]
Abstract
Societies with exposure to preindustrial diets exhibit improved markers of health. Our study used a comprehensive multi-omic approach to reveal that the gut microbiome of the Ju/'hoansi hunter-gatherers, one of the most remote KhoeSan groups, exhibit a higher diversity and richness, with an abundance of microbial species lost in the western population. The Ju/'hoansi microbiome showed enhanced global transcription and enrichment of complex carbohydrate metabolic and energy generation pathways. The Ju/'hoansi also show high abundance of short-chain fatty acids that are associated with health and optimal immune function. In contrast, these pathways and their respective species were found in low abundance or completely absent in Western populations. Amino acid and fatty acid metabolism pathways were observed prevalent in the Western population, associated with biomarkers of chronic inflammation. Our study provides the first in-depth multi-omic characterization of the Ju/'hoansi microbiome, revealing uncharacterized species and functional pathways that are associated with health.
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Ma Z, Xu W, Li S, Chen S, Yang Y, Li Z, Xing T, Zhao Z, Hou D, Li Q, Lu Z, Zhang H. Effect of RpoS on the survival, induction, resuscitation, morphology, and gene expression of viable but non-culturable Salmonella Enteritidis in powdered infant formula. Int J Food Microbiol 2024; 410:110463. [PMID: 38039925 DOI: 10.1016/j.ijfoodmicro.2023.110463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 10/19/2023] [Accepted: 10/27/2023] [Indexed: 12/03/2023]
Abstract
Involvement of the transcriptional regulator RpoS in the persistence of viable but non-culturable (VBNC) state has been demonstrated in several species of bacteria. This study investigated the role of the RpoS in the formation and resuscitation of VBNC state in Salmonella enterica serovar Enteritidis CICC 21482 by measuring bacterial survival, morphology, physiological characteristics, and gene expression in wild-type (WT) and rpoS-deletion (ΔrpoS) strains during long-term storage in powdered infant formula (PIF). The ΔrpoS strain was produced by allelic exchange using a suicide plasmid. Bacteria were inoculated into PIF for 635-day storage. Survival, morphology, intracellular reactive oxygen species (ROS) levels and intercellular quorum sensing autoinducer-2 (AI-2) contents were regularly measured. Resuscitation assays were conducted after obtaining VBNC cells. Gene expression was measured using real-time quantitative polymerase chain reaction (qPCR). The results showed that RpoS and low temperature conditions were associated with enhanced culturability and recoverability of Salmonella Enteritidis after desiccation storage in low water activity (aw) PIF. In addition, the synthesis of intracellular ROS and intercellular quorum sensing AI-2 was regulated by RpoS, inducing the formation and resuscitation of VBNC cells. Gene expression of soxS, katG and relA was found strongly associated with RpoS. Due to the lack of RpoS factor, the ΔrpoS strain could not normally synthesize SoxS, catalase and (p)ppGpp, resulting in its early shift to the VBNC state. This study elucidates the role of rpoS in desiccation stress and the formation and resuscitation mechanism of VBNC cells under desiccation stress. It serves as the basis for preventing and controlling the recovery of pathogenic bacteria in VBNC state in low aw foods.
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Affiliation(s)
- Zhuolin Ma
- College of Biological and Pharmaceutical Science, Guangdong University of Technology, No. 100 Waihuan Xi Road, Panyu District, Guangzhou 510006, China
| | - Weiying Xu
- College of Biological and Pharmaceutical Science, Guangdong University of Technology, No. 100 Waihuan Xi Road, Panyu District, Guangzhou 510006, China
| | - Shaoting Li
- College of Biological and Pharmaceutical Science, Guangdong University of Technology, No. 100 Waihuan Xi Road, Panyu District, Guangzhou 510006, China
| | - Siyi Chen
- College of Biological and Pharmaceutical Science, Guangdong University of Technology, No. 100 Waihuan Xi Road, Panyu District, Guangzhou 510006, China
| | - Yuheng Yang
- College of Biological and Pharmaceutical Science, Guangdong University of Technology, No. 100 Waihuan Xi Road, Panyu District, Guangzhou 510006, China
| | - Zefeng Li
- College of Biological and Pharmaceutical Science, Guangdong University of Technology, No. 100 Waihuan Xi Road, Panyu District, Guangzhou 510006, China
| | - Tong Xing
- College of Biological and Pharmaceutical Science, Guangdong University of Technology, No. 100 Waihuan Xi Road, Panyu District, Guangzhou 510006, China
| | - Zepeng Zhao
- College of Biological and Pharmaceutical Science, Guangdong University of Technology, No. 100 Waihuan Xi Road, Panyu District, Guangzhou 510006, China
| | - Dongping Hou
- College of Biological and Pharmaceutical Science, Guangdong University of Technology, No. 100 Waihuan Xi Road, Panyu District, Guangzhou 510006, China
| | - Qingqing Li
- College of Biological and Pharmaceutical Science, Guangdong University of Technology, No. 100 Waihuan Xi Road, Panyu District, Guangzhou 510006, China
| | - Ziying Lu
- College of Biological and Pharmaceutical Science, Guangdong University of Technology, No. 100 Waihuan Xi Road, Panyu District, Guangzhou 510006, China
| | - Hongmei Zhang
- College of Biological and Pharmaceutical Science, Guangdong University of Technology, No. 100 Waihuan Xi Road, Panyu District, Guangzhou 510006, China.
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Li Y, Li D, Liang Y, Cui J, He K, He D, Liu J, Hu G, Yuan L. Characterization of a Tigecycline-Resistant and blaCTX-M-Bearing Klebsiella pneumoniae Strain from a Peacock in a Chinese Zoo. Appl Environ Microbiol 2023; 89:e0176422. [PMID: 36809063 PMCID: PMC10057878 DOI: 10.1128/aem.01764-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 01/20/2023] [Indexed: 02/23/2023] Open
Abstract
In Chinese zoos, there are usually specially designed bird parks, similar to petting zoos, that allow children and adults to interact with diverse birds. However, such behaviors present a risk for the transmission of zoonotic pathogens. Recently, we isolated eight strains of Klebsiella pneumoniae and identified two blaCTX-M-positive strains from 110 birds, including parrots, peacocks, and ostriches, using anal or nasal swabs in a bird park of a zoo in China. There, K. pneumoniae LYS105A was obtained from a diseased peacock with chronic respiratory diseases by a nasal swab, which harbored the blaCTX-M-3 gene and exhibited resistance to amoxicillin, cefotaxime, gentamicin, oxytetracycline, doxycycline, tigecycline, florfenicol, and enrofloxacin. According to an analysis by whole-genome sequencing, K. pneumoniae LYS105A belongs to serotype ST859 (sequence type 859)-K19 (capsular serotype 19) and contains two plasmids, of which pLYS105A-2 can be transferred by electrotransformation and harbors numerous resistance genes such as blaCTX-M-3, aac(6')-Ib-cr5, and qnrB91. The above-mentioned genes are located in a novel mobile composite transposon, Tn7131, which makes horizontal transfer more flexible. Although no known genes were identified in the chromosome, a significant increase in SoxS upregulated the expression levels of phoPQ, acrEF-tolC, and oqxAB, which contributed to strain LYS105A acquiring resistance to tigecycline (MIC = 4 mg/L) and intermediate resistance to colistin (MIC = 2 mg/L). Altogether, our findings show that bird parks in zoos may act as important vehicles for the spread of multidrug-resistant bacteria from birds to humans and vice versa. IMPORTANCE A multidrug-resistant ST859-K19 K. pneumoniae strain, LYS105A, was obtained from a diseased peacock in a Chinese zoo. In addition, multiple resistance genes such as blaCTX-M-3, aac(6')-Ib-cr5, and qnrB91 were located in a novel composite transposon, Tn7131, of a mobile plasmid, implying that most of the resistance genes in strain LYS105A can be moved easily via horizontal gene transfer. Meanwhile, an increase in SoxS can further positively regulate the expression of phoPQ, acrEF-tolC, and oqxAB, which is the key factor for strain LYS105A to develop resistance to tigecycline and colistin. Taken together, these findings enrich our understanding of the horizontal cross-species spread of drug resistance genes, which will help us curb the development of bacterial resistance.
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Affiliation(s)
- Yinshu Li
- College of Animal Medicine, Henan Agricultural University, Zhengzhou, China
| | | | - Yulei Liang
- College of Animal Medicine, Henan Agricultural University, Zhengzhou, China
| | - Junling Cui
- College of Animal Medicine, Henan Agricultural University, Zhengzhou, China
| | - Kun He
- College of Animal Medicine, Henan Agricultural University, Zhengzhou, China
| | - Dandan He
- College of Animal Medicine, Henan Agricultural University, Zhengzhou, China
- International Joint Research Center of National Animal Immunology, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, China
| | - Jianhua Liu
- College of Animal Medicine, Henan Agricultural University, Zhengzhou, China
- International Joint Research Center of National Animal Immunology, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, China
| | - Gongzheng Hu
- College of Animal Medicine, Henan Agricultural University, Zhengzhou, China
- International Joint Research Center of National Animal Immunology, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, China
| | - Li Yuan
- College of Animal Medicine, Henan Agricultural University, Zhengzhou, China
- International Joint Research Center of National Animal Immunology, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, China
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Upadhayay A, Ling J, Pal D, Xie Y, Ping FF, Kumar A. Resistance-proof antimicrobial drug discovery to combat global antimicrobial resistance threat. Drug Resist Updat 2023; 66:100890. [PMID: 36455341 DOI: 10.1016/j.drup.2022.100890] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/11/2022] [Accepted: 11/13/2022] [Indexed: 11/18/2022]
Abstract
Drug resistance is well-defined as a serious problem in our living world. To survive, microbes develop defense strategies against antimicrobial drugs. Drugs exhibit less or no effective results against microbes after the emergence of resistance because they are unable to cross the microbial membrane, in order to alter enzymatic systems, and/or upregulate efflux pumps, etc. Drug resistance issues can be addressed effectively if a "Resistance-Proof" or "Resistance-Resistant" antimicrobial agent is developed. This article discusses first the need for resistance-proof drugs, the imminent properties of resistance-proof drugs, current and future research progress in the discovery of resistance-proof antimicrobials, the inherent challenges, and opportunities. A molecule having imminent resistance-proof properties could target microbes efficiently, increase potency, and rule out the possibility of early resistance. This review triggers the scientific community to think about how an upsurge in drug resistance can be averted and emphasizes the discussion on the development of next-generation antimicrobials that will provide a novel effective solution to combat the global problem of drug resistance. Hence, resistance-proof drug development is not just a requirement but rather a compulsion in the drug discovery field so that resistance can be battled effectively. We discuss several properties of resistance-proof drugs which could initiate new ways of thinking about next-generation antimicrobials to resolve the drug resistance problem. This article sheds light on the issues of drug resistance and discusses solutions in terms of the resistance-proof properties of a molecule. In summary, the article is a foundation to break new ground in the development of resistance-proof therapeutics in the field of infection biology.
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Affiliation(s)
- Aditya Upadhayay
- Department of Biotechnology, National Institute of Technology, Raipur 492010, CG, India
| | - Jingjing Ling
- Department of Good Clinical Practice, The Affiliated Wuxi Children's Hospital of Nanjing Medical University, 299 Qingyang Road, Wuxi 214023, China
| | - Dharm Pal
- Department of Chemical Engineering, National Institute of Technology, Raipur 492010, CG, India
| | - Yuhao Xie
- Institute for Biotechnology, St. John's University, New York, NY 11439, USA
| | - Feng-Feng Ping
- Department of Burns and Plastic Surgery, The Affiliated Hospital of Jiangnan University, Wuxi 214000, China.
| | - Awanish Kumar
- Department of Biotechnology, National Institute of Technology, Raipur 492010, CG, India.
