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Kirkeby C, Boklund A, Larsen LE, Ward MP. Are all avian influenza outbreaks in poultry the same? The predicted impact of poultry species and virus subtype. Zoonoses Public Health 2024; 71:314-323. [PMID: 38362732 DOI: 10.1111/zph.13116] [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: 04/21/2023] [Revised: 11/15/2023] [Accepted: 01/30/2024] [Indexed: 02/17/2024]
Abstract
AIMS Outbreaks of avian influenza in poultry farms are currently increasing in frequency, with devastating consequences for animal welfare, farmers and supply chains. Some studies have documented the direct spread of the avian influenza virus between farms. Prevention of spread between farms relies on biosecurity surveillance and control measures. However, the evolution of an outbreak on a farm might vary depending on the virus strain and poultry species involved; this would have important implications for surveillance systems, epidemiological investigations and control measures. METHODS AND RESULTS In this study, we utilized existing parameter estimates from the literature to evaluate the predicted course of an epidemic in a standard poultry flock with 10,000 birds. We used a stochastic SEIR simulation model to simulate outbreaks in different species and with different virus subtypes. The simulations predicted large differences in the duration and severity of outbreaks, depending on the virus subtypes. For both turkeys and chickens, outbreaks with HPAI were of shorter duration than outbreaks with LPAI. In outbreaks involving the infection of chickens with different virus subtypes, the shortest epidemic involved H7N7 and HPAIV H5N1 (median duration of 9 and 17 days, respectively) and the longest involved H5N2 (median duration of 68 days). The most severe outbreaks (number of chickens infected) were predicted for H5N1, H7N1 and H7N3 virus subtypes, and the least severe for H5N2 and H7N7, in which outbreaks for the latter subtype were predicted to develop most slowly. CONCLUSIONS These simulation results suggest that surveillance of certain subtypes of avian influenza virus, in chicken flocks in particular, needs to be sensitive and timely if infection is to be detected with sufficient time to implement control measures. The variability in the predictions highlights that avian influenza outbreaks are different in severity, speed and duration, so surveillance and disease response need to be nuanced and fit the specific context of poultry species and virus subtypes.
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Affiliation(s)
- Carsten Kirkeby
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Anette Boklund
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Lars Erik Larsen
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Michael P Ward
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Camden, New South Wales, Australia
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2
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Costa MM, Cardo M, Ruano Z, Alho AM, Dinis-Teixeira J, Aguiar P, Leite A. Effectiveness of antimicrobial interventions directed at tackling antimicrobial resistance in animal production: A systematic review and meta-analysis. Prev Vet Med 2023; 218:106002. [PMID: 37639825 DOI: 10.1016/j.prevetmed.2023.106002] [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: 05/16/2023] [Revised: 07/13/2023] [Accepted: 08/14/2023] [Indexed: 08/31/2023]
Abstract
BACKGROUND In the last decades, a more prudent and rational use of antimicrobials has been progressively directed towards animal production to reduce antimicrobial selective pressure and antimicrobial resistance (AMR) in microorganisms and safeguard the antimicrobial efficacy of treatments in human medicine. This systematic review evaluated the effectiveness of interventions that have been applied to reduce or improve veterinary antimicrobial usage and aimed at decreasing resistant bacteria in chicken broiler and pig production contexts. METHODS Original articles were identified by searching PubMed™, Scopus™, The Cochrane Library™, and Web of Science™, and grey literature by searching DANS EASY™, WorldCat™ and RCAAP™. Inclusion criteria included: chicken broiler or pig populations (predestined for meat production), interventions intended to reduce/improve antimicrobial use, comparator with standard or no use of antimicrobials, outcomes related to prevalence of resistant bacteria, farm level studies, original data, and analytical observational studies. Data was extracted from eligible studies and meta-analysis using random or fixed effects models was conducted for combinations including type of intervention, bacterial species, production type and animal populations. Models were selected according to heterogeneity between studies. The effectiveness of interventions was assessed using pooled odds ratio of resistance to antimicrobial substances/classes by bacteria for associations between animal populations with and without intervention. RESULTS A total of 46 studies were eligible for review. For chicken broilers, most interventions were identified as antimicrobial restrictions on all non-therapeutic use (46%), complete restriction (27%), and prohibition on antimicrobials used for growth promotion (23%). As for pig populations, restrictions were mainly observed on all non-therapeutic use (37%), complete restriction (37%) and group treatments (22%). For meta-analysis, 21 studies were pooled after assessment of existing combinations. These combinations demonstrated a protective effect for most antimicrobial classes in Escherichia coli, Campylobacter and Enterococcus isolates from samples of chicken broilers as well in Escherichia coli and Campylobacter spp. from samples of pigs, compared to animals raised under conventional production or without intervention. Increased odds of resistance were only observed for cephalosporins in E. coli and broilers raised without antimicrobials, and to fluoroquinolones and quinolones in Campylobacter and pigs raised without antimicrobials, compared to conventional production. CONCLUSIONS Our study indicates that organic production, antimicrobial-free farms, and group treatment restrictions are recommended for AMR reduction, providing information that may support decision-making to tackle AMR and better reporting to improve comparability of results between studies.
