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Tong YQ, Xin B, Zhu L. Transfer of Herb-Resistance Plasmid From Escherichia coli to Staphylococcus aureus Residing in the Human Urinary Tract. Jundishapur J Microbiol 2014; 7:e15056. [PMID: 25147679 PMCID: PMC4138649 DOI: 10.5812/jjm.15056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Revised: 01/13/2014] [Accepted: 01/20/2014] [Indexed: 11/28/2022] Open
Abstract
Background: Plasmid transfer among bacteria provides a means for dissemination of resistance. Plasmid Analysis has made it possible to track plasmids that induce resistance in bacterial population. Objectives: To screen the presence of herb-resistance plasmid in Escherichia coli strains and determine the transferability of this resistance plasmid directly from E. coli to the Gram-positive, Staphylococcus aureus. Materials and Methods: The donor strain E. coli CP9 and recipient strain S. aureus RN450RF were isolated from UTI patients. E. coli CP9 was highly resistant to herbal concoction. Isolates of S. aureus RN450RF were fully susceptible. Total plasmid DNA was prepared and transferred into E. coli DH5α. Transconjugants were selected on agar plates containing serial dilutions of herbal concoction. Resistance plasmid was transferred to susceptible S. aureus RN450RFin triple replicas. The mating experiments were repeated twice. Results: The identified 45 kb herb-resistance plasmid could be transferred from E. coli CP9 isolates to E. coli DH5α. As a consequence E. coli DH5α transconjugant MIC increased from 0.0125 g/mL to 0.25 g/mL. The plasmid was easily transferred from E. coli CP9 strain to S. aureus RN450RF with a mean transfer rate of 1×10-2 transconjugants/recipient. The E. coli donor and the S. aureus RN450RF transconjugant contained a plasmid of the same size, which was absent in the recipient before mating. Susceptibility testing showed that the S. aureus RN450RF transconjugant was resistant to herbal concoction. Conclusions: E. coli herb-resistance plasmid can replicate and be expressed in S. aureus.
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Affiliation(s)
- Yan Qing Tong
- Department of Nephrology, The First Affiliated Hospital to Changchun University of Chinese Medicine, Changchun, China
- Corresponding author: Yan Qing Tong, Department of Nephrology, The First Affiliated Hospital to Changchun University of Chinese Medicine, Gongnong Road, No 1478, Changchun city, Jilin province, China. Tel: +86-43186178717, Fax: +86-43186177222, E-mail:
| | - Bing Xin
- Department of Microbiology, The First Affiliated Hospital to Changchun University of Chinese Medicine, Changchun, China
| | - Li Zhu
- Department of Microbiology, The First Affiliated Hospital to Changchun University of Chinese Medicine, Changchun, China
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102
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Hou Q, He J, Yu J, Ye Y, Zhou D, Sun Y, Zhang D, Ma L, Shen B, Zhu C. A case of horizontal gene transfer from Wolbachia to Aedes albopictus C6/36 cell line. Mob Genet Elements 2014; 4:e28914. [PMID: 24812591 PMCID: PMC4013104 DOI: 10.4161/mge.28914] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 04/01/2014] [Accepted: 04/15/2014] [Indexed: 11/28/2022] Open
Abstract
Horizontal gene transfer plays an essential role in evolution and ecological adaptation, yet this phenomenon has remained controversial, particularly where it occurs between prokaryotes and eukaryotes. There are a handful of reported examples of horizontal gene transfer occurring between prokaryotes and eukaryotes in the literature, with most of these documented cases pertaining to invertebrates and endosymbionts. However, the vast majority of these horizontally transferred genes were either eventually excluded or rapidly became nonfunctional in the recipient genome. In this study, we report the discovery of a horizontal gene transfer from the endosymbiont Wolbachia in the C6/36 cell line derived from the mosquito Aedes albopictus. Moreover, we report that this horizontally transferred gene displayed high transcription level. This finding and the results of further experimentation strongly suggest this gene is functional and has been expressed and translated into a protein in the mosquito host cells.
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Affiliation(s)
- Qing Hou
- Department of Pathogen Biology; Nanjing Medical University; Nanjing, Jiangsu People's Republic of China
| | - Ji He
- Department of Pathogen Biology; Nanjing Medical University; Nanjing, Jiangsu People's Republic of China ; State Key Laboratory of Surveillance and Detection for Medical Vectors; Xiamen Entry-Exit Inspection and Quarantine Bureau; Xiamen, Fujian People's Republic of China
| | - Jing Yu
- Department of Pathogen Biology; Nanjing Medical University; Nanjing, Jiangsu People's Republic of China
| | - Yuting Ye
- Department of Pathogen Biology; Nanjing Medical University; Nanjing, Jiangsu People's Republic of China
| | - Dan Zhou
- Department of Pathogen Biology; Nanjing Medical University; Nanjing, Jiangsu People's Republic of China
| | - Yan Sun
- Department of Pathogen Biology; Nanjing Medical University; Nanjing, Jiangsu People's Republic of China
| | - Donghui Zhang
- Department of Pathogen Biology; Nanjing Medical University; Nanjing, Jiangsu People's Republic of China
| | - Lei Ma
- Department of Pathogen Biology; Nanjing Medical University; Nanjing, Jiangsu People's Republic of China
| | - Bo Shen
- Department of Pathogen Biology; Nanjing Medical University; Nanjing, Jiangsu People's Republic of China
| | - Changliang Zhu
- Department of Pathogen Biology; Nanjing Medical University; Nanjing, Jiangsu People's Republic of China
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Laxminarayan R, Duse A, Wattal C, Zaidi AKM, Wertheim HFL, Sumpradit N, Vlieghe E, Hara GL, Gould IM, Goossens H, Greko C, So AD, Bigdeli M, Tomson G, Woodhouse W, Ombaka E, Peralta AQ, Qamar FN, Mir F, Kariuki S, Bhutta ZA, Coates A, Bergstrom R, Wright GD, Brown ED, Cars O. Antibiotic resistance-the need for global solutions. THE LANCET. INFECTIOUS DISEASES 2013; 13:1057-98. [PMID: 24252483 DOI: 10.1016/s1473-3099(13)70318-9] [Citation(s) in RCA: 2540] [Impact Index Per Article: 230.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The causes of antibiotic resistance are complex and include human behaviour at many levels of society; the consequences affect everybody in the world. Similarities with climate change are evident. Many efforts have been made to describe the many different facets of antibiotic resistance and the interventions needed to meet the challenge. However, coordinated action is largely absent, especially at the political level, both nationally and internationally. Antibiotics paved the way for unprecedented medical and societal developments, and are today indispensible in all health systems. Achievements in modern medicine, such as major surgery, organ transplantation, treatment of preterm babies, and cancer chemotherapy, which we today take for granted, would not be possible without access to effective treatment for bacterial infections. Within just a few years, we might be faced with dire setbacks, medically, socially, and economically, unless real and unprecedented global coordinated actions are immediately taken. Here, we describe the global situation of antibiotic resistance, its major causes and consequences, and identify key areas in which action is urgently needed.
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Affiliation(s)
- Ramanan Laxminarayan
- Center for Disease Dynamics, Economics and Policy, Washington, DC, USA; Princeton University, Princeton NJ, USA; Public Health Foundation of India, New Delhi, India
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104
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Strategies to minimize antibiotic resistance. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2013; 10:4274-305. [PMID: 24036486 PMCID: PMC3799537 DOI: 10.3390/ijerph10094274] [Citation(s) in RCA: 229] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 09/02/2013] [Accepted: 09/03/2013] [Indexed: 02/07/2023]
Abstract
Antibiotic resistance can be reduced by using antibiotics prudently based on guidelines of antimicrobial stewardship programs (ASPs) and various data such as pharmacokinetic (PK) and pharmacodynamic (PD) properties of antibiotics, diagnostic testing, antimicrobial susceptibility testing (AST), clinical response, and effects on the microbiota, as well as by new antibiotic developments. The controlled use of antibiotics in food animals is another cornerstone among efforts to reduce antibiotic resistance. All major resistance-control strategies recommend education for patients, children (e.g., through schools and day care), the public, and relevant healthcare professionals (e.g., primary-care physicians, pharmacists, and medical students) regarding unique features of bacterial infections and antibiotics, prudent antibiotic prescribing as a positive construct, and personal hygiene (e.g., handwashing). The problem of antibiotic resistance can be minimized only by concerted efforts of all members of society for ensuring the continued efficiency of antibiotics.