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Abd El-Aziz NK, Tartor YH, Gharieb RMA, Erfan AM, Khalifa E, Said MA, Ammar AM, Samir M. Extensive Drug-Resistant Salmonella enterica Isolated From Poultry and Humans: Prevalence and Molecular Determinants Behind the Co-resistance to Ciprofloxacin and Tigecycline. Front Microbiol 2021; 12:738784. [PMID: 34899627 PMCID: PMC8660588 DOI: 10.3389/fmicb.2021.738784] [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: 07/21/2021] [Accepted: 10/14/2021] [Indexed: 12/12/2022] Open
Abstract
The emergence of extensive drug-resistant (XDR) Salmonella in livestock animals especially in poultry represents a serious public health and therapeutic challenge. Despite the wealth of information available on Salmonella resistance to various antimicrobials, there have been limited data on the genetic determinants of XDR Salmonella exhibiting co-resistance to ciprofloxacin (CIP) and tigecycline (TIG). This study aimed to determine the prevalence and serotype diversity of XDR Salmonella in poultry flocks and contact workers and to elucidate the genetic determinants involved in the co-resistance to CIP and TIG. Herein, 115 Salmonella enterica isolates of 35 serotypes were identified from sampled poultry (100/1210, 8.26%) and humans (15/375, 4.00%), with the most frequent serotype being Salmonella Typhimurium (26.96%). Twenty-nine (25.22%) Salmonella enterica isolates exhibited XDR patterns; 25 out of them (86.21%) showed CIP/TIG co-resistance. Exposure of CIP- and TIG-resistant isolates to the carbonyl cyanide 3-chlorophenylhydrazone (CCCP) efflux pump inhibitor resulted in an obvious reduction in their minimum inhibitory concentrations (MICs) values and restored the susceptibility to CIP and TIG in 17.24% (5/29) and 92% (23/25) of the isolates, respectively. Molecular analysis revealed that 89.66% of the isolates contained two to six plasmid-mediated quinolone resistance genes with the predominance of qepA gene (89.66%). Mutations in the gyrA gene were detected at codon S83 (34.62%) or D87 (30.77%) or both (34.62%) in 89.66% of XDR Salmonella. The tet(A) and tet(X4) genes were detected in 100% and 3.45% of the XDR isolates, respectively. Twelve TIG-resistant XDR Salmonella had point mutations at codons 120, 121, and 181 in the tet(A) interdomain loop region. All CIP and TIG co-resistant XDR Salmonella overexpressed ramA gene; 17 (68%) out of them harbored 4-bp deletion in the ramR binding region (T-288/A-285). However, four CIP/TIG co-resistant isolates overexpressed the oqxB gene. In conclusion, the emergence of XDR S. enterica exhibiting CIP/TIG co-resistance in poultry and humans with no previous exposure to TIG warrants an urgent need to reduce the unnecessary antimicrobial use in poultry farms in Egypt.
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Affiliation(s)
- Norhan K. Abd El-Aziz
- Department of Microbiology, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Egypt
| | - Yasmine H. Tartor
- Department of Microbiology, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Egypt
| | - Rasha M. A. Gharieb
- Department of Zoonoses, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Egypt
| | - Ahmed M. Erfan
- Reference Laboratory for Veterinary Quality Control on Poultry Production, Animal Health Research Institute, Agricultural Research Center, Giza, Egypt
| | - Eman Khalifa
- Department of Microbiology, Faculty of Veterinary Medicine, Matrouh University, Marsa Matruh, Egypt
| | | | - Ahmed M. Ammar
- Department of Microbiology, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Egypt
| | - Mohamed Samir
- Department of Zoonoses, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Egypt
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Cappable-Seq Reveals Specific Patterns of Metabolism and Virulence for Salmonella Typhimurium Intracellular Survival within Acanthamoeba castellanii. Int J Mol Sci 2021; 22:ijms22169077. [PMID: 34445780 PMCID: PMC8396566 DOI: 10.3390/ijms22169077] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 08/16/2021] [Accepted: 08/19/2021] [Indexed: 01/21/2023] Open
Abstract
The bacterial pathogen Salmonella enterica, which causes enteritis, has a broad host range and extensive environmental longevity. In water and soil, Salmonella interacts with protozoa and multiplies inside their phagosomes. Although this relationship resembles that between Salmonella and mammalian phagocytes, the interaction mechanisms and bacterial genes involved are unclear. Here, we characterized global gene expression patterns of S. enterica serovar Typhimurium within Acanthamoeba castellanii at the early stage of infection by Cappable-Seq. Gene expression features of S. Typhimurium within A. castellanii were presented with downregulation of glycolysis-related, and upregulation of glyoxylate cycle-related genes. Expression of Salmonella Pathogenicity Island-1 (SPI-1), chemotaxis system, and flagellar apparatus genes was upregulated. Furthermore, expression of genes mediating oxidative stress response and iron uptake was upregulated within A. castellanii as well as within mammalian phagocytes. Hence, global S. Typhimurium gene expression patterns within A. castellanii help better understand the molecular mechanisms of Salmonella adaptation to an amoeba cell and intracellular persistence in protozoa inhabiting water and soil ecosystems.
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Wójcicki M, Świder O, Daniluk KJ, Średnicka P, Akimowicz M, Roszko MŁ, Sokołowska B, Juszczuk-Kubiak E. Transcriptional Regulation of the Multiple Resistance Mechanisms in Salmonella-A Review. Pathogens 2021; 10:pathogens10070801. [PMID: 34202800 PMCID: PMC8308502 DOI: 10.3390/pathogens10070801] [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: 05/26/2021] [Revised: 06/21/2021] [Accepted: 06/23/2021] [Indexed: 02/07/2023] Open
Abstract
The widespread use of antibiotics, especially those with a broad spectrum of activity, has resulted in the development of multidrug resistance in many strains of bacteria, including Salmonella. Salmonella is among the most prevalent causes of intoxication due to the consumption of contaminated food and water. Salmonellosis caused by this pathogen is pharmacologically treated using antibiotics such as fluoroquinolones, ceftriaxone, and azithromycin. This foodborne pathogen developed several molecular mechanisms of resistance both on the level of global and local transcription modulators. The increasing rate of antibiotic resistance in Salmonella poses a significant global concern, and an improved understanding of the multidrug resistance mechanisms in Salmonella is essential for choosing the suitable antibiotic for the treatment of infections. In this review, we summarized the current knowledge of molecular mechanisms that control gene expression related to antibiotic resistance of Salmonella strains. We characterized regulators acting as transcription activators and repressors, as well as two-component signal transduction systems. We also discuss the background of the molecular mechanisms of the resistance to metals, regulators of multidrug resistance to antibiotics, global regulators of the LysR family, as well as regulators of histone-like proteins.
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Affiliation(s)
- Michał Wójcicki
- Laboratory of Biotechnology and Molecular Engineering, Department of Microbiology, Prof. Wacław Dąbrowski Institute of Agricultural and Food Biotechnology—State Research Institute, Rakowiecka 36 Street, 02-532 Warsaw, Poland; (M.W.); (P.Ś.); (M.A.)
| | - Olga Świder
- Department of Food Safety and Chemical Analysis, Prof. Wacław Dąbrowski Institute of Agricultural and Food Biotechnology—State Research Institute, Rakowiecka 36 Street, 02-532 Warsaw, Poland; (O.Ś.); (M.Ł.R.)
| | - Kamila J. Daniluk
- Department of Microbiology, Prof. Wacław Dąbrowski Institute of Agricultural and Food Biotechnology—State Research Institute, Rakowiecka 36 Street, 02-532 Warsaw, Poland; (K.J.D.); (B.S.)
| | - Paulina Średnicka
- Laboratory of Biotechnology and Molecular Engineering, Department of Microbiology, Prof. Wacław Dąbrowski Institute of Agricultural and Food Biotechnology—State Research Institute, Rakowiecka 36 Street, 02-532 Warsaw, Poland; (M.W.); (P.Ś.); (M.A.)
| | - Monika Akimowicz
- Laboratory of Biotechnology and Molecular Engineering, Department of Microbiology, Prof. Wacław Dąbrowski Institute of Agricultural and Food Biotechnology—State Research Institute, Rakowiecka 36 Street, 02-532 Warsaw, Poland; (M.W.); (P.Ś.); (M.A.)
| | - Marek Ł. Roszko
- Department of Food Safety and Chemical Analysis, Prof. Wacław Dąbrowski Institute of Agricultural and Food Biotechnology—State Research Institute, Rakowiecka 36 Street, 02-532 Warsaw, Poland; (O.Ś.); (M.Ł.R.)
| | - Barbara Sokołowska
- Department of Microbiology, Prof. Wacław Dąbrowski Institute of Agricultural and Food Biotechnology—State Research Institute, Rakowiecka 36 Street, 02-532 Warsaw, Poland; (K.J.D.); (B.S.)
| | - Edyta Juszczuk-Kubiak
- Laboratory of Biotechnology and Molecular Engineering, Department of Microbiology, Prof. Wacław Dąbrowski Institute of Agricultural and Food Biotechnology—State Research Institute, Rakowiecka 36 Street, 02-532 Warsaw, Poland; (M.W.); (P.Ś.); (M.A.)
- Correspondence: ; Tel.: +48-22-6063605
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Majewski P, Gutowska A, Sacha P, Schneiders T, Talalaj M, Majewska P, Zebrowska A, Ojdana D, Wieczorek P, Hauschild T, Kowalczuk O, Niklinski J, Radziwon P, Tryniszewska E. Expression of AraC/XylS stress response regulators in two distinct carbapenem-resistant Enterobacter cloacae ST89 biotypes. J Antimicrob Chemother 2021; 75:1146-1150. [PMID: 31960042 DOI: 10.1093/jac/dkz569] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 12/09/2019] [Accepted: 12/20/2019] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The growing incidence of MDR Gram-negative bacteria is a rapidly emerging challenge in modern medicine. OBJECTIVES We sought to establish the role of intrinsic drug-resistance regulators in combination with specific genetic mutations in 11 Enterobacter cloacae isolates obtained from a single patient within a 7 week period. METHODS The molecular characterization of eight carbapenem-resistant and three carbapenem-susceptible E. cloacae ST89 isolates included expression-level analysis and WGS. Quantitative PCR included: (i) chromosomal cephalosporinase gene (ampC); (ii) membrane permeability factor genes, e.g. ompF, ompC, acrA, acrB and tolC; and (iii) intrinsic regulatory genes, e.g. ramA, ampR, rob, marA and soxS, which confer reductions in antibiotic susceptibility. RESULTS In this study we describe the influence of the alterations in membrane permeability (ompF and ompC levels), intrinsic regulatory genes (ramA, marA, soxS) and intrinsic chromosomal cephalosporinase AmpC on reductions in carbapenem susceptibility of E. cloacae clinical isolates. Interestingly, only the first isolate possessed the acquired VIM-4 carbapenemase, which has been lost in subsequent isolates. The remaining XDR E. cloacae ST89 isolates presented complex carbapenem-resistance pathways, which included perturbations in permeability of bacterial membranes mediated by overexpression of ramA, encoding an AraC/XylS global regulator. Moreover, susceptible isolates differed significantly from other isolates in terms of marA down-regulation and soxS up-regulation. CONCLUSIONS Molecular mechanisms of resistance among carbapenem-resistant E. cloacae included production of acquired VIM-4 carbapenemase, significant alterations in membrane permeability due to increased expression of ramA, encoding an AraC/XylS global regulator, and the overproduction of chromosomal AmpC cephalosporinase.