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Affiliation(s)
- Miguel Mendes Costa
- NOVA National School of Public Health, Public Health Research Center, Comprehensive Health Research Center, CHRC, NOVA University Lisbon, Lisbon, Portugal.
| | - Miguel Cardo
- CIISA-Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, 1300-477 Lisbon, Portugal
| | - Zita Ruano
- Veterinary and Animal Research Centre (CECAV), Universidade de Trás-os-Montes e Alto Douro, Vila Real, Portugal
| | - Ana Margarida Alho
- NOVA National School of Public Health, Public Health Research Center, Comprehensive Health Research Center, CHRC, NOVA University Lisbon, Lisbon, Portugal; Public Health Unit USP Francisco George, ACES Lisboa Norte, Largo Professor Arnaldo Sampaio, 1549-010 Lisboa, Portugal; Global Health and Tropical Medicine, GHTM, Instituto de Higiene e Medicina Tropical, IHMT, Universidade NOVA de Lisboa, Portugal
| | - José Dinis-Teixeira
- NOVA National School of Public Health, NOVA University Lisbon, Lisbon, Portugal; Public Health Unit of Sintra, Lisbon and Tagus Valley Regional Health Administration, Lisbon, Portugal; WHO Collaborating Centre for Education, Research and Evaluation of Safety and Quality in Healthcare, Lisbon, Portugal
| | - Pedro Aguiar
- NOVA National School of Public Health, Public Health Research Center, Comprehensive Health Research Center, CHRC, NOVA University Lisbon, Lisbon, Portugal
| | - Andreia Leite
- NOVA National School of Public Health, Public Health Research Center, Comprehensive Health Research Center, CHRC, NOVA University Lisbon, Lisbon, Portugal; Department of Epidemiology, National Health Institute Doctor Ricardo Jorge (INSA), 1600-560 Lisboa, Portugal
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Gomes B, Dias M, Cervantes R, Pena P, Santos J, Vasconcelos Pinto M, Viegas C. One Health Approach to Tackle Microbial Contamination on Poultries-A Systematic Review. TOXICS 2023; 11:374. [PMID: 37112601 PMCID: PMC10142658 DOI: 10.3390/toxics11040374] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 04/05/2023] [Accepted: 04/11/2023] [Indexed: 06/19/2023]
Abstract
This study reports the search of available data published regarding microbial occupational exposure assessment in poultries, following the PRISMA methodology. Air collection through filtration was the most frequently used. The most commonly used passive sampling method was material collection such as dust, cages, soils, sediment, and wastewater. Regarding assays applied, the majority of studies comprised culture-based methods, but molecular tools were also frequently used. Screening for antimicrobial susceptibility was performed only for bacteria; cytotoxicity, virological and serological assays were also performed. Most of the selected studies focused on bacteria, although fungi, endotoxins, and β-glucans were also assessed. The only study concerning fungi and mycotoxins reported the carcinogenic mycotoxin AFB1. This study gives a comprehensive overview of microbial contamination in the poultry industry, emphasizing this setting as a potential reservoir of microbial pathogens threatening human, animal, and environmental health. Additionally, this research helps to provide a sampling and analysis protocol proposal to evaluate the microbiological contamination in these facilities. Few articles were found reporting fungal contamination in poultry farms worldwide. In addition, information concerning fungal resistance profile and mycotoxin contamination remain scarce. Overall, a One Health approach should be incorporated in exposure assessments and the knowledge gaps identified in this paper should be addressed in further research.