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105
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Antimicrobial-resistant Escherichia coli in public beach waters in Quebec. CANADIAN JOURNAL OF INFECTIOUS DISEASES & MEDICAL MICROBIOLOGY 2013; 23:e20-5. [PMID: 23730315 DOI: 10.1155/2012/378602] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
INTRODUCTION Human exposure to antimicrobial-resistant bacteria may result in the transfer of resistance to commensal or pathogenic microbes present in the gastrointestinal tract, which may lead to severe health consequences and difficulties in treatment of future bacterial infections. It was hypothesized that the recreational waters from beaches represent a source of antimicrobial-resistant Escherichia coli for people engaging in water activities. OBJECTIVE To describe the occurrence of antimicrobial-resistant E coli in the recreational waters of beaches in southern Quebec. METHODS Sampling occurred over two summers; in 2004, 674 water samples were taken from 201 beaches, and in 2005, 628 water samples were taken from 177 beaches. The minimum inhibitory concentrations of the antimicrobial-resistant E coli isolates against a panel of 16 antimicrobials were determined using microbroth dilution. RESULTS For 2004 and 2005, respectively, 28% and 38% of beaches sampled had at least one water sample contaminated by E coli resistant to one or more antimicrobials, and more than 10% of the resistant isolates were resistant to at least one antimicrobial of clinical importance for human medicine. The three antimicrobials with the highest frequency of resistance were tetracycline, ampicillin and sulfamethoxazole. DISCUSSION The recreational waters of these beaches represent a potential source of antimicrobial-resistant bacteria for people engaging in water activities. Investigations relating the significance of these findings to public health should be pursued.
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106
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Proximity to animal or crop operations may be associated with de novo daptomycin-non-susceptible Enterococcus infection. Epidemiol Infect 2013; 142:221-4. [PMID: 23587411 DOI: 10.1017/s0950268813000885] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Daptomycin-non-susceptible enterococci (DNSE) are emerging pathogens. We have previously reported de novo DNSE isolates in patients with agricultural activities and exposure to livestock. We studied the geographical distribution of the residencies of 34 patients with DNSE infections described in a tertiary centre over a 5-year period in an effort to explore the association between patients' residential locations and agricultural and farm lands. Nine patients had no prior exposure to daptomycin (de novo) and seven of these lived in areas with animal or crop operations. Of those living near an animal or crop operation, the mean number of operations in the proximity of the residence of patients with daptomycin-exposed DNSE was 13.8 (range 1-67) compared to 98.6 (3-529) for those patients with de novo DNSE (P = 0.0486). These data are consistent with previous reports that the transport of daptomycin resistance genes between animals and humans may be a possible mechanism for development of de novo daptomycin resistance in enterococci.
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107
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Cavaco LM, Aarestrup FM. Resistance in bacteria of the food chain: epidemiology and control strategies. Microb Drug Resist 2013. [DOI: 10.2217/ebo.12.361] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Affiliation(s)
- Lina Maria Cavaco
- Lina Maria Cavaco is a Senior Scientist at the Technical University of Denmark (Lyngby, Denmark). Her main research fields are antimicrobial resistance in bacteria and selection of resistances in the animal population, with special focus on quinolone and β-lactam resistance in Enterobacteriaceae and methicillin-resistant Staphylococcus aureus. She is also involved in international activities within the EU Reference Laboratory for antimicrobial resistance
| | - Frank Møller Aarestrup
- Frank Møller Aarestrup is a Professor in Microbiology at the Technical University of Denmark, and Head of the WHO collaborating center and the EU Reference Laboratory for antimicrobial resistance. His research has been primarily targeted on the association between use of antimicrobial agents to farm animals, the emergence and spread of antimicrobial resistance, and, more recently, on the development of tools to analyze and interpret whole-genome sequencing data for use in typing and global surveillance
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108
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Sting R, Richter A, Popp C, Hafez HM. Occurrence of vancomycin-resistant enterococci in turkey flocks. Poult Sci 2013; 92:346-51. [PMID: 23300299 DOI: 10.3382/ps.2012-02652] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In the present study, the prevalence of vancomycin-resistant enterococci (VRE) in turkeys in the southwest of Germany was investigated. For this purpose, 200 cloacal swab samples and 5 environmental dust samples (tested as a pooled sample) of each of the 20 flocks (10 female and 10 male flocks) included in this study were examined. The VRE could be isolated by means of a procedure combining bacterial cultivation in an enrichment broth and on a selective solid media. Enterococci were identified biochemically and subsequently tested on the presence of the vancomycin resistance genes vanA, vanB (B1/B2/B3), and vanC (C1/C2/C3) using real-time PCR assays. In 54 (27%) turkeys originating from 11 (55%) flocks and in 14 (70%) of the dust samples, exclusively vanA and vanC1 genes could be detected. Of the turkeys examined, 46 were colonized with VRE bearing the resistance gene vanC1 and 8 vanA, originating from 9 and 2 flocks, respectively. None of the birds carried vanB, vanC2, or vanC3 positive VRE. The results obtained from the birds are largely confirmed by the dust samples originating from 4 vanA and 10 vanC1 positive flocks. However, one flock housing animals colonized with vanC1 positive VRE could not be confirmed by the dust samples that revealed vanA bearing VRE. However, in one case vanA and in 3 cases vanC1 carrying VRE could be detected in dust samples of the turkey houses, but not in the turkeys of the associated flock. In 5 flocks the turkeys as well as the dust samples were free of VRE.
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Affiliation(s)
- R Sting
- Chemisches und Veterinäruntersuchungsamt Stuttgart, Chemical and Veterinary Investigation Office Stuttgart, Schaflandstr. 3/3, 70736 Fellbach, Germany.
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109
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Klibi N, Said LB, Jouini A, Slama KB, López M, Sallem RB, Boudabous A, Torres C. Species distribution, antibiotic resistance and virulence traits in enterococci from meat in Tunisia. Meat Sci 2013; 93:675-80. [DOI: 10.1016/j.meatsci.2012.11.020] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2012] [Revised: 09/07/2012] [Accepted: 11/10/2012] [Indexed: 10/27/2022]
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110
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Capita R, Alonso-Calleja C. Antibiotic-resistant bacteria: a challenge for the food industry. Crit Rev Food Sci Nutr 2013; 53:11-48. [PMID: 23035919 DOI: 10.1080/10408398.2010.519837] [Citation(s) in RCA: 229] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Antibiotic-resistant bacteria were first described in the 1940s, but whereas new antibiotics were being discovered at a steady rate, the consequences of this phenomenon were slow to be appreciated. At present, the paucity of new antimicrobials coming into the market has led to the problem of antibiotic resistance fast escalating into a global health crisis. Although the selective pressure exerted by the use of antibiotics (particularly overuse or misuse) has been deemed the major factor in the emergence of bacterial resistance to these antimicrobials, concerns about the role of the food industry have been growing in recent years and have been raised at both national and international levels. The selective pressure exerted by the use of antibiotics (primary production) and biocides (e.g., disinfectants, food and feed preservatives, or decontaminants) is the main driving force behind the selection and spread of antimicrobial resistance throughout the food chain. Genetically modified (GM) crops with antibiotic resistance marker genes, microorganisms added intentionally to the food chain (probiotic or technological) with potentially transferable antimicrobial resistance genes, and food processing technologies used at sub-lethal doses (e.g., alternative non-thermal treatments) are also issues for concern. This paper presents the main trends in antibiotic resistance and antibiotic development in recent decades, as well as their economic and health consequences, current knowledge concerning the generation, dissemination, and mechanisms of antibacterial resistance, progress to date on the possible routes for emergence of resistance throughout the food chain and the role of foods as a vehicle for antibiotic-resistant bacteria. The main approaches to prevention and control of the development, selection, and spread of antibacterial resistance in the food industry are also addressed.
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Affiliation(s)
- Rosa Capita
- Department of Food Hygiene and Food Technology, Veterinary Faculty, University of León, Spain.