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Affiliation(s)
- Piotr Majewski
- Department of Microbiological Diagnostics and Infectious Immunology, Medical University of Bialystok, Bialystok, Poland
| | - Anna Gutowska
- Department of Microbiological Diagnostics and Infectious Immunology, Medical University of Bialystok, Bialystok, Poland
| | - Pawel Sacha
- Department of Microbiological Diagnostics and Infectious Immunology, Medical University of Bialystok, Bialystok, Poland
| | | | - Mariola Talalaj
- Department of Anaesthesiology and Intensive Care with Postoperative Unit, University Children's Clinical Hospital, Bialystok, Poland
| | | | | | - Dominika Ojdana
- Department of Microbiological Diagnostics and Infectious Immunology, Medical University of Bialystok, Bialystok, Poland
| | - Piotr Wieczorek
- Department of Microbiological Diagnostics and Infectious Immunology, Medical University of Bialystok, Bialystok, Poland
| | - Tomasz Hauschild
- Department of Microbiology, Institute of Biology, University of Bialystok, Bialystok, Poland
| | - Oksana Kowalczuk
- Department of Clinical Molecular Biology, Medical University of Bialystok, Bialystok, Poland
| | - Jacek Niklinski
- Department of Clinical Molecular Biology, Medical University of Bialystok, Bialystok, Poland
| | - Piotr Radziwon
- Regional Centre for Transfusion Medicine, Bialystok, Poland.,Department of Hematology, Medical University of Bialystok, Bialystok, Poland
| | - Elzbieta Tryniszewska
- Department of Microbiological Diagnostics and Infectious Immunology, Medical University of Bialystok, Bialystok, Poland
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Abdelhamid AG, Yousef AE. Collateral adaptive responses induced by desiccation stress in Salmonella enterica. Lebensm Wiss Technol 2020. [DOI: 10.1016/j.lwt.2020.110089] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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10
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11
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Colclough AL, Alav I, Whittle EE, Pugh HL, Darby EM, Legood SW, McNeil HE, Blair JM. RND efflux pumps in Gram-negative bacteria; regulation, structure and role in antibiotic resistance. Future Microbiol 2020; 15:143-157. [PMID: 32073314 DOI: 10.2217/fmb-2019-0235] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Rresistance-nodulation-division (RND) efflux pumps in Gram-negative bacteria remove multiple, structurally distinct classes of antimicrobials from inside bacterial cells therefore directly contributing to multidrug resistance. There is also emerging evidence that many other mechanisms of antibiotic resistance rely on the intrinsic resistance conferred by RND efflux. In addition to their role in antibiotic resistance, new information has become available about the natural role of RND pumps including their established role in virulence of many Gram-negative organisms. This review also discusses the recent advances in understanding the regulation and structure of RND efflux pumps.
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Affiliation(s)
- Abigail L Colclough
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Ilyas Alav
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Emily E Whittle
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Hannah L Pugh
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Elizabeth M Darby
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Simon W Legood
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Helen E McNeil
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Jessica Ma Blair
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
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12
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Association of Salmonella Serotypes with Quinolone Resistance in Broilers. Food Saf (Tokyo) 2018; 6:156-159. [PMID: 31998577 PMCID: PMC6795393 DOI: 10.14252/foodsafetyfscj.2018012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 11/06/2018] [Indexed: 12/04/2022] Open
Abstract
Fluoroquinolone is widely used for the treatment of bacterial diseases, and the emergence of
quinolone resistance has become a serious concern in recent years, owing to an increase and
inappropriate use of antimicrobials. Here, we attempted to understand the differences in the
emergence frequency of quinolone-resistant bacterial variants in three
Salmonella serotypes S. Infantis, S.
Schwarzengrund, and S. Manhattan—which are mainly found in broiler industries
in Japan. Emergence frequency tests for quinolone-resistant variants using
enrofloxacin-containing agar plates and sequence analysis in the quinolone
resistance-determining region (QRDR) of gyrA in DNA gyrase were performed. The
results showed no significant difference in the emergence frequency among the three serotypes,
and most of the resistant variants had mutations in the QRDR region. These findings suggest
that differences in the serotypes tested are not associated with the emergence frequency of
quinolone-resistant variants.
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13
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Zhang CZ, Chang MX, Yang L, Liu YY, Chen PX, Jiang HX. Upregulation of AcrEF in Quinolone Resistance Development inEscherichia coliWhen AcrAB-TolC Function Is Impaired. Microb Drug Resist 2018; 24:18-23. [DOI: 10.1089/mdr.2016.0207] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Chuan-Zhen Zhang
- College of Veterinary Medicine, Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics, Development and Safety Evaluation, South China Agricultural University (SCAU), Guangzhou, China
| | - Man-Xia Chang
- College of Veterinary Medicine, Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics, Development and Safety Evaluation, South China Agricultural University (SCAU), Guangzhou, China
| | - Lei Yang
- College of Veterinary Medicine, Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics, Development and Safety Evaluation, South China Agricultural University (SCAU), Guangzhou, China
| | - Yan-Yan Liu
- College of Veterinary Medicine, Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics, Development and Safety Evaluation, South China Agricultural University (SCAU), Guangzhou, China
| | - Pin-Xian Chen
- College of Veterinary Medicine, Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics, Development and Safety Evaluation, South China Agricultural University (SCAU), Guangzhou, China
| | - Hong-Xia Jiang
- College of Veterinary Medicine, Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics, Development and Safety Evaluation, South China Agricultural University (SCAU), Guangzhou, China
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14
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Weston N, Sharma P, Ricci V, Piddock LJV. Regulation of the AcrAB-TolC efflux pump in Enterobacteriaceae. Res Microbiol 2017; 169:425-431. [PMID: 29128373 DOI: 10.1016/j.resmic.2017.10.005] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 10/16/2017] [Accepted: 10/31/2017] [Indexed: 11/18/2022]
Abstract
Bacterial multidrug efflux systems are a major mechanism of antimicrobial resistance and are fundamental to the physiology of Gram-negative bacteria. The resistance-nodulation-division (RND) family of efflux pumps is the most clinically significant, as it is associated with multidrug resistance. Expression of efflux systems is subject to multiple levels of regulation, involving local and global transcriptional regulation as well as post-transcriptional and post-translational regulation. The best-characterised RND system is AcrAB-TolC, which is present in Enterobacteriaceae. This review describes the current knowledge and new data about the regulation of the acrAB and tolC genes in Escherichia coli and Salmonella enterica.
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Affiliation(s)
- Natasha Weston
- Institute of Microbiology and Infection, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Prateek Sharma
- Institute of Microbiology and Infection, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Vito Ricci
- Institute of Microbiology and Infection, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Laura J V Piddock
- Institute of Microbiology and Infection, University of Birmingham, Birmingham B15 2TT, United Kingdom.
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15
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Liao SW, Lee JJ, Ptak CP, Wu YC, Hsuan SL, Kuo CJ, Chen TH. Effects of L-arabinose efflux on λ Red recombination-mediated gene knockout in multiple-antimicrobial-resistant Salmonella enterica serovar Choleraesuis. Arch Microbiol 2017; 200:219-225. [PMID: 28975374 DOI: 10.1007/s00203-017-1436-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 09/08/2017] [Accepted: 09/20/2017] [Indexed: 11/24/2022]
Abstract
In this study, six swine-derived multiple-antimicrobial-resistant (MAR) strains of Salmonella Choleraesuis (S. Choleraesuis) were demonstrated to possess higher efflux pump activity than the wild-type (WT). L-Arabinose, a common inducer for gene expression, modulated S. Choleraesuis efflux pump activity in a dose-dependent manner. At low L-arabinose concentrations, increasing L-arabinose led to a corresponding increase in fluorophore efflux, while at higher L-arabinose concentrations, increasing L-arabinose decreased fluorophore efflux activity. The WT S. Choleraesuis that lacks TolC (ΔtolC), an efflux protein associated with bacterial antibiotic resistance and virulence, was demonstrated to possess a significantly reduced ability to extrude L-arabinose. Further, due to the rapid export of L-arabinose, an efficient method for recombination-mediated gene knockout, the L-arabinose-inducible bacteriophage λ Red recombinase system, has a reduced recombination frequency (~ 12.5%) in clinically isolated MAR Salmonella strains. An increased recombination frequency (up to 60%) can be achieved using a higher concentration of L-arabinose (fivefold) for genetic manipulation and functional analysis for MAR Salmonella using the λ Red system. The study suggests that L-arabinose serves not only as an inducer of the TolC-dependent efflux system but also acts as a competitive substrate of the efflux system. In addition, understanding the TolC-dependent efflux of L-arabinose should facilitate the optimization of L-arabinose induction in strains with high efflux activity.
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Affiliation(s)
- Shi-Wei Liao
- Graduate Institute of Microbiology and Public Health, National Chung Hsing University, Taichung, Taiwan
| | - Jen-Jie Lee
- Graduate Institute of Veterinary Pathobiology, National Chung Hsing University, Taichung, Taiwan
| | - Christopher P Ptak
- Department of Molecular Medicine, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA
| | - Ying-Chen Wu
- Graduate Institute of Veterinary Pathobiology, National Chung Hsing University, Taichung, Taiwan
| | - Shih-Ling Hsuan
- Graduate Institute of Veterinary Pathobiology, National Chung Hsing University, Taichung, Taiwan
| | - Chih-Jung Kuo
- Department of Veterinary Medicine, National Chung Hsing University, Taichung, Taiwan.
| | - Ter-Hsin Chen
- Graduate Institute of Veterinary Pathobiology, National Chung Hsing University, Taichung, Taiwan.
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16
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Miao M, Cao W, Wang H, Yan J, Wang M, Zheng Y, Xie X, Zhang X, Zhang H, Du H. ramR is not involved in the regulation of ramA associated antibiotic resistance in Salmonella enterica serovar Typhi. Microb Pathog 2017; 111:198-202. [DOI: 10.1016/j.micpath.2017.08.052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2017] [Revised: 08/20/2017] [Accepted: 08/30/2017] [Indexed: 11/16/2022]
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17
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Shen J, Yang B, Gu Q, Zhang G, Yang J, Xue F, Shao J, Yi X, Jiang Y. The Role of AcrAB-TolC Efflux Pump in Mediating Fluoroquinolone Resistance in Naturally Occurring Salmonella Isolates from China. Foodborne Pathog Dis 2017; 14:728-734. [PMID: 28926285 DOI: 10.1089/fpd.2017.2291] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The involvement of AcrAB-TolC efflux pump in regulating fluoroquinolone resistance of naturally occurring Salmonella isolates is insufficiently investigated. In this study, the regulatory genes, acrR, ramR, marRAB, and soxRS of AcrAB-TolC efflux pump, of 27 naturally occurring fluoroquinolone-resistant Salmonella isolates collected in China were sequenced. The expression levels of acrB, ramA, marA, and soxS were also examined using quantitative real-time polymerase chain reaction. Gene alterations were mainly observed for acrR (three mutation types) and ramR (four mutation types), not for marRAB (no mutation) or soxRS (one mutaton type). Overexpressions were also mainly observed for acrB and ramA, not for marA or soxS. Some mutations/deletions in ramR caused highly elevated expression of ramA. Complementation with wild-type ramR gene reduced mRNA levels of acrB and ramA by 1.7- to 2.2-fold and 10.5- to 30.1-fold, respectively, and lowered fluoroquinolones (FQ) minimum inhibitory concentrations by 2- to 8-fold. Neither MarA nor SoxS was found to be associated with increased FQ resistance. This study shows that the AcrAB efflux pump is playing a role in mediating fluoroquinolone resistance, and RamA may be the major global regulator of AcrAB-TolC-mediated fluoroquinolone resistance in Salmonella.