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Affiliation(s)
- Bianca Gomes
- CE3C—Center for Ecology, Evolution and Environmental Change, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisbon, Portugal
- H&TRC—Health & Technology Research Center, ESTeSL—Escola Superior de Tecnologia e Saúde, Instituto Politécnico de Lisboa, 1990-096 Lisbon, Portugal
| | - Marta Dias
- H&TRC—Health & Technology Research Center, ESTeSL—Escola Superior de Tecnologia e Saúde, Instituto Politécnico de Lisboa, 1990-096 Lisbon, Portugal
- NOVA National School of Public Health, Public Health Research Centre, Comprehensive Health Research Center, CHRC, NOVA University Lisbon, 1600-560 Lisbon, Portugal
| | - Renata Cervantes
- H&TRC—Health & Technology Research Center, ESTeSL—Escola Superior de Tecnologia e Saúde, Instituto Politécnico de Lisboa, 1990-096 Lisbon, Portugal
- NOVA National School of Public Health, Public Health Research Centre, Comprehensive Health Research Center, CHRC, NOVA University Lisbon, 1600-560 Lisbon, Portugal
| | - Pedro Pena
- H&TRC—Health & Technology Research Center, ESTeSL—Escola Superior de Tecnologia e Saúde, Instituto Politécnico de Lisboa, 1990-096 Lisbon, Portugal
- NOVA National School of Public Health, Public Health Research Centre, Comprehensive Health Research Center, CHRC, NOVA University Lisbon, 1600-560 Lisbon, Portugal
| | - Joana Santos
- CISAS—Center for Research and Development in Agrifood Systems and Sustainability, Instituto Politécnico de Viana do Castelo, 4900-347 Viana do Castelo, Portugal
| | - Marta Vasconcelos Pinto
- CISAS—Center for Research and Development in Agrifood Systems and Sustainability, Instituto Politécnico de Viana do Castelo, 4900-347 Viana do Castelo, Portugal
- Polytechnic Institute of Coimbra, Escola Superior de Tecnologia da Saúde de Coimbra, Rua 5 de Outubro, 3046-854 Coimbra, Portugal
| | - Carla Viegas
- H&TRC—Health & Technology Research Center, ESTeSL—Escola Superior de Tecnologia e Saúde, Instituto Politécnico de Lisboa, 1990-096 Lisbon, Portugal
- NOVA National School of Public Health, Public Health Research Centre, Comprehensive Health Research Center, CHRC, NOVA University Lisbon, 1600-560 Lisbon, Portugal
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Mirzaie S, Faghiri I, Askari Badouei M, Madani SA. Molecular detection and occurrence of vancomycin resistance genes (van A, B, C1, C2/C3) among Enterococcus species isolated from farm ostriches. Vet Med Sci 2022; 9:226-233. [PMID: 36458992 PMCID: PMC9857099 DOI: 10.1002/vms3.1010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Evaluating the prevalence of vancomycin resistance genes (van genes) in enterococcal isolates from food-producing animals is an important public health issue because of the possibility of resistance genes spread to human. OBJECTIVES The present study aimed to determine the occurrence of vancomycin resistance genes among Enterococcus species obtained from ostrich faecal samples. METHODS One hundred and twenty-five faecal samples of apparently healthy ostriches from five different farms were investigated. Genes encoding vancomycin resistance were studied by multiplex-PCR, and susceptibility to six antibiotics was evaluated by disk-diffusion method. RESULTS In total, 107 Enterococcus spp. isolates were obtained and confirmed by biochemical and molecular tests. Enterococcus faecium was the prevailing species (56 isolates of 107; 52.3%), followed by E. hirae (24 isolates; 22.4%) and E. gallinarum (12 isolates; 11.2%). Of the 107 recovered isolates, 44% harboured at least a type of van genes. vanA, vanC2/3 and vanC1 were identified in 34 (31.7%), 13 isolates (12.1%) and 4 (3.7%) isolates respectively. Additionally, four isolates (E. gallinarum, E. rafinosus) co-harboured the the vanA and vanC1 or vanA and vanC2/3. Enterococcus faecium and Enterococcus hirae strains with the vanA genotype were the most frequent van-carrying enterococci from ostrich faecal samples. Among van-carrying enterococcal isolates, 23.4% were phenotypically resistant to vancomycin. This study revealed a relatively high prevalence (44%) of van-carrying enterococci in ostrich faecal samples. CONCLUSIONS Results of the present study suggest that ostrich faeces could be considered as a reservoir of vancomycin resistance genes, especially vanA containing enterococci that could be potentially transferred to human through the food chain.