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111
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Sánchez Valenzuela A, Lavilla Lerma L, Benomar N, Gálvez A, Pérez Pulido R, Abriouel H. Phenotypic and Molecular Antibiotic Resistance Profile ofEnterococcus faecalisandEnterococcus faeciumIsolated from Different Traditional Fermented Foods. Foodborne Pathog Dis 2013; 10:143-9. [DOI: 10.1089/fpd.2012.1279] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Antonio Sánchez Valenzuela
- Microbiology Area, Department of Health Sciences, Faculty of Experimental Sciences, University of Jaén, Jaén, Spain
| | - Leyre Lavilla Lerma
- Microbiology Area, Department of Health Sciences, Faculty of Experimental Sciences, University of Jaén, Jaén, Spain
| | - Nabil Benomar
- Microbiology Area, Department of Health Sciences, Faculty of Experimental Sciences, University of Jaén, Jaén, Spain
| | - Antonio Gálvez
- Microbiology Area, Department of Health Sciences, Faculty of Experimental Sciences, University of Jaén, Jaén, Spain
| | - Rubén Pérez Pulido
- Microbiology Area, Department of Health Sciences, Faculty of Experimental Sciences, University of Jaén, Jaén, Spain
| | - Hikmate Abriouel
- Microbiology Area, Department of Health Sciences, Faculty of Experimental Sciences, University of Jaén, Jaén, Spain
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112
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Tremblay CL, Letellier A, Quessy S, Daignault D, Archambault M. Antibiotic-resistant Enterococcus faecalis in abattoir pigs and plasmid colocalization and cotransfer of tet(M) and erm(B) genes. J Food Prot 2012; 75:1595-602. [PMID: 22947466 DOI: 10.4315/0362-028x.jfp-12-047] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This study was conducted to determine plasmid colocalization and transferability of both erm(B) and tet(M) genes in Enterococcus faecalis isolates from abattoir pigs in Canada. A total of 124 E. faecalis isolates from cecal contents of abattoir pigs were examined for antibiotic susceptibility. High percentages of resistance to macrolides and tetracyclines were found. Two predominant multiresistance patterns of E. faecalis were examined by PCR and sequencing for the presence of genes encoding antibiotic resistance. Various combinations of antibiotic resistance genes were detected; erm(B) and tet(M) were the most common genes. Plasmid profiling and hybridization revealed that both genes were colocated on a ~9-kb transferable plasmid in six strains with the two predominant multiresistant patterns. Plasmid colocalization and cotransfer of tet(M) and erm(B) genes in porcine E. faecalis isolates indicates that antibiotic coselection and transferability could occur via this single genetic element. To our knowledge, this is the first report on plasmid colocalization and transferability of erm(B) and tet(M) genes in E. faecalis on a mobile genetic element of ~9 kb. Physical linkage between important antibiotic resistance determinants in enterococci is of interest for predicting potential transfer to other bacterial genera.
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Affiliation(s)
- Cindy-Love Tremblay
- Swine Infectious Disease Research Center, Department of Pathology and Microbiology, University of Montreal, Faculty of Veterinary Medicine, Saint-Hyacinthe, Quebec, Canada
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113
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Delpech G, Pourcel G, Schell C, De Luca M, Basualdo J, Bernstein J, Grenovero S, Sparo M. Antimicrobial resistance profiles of Enterococcus faecalis and Enterococcus faecium isolated from artisanal food of animal origin in Argentina. Foodborne Pathog Dis 2012; 9:939-44. [PMID: 22953740 DOI: 10.1089/fpd.2012.1192] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Enterococci are part of the indigenous microbiota of human gastrointestinal tract and food of animal origin. Enterococci inhabiting non-human reservoirs play a critical role in the acquisition and dissemination of antimicrobial resistance determinants. The aim of this work was to investigate the antimicrobial resistance in Enterococcus faecalis and Enterococcus faecium strains recovered from artisanal food of animal origin. Samples of goat cheese (n = 42), cow cheese (n = 40), artisanal salami (n = 30), and minced meat for the manufacture of hamburgers (n = 60) were analyzed. Phenotypic and genotypic tests for species-level identification of the recovered isolates were carried out. Minimum inhibitory concentration (MIC) study for in vitro quantitative antimicrobial resistance assessment was performed, and 71 E. faecalis and 22 E. faecium were isolated. The recovered enterococci showed different multi-drug resistance patterns that included tretracycline, erythromycin, ciprofloxacin, linezolid, penicillin, ampicillin, vancomycin, teicoplanin, gentamicin (high-level resistance), and streptomycin (high-level resistance). VanA-type E. faecium were detected. β-lactamase activity was not observed. Artisanal foods of animal origin act as a non-human reservoir of E. faecalis and E. faecuim strains, expressing multi-resistance to antimicrobials. In conclusion, the implementation of a continuous antimicrobial resistance surveillance in enterococci isolated from artisanal food of animal origin is important.
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Affiliation(s)
- Gastón Delpech
- Escuela Superior de Ciencias de la Salud, Universidad Nacional del Centro de la Provincia de Buenos Aires, Olavarría, Argentina
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114
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Dantas G, Sommer MOA. Context matters - the complex interplay between resistome genotypes and resistance phenotypes. Curr Opin Microbiol 2012; 15:577-82. [PMID: 22954750 DOI: 10.1016/j.mib.2012.07.004] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2012] [Revised: 07/11/2012] [Accepted: 07/13/2012] [Indexed: 12/13/2022]
Abstract
Application of metagenomic functional selections to study antibiotic resistance genes is revealing a highly diverse and complex network of genetic exchange between bacterial pathogens and environmental reservoirs, which likely contributes significantly to increasing resistance levels in pathogens. In some cases, clinically relevant resistance genes have been acquired from organisms where their native function is not antibiotic resistance, and which may not even confer a resistance phenotype in their native context. In this review, we attempt to distinguish the resistance phenotype from the resistome genotype, and we highlight examples of genes and their hosts where this distinction becomes important in order to understand the relevance of environmental niches that contribute most to clinical problems associated with antibiotic resistance.
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Affiliation(s)
- Gautam Dantas
- Center for Genome Sciences & Systems Biology, Washington University School of Medicine, St Louis, MO, USA.
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115
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Jamet E, Akary E, Poisson MA, Chamba JF, Bertrand X, Serror P. Prevalence and characterization of antibiotic resistant Enterococcus faecalis in French cheeses. Food Microbiol 2012; 31:191-8. [DOI: 10.1016/j.fm.2012.03.009] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2011] [Revised: 02/17/2012] [Accepted: 03/19/2012] [Indexed: 11/28/2022]
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116
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Kelesidis T, Humphries R, Uslan DZ, Pegues D. De novo daptomycin-nonsusceptible enterococcal infections. Emerg Infect Dis 2012; 18:674-6. [PMID: 22469288 PMCID: PMC3309676 DOI: 10.3201/eid1804.110932] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Potential emergence of enterococcal daptomycin nonsusceptibility among patients with no prior exposure to daptomycin poses clinical and public health challenges. We found that development of infections with daptomycin-nonsusceptible enterococci in these patients could be associated with sporadic emergence and clonal spread.
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Affiliation(s)
- Theodoros Kelesidis
- David Geffen School of Medicine at UCLA, Los Angeles, California 90095, USA.
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117
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The role of reticulate evolution in creating innovation and complexity. INTERNATIONAL JOURNAL OF EVOLUTIONARY BIOLOGY 2012; 2012:418964. [PMID: 22844638 PMCID: PMC3403396 DOI: 10.1155/2012/418964] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Revised: 05/08/2012] [Accepted: 05/10/2012] [Indexed: 12/31/2022]
Abstract
Reticulate evolution encompasses processes that conflict with traditional Tree of Life efforts. These processes, horizontal gene transfer (HGT), gene and whole-genome duplications through allopolyploidization, are some of the main driving forces for generating innovation and complexity. HGT has a profound impact on prokaryotic and eukaryotic evolution. HGTs can lead to the invention of new metabolic pathways and the expansion and enhancement of previously existing pathways. It allows for organismal adaptation into new ecological niches and new host ranges. Although many HGTs appear to be selected for because they provide some benefit to their recipient lineage, other HGTs may be maintained by chance through random genetic drift. Moreover, some HGTs that may initially seem parasitic in nature can cause complexity to arise through pathways of neutral evolution. Another mechanism for generating innovation and complexity, occurring more frequently in eukaryotes than in prokaryotes, is gene and genome duplications, which often occur through allopolyploidizations. We discuss how these different evolutionary processes contribute to generating innovation and complexity.