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Affiliation(s)
- Jinling Shen
- 1 Technology Center of Zhangjiagang Entry-Exit Inspection and Quarantine Bureau of the People's Republic of China , Zhangjiagang, China .,4 Technical Center for Animal Plant and Food Inspection and Qurantine , Shanghai Entry-Exit Inspection and Quarantine Bureau of the People's Republic of China, Shanghai, China
| | - Baowei Yang
- 2 College of Food Science and Engineering, Northwest A&F University , Yangling, China
| | - Qiang Gu
- 1 Technology Center of Zhangjiagang Entry-Exit Inspection and Quarantine Bureau of the People's Republic of China , Zhangjiagang, China
| | - Guodong Zhang
- 3 Center for Food Safety and Applied Nutrition , U.S. Food and Drug Administration, College Park, Maryland
| | - Jielin Yang
- 4 Technical Center for Animal Plant and Food Inspection and Qurantine , Shanghai Entry-Exit Inspection and Quarantine Bureau of the People's Republic of China, Shanghai, China
| | - Feng Xue
- 5 College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, China .,6 Jiangsu Collaborative Innovation Center of Meat Production and Processing , Nanjing, China
| | - Jingdong Shao
- 1 Technology Center of Zhangjiagang Entry-Exit Inspection and Quarantine Bureau of the People's Republic of China , Zhangjiagang, China
| | - Xiaojuan Yi
- 1 Technology Center of Zhangjiagang Entry-Exit Inspection and Quarantine Bureau of the People's Republic of China , Zhangjiagang, China
| | - Yuan Jiang
- 4 Technical Center for Animal Plant and Food Inspection and Qurantine , Shanghai Entry-Exit Inspection and Quarantine Bureau of the People's Republic of China, Shanghai, China .,6 Jiangsu Collaborative Innovation Center of Meat Production and Processing , Nanjing, China
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18
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Chen Y, Hu D, Zhang Q, Liao XP, Liu YH, Sun J. Efflux Pump Overexpression Contributes to Tigecycline Heteroresistance in Salmonella enterica serovar Typhimurium. Front Cell Infect Microbiol 2017; 7:37. [PMID: 28261566 PMCID: PMC5313504 DOI: 10.3389/fcimb.2017.00037] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 01/31/2017] [Indexed: 01/09/2023] Open
Abstract
Bacterial heteroresistance has been identified in several combinations of bacteria and antibiotics, and it complicated the therapeutic strategies. Tigecycline is being used as one of the optimal options for the treatment of infections caused by multidrug-resistant Salmonella. This study investigated whether heterorresistance to tigecycline exists in a Salmonella enterica serovar Typhimurium strain harboring the oqxAB-bearing IncHI2 plasmid pHXY0908. MIC and population analyses were performed to evaluate population-wide susceptibility to tigecycline. The effects of efflux pumps on MIC levels were assessed using the efflux pump inhibitor Phe-Arg-β-naphthylamide, measuring intracellular tigecycline accumulation as well as mRNA levels of regulatory and efflux pump genes. DNA sequencing of regulatory regions were performed and plasmid curing from a resistant strain provided an appropriate control. Results showed that MICs of a parental strain with and without pHXY0908 as well as a plasmid-cured strain 14028/Δp52 were 0.5, 1, and 1 μg/mL, respectively. Population analysis profiling (PAP) illustrated that only the pHXY0908-containg strain was heteroresistant to tigecycline. A fraction of colonies exhibited stable profiles with 4- to 8-fold increases in MIC. The frequencies of emergence of these isolates were higher in the plasmid-containing strain pHXY0908 than either the parental or the 14028/Δp52 strain. Phe-Arg-β-naphthylamide addition restored tigecycline susceptibility of these isolates and intracellular tigecycline accumulation was reduced. Heteroresistant isolates of the strain containing pHXY0908 also had elevated expression of acrB, ramA, and oqxB. DNA sequencing identified numerous mutations in RamR that have been shown to lead to ramA overexpression. In conclusions, heteroresistance to tigecycline in Salmonella enterica serovar Typhimurium was manifested in a plasmid-bearing strain. Our results suggest that this phenotype was associated with overexpression of the AcrAB-TolC and OqxAB efflux pumps.
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Affiliation(s)
- Yi Chen
- National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural UniversityGuangzhou, China; Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural UniversityGuangzhou, China
| | - Daxing Hu
- National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural UniversityGuangzhou, China; Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural UniversityGuangzhou, China
| | - Qijing Zhang
- Department of Veterinary Microbiology and Preventive Medicine, Iowa State University Ames, IA, USA
| | - Xiao-Ping Liao
- National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural UniversityGuangzhou, China; Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural UniversityGuangzhou, China
| | - Ya-Hong Liu
- National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural UniversityGuangzhou, China; Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural UniversityGuangzhou, China
| | - Jian Sun
- National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural UniversityGuangzhou, China; Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural UniversityGuangzhou, China
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19
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Xie X, Zhang H, Zheng Y, Li A, Wang M, Zhou H, Zhu X, Schneider Z, Chen L, Kreiswirth BN, Du H. RpoE is a Putative Antibiotic Resistance Regulator of Salmonella enteric Serovar Typhi. Curr Microbiol 2016; 72:457-64. [PMID: 26742769 DOI: 10.1007/s00284-015-0983-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 12/02/2015] [Indexed: 11/27/2022]
Abstract
Bacterial antimicrobial resistance has been associated with the up regulation of genes encoding efflux pumps and the down regulation of genes encoding outer membrane proteins (OMPs). Gene expression in bacteria is primarily initiated by sigma factors (σ factors) such as RpoE, which plays an important role in responding to many environmental stresses. Here, we report the first observation that RpoE serves as an antibiotic resistance regulator in Salmonella enteric serovar Typhi (S. Typhi). In this study, we found that the rpoE mutant (ΔrpoE) of S. Typhi GIFU10007 has elevated resistance to several antimicrobial agents, including β-lactams, quinolones, and aminoglycosides. Genomic DNA microarray analysis was used to investigate the differential gene expression profiles between a wild type and rpoE mutant in response to ampicillin. The results showed that a total of 57 genes displayed differential expression (two-fold increase or decrease) in ΔrpoE versus the wild-type strain. The expressions of two outer membrane protein genes, ompF and ompC, were significantly down-regulated in ΔrpoE (six and seven-fold lower in comparison to wild-type strain) and RamA, a member of the efflux pump AraC/XylS family, was up-regulated about four-fold in the ΔrpoE. Our results suggest RpoE is a potential antimicrobial regulator in S. Typhi, controlling both the down regulation of the OMP genes and up-regulating the efflux system.
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Affiliation(s)
- Xiaofang Xie
- Department of Clinical Laboratory, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, Jiangsu, People's Republic of China
| | - Haifang Zhang
- Department of Clinical Laboratory, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, Jiangsu, People's Republic of China
| | - Yi Zheng
- Department of Clinical Laboratory, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, Jiangsu, People's Republic of China
| | - Aiqing Li
- Department of Clinical Laboratory, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, Jiangsu, People's Republic of China
| | - Min Wang
- Department of Clinical Laboratory, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, Jiangsu, People's Republic of China
| | - Huiqin Zhou
- Department of Clinical Laboratory, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, Jiangsu, People's Republic of China
| | - Xueming Zhu
- Department of Clinical Laboratory, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, Jiangsu, People's Republic of China
| | - Zachary Schneider
- Public Health Research Institute Center, New Jersey Medical School, Rutgers University, Newark, NJ, 07103, USA
| | - Liang Chen
- Public Health Research Institute Center, New Jersey Medical School, Rutgers University, Newark, NJ, 07103, USA
| | - Barry N Kreiswirth
- Public Health Research Institute Center, New Jersey Medical School, Rutgers University, Newark, NJ, 07103, USA
| | - Hong Du
- Department of Clinical Laboratory, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, Jiangsu, People's Republic of China.
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20
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Fàbrega A, Ballesté-Delpierre C, Vila J. Differential impact of ramRA mutations on both ramA transcription and decreased antimicrobial susceptibility in Salmonella Typhimurium. J Antimicrob Chemother 2015; 71:617-24. [PMID: 26679248 DOI: 10.1093/jac/dkv410] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 11/03/2015] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES This study was focused on analysing the heterogeneity of mutations occurring in the regulators of efflux-mediated MDR in Salmonella Typhimurium. Moreover, the impact of such mutations on impairing the transcription of ramA, acrB, tolC and acrF was also assessed as was the impact on the resistance or decreased susceptibility phenotype. METHODS Strains were selected in vitro under increasing ciprofloxacin concentrations. Etest and broth microdilution tests were used to determine the MICs of several unrelated compounds. Screening of mutations in the quinolone target genes and MDR regulators was performed. RT-PCR analysis was used to detect the levels of expression of acrB, tolC, ompF, acrF, emrB, acrR, ramA, soxS and marA. RESULTS All mutant strains showed increased MICs of most of the antimicrobials tested, with the exception of kanamycin. Mutations in the quinolone target genes did not occur in all the mutants, which all harboured mutations in the ramRA regulatory region. All the mutants overexpressed ramA, tolC and acrB (only tested in 60-wt derivatives), whereas differential results were seen for the remaining genes. CONCLUSIONS Mutations in the ramRA region related to resistance and/or decreased susceptibility to antimicrobials predominate in Salmonella. There is heterogeneity in the types of mutations, with deletions affecting RamR-binding sites having a greater impact on ramA expression and the MDR phenotype.
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Affiliation(s)
- Anna Fàbrega
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain
| | - Clara Ballesté-Delpierre
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain
| | - Jordi Vila
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain Department of Clinical Microbiology, Hospital Clínic, School of Medicine, University of Barcelona, Barcelona, Spain
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21
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In Vivo Evolution of Bacterial Resistance in Two Cases of Enterobacter aerogenes Infections during Treatment with Imipenem. PLoS One 2015; 10:e0138828. [PMID: 26398358 PMCID: PMC4580588 DOI: 10.1371/journal.pone.0138828] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 09/03/2015] [Indexed: 11/24/2022] Open
Abstract
Infections caused by multidrug resistant (MDR) bacteria are a major concern worldwide. Changes in membrane permeability, including decreased influx and/or increased efflux of antibiotics, are known as key contributors of bacterial MDR. Therefore, it is of critical importance to understand molecular mechanisms that link membrane permeability to MDR in order to design new antimicrobial strategies. In this work, we describe genotype-phenotype correlations in Enterobacter aerogenes, a clinically problematic and antibiotic resistant bacterium. To do this, series of clinical isolates have been periodically collected from two patients during chemotherapy with imipenem. The isolates exhibited different levels of resistance towards multiple classes of antibiotics, consistently with the presence or the absence of porins and efflux pumps. Transport assays were used to characterize membrane permeability defects. Simultaneous genome-wide analysis allowed the identification of putative mutations responsible for MDR. The genome of the imipenem-susceptible isolate G7 was sequenced to closure and used as a reference for comparative genomics. This approach uncovered several loci that were specifically mutated in MDR isolates and whose products are known to control membrane permeability. These were omp35 and omp36, encoding the two major porins; rob, encoding a global AraC-type transcriptional activator; cpxA, phoQ and pmrB, encoding sensor kinases of the CpxRA, PhoPQ and PmrAB two-component regulatory systems, respectively. This report provides a comprehensive analysis of membrane alterations relative to mutational steps in the evolution of MDR of a recognized nosocomial pathogen.