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Affiliation(s)
- Sara Mirzaie
- Department of AgricultureIranian Research Organization for Science and Technology (IROST)TehranIran
| | - Isa Faghiri
- Department of PathobiologyFaculty of Veterinary MedicineGarmsar BranchIslamic Azad UniversityGarmsarIran
| | - Mahdi Askari Badouei
- Department of PathobiologyFaculty of Veterinary MedicineFerdowsi University of MashhadMashhadIran
| | - Seyed Ahmad Madani
- Faculty of Veterinary MedicineDepartment of Animal and Poultry Health and NutritionUniversity of TehranTehranIran
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Gião J, Leão C, Albuquerque T, Clemente L, Amaro A. Antimicrobial Susceptibility of Enterococcus Isolates from Cattle and Pigs in Portugal: Linezolid Resistance Genes optrA and poxtA. Antibiotics (Basel) 2022; 11:615. [PMID: 35625259 PMCID: PMC9137492 DOI: 10.3390/antibiotics11050615] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 04/22/2022] [Accepted: 04/26/2022] [Indexed: 11/16/2022] Open
Abstract
Enterococci are part of the commensal gut microbiota of mammals, with Enterococcus faecalis and Enterococcus faecium being the most clinically relevant species. This study assesses the prevalence and diversity of enterococcal species in cattle (n = 201) and pig (n = 249) cecal samples collected in 2017. Antimicrobial susceptibility profiles of E. faecium (n = 48) and E. faecalis (n = 84) were assessed by agar and microdilution methods. Resistance genes were screened through PCR and nine strains were analyzed by Whole Genome Sequencing. A wide range of enterococci species was found colonizing the intestines of pigs and cattle. Overall, the prevalence of resistance to critically important antibiotics was low (except for erythromycin), and no glycopeptide-resistant isolates were identified. Two daptomycin-resistant E. faecalis ST58 and ST93 were found. Linezolid-resistant strains of E. faecalis (n = 3) and E. faecium (n = 1) were detected. Moreover, oxazolidinone resistance determinants optrA (n = 8) and poxtA (n = 2) were found in E. faecalis (ST16, ST58, ST207, ST474, ST1178) and E. faecium (ST22, ST2138). Multiple variants of optrA were found in different genetic contexts, either in the chromosome or plasmids. We highlight the importance of animals as reservoirs of resistance genes to critically important antibiotics.
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Affiliation(s)
- Joana Gião
- Laboratory of Bacteriology and Mycology, INIAV—National Institute of Agrarian and Veterinary Research, 2780-157 Oeiras, Portugal; (J.G.); (C.L.); (T.A.); (L.C.)
- Department of Veterinary Medicine, University of Évora, 7002-554 Évora, Portugal
| | - Célia Leão
- Laboratory of Bacteriology and Mycology, INIAV—National Institute of Agrarian and Veterinary Research, 2780-157 Oeiras, Portugal; (J.G.); (C.L.); (T.A.); (L.C.)
- MED—Mediterranean Institute for Agriculture, Environment and Development, 7006-554 Évora, Portugal
| | - Teresa Albuquerque
- Laboratory of Bacteriology and Mycology, INIAV—National Institute of Agrarian and Veterinary Research, 2780-157 Oeiras, Portugal; (J.G.); (C.L.); (T.A.); (L.C.)
| | - Lurdes Clemente
- Laboratory of Bacteriology and Mycology, INIAV—National Institute of Agrarian and Veterinary Research, 2780-157 Oeiras, Portugal; (J.G.); (C.L.); (T.A.); (L.C.)
- CIISA—Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Science, University of Lisbon, 1300-477 Lisboa, Portugal
| | - Ana Amaro
- Laboratory of Bacteriology and Mycology, INIAV—National Institute of Agrarian and Veterinary Research, 2780-157 Oeiras, Portugal; (J.G.); (C.L.); (T.A.); (L.C.)