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118
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Kim J, Lee S, Choi S. Copper resistance and its relationship to erythromycin resistance in Enterococcus isolates from bovine milk samples in Korea. J Microbiol 2012; 50:540-3. [DOI: 10.1007/s12275-012-1579-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2011] [Accepted: 02/14/2012] [Indexed: 10/28/2022]
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119
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Nilsson O. Vancomycin resistant enterococci in farm animals - occurrence and importance. Infect Ecol Epidemiol 2012; 2:IEE-2-16959. [PMID: 22957131 PMCID: PMC3426332 DOI: 10.3402/iee.v2i0.16959] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2011] [Revised: 03/16/2012] [Accepted: 03/28/2012] [Indexed: 11/14/2022] Open
Abstract
The view on enterococci has over the years shifted from harmless commensals to opportunistic but important pathogens mainly causing nosocomial infections. One important part of this development is the emergence of vancomycin resistance enterococci (VRE). The term VRE includes several combinations of bacterial species and resistance genes of which the most clinically important is Enterococcus faecium with vanA type vancomycin resistance. This variant is also the most common VRE among farm animals. The reason for VRE being present among farm animals is selection by extensive use of the vancomycin analog avoparcin for growth promotion. Once the use of avoparcin was discontinued, the prevalence of VRE among farm animals decreased. However, VRE are still present among farm animals and by spread via food products they could potentially have a negative impact on public health. This review is based on the PhD thesis Vancomycin Resistant Enterococci in Swedish Broilers - Emergence, Epidemiology and Elimination and makes a short summary of VRE in humans and food producing animals. The specific situation regarding VRE in Swedish broiler production is also mentioned.
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Affiliation(s)
- Oskar Nilsson
- Department of Animal health and Antimicrobial strategies, National Veterinary Institute, Uppsala, Sweden
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Ramulu HG, Raoult D, Pontarotti P. The rhizome of life: what about metazoa? Front Cell Infect Microbiol 2012; 2:50. [PMID: 22919641 PMCID: PMC3417402 DOI: 10.3389/fcimb.2012.00050] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Accepted: 03/23/2012] [Indexed: 02/03/2023] Open
Abstract
The increase in huge number of genomic sequences in recent years has contributed to various genetic events such as horizontal gene transfer (HGT), gene duplication and hybridization of species. Among them HGT has played an important role in the genome evolution and was believed to occur only in Bacterial and Archaeal genomes. As a result, genomes were found to be chimeric and the evolution of life was represented in different forms such as forests, networks and species evolution was described more like a rhizome, rather than a tree. However, in the last few years, HGT has also been evidenced in other group such as metazoa (for example in root-knot nematodes, bdelloid rotifers and mammals). In addition to HGT, other genetic events such as transfer by retrotransposons and hybridization between more closely related lineages are also well established. Therefore, in the light of such genetic events, whether the evolution of metazoa exists in the form of a tree, network or rhizome is highly questionable and needs to be determined. In the current review, we will focus on the role of HGT, retrotransposons and hybridization in the metazoan evolution.
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Affiliation(s)
- Hemalatha G. Ramulu
- LATP UMR-CNRS 7353, Evolution Biologique et Modélisation, Aix-Marseille UniversitéeMarseille, France
- URMITE CNRS-IRD UMR6236-198Marseille, France
| | | | - Pierre Pontarotti
- LATP UMR-CNRS 7353, Evolution Biologique et Modélisation, Aix-Marseille UniversitéeMarseille, France
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121
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Nilsson O, Greko C, Bengtsson B, Englund S. Genetic diversity among VRE isolates from Swedish broilers with the coincidental finding of transferrable decreased susceptibility to narasin. J Appl Microbiol 2012; 112:716-22. [DOI: 10.1111/j.1365-2672.2012.05254.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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122
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Olsen RH, Schønheyder HC, Christensen H, Bisgaard M. Enterococcus faecalis of human and poultry origin share virulence genes supporting the zoonotic potential of E. faecalis. Zoonoses Public Health 2011; 59:256-63. [PMID: 22122842 DOI: 10.1111/j.1863-2378.2011.01442.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Enterococcus faecalis is a major cause of nosocomial infections in humans and has been linked to severe extra-intestinal infections in poultry. A zoonotic potential has been suggested and the aim of the present study was to investigate similarities in virulence gene profiles of E. faecalis originating from infections in humans and poultry respectively. A total of 106 isolates of E. faecalis [26 human clinical isolates, 60 poultry clinical isolates (including two small-colony variants (SCVs) and 20 poultry cloacal isolates] were investigated for presence of seven virulence-associated genes: ace, asa1, cylA, efaA, EF0591, esp and gelE. For each gene, the PCR-amplification product was sequenced from one isolate in each group to explore intragenic variations between genes of human and poultry origin. Haemolytic and protease activities were assessed and isolates were assigned a sequence type (ST). Three of the seven genes investigated (ace, efaA and gelE) were present in all isolates. The asa1 was detected in 63/80 and 13/26 isolates of poultry and human origin respectively. For cylA, the numbers were 46/80 and 14/26 respectively. Among poultry isolates, esp and EF0591 were the least frequently observed genes (1/80 and 20/80 respectively); the prevalences among human isolates were 1/26 and 18/26 respectively. A high degree of similarity between genes in human and poultry isolates were confirmed by sequencing of amplification products. None of the cylA-positive isolates demonstrated haemolytic activity, while the phenotypic expression of gelatinase varied. The ST16 was the only ST shared by human and poultry isolates. The SCV isolates did not show a unique virulence profile or phylogeny. In conclusion, regardless of the distinct phylogenetic background of most E. faecalis isolates of human and poultry origin, we found major similarities in virulence gene profile and gene sequences in isolates from the two sources, supporting the zoonotic risk associated with this organism.
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Affiliation(s)
- R H Olsen
- Department of Veterinary Disease Biology, Faculty of Life Sciences, University of Copenhagen, Frederiksberg C, Denmark.
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123
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Smillie CS, Smith MB, Friedman J, Cordero OX, David LA, Alm EJ. Ecology drives a global network of gene exchange connecting the human microbiome. Nature 2011; 480:241-4. [PMID: 22037308 DOI: 10.1038/nature10571] [Citation(s) in RCA: 591] [Impact Index Per Article: 45.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Accepted: 09/19/2011] [Indexed: 12/13/2022]
Abstract
Horizontal gene transfer (HGT), the acquisition of genetic material from non-parental lineages, is known to be important in bacterial evolution. In particular, HGT provides rapid access to genetic innovations, allowing traits such as virulence, antibiotic resistance and xenobiotic metabolism to spread through the human microbiome. Recent anecdotal studies providing snapshots of active gene flow on the human body have highlighted the need to determine the frequency of such recent transfers and the forces that govern these events. Here we report the discovery and characterization of a vast, human-associated network of gene exchange, large enough to directly compare the principal forces shaping HGT. We show that this network of 10,770 unique, recently transferred (more than 99% nucleotide identity) genes found in 2,235 full bacterial genomes, is shaped principally by ecology rather than geography or phylogeny, with most gene exchange occurring between isolates from ecologically similar, but geographically separated, environments. For example, we observe 25-fold more HGT between human-associated bacteria than among ecologically diverse non-human isolates (P = 3.0 × 10(-270)). We show that within the human microbiome this ecological architecture continues across multiple spatial scales, functional classes and ecological niches with transfer further enriched among bacteria that inhabit the same body site, have the same oxygen tolerance or have the same ability to cause disease. This structure offers a window into the molecular traits that define ecological niches, insight that we use to uncover sources of antibiotic resistance and identify genes associated with the pathology of meningitis and other diseases.