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22
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Preethi B, Ramanathan K. Molecular level understanding of resistance to nalidixic acid in Salmonella enteric serovar typhimurium associates with the S83F sequence type. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2015; 45:35-44. [PMID: 26329667 DOI: 10.1007/s00249-015-1073-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 07/15/2015] [Accepted: 08/12/2015] [Indexed: 02/04/2023]
Abstract
Nalidixic acid is an antibiotic drug used for treatment of Salmonellosis, a gastrointestinal infection. DNA gyrase subunit A (GyrA) of Salmonella typhimurium is the drug target for nalidixic acid. Resistance of GyrA to nalidixic acid, because of a point mutation in S. typhimurium, was recently reported. Substitution of Phe in place of Ser at locus 83 in GyrA of S. typhimurium has been experimentally associated with nalidixic acid resistance. Despite recent efforts, the mechanism of this resistance is not well understood. In this investigation we used computational techniques to address this shortcoming. Our results showed that contact with residue Arg 91 is certainly important for efficient binding of nalidixic acid to the target protein, and that mutation of this residue results in 180° rotation of the antibiotic in its binding pocket, around its own long axis. It is hoped these findings may enable development of new antibiotics against resistant forms of Salmonella.
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Affiliation(s)
- B Preethi
- Industrial Biotechnology Division, School of Bio Sciences and Technology, VIT University, Vellore, 632014, Tamil Nadu, India
| | - K Ramanathan
- Industrial Biotechnology Division, School of Bio Sciences and Technology, VIT University, Vellore, 632014, Tamil Nadu, India.
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23
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Preethi B, Shanthi V, Ramanathan K. Investigation of Nalidixic Acid Resistance Mechanism in Salmonella enterica Using Molecular Simulation Techniques. Appl Biochem Biotechnol 2015. [DOI: 10.1007/s12010-015-1760-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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24
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Li XZ, Plésiat P, Nikaido H. The challenge of efflux-mediated antibiotic resistance in Gram-negative bacteria. Clin Microbiol Rev 2015; 28:337-418. [PMID: 25788514 PMCID: PMC4402952 DOI: 10.1128/cmr.00117-14] [Citation(s) in RCA: 939] [Impact Index Per Article: 104.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The global emergence of multidrug-resistant Gram-negative bacteria is a growing threat to antibiotic therapy. The chromosomally encoded drug efflux mechanisms that are ubiquitous in these bacteria greatly contribute to antibiotic resistance and present a major challenge for antibiotic development. Multidrug pumps, particularly those represented by the clinically relevant AcrAB-TolC and Mex pumps of the resistance-nodulation-division (RND) superfamily, not only mediate intrinsic and acquired multidrug resistance (MDR) but also are involved in other functions, including the bacterial stress response and pathogenicity. Additionally, efflux pumps interact synergistically with other resistance mechanisms (e.g., with the outer membrane permeability barrier) to increase resistance levels. Since the discovery of RND pumps in the early 1990s, remarkable scientific and technological advances have allowed for an in-depth understanding of the structural and biochemical basis, substrate profiles, molecular regulation, and inhibition of MDR pumps. However, the development of clinically useful efflux pump inhibitors and/or new antibiotics that can bypass pump effects continues to be a challenge. Plasmid-borne efflux pump genes (including those for RND pumps) have increasingly been identified. This article highlights the recent progress obtained for organisms of clinical significance, together with methodological considerations for the characterization of MDR pumps.
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Affiliation(s)
- Xian-Zhi Li
- Human Safety Division, Veterinary Drugs Directorate, Health Products and Food Branch, Health Canada, Ottawa, Ontario, Canada
| | - Patrick Plésiat
- Laboratoire de Bactériologie, Faculté de Médecine-Pharmacie, Centre Hospitalier Régional Universitaire, Université de Franche-Comté, Besançon, France
| | - Hiroshi Nikaido
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
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25
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Increase of multidrug efflux pump expression in fluoroquinolone-resistant Salmonella mutants induced by ciprofloxacin selective pressure. Res Vet Sci 2014; 97:182-6. [DOI: 10.1016/j.rvsc.2014.07.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Revised: 07/06/2014] [Accepted: 07/25/2014] [Indexed: 01/13/2023]
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26
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Condell O, Power KA, Händler K, Finn S, Sheridan A, Sergeant K, Renaut J, Burgess CM, Hinton JCD, Nally JE, Fanning S. Comparative analysis of Salmonella susceptibility and tolerance to the biocide chlorhexidine identifies a complex cellular defense network. Front Microbiol 2014; 5:373. [PMID: 25136333 PMCID: PMC4117984 DOI: 10.3389/fmicb.2014.00373] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Accepted: 07/03/2014] [Indexed: 12/04/2022] Open
Abstract
Chlorhexidine is one of the most widely used biocides in health and agricultural settings as well as in the modern food industry. It is a cationic biocide of the biguanide class. Details of its mechanism of action are largely unknown. The frequent use of chlorhexidine has been questioned recently, amidst concerns that an overuse of this compound may select for bacteria displaying an altered susceptibility to antimicrobials, including clinically important anti-bacterial agents. We generated a Salmonella enterica serovar Typhimurium isolate (ST24(CHX)) that exhibited a high-level tolerant phenotype to chlorhexidine, following several rounds of in vitro selection, using sub-lethal concentrations of the biocide. This mutant showed altered suceptibility to a panel of clinically important antimicrobial compounds. Here we describe a genomic, transcriptomic, proteomic, and phenotypic analysis of the chlorhexidine tolerant S. Typhimurium compared with its isogenic sensitive progenitor. Results from this study describe a chlorhexidine defense network that functions in both the reference chlorhexidine sensitive isolate and the tolerant mutant. The defense network involved multiple cell targets including those associated with the synthesis and modification of the cell wall, the SOS response, virulence, and a shift in cellular metabolism toward anoxic pathways, some of which were regulated by CreB and Fur. In addition, results indicated that chlorhexidine tolerance was associated with more extensive modifications of the same cellular processes involved in this proposed network, as well as a divergent defense response involving the up-regulation of additional targets such as the flagellar apparatus and an altered cellular phosphate metabolism. These data show that sub-lethal concentrations of chlorhexidine induce distinct changes in exposed Salmonella, and our findings provide insights into the mechanisms of action and tolerance to this biocidal agent.
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Affiliation(s)
- Orla Condell
- UCD Centre for Food Safety, School of Public Health, Physiotherapy and Population Science, University College DublinBelfield, Dublin, Ireland
- European Program for Public Health Microbiology Training, European Centre for Disease Prevention and ControlStockholm, Sweden
| | - Karen A. Power
- UCD Centre for Food Safety, School of Public Health, Physiotherapy and Population Science, University College DublinBelfield, Dublin, Ireland
| | - Kristian Händler
- Department of Microbiology, School of Genetics and Microbiology, Moyne Institute of Preventive Medicine, Trinity College DublinDublin, Ireland
| | - Sarah Finn
- UCD Centre for Food Safety, School of Public Health, Physiotherapy and Population Science, University College DublinBelfield, Dublin, Ireland
| | - Aine Sheridan
- Food Safety Department, Teagasc Food Research CentreAshtown, Dublin, Ireland
| | - Kjell Sergeant
- Department of Environment and Agrobiotechnologies (EVA), Centre de Recherche Public-Gabriel LippmannBelvaux, Luxembourg
| | - Jenny Renaut
- Department of Environment and Agrobiotechnologies (EVA), Centre de Recherche Public-Gabriel LippmannBelvaux, Luxembourg
| | | | - Jay C. D. Hinton
- Department of Microbiology, School of Genetics and Microbiology, Moyne Institute of Preventive Medicine, Trinity College DublinDublin, Ireland
- Institute of Integrative Biology, University of LiverpoolLiverpool, UK
| | - Jarlath E. Nally
- School of Veterinary Medicine, University College DublinBelfield, Dublin, Ireland
| | - Séamus Fanning
- UCD Centre for Food Safety, School of Public Health, Physiotherapy and Population Science, University College DublinBelfield, Dublin, Ireland
- Institute for Global Food Security, Queen's University BelfastBelfast, Northern Ireland
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Fàbrega A, Soto SM, Ballesté-Delpierre C, Fernández-Orth D, Jiménez de Anta MT, Vila J. Impact of quinolone-resistance acquisition on biofilm production and fitness in Salmonella enterica. J Antimicrob Chemother 2014; 69:1815-24. [PMID: 24706735 DOI: 10.1093/jac/dku078] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES To investigate the potential relationship between quinolone resistance and biofilm production in a collection of Salmonella enterica clinical isolates and in S. enterica serovar Typhimurium serial mutants with increasing resistance to ciprofloxacin. METHODS Nalidixic acid susceptibility and biofilm formation were assessed in a collection of 122 S. enterica clinical isolates. An in vitro quinolone-resistant mutant, 59-64, was obtained from a biofilm-producing and quinolone-susceptible clinical isolate, 59-wt, in a multistep selection process after increasing ciprofloxacin concentrations. The quinolone resistance mechanisms [target gene and multidrug resistance (MDR) regulatory mutations, MICs of several antibiotics, cell envelope protein analysis, real-time PCR and ciprofloxacin accumulation] were characterized for mutant strains. In addition, analysis of fitness, biofilm formation, rdar morphotype and expression of biofilm-related genes by real-time PCR were also determined. RESULTS Nalidixic acid-susceptible S. enterica strains were more prevalent in producing biofilm than the resistant counterparts. Strain 59-64 acquired five target gene mutations and showed an MDR phenotype. AcrAB and acrF overexpression were ruled out, whereas TolC did show increased expression in 59-64, which, in addition, accumulated less ciprofloxacin. Consistently, increased ramA expression was seen in 59-64 and attributed to a mutation within its promoter. Reduced biofilm production related to diminished csgB expression as well as reduced fitness was seen for 59-64, which was unable to form the rdar morphotype. CONCLUSIONS Quinolone resistance acquisition may be associated with decreased production of biofilm due to lower csgB expression. Efflux, biofilm production and fitness seem to be interrelated.
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Affiliation(s)
- Anna Fàbrega
- Barcelona Centre for International Health Research (CRESIB, Hospital Clínic-Universitat de Barcelona), Barcelona, Spain
| | - Sara M Soto
- Barcelona Centre for International Health Research (CRESIB, Hospital Clínic-Universitat de Barcelona), Barcelona, Spain
| | - Clara Ballesté-Delpierre
- Barcelona Centre for International Health Research (CRESIB, Hospital Clínic-Universitat de Barcelona), Barcelona, Spain
| | - Dietmar Fernández-Orth
- Barcelona Centre for International Health Research (CRESIB, Hospital Clínic-Universitat de Barcelona), Barcelona, Spain
| | - M Teresa Jiménez de Anta
- Department of Clinical Microbiology, Hospital Clínic, School of Medicine, University of Barcelona, Barcelona, Spain
| | - Jordi Vila
- Barcelona Centre for International Health Research (CRESIB, Hospital Clínic-Universitat de Barcelona), Barcelona, Spain Department of Clinical Microbiology, Hospital Clínic, School of Medicine, University of Barcelona, Barcelona, Spain
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Tavío MM, Aquili VD, Vila J, Poveda JB. Resistance to ceftazidime in Escherichia coli associated with AcrR, MarR and PBP3 mutations and overexpression of sdiA. J Med Microbiol 2014; 63:56-65. [DOI: 10.1099/jmm.0.063727-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The mechanisms responsible for the increase in ceftazidime MIC in two Escherichia coli in vitro selected mutants, Caz/20-1 and Caz/20-2, were studied. OmpF loss and overexpression of acrB, acrD and acrF that were associated with acrR and marR mutations and sdiA overexpression, together with mutations A233T and I332V in FtSI (PBP3) resulted in ceftazidime resistance in Caz/20-2, multiplying by 128-fold the ceftazidime MIC in the parental clinical isolate PS/20. Absence of detectable β-lactamase hydrolytic activity in the crude extract of Caz/20-2 was observed, and coincided with Q191K and P209S mutations in AmpC and a nucleotide substitution at −28 in the ampC promoter, whereas β-lactamase hydrolytic activity in crude extracts of PS/20 and Caz/20-1 strains was detected. Nevertheless, a fourfold increase in ceftazidime MIC in Caz/20-1 compared with that in PS/20 was due to the increased transcript level of acrB derived from acrR mutation. The two Caz mutants and PS/20 showed the same mutations in AmpG and ParE.