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Nobrega DB, Tang KL, Caffrey NP, De Buck J, Cork SC, Ronksley PE, Polachek AJ, Ganshorn H, Sharma N, Kastelic JP, Kellner JD, Ghali WA, Barkema HW. Prevalence of antimicrobial resistance genes and its association with restricted antimicrobial use in food-producing animals: a systematic review and meta-analysis. J Antimicrob Chemother 2021; 76:561-575. [PMID: 33146719 DOI: 10.1093/jac/dkaa443] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Accepted: 09/28/2020] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND There is ongoing debate regarding potential associations between restrictions of antimicrobial use and prevalence of antimicrobial resistance (AMR) in bacteria. OBJECTIVES To summarize the effects of interventions reducing antimicrobial use in food-producing animals on the prevalence of AMR genes (ARGs) in bacteria from animals and humans. METHODS We published a full systematic review of restrictions of antimicrobials in food-producing animals and their associations with AMR in bacteria. Herein, we focus on studies reporting on the association between restricted antimicrobial use and prevalence of ARGs. We used multilevel mixed-effects models and a semi-quantitative approach based on forest plots to summarize findings from studies. RESULTS A positive effect of intervention [reduction in prevalence or number of ARGs in group(s) with restricted antimicrobial use] was reported from 29 studies for at least one ARG. We detected significant associations between a ban on avoparcin and diminished presence of the vanA gene in samples from animals and humans, whereas for the mecA gene, studies agreed on a positive effect of intervention in samples only from animals. Comparisons involving mcr-1, blaCTX-M, aadA2, vat(E), sul2, dfrA5, dfrA13, tet(E) and tet(P) indicated a reduced prevalence of genes in intervention groups. Conversely, no effects were detected for β-lactamases other than blaCTX-M and the remaining tet genes. CONCLUSIONS The available body of scientific evidence supported that restricted use of antimicrobials in food animals was associated with an either lower or equal presence of ARGs in bacteria, with effects dependent on ARG, host species and restricted drug.
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Affiliation(s)
- Diego B Nobrega
- Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada.,Mastitis Network, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, Canada
| | - Karen L Tang
- Department of Medicine, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Niamh P Caffrey
- Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada
| | - Jeroen De Buck
- Department of Production Animal Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada
| | - Susan C Cork
- Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada
| | - Paul E Ronksley
- Department of Community Health Sciences, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Alicia J Polachek
- W21C Research and Innovation Centre, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Heather Ganshorn
- Libraries and Cultural Resources, University of Calgary, Calgary, AB, Canada
| | - Nishan Sharma
- W21C Research and Innovation Centre, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - John P Kastelic
- Department of Production Animal Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada
| | - James D Kellner
- Department of Pediatrics, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - William A Ghali
- Department of Medicine, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Herman W Barkema
- Mastitis Network, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, Canada.,Department of Production Animal Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada.,Department of Community Health Sciences, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
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Simm R, Slettemeås JS, Norström M, Dean KR, Kaldhusdal M, Urdahl AM. Significant reduction of vancomycin resistant E. faecium in the Norwegian broiler population coincided with measures taken by the broiler industry to reduce antimicrobial resistant bacteria. PLoS One 2019; 14:e0226101. [PMID: 31830083 PMCID: PMC6907784 DOI: 10.1371/journal.pone.0226101] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Accepted: 11/18/2019] [Indexed: 12/30/2022] Open
Abstract
Vancomycin resistant enterococci (VRE) belong to the most common causes of nosocomial infections worldwide. It has been reported that use of the glycopeptide growth promoter avoparcin selected for a significant livestock-reservoir of VRE in many European countries, including Norway. However, although avoparcin was banned as a feed-additive in 1995, VRE have for unknown reasons consistently been reported in samples from Norwegian broilers. When avoparcin was banned, broiler-feed was supplemented with the polyether ionophore narasin in order to control the diseases coccidiosis and the frequent sequela necrotic enteritis. A potential link between transferrable vancomycin resistance and reduced susceptibility to narasin was recently reported. The use of narasin as a feed additive was abolished by the Norwegian broiler industry in 2016 and since then, broilers have been reared without in-feed antibacterial supplements. In this study, we demonstrate that all VRE isolates from Norwegian broilers collected in 2006-2014 displayed reduced susceptibility to narasin. Surveillance data collected two years after the narasin abolishment show a significant reduction in VRE, below the detection limit of the surveillance method, and a concurrent marked reduction in Enterococcus faecium with reduced susceptibility to narasin. The significant decline of E. faecium with reduced susceptibility to these antimicrobial compounds also coincided with an increased focus on cleaning and disinfection between broiler flocks. Furthermore, data from a controlled in vivo experiment using Ross 308 broilers indicate that the proportion of E. faecium with reduced susceptibility to narasin was heavily reduced in broilers fed a narasin-free diet compared to a diet supplemented with narasin. Our results are consistent with that the abolishment of this feed additive, possibly in combination with the increased focus on cleaning and disinfection, has had a substantial impact on the occurrence of VRE in the Norwegian broiler population.