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Affiliation(s)
- Chris S Smillie
- Computational and Systems Biology Initiative, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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124
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Antibiotics and the resistant microbiome. Curr Opin Microbiol 2011; 14:556-63. [DOI: 10.1016/j.mib.2011.07.005] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Accepted: 07/02/2011] [Indexed: 11/19/2022]
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125
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Haug MC, Tanner SA, Lacroix C, Stevens MJ, Meile L. Monitoring horizontal antibiotic resistance gene transfer in a colonic fermentation model. FEMS Microbiol Ecol 2011; 78:210-9. [DOI: 10.1111/j.1574-6941.2011.01149.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
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126
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Choi HK, Kim KH, Lee SH, Lee SJ. Risk factors for recurrence of Clostridium difficile infection: effect of vancomycin-resistant enterococci colonization. J Korean Med Sci 2011; 26:859-64. [PMID: 21738336 PMCID: PMC3124713 DOI: 10.3346/jkms.2011.26.7.859] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Accepted: 04/21/2011] [Indexed: 01/20/2023] Open
Abstract
Recurrent Clostridium difficile infection (CDI) is one of the most difficult problems in healthcare infection control. We evaluated the risk factors associated with recurrence in patients with CDI. A retrospective cohort study of 84 patients with CDI from December 2008 through October 2010 was performed at Pusan National University Yangsan Hospital. Recurrence occurred in 13.1% (11/84) of the cases and in-hospital mortality rate was 7.1% (6/84). Stool colonization with vancomycin-resistant enterococci (VRE) (P = 0.006), exposure to more than 3 antibiotics (P = 0.009), low hemoglobin levels (P = 0.025) and continued use of previous antibiotics (P = 0.05) were found to be more frequent in the recurrent group. Multivariate analysis indicated that, stool VRE colonization was independently associated with CDI recurrence (odds ratio, 14.519; 95% confidence interval, 1.157-182.229; P = 0.038). This result suggests that stool VRE colonization is a significant risk factor for CDI recurrence.
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Affiliation(s)
- Hee Kyoung Choi
- Department of Internal Medicine, Division of Infections Disease, Medical Research Institute, Pusan National University School of Medicine, Busan, Korea
| | - Kye Hyung Kim
- Department of Internal Medicine, Division of Infections Disease, Medical Research Institute, Pusan National University School of Medicine, Busan, Korea
| | - Sun Hee Lee
- Department of Internal Medicine, Division of Infections Disease, Medical Research Institute, Pusan National University School of Medicine, Busan, Korea
| | - Su Jin Lee
- Department of Internal Medicine, Division of Infections Disease, Medical Research Institute, Pusan National University School of Medicine, Busan, Korea
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127
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Multidrug-Resistant Enterococci in Animal Meat and Faeces and Co-Transfer of Resistance from an Enterococcus durans to a Human Enterococcus faecium. Curr Microbiol 2011; 62:1438-47. [DOI: 10.1007/s00284-011-9880-x] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Accepted: 01/13/2011] [Indexed: 11/27/2022]
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Ahmad A, Ghosh A, Schal C, Zurek L. Insects in confined swine operations carry a large antibiotic resistant and potentially virulent enterococcal community. BMC Microbiol 2011; 11:23. [PMID: 21269466 PMCID: PMC3039560 DOI: 10.1186/1471-2180-11-23] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2010] [Accepted: 01/26/2011] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Extensive use of antibiotics as growth promoters in the livestock industry constitutes strong selection pressure for evolution and selection of antibiotic resistant bacterial strains. Unfortunately, the microbial ecology and spread of these bacteria in the agricultural, urban, and suburban environments are poorly understood. Insects such as house flies (Musca domestica) and German cockroaches (Blattella germanica) can move freely between animal waste and food and may play a significant role in the dissemination of antibiotic resistant bacteria within and between animal production farms and from farms to residential settings. RESULTS Enterococci from the digestive tract of house flies (n = 162), and feces of German cockroaches (n = 83) and pigs (n = 119), collected from two commercial swine farms were isolated, quantified, identified, and screened for antibiotic resistance and virulence. The majority of samples (93.7%) were positive for enterococci with concentrations 4.2 ± 0.7 × 10⁴ CFU/house fly, 5.5 ± 1.1 × 10⁶ CFU/g of cockroach feces, and 3.2 ± 0.8 × 10⁵ CFU/g of pig feces. Among all the identified isolates (n = 639) Enterococcus faecalis was the most common (55.5%), followed by E. hirae (24.9%), E. faecium (12.8%), and E. casseliflavus (6.7%). E. faecalis was most prevalent in house flies and cockroaches, and E. hirae was most common in pig feces. Our data showed that multi-drug (mainly tetracycline and erythromycin) resistant enterococci were common from all three sources and frequently carried antibiotic resistance genes including tet(M) and erm(B) and Tn916/1545 transposon family. E. faecalis frequently harbored virulence factors gelE, esp, and asa1. PFGE analysis of selected E. faecalis and E. faecium isolates demonstrated that cockroaches and house flies shared some of the same enterococcal clones that were detected in the swine manure indicating that insects acquired enterococci from swine manure. CONCLUSIONS This study shows that house flies and German cockroaches in the confined swine production environment likely serve as vectors and/or reservoirs of antibiotic resistant and potentially virulent enterococci and consequently may play an important role in animal and public health.
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Affiliation(s)
- Aqeel Ahmad
- Department of Entomology, Kansas State University, Manhattan, KS, USA
- Monsanto Company, St. Louis, MO 63167, USA
| | - Anuradha Ghosh
- Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, KS, USA
| | - Coby Schal
- Department of Entomology, North Carolina State University, Raleigh, NC, USA
| | - Ludek Zurek
- Department of Entomology, Kansas State University, Manhattan, KS, USA
- Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, KS, USA
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129
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Assessment of bacterial antibiotic resistance transfer in the gut. Int J Microbiol 2011; 2011:312956. [PMID: 21318188 PMCID: PMC3034945 DOI: 10.1155/2011/312956] [Citation(s) in RCA: 111] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2010] [Revised: 11/21/2010] [Accepted: 12/09/2010] [Indexed: 12/21/2022] Open
Abstract
We assessed horizontal gene transfer between bacteria in the gastrointestinal (GI) tract. During the last decades, the emergence of antibiotic resistant strains and treatment failures of bacterial infections have increased the public awareness of antibiotic usage. The use of broad spectrum antibiotics creates a selective pressure on the bacterial flora, thus increasing the emergence of multiresistant bacteria, which results in a vicious circle of treatments and emergence of new antibiotic resistant bacteria. The human gastrointestinal tract is a massive reservoir of bacteria with a potential for both receiving and transferring antibiotic resistance genes. The increased use of fermented food products and probiotics, as food supplements and health promoting products containing massive amounts of bacteria acting as either donors and/or recipients of antibiotic resistance genes in the human GI tract, also contributes to the emergence of antibiotic resistant strains. This paper deals with the assessment of antibiotic resistance gene transfer occurring in the gut.
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130
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Smet A, Rasschaert G, Martel A, Persoons D, Dewulf J, Butaye P, Catry B, Haesebrouck F, Herman L, Heyndrickx M. In situ ESBL conjugation from avian to human Escherichia coli during cefotaxime administration. J Appl Microbiol 2010; 110:541-9. [DOI: 10.1111/j.1365-2672.2010.04907.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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131
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Werner G, Freitas AR, Coque TM, Sollid JE, Lester C, Hammerum AM, Garcia-Migura L, Jensen LB, Francia MV, Witte W, Willems RJ, Sundsfjord A. Host range of enterococcal vanA plasmids among Gram-positive intestinal bacteria. J Antimicrob Chemother 2010; 66:273-82. [PMID: 21131318 DOI: 10.1093/jac/dkq455] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVES The most prevalent type of acquired glycopeptide resistance is encoded by the vanA transposon Tn1546 located mainly on transferable plasmids in Enterococcus faecium. The limited occurrence in other species could be due to the lack of inter-species transferability and/or stability of Tn1546-containing plasmids in other species. We investigated the in vitro transferability of 14 pre-characterized vanA-containing plasmids hosted by E. faecium (n = 9), Enterococcus faecalis (n = 4) and Enterococcus raffinosus (n = 1) into several enterococcal, lactobacterial, lactococcal and bifidobacterial recipients. METHODS A filter-mating protocol was harmonized using procedures of seven partner laboratories. Donor strains were mated with three E. faecium recipients, three E. faecalis recipients, a Lactobacillus acidophilus recipient, a Lactococcus lactis recipient and two Bifidobacterium recipients. Transfer rates were calculated per donor and recipient. Transconjugants were confirmed by determining their phenotypic and genotypic properties. Stability of plasmids in the new host was assessed in long-term growth experiments. RESULTS In total, 282 enterococcal matings and 73 inter-genus matings were performed and evaluated. In summary, intra-species transfer was far more frequent than inter-species transfer, if that was detectable at all. All recipients of the same species behaved similarly. Inter-genus transfer was shown for broad host range control plasmids (pIP501/pAMβ1) only. Acquired resistance plasmids remained stable in the new host. CONCLUSIONS Intra-species transfer of enterococcal vanA plasmids was far more frequent than transfer across species or genus barriers and may thus explain the preferred prevalence of vanA-containing plasmids among E. faecium. A reservoir of vanA plasmids in non-enterococcal intestinal colonizers does not seem to be reasonable.