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Affiliation(s)
- María M. Tavío
- Unidad de Epidemiología y Medicina Preventiva, Instituto Universitario de Sanidad Animal (IUSA), Universidad de Las Palmas de Gran Canaria, Arucas, Spain
- Microbiología, Departamento de Ciencias Clínicas, Facultad de Ciencias de la Salud, Universidad de Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain
| | - Virginia D. Aquili
- Microbiología, Departamento de Ciencias Clínicas, Facultad de Ciencias de la Salud, Universidad de Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain
| | - Jordi Vila
- Departamento de Microbiología, IDIBAPS, Facultad de Medicina, Universidad de Barcelona, Barcelona, Spain
| | - José B. Poveda
- Unidad de Epidemiología y Medicina Preventiva, Instituto Universitario de Sanidad Animal (IUSA), Universidad de Las Palmas de Gran Canaria, Arucas, Spain
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The crystal structure of multidrug-resistance regulator RamR with multiple drugs. Nat Commun 2013; 4:2078. [PMID: 23800819 DOI: 10.1038/ncomms3078] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2013] [Accepted: 05/30/2013] [Indexed: 11/08/2022] Open
Abstract
RamR is a transcriptional repressor of the gene-encoding RamA protein, which controls the expression of the multidrug efflux system genes acrAB-tolC. RamR is an important multidrug-resistance factor, however, its structure and the identity of the molecules to which it responds have been unknown. Here, we report the crystal structure of RamR in complex with multiple drugs, including berberine, crystal violet, dequalinium, ethidium bromide and rhodamine 6G. All compounds are found to interact with Phe155 of RamR, and each compound is surrounded by different amino acid residues. Binding of these compounds to RamR reduces its DNA-binding affinity, which results in the increased expression of ramA. Our results reveal significant flexibility in the substrate-recognition region of RamR, which regulates the bacterial efflux participating in multidrug resistance.
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30
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Ricci V, Blair JMA, Piddock LJV. RamA, which controls expression of the MDR efflux pump AcrAB-TolC, is regulated by the Lon protease. J Antimicrob Chemother 2013; 69:643-50. [PMID: 24169580 PMCID: PMC3922155 DOI: 10.1093/jac/dkt432] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES RamA regulates the AcrAB-TolC multidrug efflux system. Using Salmonella Typhimurium, we investigated the stability of RamA and its impact on antibiotic resistance. METHODS To detect RamA, we introduced ramA::3XFLAG::aph into plasmid pACYC184 and transformed this into Salmonella Typhimurium SL1344ramA::cat and lon::aph mutants. An N-terminus-deleted mutant [pACYC184ramA(Δ2-21)::3XFLAG::aph] in which the first 20 amino acids of RamA were deleted was also constructed. To determine the abundance and half-life of FLAG-tagged RamA, we induced RamA with chlorpromazine (50 mg/L) and carried out western blotting using anti-FLAG antibody. Susceptibility to antibiotics and phenotypic characterization of the lon mutant was also carried out. RESULTS We show that on removal of chlorpromazine, a known inducer of ramA, the abundance of RamA decreased to pre-induced levels. However, in cells lacking functional Lon, we found that the RamA protein was not degraded. We also demonstrated that the 21 amino acid residues of the RamA N-terminus are required for recognition by the Lon protease. Antimicrobial susceptibility and phenotypic tests showed that the lon mutant was more susceptible to fluoroquinolone antibiotics, was filamentous when observed by microscopy and grew poorly, but showed no difference in motility or the ability to form a biofilm. There was also no difference in the ability of the lon mutant to invade human intestinal cells (INT-407). CONCLUSIONS In summary, we show that the ATP-dependent Lon protease plays an important role in regulating the expression of RamA and therefore multidrug resistance via AcrAB-TolC in Salmonella Typhimurium.
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Affiliation(s)
- Vito Ricci
- Antimicrobials Research Group, School of Immunity and Infection and Institute of Microbiology and Infection, University of Birmingham, Birmingham B15 2TT, UK
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Analysis of triclosan-selected Salmonella enterica mutants of eight serovars revealed increased aminoglycoside susceptibility and reduced growth rates. PLoS One 2013; 8:e78310. [PMID: 24205194 PMCID: PMC3799642 DOI: 10.1371/journal.pone.0078310] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Accepted: 09/19/2013] [Indexed: 11/19/2022] Open
Abstract
The biocide triclosan (TRC) is used in a wide range of household, personal care, veterinary, industrial and medical products to control microbial growth. This extended use raises concerns about a possible association between the application of triclosan and the development of antibiotic resistance. In the present study we determined triclosan mutant prevention concentrations (MPC) for Salmonella enterica isolates of eight serovars and investigated selected mutants for their mechanisms mediating decreased susceptibility to triclosan. MPCTRC values were 8 - 64-fold higher than MIC values and ranged between 1 - 16 µg/ml. The frequencies at which mutants were selected varied between 1.3 x 10-10 - 9.9 x 10-11. Even if MIC values of mutants decreased by 3-7 dilution steps in the presence of the efflux pump inhibitor Phe-Arg-β-naphtylamide, only minor changes were observed in the expression of genes encoding efflux components or regulators, indicating that neither the major multidrug efflux pump AcrAB-TolC nor AcrEF are up-regulated in triclosan-selected mutants. Nucleotide sequence comparisons confirmed the absence of alterations in the regulatory regions acrRA, soxRS, marORAB, acrSE and ramRA of selected mutants. Single bp and deduced Gly93→Val amino acid exchanges were present in fabI, the target gene of triclosan, starting from a concentration of 1 µg/ml TRC used for MPC determinations. The fabI genes were up to 12.4-fold up-regulated. Complementation experiments confirmed the contribution of Gly93→Val exchanges and fabI overexpression to decreased triclosan susceptibility. MIC values of mutants compared to parent strains were even equal or resulted in a more susceptible phenotype (1-2 dilution steps) for the aminoglycoside antibiotics kanamycin and gentamicin as well as for the biocide chlorhexidine. Growth rates of selected mutants were significantly lower and hence, might partly explain the rare occurrence of Salmonella field isolates exhibiting decreased susceptibility to triclosan.
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32
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Lawler AJ, Ricci V, Busby SJW, Piddock LJV. Genetic inactivation of acrAB or inhibition of efflux induces expression of ramA. J Antimicrob Chemother 2013; 68:1551-7. [PMID: 23493314 PMCID: PMC3682690 DOI: 10.1093/jac/dkt069] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Objectives The transcriptional activator RamA regulates production of the multidrug resistance efflux AcrAB–TolC system in several Enterobacteriaceae. This study investigated factors that lead to increased expression of ramA. Methods In order to monitor changes in ramA expression, the promoter region of ramA was fused to a gfp gene encoding an unstable green fluorescence protein (GFP) on the reporter plasmid, pMW82. The ramA reporter plasmid was transformed into Salmonella Typhimurium SL1344 and a ΔacrB mutant. The response of the reporter to subinhibitory concentrations of antibiotics, dyes, biocides, psychotropic agents and efflux inhibitors was measured during growth over a 5 h time period. Results Our data revealed that the expression of ramA was increased in a ΔacrB mutant and also in the presence of the efflux inhibitors phenylalanine-arginine-β-naphthylamide, carbonyl cyanide m-chlorophenylhydrazone and 1-(1-naphthylmethyl)-piperazine. The phenothiazines chlorpromazine and thioridazine also increased ramA expression, triggering the greatest increase in GFP expression. However, inducers of Escherichia coli marA and soxS and 12 of 17 tested antibiotic substrates of AcrAB–TolC did not induce ramA expression. Conclusions This study shows that expression of ramA is not induced by most substrates of the AcrAB–TolC efflux system, but is increased by mutational inactivation of acrB or when efflux is inhibited.
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Affiliation(s)
- A J Lawler
- Antimicrobials Research Group, School of Immunity and Infection, Institute of Microbiology and Infection, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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33
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Ferrari RG, Galiana A, Cremades R, Rodríguez JC, Magnani M, Tognim MCB, Oliveira TCRM, Royo G. Expression of the marA, soxS, acrB and ramA genes related to the AcrAB/TolC efflux pump in Salmonella enterica strains with and without quinolone resistance-determining regions gyrA gene mutations. Braz J Infect Dis 2013; 17:125-30. [PMID: 23453941 PMCID: PMC9427363 DOI: 10.1016/j.bjid.2012.09.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Revised: 09/10/2012] [Accepted: 09/13/2012] [Indexed: 12/02/2022] Open
Abstract
Several studies have been conducted in recent years to elucidate the structure, function and significance of AcrB, MarA, SoxS and RamA in Salmonella enterica. In this study, the relative quantification of acrB, soxS, marA and ramA genes expression was evaluated in 14 strains of S. enterica, with or without accompanying mutations in the quinolone resistance-determining regions of the gyrA gene, that were exposed to ciprofloxacin during the exponential growth phase. The presence of ciprofloxacin during the log phase of bacterial growth activated the genes marA, soxS, ramA and acrB in all S. enterica strains analyzed in this study. The highest expression levels for acrB were observed in strains with gyrA mutation, and marA showed the highest expression in the strains without mutation. Considering only the strains with ciprofloxacin minimum inhibitory concentration values < 0.125 μg/mL (sensitive to ciprofloxacin), the most expressed gene in the strains both with and without mutations was acrB. In the strains with ciprofloxacin minimum inhibitory concentration values ≥ 0.125 μg/mL (low susceptibility), with and without mutations in gyrA, the most expressed gene was marA. In this study, we observed that strains resistant to nalidixic acid may express genes associated with the efflux pump and the expression of the AcrAB-TolC pump genes seems to occur independently of mutations in gyrA.
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Affiliation(s)
- Rafaela Gomes Ferrari
- Agricultural Sciences Center, Department of Food Science and Technology, Universidade Estadual de Londrina, Londrina, PR, Brazil.