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Affiliation(s)
- Roger Simm
- Institute of Oral Biology, University of Oslo, Oslo, Norway
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8
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Tang KL, Caffrey NP, Nóbrega DB, Cork SC, Ronksley PE, Barkema HW, Polachek AJ, Ganshorn H, Sharma N, Kellner JD, Checkley SL, Ghali WA. Comparison of different approaches to antibiotic restriction in food-producing animals: stratified results from a systematic review and meta-analysis. BMJ Glob Health 2019; 4:e001710. [PMID: 31543995 PMCID: PMC6730577 DOI: 10.1136/bmjgh-2019-001710] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 07/26/2019] [Accepted: 08/18/2019] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND We have previously reported, in a systematic review of 181 studies, that restriction of antibiotic use in food-producing animals is associated with a reduction in antibiotic-resistant bacterial isolates. While informative, that report did not concretely specify whether different types of restriction are associated with differential effectiveness in reducing resistance. We undertook a sub-analysis of the systematic review to address this question. METHODS We created a classification scheme of different approaches to antibiotic restriction: (1) complete restriction; (2) single antibiotic-class restriction; (3) single antibiotic restriction; (4) all non-therapeutic use restriction; (5) growth promoter and prophylaxis restriction; (6) growth promoter restriction and (7) other/undetermined. All studies in the original systematic review that were amenable to meta-analysis were included into this substudy and coded by intervention type. Meta-analyses were conducted using random effects models, stratified by intervention type. RESULTS A total of 127 studies were included. The most frequently studied intervention type was complete restriction (n=51), followed by restriction of non-therapeutic (n=33) and growth promoter (n=19) indications. None examined growth promoter and prophylaxis restrictions together. Three and seven studies examined single antibiotic-class and single antibiotic restrictions, respectively; these two intervention types were not significantly associated with reductions in antibiotic resistance. Though complete restrictions were associated with a 15% reduction in antibiotic resistance, less prohibitive approaches also demonstrated reduction in antibiotic resistance of 9%-30%. CONCLUSION Broad interventions that restrict global antibiotic use appear to be more effective in reducing antibiotic resistance compared with restrictions that narrowly target one specific antibiotic or antibiotic class. Importantly, interventions that allow for therapeutic antibiotic use appear similarly effective compared with those that restrict all uses of antibiotics, suggesting that complete bans are not necessary. These findings directly inform the creation of specific policies to restrict antibiotic use in food-producing animals.