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132
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Hammerum AM, Lester CH, Heuer OE. Antimicrobial-resistant enterococci in animals and meat: a human health hazard? Foodborne Pathog Dis 2010; 7:1137-46. [PMID: 20578915 DOI: 10.1089/fpd.2010.0552] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Enterococcus faecium and Enterococcus faecalis belong to the gastrointestinal flora of humans and animals. Although normally regarded harmless commensals, enterococci may cause a range of different infections in humans, including urinary tract infections, sepsis, and endocarditis. The use of avoparcin, gentamicin, and virginiamycin for growth promotion and therapy in food animals has lead to the emergence of vancomycin- and gentamicin-resistant enterococci and quinupristin/dalfopristin-resistant E. faecium in animals and meat. This implies a potential risk for transfer of resistance genes or resistant bacteria from food animals to humans. The genes encoding resistance to vancomycin, gentamicin, and quinupristin/dalfopristin have been found in E. faecium of human and animal origin; meanwhile, certain clones of E. faecium are found more frequently in samples from human patients, while other clones predominate in certain animal species. This may suggest that antimicrobial-resistant E. faecium from animals could be regarded less hazardous to humans; however, due to their excellent ability to acquire and transfer resistance genes, E. faecium of animal origin may act as donors of antimicrobial resistance genes for other more virulent enterococci. For E. faecalis, the situation appears different, as similar clones of, for example, vancomycin- and gentamicin-resistant E. faecalis have been obtained from animals and from human patients. Continuous surveillance of antimicrobial resistance in enterococci from humans and animals is essential to follow trends and detect emerging resistance.
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Affiliation(s)
- Anette M Hammerum
- Antimicrobial Resistance Reference Laboratory and Surveillance Unit, Department of Microbiological Surveillance and Research, Statens Serum Institut, Artillerivej 5, Copenhagen, Denmark.
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Haug MC, Tanner SA, Lacroix C, Meile L, Stevens MJA. Construction and characterization of Enterococcus faecalis CG110/gfp/pRE25*, a tool for monitoring horizontal gene transfer in complex microbial ecosystems. FEMS Microbiol Lett 2010; 313:111-9. [PMID: 21029153 DOI: 10.1111/j.1574-6968.2010.02131.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Enterococci are among the most notorious bacteria involved in the spread of antibiotic resistance (ABR) determinants via horizontal gene transfer, a process that leads to increased prevalence of antibiotic-resistant bacteria. In complex microbial communities with a high background of ABR genes, detection of gene transfer is possible only when the ABR determinant is marked. Therefore, the conjugative multiresistance plasmid pRE25, originating from a sausage-associated Enterococcus faecalis, was tagged with a 34-bp random sequence marker spliced by tet(M). The plasmid constructed, designated pRE25(*) , was introduced into E. faecalis CG110/gfp, a strain containing a gfp gene as chromosomal marker. The plasmid pRE25(*) is fully functional compared with its parental pRE25, occurs at one to two copies per chromosome, and can be transferred to Listeria monocytogenes and Listeria innocua at frequencies of 6 × 10(-6) to 8 × 10(-8) transconjugants per donor. The markers on the chromosome and the plasmid enable independent quantification of donor and plasmid, even if ABR genes occur at high numbers in the background ecosystem. Both markers were stable for at least 200 generations, permitting application of the strain in long-running experiments. Enterococcus faecalis CG110/gfp/pRE25(*) is a potent tool for the investigation of horizontal ABR gene transfer in complex environments such as food matrices, biofilms or colonic models.
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Affiliation(s)
- Martina C Haug
- Laboratory of Food Biotechnology, Institute of Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland
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134
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Jernberg C, Löfmark S, Edlund C, Jansson JK. Long-term impacts of antibiotic exposure on the human intestinal microbiota. MICROBIOLOGY-SGM 2010; 156:3216-3223. [PMID: 20705661 DOI: 10.1099/mic.0.040618-0] [Citation(s) in RCA: 686] [Impact Index Per Article: 49.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Although it is known that antibiotics have short-term impacts on the human microbiome, recent evidence demonstrates that the impacts of some antibiotics remain for extended periods of time. In addition, antibiotic-resistant strains can persist in the human host environment in the absence of selective pressure. Both molecular- and cultivation-based approaches have revealed ecological disturbances in the microbiota after antibiotic administration, in particular for specific members of the bacterial community that are susceptible or alternatively resistant to the antibiotic in question. A disturbing consequence of antibiotic treatment has been the long-term persistence of antibiotic resistance genes, for example in the human gut. These data warrant use of prudence in the administration of antibiotics that could aggravate the growing battle with emerging antibiotic-resistant pathogenic strains.
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Affiliation(s)
- Cecilia Jernberg
- Department of Bacteriology, Swedish Institute for Infectious Disease Control, SE-171 82 Solna, Sweden
| | - Sonja Löfmark
- Department of Genetics, Microbiology and Toxicology, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Charlotta Edlund
- Department of Laboratory Medicine, Karolinska Institute, SE-141 86 Stockholm, Sweden.,Medical Products Agency, SE-751 03 Uppsala, Sweden
| | - Janet K Jansson
- Lawrence Berkeley National Laboratory, Division of Earth Sciences, 1 Cyclotron Rd, Berkeley, CA 94720, USA.,Department of Microbiology, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden
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135
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Lester CH, Hammerum AM. Transfer of vanA from an Enterococcus faecium isolate of chicken origin to a CC17 E. faecium isolate in the intestine of cephalosporin-treated mice. J Antimicrob Chemother 2010; 65:1534-6. [DOI: 10.1093/jac/dkq170] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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136
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Egervärn M, Lindmark H, Olsson J, Roos S. Transferability of a tetracycline resistance gene from probiotic Lactobacillus reuteri to bacteria in the gastrointestinal tract of humans. Antonie Van Leeuwenhoek 2009; 97:189-200. [PMID: 19997864 DOI: 10.1007/s10482-009-9401-0] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2009] [Accepted: 11/23/2009] [Indexed: 11/27/2022]
Abstract
The potential of Lactobacillus reuteri as a donor of antibiotic resistance genes in the human gut was investigated by studying the transferability of the tetracycline resistance gene tet(W) to faecal enterococci, bifidobacteria and lactobacilli. In a double-blind clinical study, seven subjects consumed L. reuteri ATCC 55730 harbouring a plasmid-encoded tet(W) gene (tet(W)-reuteri) and an equal number of subjects consumed L. reuteri DSM 17938 derived from the ATCC 55730 strain by the removal of two plasmids, one of which contained the tet(W) gene. Faecal samples were collected before, during and after ingestion of 5 x 10(8) CFU of L. reuteri per day for 14 days. Both L. reuteri strains were detectable at similar levels in faeces after 14 days of intake but neither was detected after a two-week wash-out period. After enrichment and isolation of tetracycline resistant enterococci, bifidobacteria and lactobacilli from each faecal sample, DNA was extracted and analysed for presence of tet(W)-reuteri using a real-time PCR allelic discrimination method developed in this study. No tet(W)-reuteri signal was produced from any of the DNA samples and thus gene transfer to enterococci, bifidobacteria and lactobacilli during intestinal passage of the probiotic strain was non-detectable under the conditions tested, although transfer at low frequencies or to the remaining faecal bacterial population cannot be excluded.
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Affiliation(s)
- Maria Egervärn
- Microbiology Division, National Food Administration, Box 622, 751 26 Uppsala, Sweden.