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Giraud E, Baucheron S, Virlogeux-Payant I, Nishino K, Cloeckaert A. Effects of Natural Mutations in the ramRA Locus on Invasiveness of Epidemic Fluoroquinolone-Resistant Salmonella enterica Serovar Typhimurium Isolates. J Infect Dis 2012; 207:794-802. [DOI: 10.1093/infdis/jis755] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Effect of transcriptional activators SoxS, RobA, and RamA on expression of multidrug efflux pump AcrAB-TolC in Enterobacter cloacae. Antimicrob Agents Chemother 2012; 56:6256-66. [PMID: 23006750 DOI: 10.1128/aac.01085-12] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Control of membrane permeability is a key step in regulating the intracellular concentration of antibiotics. Efflux pumps confer innate resistance to a wide range of toxic compounds such as antibiotics, dyes, detergents, and disinfectants in members of the Enterobacteriaceae. The AcrAB-TolC efflux pump is involved in multidrug resistance in Enterobacter cloacae. However, the underlying mechanism that regulates the system in this microorganism remains unknown. In Escherichia coli, the transcription of acrAB is upregulated under global stress conditions by proteins such as MarA, SoxS, and Rob. In the present study, two clinical isolates of E. cloacae, EcDC64 (a multidrug-resistant strain overexpressing the AcrAB-TolC efflux pump) and Jc194 (a strain with a basal AcrAB-TolC expression level), were used to determine whether similar global stress responses operate in E. cloacae and also to establish the molecular mechanisms underlying this response. A decrease in susceptibility to erythromycin, tetracycline, telithromycin, ciprofloxacin, and chloramphenicol was observed in clinical isolate Jc194 and, to a lesser extent in EcDC64, in the presence of salicylate, decanoate, tetracycline, and paraquat. Increased expression of the acrAB promoter in the presence of the above-described conditions was observed by flow cytometry and reverse transcription-PCR, by using a reporter fusion protein (green fluorescent protein). The expression level of the AcrAB promoter decreased in E. cloacae EcDC64 derivates deficient in SoxS, RobA, and RamA. Accordingly, the expression level of the AcrAB promoter was higher in E. cloacae Jc194 strains overproducing SoxS, RobA, and RamA. Overall, the data showed that SoxS, RobA, and RamA regulators were associated with the upregulation of acrAB, thus conferring antimicrobial resistance as well as a stress response in E. cloacae. In summary, the regulatory proteins SoxS, RobA, and RamA were cloned and sequenced for the first time in this species. The involvement of these proteins in conferring antimicrobial resistance through upregulation of acrAB was demonstrated in E. cloacae.
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Regulation of RamA by RamR in Salmonella enterica serovar Typhimurium: isolation of a RamR superrepressor. Antimicrob Agents Chemother 2012; 56:6037-40. [PMID: 22948865 DOI: 10.1128/aac.01320-12] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
RamA is a transcription factor involved in regulating multidrug resistance in Salmonella enterica serovar Typhimurium SL1344. Green fluorescent protein (GFP) reporter fusions were exploited to investigate the regulation of RamA expression by RamR. We show that RamR represses the ramA promoter by binding to a palindromic sequence and describe a superrepressor RamR mutant that binds to the ramA promoter sequence more efficiently, thus exhibiting a ramA inactivated phenotype.
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Nikaido E, Giraud E, Baucheron S, Yamasaki S, Wiedemann A, Okamoto K, Takagi T, Yamaguchi A, Cloeckaert A, Nishino K. Effects of indole on drug resistance and virulence of Salmonella enterica serovar Typhimurium revealed by genome-wide analyses. Gut Pathog 2012; 4:5. [PMID: 22632036 PMCID: PMC3405474 DOI: 10.1186/1757-4749-4-5] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Accepted: 05/25/2012] [Indexed: 11/10/2022] Open
Abstract
Background Many Gram-positive and Gram-negative bacteria produce large quantities of indole as an intercellular signal in microbial communities. Indole demonstrated to affect gene expression in Escherichia coli as an intra-species signaling molecule. In contrast to E. coli, Salmonella does not produce indole because it does not harbor tnaA, which encodes the enzyme responsible for tryptophan metabolism. Our previous study demonstrated that E. coli-conditioned medium and indole induce expression of the AcrAB multidrug efflux pump in Salmonella enterica serovar Typhimurium for inter-species communication; however, the global effect of indole on genes in Salmonella remains unknown. Results To understand the complete picture of genes regulated by indole, we performed DNA microarray analysis of genes in the S. enterica serovar Typhimurium strain ATCC 14028s affected by indole. Predicted Salmonella phenotypes affected by indole based on the microarray data were also examined in this study. Indole induced expression of genes related to efflux-mediated multidrug resistance, including ramA and acrAB, and repressed those related to host cell invasion encoded in the Salmonella pathogenicity island 1, and flagella production. Reduction of invasive activity and motility of Salmonella by indole was also observed phenotypically. Conclusion Our results suggest that indole is an important signaling molecule for inter-species communication to control drug resistance and virulence of S. enterica.
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Affiliation(s)
- Eiji Nikaido
- Laboratory of Microbiology and Infectious Diseases, Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka, 567-00447, Japan.,Department of Cell Membrane Biology, Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka, Japan.,Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka, Japan
| | - Etienne Giraud
- INRA, UMR1282 Infectiologie et Santé Publique, F-37380, Nouzilly, France.,Université François Rabelais de Tours, UMR1282 Infectiologie et Santé Publique, F-37000, Tours, France
| | - Sylvie Baucheron
- INRA, UMR1282 Infectiologie et Santé Publique, F-37380, Nouzilly, France.,Université François Rabelais de Tours, UMR1282 Infectiologie et Santé Publique, F-37000, Tours, France
| | - Suguru Yamasaki
- Laboratory of Microbiology and Infectious Diseases, Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka, 567-00447, Japan.,Department of Cell Membrane Biology, Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka, Japan.,Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka, Japan
| | - Agnès Wiedemann
- INRA, UMR1282 Infectiologie et Santé Publique, F-37380, Nouzilly, France.,Université François Rabelais de Tours, UMR1282 Infectiologie et Santé Publique, F-37000, Tours, France
| | - Kousuke Okamoto
- Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka, Japan
| | - Tatsuya Takagi
- Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka, Japan
| | - Akihito Yamaguchi
- Department of Cell Membrane Biology, Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka, Japan.,Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka, Japan
| | - Axel Cloeckaert
- INRA, UMR1282 Infectiologie et Santé Publique, F-37380, Nouzilly, France.,Université François Rabelais de Tours, UMR1282 Infectiologie et Santé Publique, F-37000, Tours, France
| | - Kunihiko Nishino
- Laboratory of Microbiology and Infectious Diseases, Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka, 567-00447, Japan
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Chiang SM, Schellhorn HE. Regulators of oxidative stress response genes in Escherichia coli and their functional conservation in bacteria. Arch Biochem Biophys 2012; 525:161-9. [PMID: 22381957 DOI: 10.1016/j.abb.2012.02.007] [Citation(s) in RCA: 243] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2011] [Revised: 01/31/2012] [Accepted: 02/12/2012] [Indexed: 01/24/2023]
Abstract
Oxidative stress, through the production of reactive oxygen species, is a natural consequence of aerobic metabolism. Escherichia coli has several major regulators activated during oxidative stress, including OxyR, SoxRS, and RpoS. OxyR and SoxR undergo conformation changes when oxidized in the presence of hydrogen peroxide and superoxide radicals, respectively, and subsequently control the expression of cognate genes. In contrast, the RpoS regulon is induced by an increase in RpoS levels. Current knowledge regarding the activation and function of these regulators and their dependent genes in E. coli during oxidative stress forms the scope of this review. Despite the enormous genomic diversity of bacteria, oxidative stress response regulators in E. coli are functionally conserved in a wide range of bacterial groups, possibly reflecting positive selection of these regulators. SoxRS and RpoS homologs are present and respond to oxidative stress in Proteobacteria, and OxyR homologs are present and function in H(2)O(2) resistance in a range of bacteria, from gammaproteobacteria to Actinobacteria. Bacteria have developed complex, adapted gene regulatory responses to oxidative stress, perhaps due to the prevalence of reactive oxygen species produced endogenously through metabolism or due to the necessity of aerotolerance mechanisms in anaerobic bacteria exposed to oxygen.
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Affiliation(s)
- Sarah M Chiang
- Department of Biology, McMaster University, 1280 Main St. West, Life Sciences Building, Hamilton, ON, Canada L8S 4K1
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Ricci V, Loman N, Pallen M, Ivens A, Fookes M, Langridge GC, Wain J, Piddock LJV. The TCA cycle is not required for selection or survival of multidrug-resistant Salmonella. J Antimicrob Chemother 2011; 67:589-99. [PMID: 22186876 DOI: 10.1093/jac/dkr515] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES The initial aim of this study was to use a systems biology approach to analyse a ciprofloxacin-selected multidrug-resistant (MDR) Salmonella enterica serotype Typhimurium, L664. METHODS The whole genome sequence and transcriptome of L664 were analysed. Site-directed mutagenesis to recreate each mutation was carried out, followed by phenotypic characterization and mutation frequency analysis. As a mutation in the TCA cycle was detected we tested the controversial hypothesis regarding the bacterial response to bactericidal antibiotics, put forward by Kohanski et al. (Cell 2007; 130: 797-810 and Mol Cell 2010; 37: 311-20), that exposure of bacteria to agents such as ciprofloxacin produces reactive oxygen species (ROS), which transiently increase the mutation rate giving rise to MDR bacteria. RESULTS L664 contained a mutation in ramR that conferred MDR. A mutation in tctA affected the TCA cycle and conferred the inability to grow on minimal agar. The virulence of L664 was not attenuated. Ciprofloxacin exposure produced ROS in L664 and SL1344 (tctA::aph), but it was reduced and occurred later. There were no significant differences in the rates of killing or mutations per generation to antibiotic resistance between the strains. CONCLUSIONS Whilst we confirm production of ROS in response to ciprofloxacin, we have no data to support the hypothesis that this leads to selection of MDR strains. Our results indicate that the mutations in tctA and glgA were random as they did not pre-exist in the parental strain, and that the mutation in tctA did not provide a survival advantage or disadvantage in the presence of antibiotic.
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Affiliation(s)
- Vito Ricci
- Antimicrobial Agents Research Group, School of Immunity and Infection, University of Birmingham, Edgbaston, Birmingham, UK
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Binding of the RamR repressor to wild-type and mutated promoters of the RamA gene involved in efflux-mediated multidrug resistance in Salmonella enterica serovar Typhimurium. Antimicrob Agents Chemother 2011; 56:942-8. [PMID: 22123696 DOI: 10.1128/aac.05444-11] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The transcriptional activator RamA is involved in multidrug resistance (MDR) by increasing expression of the AcrAB-TolC RND-type efflux system in several pathogenic Enterobacteriaceae. In Salmonella enterica serovar Typhimurium (S. Typhimurium), ramA expression is negatively regulated at the local level by RamR, a transcriptional repressor of the TetR family. We here studied the DNA-binding activity of the RamR repressor with the ramA promoter (P(ramA)). As determined by high-resolution footprinting, the 28-bp-long RamR binding site covers essential features of P(ramA), including the -10 conserved region, the transcriptional start site of ramA, and two 7-bp inverted repeats. Based on the RamR footprint and on electrophoretic mobility shift assays (EMSAs), we propose that RamR interacts with P(ramA) as a dimer of dimers, in a fashion that is structurally similar to the QacR-DNA binding model. Surface plasmon resonance (SPR) measurements indicated that RamR has a 3-fold-lower affinity (K(D) [equilibrium dissociation constant] = 191 nM) for the 2-bp-deleted P(ramA) of an MDR S. Typhimurium clinical isolate than for the wild-type P(ramA) (K(D) = 66 nM). These results confirm the direct regulatory role of RamR in the repression of ramA transcription and precisely define how an alteration of its binding site can give rise to an MDR phenotype.
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Haznedaroglu BZ, Yates MV, Maduro MF, Walker SL. Effects of residual antibiotics in groundwater on Salmonella typhimurium: changes in antibiotic resistance, in vivo and in vitro pathogenicity. ACTA ACUST UNITED AC 2011; 14:41-7. [PMID: 22051852 DOI: 10.1039/c1em10723b] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
An outbreak-causing strain of Salmonella enterica serovar Typhimurium was exposed to groundwater with residual antibiotics for up to four weeks. Representative concentrations (0.05, 1, and 100 μg L(-1)) of amoxicillin, tetracycline, and a mixture of several other antibiotics (1 μg L(-1) each) were spiked into artificially prepared groundwater (AGW). Antibiotic susceptibility analysis and the virulence response of stressed Salmonella were determined on a weekly basis by using human epithelial cells (HEp2) and soil nematodes (C. elegans). Results have shown that Salmonella typhimurium remains viable for long periods of exposure to antibiotic-supplemented groundwater; however, they failed to cultivate as an indication of a viable but nonculturable state. Prolonged antibiotics exposure did not induce any changes in the antibiotic susceptibility profile of the S. typhimurium strain used in this study. S. typhimurium exposed to 0.05 and 1 μg L(-1) amoxicillin, and 1 μg L(-1) tetracycline showed hyper-virulent profiles in both in vitro and in vivo virulence assays with the HEp2 cells and C. elegans respectively, most evident following 2nd and 3rd weeks of exposure.