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Affiliation(s)
- Karen L Tang
- Department of Medicine, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Niamh P Caffrey
- Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Diego B Nóbrega
- Department of Production Animal Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Susan C Cork
- Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Paul E Ronksley
- Department of Community Health Sciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Herman W Barkema
- Department of Production Animal Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Alicia J Polachek
- W21C Research and Innovation Centre, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Heather Ganshorn
- Libraries and Cultural Resources, University of Calgary, Calgary, Alberta, Canada
| | - Nishan Sharma
- W21C Research and Innovation Centre, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - James D Kellner
- Department of Pediatrics, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Sylvia L Checkley
- Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
| | - William A Ghali
- Department of Medicine, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
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9
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O'Dea M, Sahibzada S, Jordan D, Laird T, Lee T, Hewson K, Pang S, Abraham R, Coombs GW, Harris T, Pavic A, Abraham S. Genomic, Antimicrobial Resistance, and Public Health Insights into Enterococcus spp. from Australian Chickens. J Clin Microbiol 2019; 57:e00319-19. [PMID: 31118269 PMCID: PMC6663891 DOI: 10.1128/jcm.00319-19] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 05/16/2019] [Indexed: 12/15/2022] Open
Abstract
Due to Australia's management of antimicrobial use in poultry, particularly the discontinued use of avoparcin for nearly 20 years, it is hypothesized that vancomycin-resistant enterococci associated with human disease are not derived from poultry isolates. This study evaluated antimicrobial resistance (AMR) of five enterococcal species isolated from Australian meat chickens, genomic features of Enterococcus faecium and Enterococcus faecalis, and the phylogenetic relationship of the poultry-derived E. faecium with isolates from human sepsis cases. All enterococcal isolates from chicken ceca were subjected to antimicrobial susceptibility testing. E. faecium and E. faecalis underwent whole-genome sequencing. E. faecium was compared at the core genome level to a collection of human isolates (n = 677) obtained from cases of sepsis over a 2-year period spanning 2015 to 2016. Overall, 205 enterococci were isolated consisting of five different species. E. faecium was the most frequently isolated species (37.6%), followed by E. durans (29.7%), E. faecalis (20%), E. hirae (12.2%), and E. gallinarum (0.5%). All isolates were susceptible to vancomycin and gentamicin, while one isolate was linezolid resistant (MIC 16 mg/liter). Core genome analysis of the E. faecium demonstrated two clades consisting predominantly of human or chicken isolates in each clade, with minimal overlap. Principal component analysis for total gene content revealed three clusters comprised of vanA-positive, vanB-positive, and both vanA- and vanB-negative E. faecium populations. The results of this study provide strong evidence that Australian chicken E. faecium isolates are unlikely to be precursor strains to the currently circulating vancomycin-resistant strains being isolated in Australian hospitals.
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Affiliation(s)
- Mark O'Dea
- Antimicrobial Resistance and Infectious Diseases Laboratory, Murdoch University, Murdoch, WA, Australia
| | - Shafi Sahibzada
- Antimicrobial Resistance and Infectious Diseases Laboratory, Murdoch University, Murdoch, WA, Australia
| | - David Jordan
- New South Wales Department of Primary Industries, Wollongbar, NSW, Australia
| | - Tanya Laird
- Antimicrobial Resistance and Infectious Diseases Laboratory, Murdoch University, Murdoch, WA, Australia
| | - Terence Lee
- Antimicrobial Resistance and Infectious Diseases Laboratory, Murdoch University, Murdoch, WA, Australia
| | - Kylie Hewson
- Australian Chicken Meat Federation, North Sydney, NSW, Australia
| | - Stanley Pang
- Antimicrobial Resistance and Infectious Diseases Laboratory, Murdoch University, Murdoch, WA, Australia
- PathWest Laboratory Medicine, Fiona Stanley Hospital, Murdoch, WA, Australia
| | - Rebecca Abraham
- Antimicrobial Resistance and Infectious Diseases Laboratory, Murdoch University, Murdoch, WA, Australia
| | - Geoffrey W Coombs
- Antimicrobial Resistance and Infectious Diseases Laboratory, Murdoch University, Murdoch, WA, Australia
- PathWest Laboratory Medicine, Fiona Stanley Hospital, Murdoch, WA, Australia
| | - Taha Harris
- Birling Avian Laboratories, Bringelly, NSW, Australia
| | - Anthony Pavic
- Birling Avian Laboratories, Bringelly, NSW, Australia
| | - Sam Abraham
- Antimicrobial Resistance and Infectious Diseases Laboratory, Murdoch University, Murdoch, WA, Australia