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Scientific Advisory Group on Antimi. Reflection paper on the use of third and fourth generation cephalosporins in food producing animals in the European Union: development of resistance and impact on human and animal health. J Vet Pharmacol Ther 2009; 32:515-33. [DOI: 10.1111/j.1365-2885.2009.01075.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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138
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139
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Transfer of plasmid-mediated CTX-M-9 from Salmonella enterica serotype Virchow to Enterobacteriaceae in human flora-associated rats treated with cefixime. Antimicrob Agents Chemother 2009; 54:164-9. [PMID: 19901088 DOI: 10.1128/aac.00310-09] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Food animals are a potential source of CTX-M resistance genes for humans. We evaluated the transfer of the bla(CTX-M-9) gene from an animal strain of Salmonella enterica serotype Virchow to Enterobacteriaceae of the human intestinal flora by using human flora-associated (HFA) rats with and without cefixime treatment. In the absence of antibiotic, no transconjugant enterobacteria were found in the feces of HFA rats. However, the transfer rate was high if Escherichia coli J5 recipient strains were coinoculated orally with Salmonella. S. enterica serotype Virchow persisted in the rat fecal flora both during and after treatment with therapeutic doses of cefixime. The drug did not increase the transfer rate, and E. coli J5 transconjugants were eliminated from the flora before the end of cefixime treatment. No cefixime was recovered in the rat feces. In the presence of recipient strains, the bla(CTX-M-9) resistance gene was transferred from a strain of animal origin to the human intestinal flora, although transconjugant colonization was transient. Antibiotic use enhanced the persistence of donor strains, increasing the resistance gene pool and the risk of its spread.
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140
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Haenni M, Saras E, Châtre P, Meunier D, Martin S, Lepage G, Ménard MF, Lebreton P, Rambaud T, Madec JY. vanAinEnterococcus faecium, Enterococcus faecalis, andEnterococcus casseliflavusDetected in French Cattle. Foodborne Pathog Dis 2009; 6:1107-11. [DOI: 10.1089/fpd.2009.0303] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Marisa Haenni
- Agence Française de Sécurité Sanitaire des Aliments (AFSSA), Unité Bactériologie Bovine et Hygiène des Viandes, Lyon, France
| | - Estelle Saras
- Agence Française de Sécurité Sanitaire des Aliments (AFSSA), Unité Bactériologie Bovine et Hygiène des Viandes, Lyon, France
| | - Pierre Châtre
- Agence Française de Sécurité Sanitaire des Aliments (AFSSA), Unité Bactériologie Bovine et Hygiène des Viandes, Lyon, France
| | - Danièle Meunier
- Agence Française de Sécurité Sanitaire des Aliments (AFSSA), Unité Bactériologie Bovine et Hygiène des Viandes, Lyon, France
| | | | | | | | | | | | - Jean-Yves Madec
- Agence Française de Sécurité Sanitaire des Aliments (AFSSA), Unité Bactériologie Bovine et Hygiène des Viandes, Lyon, France
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141
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Akhtar M, Hirt H, Zurek L. Horizontal transfer of the tetracycline resistance gene tetM mediated by pCF10 among Enterococcus faecalis in the house fly (Musca domestica L.) alimentary canal. MICROBIAL ECOLOGY 2009; 58:509-518. [PMID: 19475445 DOI: 10.1007/s00248-009-9533-9] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2009] [Accepted: 05/04/2009] [Indexed: 05/27/2023]
Abstract
The house fly (Musca domestica L.) alimentary canal was evaluated for the potential of horizontal transfer of tetM on plasmid pCF10 among Enterococcus faecalis. Two sets of experiments were conducted: (1) house flies without surface sterilization and (2) surface-sterilized flies. Both sets of flies were exposed to E. faecalis OG1RF:pCF10 as donor for 12 h and then E. faecalis OG1SSp as recipient for 1 h. Another group of flies received the recipient first for 12 h followed by exposure to the donor strain for 1 h. House flies were screened daily to determine the donor, recipient, and transconjugant bacterial load for up to 5 days. In addition, the sponge-like mouth parts used for food uptake (labellum) of surface-sterilized house flies were removed and analyzed for donors, recipients, and transconjugants, separately. In both groups of flies (n = 90 flies/group), transfer occurred within 24 h after exposure with a transconjugant/donor rate from 8.6 x 10(-5) to 4.5 x 10(1). Transconjugants were also isolated from the house fly labellum. Our data suggest that the house fly digestive tract provides a suitable environment for horizontal transfer of conjugative plasmids and antibiotic resistance genes among enterococci. Our results emphasize the importance of this insect as a potential vector of antibiotic-resistant bacterial strains.
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Affiliation(s)
- Mastura Akhtar
- Department of Entomology, Kansas State University, Manhattan, KS 66506, USA
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142
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Gaspar F, Teixeira N, Rigottier-Gois L, Marujo P, Nielsen-LeRoux C, Crespo MTB, Lopes MDFS, Serror P. Virulence of Enterococcus faecalis dairy strains in an insect model: the role of fsrB and gelE. MICROBIOLOGY-SGM 2009; 155:3564-3571. [PMID: 19696101 DOI: 10.1099/mic.0.030775-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Despite the existence of various virulence factors in the Enterococcus genus, enterococcal virulence is still a debated issue. A main consideration is the detection of the same virulence genes in strains isolated from nosocomial or community-acquired infections, and from food products. The goal of this study was to evaluate the roles of two well-characterized enterococcal virulence factors, Fsr and gelatinase, in the potential virulence of Enterococcus faecalis food strains. Virulence of unrelated Enterococcus isolates, including dairy strains carrying fsr and gelE operons, was compared in the Galleria mellonella insect model. E. faecalis dairy strains were able to kill larvae and were as virulent as strain OG1RF, one of the most widely used for virulence studies. In contrast, Enterococcus durans and Enterococcus faecium strains were avirulent or poorly virulent for G. mellonella. To evaluate the role of fsrB and gelE in virulence of E. faecalis dairy strains, both genes were deleted independently in two strains. The Delta fsrB and Delta gelE deletion mutants both produced a gelatinase-negative phenotype. Although both mutations significantly attenuated virulence in G. mellonella, the Delta fsrB strains were more strongly attenuated. These results agree with previous findings suggesting the involvement of fsrB in the control of other cell functions relevant to virulence. Our work demonstrates that the presence of functional fsrB, and to a lesser extent gelE, in dairy enterococci should be considered with caution.
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Affiliation(s)
- Frédéric Gaspar
- IBET and ITQB-UNL, Quinta do marquês, Av da República, 2781-901 Oeiras, Portugal
| | - Neuza Teixeira
- IBET and ITQB-UNL, Quinta do marquês, Av da República, 2781-901 Oeiras, Portugal
| | | | - Paulo Marujo
- IBET and ITQB-UNL, Quinta do marquês, Av da República, 2781-901 Oeiras, Portugal
| | | | | | | | - Pascale Serror
- INRA-U888-UBLO, Domaine de Vilvert, 78352 Jouy en Josas cedex, France
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143
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Impact of therapeutic treatment with beta-lactam on transfer of the bla(CTX-M-9) resistance gene from Salmonella enterica serovar Virchow to Escherichia coli in gnotobiotic rats. Appl Environ Microbiol 2009; 75:5523-8. [PMID: 19581466 DOI: 10.1128/aem.00020-09] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The conjugative transfer of the plasmid carrying the bla(CTX-M-9) gene from Salmonella enterica serovar Virchow isolated from a chicken farm to a recipient Escherichia coli strain was evaluated in vitro and in axenic rats inoculated with both strains, with or without selective pressure due to therapeutic doses of cefixime. The transfer of the bla(CTX-M-9) gene of S. enterica serovar Virchow to E. coli was confirmed in vitro, at a low frequency of 5.9 x 10(-8) transconjugants/donors. This transfer rate was higher in gnotobiotic rats and reached approximately 10(-5) transconjugants/donors without selective pressure. This frequency was not affected by the addition of therapeutic doses of cefixime. Thus, estimates of in vitro transfer underestimated potential transfer in the digestive tract, and therapeutic doses of cefixime did not increase the selection for transconjugants.
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144
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Roberts M, Soge O, Giardino M, Mazengia E, Ma G, Meschke J. Vancomycin-resistantEnterococcusspp. in marine environments from the West Coast of the USA. J Appl Microbiol 2009; 107:300-7. [DOI: 10.1111/j.1365-2672.2009.04207.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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145
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Johnsen PJ, Townsend JP, Bøhn T, Simonsen GS, Sundsfjord A, Nielsen KM. Factors affecting the reversal of antimicrobial-drug resistance. THE LANCET. INFECTIOUS DISEASES 2009; 9:357-64. [PMID: 19467475 DOI: 10.1016/s1473-3099(09)70105-7] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The persistence or loss of acquired antimicrobial-drug resistance in bacterial populations previously exposed to drug-selective pressure depends on several biological processes. We review mechanisms promoting or preventing the loss of resistance, including rates of reacquisition, effects of resistance traits on bacterial fitness, linked selection, and segregational stability of resistance determinants. As a case study, we discuss the persistence of glycopeptide-resistant enterococci in Norwegian and Danish poultry farms 12 years after the ban of the animal growth promoter avoparcin. We conclude that complete eradication of antimicrobial resistance in bacterial populations following relaxed drug-selective pressures is not straightforward. Resistance determinants may persist at low, but detectable, levels for many years in the absence of the corresponding drugs.