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Affiliation(s)
- Berat Z Haznedaroglu
- Department of Chemical and Environmental Engineering, University of California, Riverside, CA 92521, USA.
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Akiyama T, Khan AA. Molecular characterization of strains of fluoroquinolone-resistant Salmonella enterica serovar Schwarzengrund carrying multidrug resistance isolated from imported foods. J Antimicrob Chemother 2011; 67:101-10. [DOI: 10.1093/jac/dkr414] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Sun Y, Dai M, Hao H, Wang Y, Huang L, Almofti YA, Liu Z, Yuan Z. The role of RamA on the development of ciprofloxacin resistance in Salmonella enterica serovar Typhimurium. PLoS One 2011; 6:e23471. [PMID: 21858134 PMCID: PMC3155569 DOI: 10.1371/journal.pone.0023471] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2011] [Accepted: 07/18/2011] [Indexed: 01/13/2023] Open
Abstract
Active efflux pump is a primary fluoroquinolone resistant mechanism of clinical isolates of Salmonella enterica serovar Typhimurium. RamA is an essential element in producing multidrug resistant (MDR) S.enterica serovar Typhimurium. The aim of the present study was to elucidate the roles of RamA on the development of ciprofloxacin, the first choice for the treatment of salmonellosis, resistance in S. enterica serovar Typhimurium. Spontaneous mutants were selected via several passages of S. enterica serovar Typhimurium CVCC541 susceptible strain (ST) on M-H agar with increasing concentrations of ciprofloxacin (CIP). Accumulation of ciprofloxacin was tested by the modified fluorometric method. The expression levels of MDR efflux pumps were determined by real time RT-PCR. In ST and its spontaneous mutants, the ramA gene was inactivated by insertion of the kan gene and compensated on a recombinant plasmid pGEXΦ(gst-ramA). The mutant prevention concentration (MPC) and mutant frequencies of ciprofloxacin against ST and a spontaneous mutant in the presence, absence and overexpression of RamA were tested. Four spontaneous mutants (SI1-SI4) were obtained. The SI1 (CIP MICs, 0.1 mg/L) without any target site mutation in its quinolone resistant determining regions (QRDRs) and SI3 (CIP MICs, 16 mg/L) harboring the Ser83→Phe mutation in its QRDR of GyrA strains exhibited reduced susceptibility and resistance to multidrugs, respectively. In SI1, RamA was the main factor that controlled the susceptibility to ciprofloxacin by activating MdtK as well as increasing the expression level of acrAB. In SI3, RamA played predominant role in ciprofloxacin resistance via increasing the expression level of acrAB. Likewise, the deficiency of RamA decreased the MPCs and mutant frequencies of ST and SI2 to ciprofloxacin. In conclusion, the expression of RamA promoted the development of ciprofloxacin resistant mutants of S. enterica serovar Typhimurium. The inhibition of RamA could decrease the appearance of the ciprofloxacin resistant mutants.
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Affiliation(s)
- Yawei Sun
- MOA Key Laboratory of Food Safety Evaluation/National Reference Laboratory of Veterinary Drug Residues (HZAU), Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China
| | - Menghong Dai
- MOA Key Laboratory of Food Safety Evaluation/National Reference Laboratory of Veterinary Drug Residues (HZAU), Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China
| | - Haihong Hao
- MOA Key Laboratory of Food Safety Evaluation/National Reference Laboratory of Veterinary Drug Residues (HZAU), Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China
| | - Yulian Wang
- MOA Key Laboratory of Food Safety Evaluation/National Reference Laboratory of Veterinary Drug Residues (HZAU), Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China
| | - Lingli Huang
- MOA Key Laboratory of Food Safety Evaluation/National Reference Laboratory of Veterinary Drug Residues (HZAU), Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China
| | - Yassir A. Almofti
- MOA Key Laboratory of Food Safety Evaluation/National Reference Laboratory of Veterinary Drug Residues (HZAU), Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China
| | - Zhenli Liu
- MOA Key Laboratory of Food Safety Evaluation/National Reference Laboratory of Veterinary Drug Residues (HZAU), Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China
| | - Zonghui Yuan
- MOA Key Laboratory of Food Safety Evaluation/National Reference Laboratory of Veterinary Drug Residues (HZAU), Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China
- * E-mail:
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Glatz K, Tó th A, Pászti J. The cyclohexane tolerance and Phe-Arg-b-naphtylamide susceptibility of multidrug-resistant Enterobacter cloacae clinical isolates, and the predominance of one PFGE clone in Hungary. Clin Microbiol Infect 2011; 17:1254-61. [DOI: 10.1111/j.1469-0691.2010.03408.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Zheng J, Tian F, Cui S, Song J, Zhao S, Brown EW, Meng J. Differential gene expression by RamA in ciprofloxacin-resistant Salmonella Typhimurium. PLoS One 2011; 6:e22161. [PMID: 21811569 PMCID: PMC3139621 DOI: 10.1371/journal.pone.0022161] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Accepted: 06/16/2011] [Indexed: 11/22/2022] Open
Abstract
Overexpression of ramA has been implicated in resistance to multiple drugs in several enterobacterial pathogens. In the present study, Salmonella Typhimurium strain LTL with constitutive expression of ramA was compared to its ramA-deletion mutant by employing both DNA microarrays and phenotype microarrays (PM). The mutant strain with the disruption of ramA showed differential expression of at least 33 genes involved in 11 functional groups. The study confirmed at the transcriptional level that the constitutive expression of ramA was directly associated with increased expression of multidrug efflux pump AcrAB-TolC and decreased expression of porin protein OmpF, thereby conferring multiple drug resistance phenotype. Compared to the parent strain constitutively expressing ramA, the ramA mutant had increased susceptibility to over 70 antimicrobials and toxic compounds. The PM analysis also uncovered that the ramA mutant was better in utilization of 10 carbon sources and 5 phosphorus sources. This study suggested that the constitutive expression of ramA locus regulate not only multidrug efflux pump and accessory genes but also genes involved in carbon metabolic pathways.
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Affiliation(s)
- Jie Zheng
- Joint Institute for Food Safety and Applied Nutrition, and Department of Nutrition and Food Science, University of Maryland, College Park, Maryland, United States of America
- Center for Food Safety & Applied Nutrition, U.S. Food & Drug Administration, Maryland, University of Maryland, College Park, Maryland, United States of America
| | - Fei Tian
- Department of Animal and Avian Science, University of Maryland, College Park, Maryland, United States of America
| | - Shenghui Cui
- State Food and Drug Administration, Beijing, China
| | - Jiuzhou Song
- Department of Animal and Avian Science, University of Maryland, College Park, Maryland, United States of America
| | - Shaohua Zhao
- Center for Veterinary Medicine, U.S. Food and Drug Administration, Maryland, University of Maryland, College Park, Maryland, United States of America
| | - Eric W. Brown
- Center for Food Safety & Applied Nutrition, U.S. Food & Drug Administration, Maryland, University of Maryland, College Park, Maryland, United States of America
| | - Jianghong Meng
- Joint Institute for Food Safety and Applied Nutrition, and Department of Nutrition and Food Science, University of Maryland, College Park, Maryland, United States of America
- * E-mail:
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Usui M, Asai T, Sato S. Low expression of AcrB in the deoxycholate-sensitive strains of Salmonella enterica subspecies enterica serovar Pullorum. Microbiol Immunol 2011; 55:366-8. [DOI: 10.1111/j.1348-0421.2011.00321.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Kim KY, Woo GJ. Expression of acrB and ramA in fluoroquinolone resistant mutants from multi-drug resistant Salmonella enterica serovar Haardt. Lett Appl Microbiol 2011; 52:484-90. [DOI: 10.1111/j.1472-765x.2011.03027.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Amaral L, Fanning S, Pagès JM. Efflux pumps of gram-negative bacteria: genetic responses to stress and the modulation of their activity by pH, inhibitors, and phenothiazines. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2011; 77:61-108. [PMID: 21692367 DOI: 10.1002/9780470920541.ch2] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Affiliation(s)
- Leonard Amaral
- Unit of Mycobacteriology, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon, Portugal
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USUI M, UCHIYAMA M, BABA K, NAGAI H, YAMAMOTO Y, ASAI T. Contribution of Enhanced Efflux to Reduced Susceptibility of Salmonella enterica Serovar Choleraesuis to Fluoroquinolone and Other Antimicrobials. J Vet Med Sci 2011; 73:279-82. [DOI: 10.1292/jvms.10-0309] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Masaru USUI
- National Veterinary Assay Laboratory, Ministry of Agriculture, Forestry and Fisheries
| | - Mariko UCHIYAMA
- National Veterinary Assay Laboratory, Ministry of Agriculture, Forestry and Fisheries
| | - Kotaro BABA
- National Veterinary Assay Laboratory, Ministry of Agriculture, Forestry and Fisheries
| | - Hidetaka NAGAI
- National Veterinary Assay Laboratory, Ministry of Agriculture, Forestry and Fisheries
| | - Yoshimi YAMAMOTO
- Department of Veterinary Sciences, Faculty of Agriculture, Yamaguchi University
| | - Tetsuo ASAI
- National Veterinary Assay Laboratory, Ministry of Agriculture, Forestry and Fisheries
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Chinni SV, Raabe CA, Zakaria R, Randau G, Hoe CH, Zemann A, Brosius J, Tang TH, Rozhdestvensky TS. Experimental identification and characterization of 97 novel npcRNA candidates in Salmonella enterica serovar Typhi. Nucleic Acids Res 2010; 38:5893-908. [PMID: 20460466 PMCID: PMC2943607 DOI: 10.1093/nar/gkq281] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
We experimentally identified and characterized 97 novel, non-protein-coding RNA candidates (npcRNAs) from the human pathogen Salmonella enterica serovar Typhi (hereafter referred to as S. typhi). Three were specific to S. typhi, 22 were restricted to Salmonella species and 33 were differentially expressed during S. typhi growth. We also identified Salmonella Pathogenicity Island-derived npcRNAs that might be involved in regulatory mechanisms of virulence, antibiotic resistance and pathogenic specificity of S. typhi. An in-depth characterization of S. typhi StyR-3 npcRNA showed that it specifically interacts with RamR, the transcriptional repressor of the ramA gene, which is involved in the multidrug resistance (MDR) of Salmonella. StyR-3 interfered with RamR–DNA binding activity and thus potentially plays a role in regulating ramA gene expression, resulting in the MDR phenotype. Our study also revealed a large number of cis-encoded antisense npcRNA candidates, supporting previous observations of global sense–antisense regulatory networks in bacteria. Finally, at least six of the npcRNA candidates interacted with the S. typhi Hfq protein, supporting an important role of Hfq in npcRNA networks. This study points to novel functional npcRNA candidates potentially involved in various regulatory roles including the pathogenicity of S. typhi.
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Affiliation(s)
- Suresh V Chinni
- Institute of Experimental Pathology (ZMBE), University of Muenster, Von-Esmarch-Str. 56, 48149 Muenster, Germany
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