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Affiliation(s)
- Pål J Johnsen
- Department of Pharmacy, Faculty of Medicine, University of Tromsø, Tromsø, Norway.
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146
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Sahlström L, Rehbinder V, Albihn A, Aspan A, Bengtsson B. Vancomycin resistant enterococci (VRE) in Swedish sewage sludge. Acta Vet Scand 2009; 51:24. [PMID: 19480649 PMCID: PMC2693504 DOI: 10.1186/1751-0147-51-24] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2008] [Accepted: 05/29/2009] [Indexed: 11/30/2022] Open
Abstract
Background Antimicrobial resistance is a serious threat in veterinary medicine and human healthcare. Resistance genes can spread from animals, through the food-chain, and back to humans. Sewage sludge may act as the link back from humans to animals. The main aims of this study were to investigate the occurrence of vancomycin resistant enterococci (VRE) in treated sewage sludge, in a Swedish waste water treatment plant (WWTP), and to compare VRE isolates from sewage sludge with isolates from humans and chickens. Methods During a four month long study, sewage sludge was collected weekly and cultured for VRE. The VRE isolates from sewage sludge were analysed and compared to each other and to human and chicken VRE isolates by biochemical typing (PhenePlate), PFGE and antibiograms. Results Biochemical typing (PhenePlate-FS) and pulsed field gel electrophoresis (PFGE) revealed prevalence of specific VRE strains in sewage sludge for up to 16 weeks. No connection was found between the VRE strains isolated from sludge, chickens and humans, indicating that human VRE did not originate from Swedish chicken. Conclusion This study demonstrated widespread occurrence of VRE in sewage sludge in the studied WWTP. This implies a risk of antimicrobial resistance being spread to new farms and to the society via the environment if the sewage sludge is used on arable land.
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147
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Aarestrup FM, Wegener HC, Collignon P. Resistance in bacteria of the food chain: epidemiology and control strategies. Expert Rev Anti Infect Ther 2008; 6:733-50. [PMID: 18847409 DOI: 10.1586/14787210.6.5.733] [Citation(s) in RCA: 240] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Bacteria have evolved multiple mechanisms for the efficient evolution and spread of antimicrobial resistance. Modern food production facilitates the emergence and spread of resistance through the intensive use of antimicrobial agents and international trade of both animals and food products. The main route of transmission between food animals and humans is via food products, although other modes of transmission, such as direct contact and through the environment, also occur. Resistance can spread as resistant pathogens or via transferable genes in different commensal bacteria, making quantification of the transmission difficult. The exposure of humans to antimicrobial resistance from food animals can be controlled by either limiting the selective pressure from antimicrobial usage or by limiting the spread of the bacteria/genes. A number of control options are reviewed, including drug licensing, removing financial incentives, banning or restricting the use of certain drugs, altering prescribers behavior, improving animal health, improving hygiene and implementing microbial criteria for certain types of resistant pathogens for use in the control of trade of both food animals and food.
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Affiliation(s)
- Frank M Aarestrup
- National Food Institute, Technical University of Denmark, Copenhagen V, Denmark.
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148
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Trobos M, Lester CH, Olsen JE, Frimodt-Møller N, Hammerum AM. Natural transfer of sulphonamide and ampicillin resistance between Escherichia coli residing in the human intestine. J Antimicrob Chemother 2008; 63:80-6. [PMID: 18957394 DOI: 10.1093/jac/dkn437] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES The aim of this study was to investigate whether the sulphonamide resistance gene sul2 could be transferred between Escherichia coli in the human gut. METHODS Nine volunteers ingested a 10(9) cfu suspension of sulphonamide-susceptible, rifampicin-resistant E. coli recipients of human origin. Three hours later, they ingested a 10(7) cfu suspension of a sulphonamide-resistant (MIC>1024 mg/L) E. coli donor of pig origin. Stool samples were collected 24 h prior to ingestion, daily for 7 days and at days 14 and 35. Samples were plated on selective plates and monitored for the acquisition of sulphonamide-resistance by the recipient from the indigenous or administrated donor E. coli. Possible transconjugants were typed by PFGE and tested for the presence of plasmids containing the sul2 gene, which was also sequenced. RESULTS Concentrations of the human and animal E. coli reached a maximum of 7.5x10(6) cfu/g faeces and colonized for more than 7 days, and 2x10(8) cfu/g for more than 14 days, respectively. On day 2, a transconjugant was detected in one volunteer. This volunteer was colonized with sulphonamide-resistant E. coli at day 0. The transconjugant was sul2-positive, had an MIC>1024 mg/L for sulfamethoxazole and the same PFGE profile as the recipient. The resident E. coli transferred a plasmid (>63 kb), containing the sul2 gene, to the recipient. The sul2 sequence of the transconjugant was identical to that of the volunteer's own E. coli from day 0, but differed from the animal strain. Co-transfer of ampicillin resistance was also demonstrated. CONCLUSIONS Transfer of sul2 was observed between E. coli bacteria in the human intestine. The transconjugant's sul2 gene came from the volunteer's own flora. The origin of the E. coli donor is unknown.
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Affiliation(s)
- Margarita Trobos
- National Center for Antimicrobials and Infection Control, Statens Serum Institut, Artillerivej 5, 2300 Copenhagen S, Denmark
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149
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Werner G, Strommenger B, Witte W. Acquired vancomycin resistance in clinically relevant pathogens. Future Microbiol 2008; 3:547-62. [DOI: 10.2217/17460913.3.5.547] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Acquired resistance to vancomycin is an increasing problem in pathogenic bacteria. It is best studied and most prevalent among Enterococcus and still remains rare in other pathogenic bacteria. Different genotypes of vancomycin resistance, vanA–G, have been described. The different van gene clusters consist of up to nine genes encoding proteins of different functions; their interplay leads to an alternative cell wall precursor less susceptible to glycopeptide binding. Variants of vanA and vanB types are found worldwide, with vanA predominating; their reservoir is Enterococcus faecium. Within this species a subpopulation of hospital-adapted types exists that acquired van gene clusters and which is responsible for outbreaks of vancomycin-resistant enterococci all over the world. Acquisition of vanA by methicillin-resistant Staphylococcus aureus (MRSA) is worrisome and seven cases have been described. Nonsusceptibility to glycopeptides also occurs independently from van genes and is a growing therapeutic challenge, especially in MRSA.
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Affiliation(s)
- Guido Werner
- FG 13 Nosocomial Infections, Robert Koch Institute, Wernigerode Branch, Burgstr. 37, Wernigerode, 38855, Germany
| | - Birgit Strommenger
- Robert Koch Institute, Wernigerode Branch, Burgstr. 37, Wernigerode, 38855, Germany
| | - Wolfgang Witte
- Robert Koch Institute, Wernigerode Branch, Burgstr. 37, Wernigerode, 38855, Germany
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150
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Meta-analysis of experimental data concerning antimicrobial resistance gene transfer rates during conjugation. Appl Environ Microbiol 2008; 74:6085-90. [PMID: 18708517 DOI: 10.1128/aem.01036-08] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
This paper presents the results of a meta-analysis of published transfer rates of antimicrobial resistance genes. A total of 34 papers were identified, of which 28 contained rates estimated in relation to either donor or recipient bacterial counts. The published rates ranged from 10(-2) to 10(-9). Generalized linear modeling was conducted to identify the factors influencing this variation. Highly significant associations between transfer frequency and both the donor (P = 1.2 x 10(-4)) and recipient (P = 1.0 x 10(-5)) genera were found. Also significant was whether the donor and recipient strains were of the same genus (P = 0.023) and the nature of the genetic element (P = 0.0019). The type of experiment, in vivo or in vitro, approached statistical significance (P = 0.12). Parameter estimates from a general linear model were used to estimate the probability of transfer of antimicrobial resistance genes to potential pathogens in the intestine following oral ingestion. The mean logarithms of these probabilities are in the range of [-7.0, -3.1]. These probability distributions are suitable for use in the quantitative assessment of the risk of transfer of antimicrobial resistance genes to the intestinal flora of humans and animals.
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