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Agricultural Origins of a Highly Persistent Lineage of Vancomycin-Resistant Enterococcus faecalis in New Zealand. Appl Environ Microbiol 2019; 85:AEM.00137-19. [PMID: 31028029 PMCID: PMC6581176 DOI: 10.1128/aem.00137-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 04/22/2019] [Indexed: 11/26/2022] Open
Abstract
Historical antimicrobial use in NZ agriculture has driven the evolution of ST108, a VRE lineage carrying a range of clinically relevant antimicrobial resistances. The persistence of this lineage in NZ for over a decade indicates that coselection may be an important stabilizing mechanism for its persistence. Enterococcus faecalis and Enterococcus faecium are human and animal gut commensals. Vancomycin-resistant enterococci (VRE) are important opportunistic pathogens with limited treatment options. Historically, the glycopeptide antibiotics vancomycin and avoparcin selected for the emergence of vancomycin resistance in human and animal isolates, respectively, resulting in global cessation of avoparcin use between 1997 and 2000. To better understand human- and animal-associated VRE strains in the postavoparcin era, we sequenced the genomes of 231 VRE isolates from New Zealand (NZ; 75 human clinical, 156 poultry) cultured between 1998 and 2009. E. faecium lineages and their antibiotic resistance carriage patterns strictly delineated between agricultural and human reservoirs, with bacitracin resistance ubiquitous in poultry but absent in clinical E. faecium strains. In contrast, one E. faecalis lineage (ST108) predominated in both poultry and human isolates in the 3 years following avoparcin discontinuation. Both phylogenetic and antimicrobial susceptibility (i.e., ubiquitous bacitracin resistance in both poultry and clinical ST108 isolates) analyses suggest an agricultural origin for the ST108 lineage. VRE isolate resistomes were carried on multiple, heterogeneous plasmids. In some isolate genomes, bacitracin, erythromycin, and vancomycin resistance elements were colocalized, indicating multiple potentially linked selection mechanisms. IMPORTANCE Historical antimicrobial use in NZ agriculture has driven the evolution of ST108, a VRE lineage carrying a range of clinically relevant antimicrobial resistances. The persistence of this lineage in NZ for over a decade indicates that coselection may be an important stabilizing mechanism for its persistence.
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11
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Anholt RM, Klima C, Allan N, Matheson-Bird H, Schatz C, Ajitkumar P, Otto SJ, Peters D, Schmid K, Olson M, McAllister T, Ralston B. Antimicrobial Susceptibility of Bacteria That Cause Bovine Respiratory Disease Complex in Alberta, Canada. Front Vet Sci 2017; 4:207. [PMID: 29255716 PMCID: PMC5723070 DOI: 10.3389/fvets.2017.00207] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 11/20/2017] [Indexed: 01/08/2023] Open
Abstract
Bovine respiratory disease (BRD) is the most important illness of feedlot cattle. Disease management targets the associated bacterial pathogens, Mannheimia haemolytica, Mycoplasma bovis, Pasteurella multocida, Histophilus somni, and Trueperella pyogenes. We conducted a cross-sectional study to measure the frequencies of antimicrobial-resistant BRD pathogens using a collaborative network of veterinarians, industry, government, and a diagnostic laboratory. Seven private veterinary practices in southern Alberta collected samples from both living and dead BRD-affected animals at commercial feedlots. Susceptibility testing of 745 isolates showed that 100% of the M. haemolytica, M. bovis, P. multocida, and T. pyogenes isolates and 66.7% of the H. somni isolates were resistant to at least one antimicrobial class. Resistance to macrolide antimicrobials (90.2% of all isolates) was notable for their importance to beef production and human medicine. Multidrug resistance (MDR) was high in all target pathogens with 47.2% of the isolates resistant to four or five antimicrobial classes and 24.0% resistance to six to nine classes. We compared the MDR profiles of isolates from two feedlots serviced by different veterinary practices. Differences in the average number of resistant classes were found for M. haemolytica (p < 0.001) and P. multocida (p = 0.002). Compared to previous studies, this study suggests an increasing trend of resistance in BRD pathogens against the antimicrobials used to manage the disease in Alberta. For the veterinary clinician, the results emphasize the importance of ongoing susceptibility testing of BRD pathogens to inform treatment protocols. Surveillance studies that collect additional epidemiological information and manage sampling bias will be necessary to develop strategies to limit the spread of resistance.
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Affiliation(s)
| | - Cassidy Klima
- Agriculture and Agri-Food Canada, Lethbridge, AB, Canada
| | - Nick Allan
- Chinook Contract Research Inc., Airdrie, AB, Canada
| | | | | | | | - Simon Jg Otto
- Alberta Ministry of Agriculture and Forestry, Airdrie, AB, Canada.,School of Public Health, University of Alberta, Edmonton, AB, Canada
| | - Delores Peters
- Alberta Ministry of Agriculture and Forestry, Airdrie, AB, Canada
| | | | - Merle Olson
- Alberta Veterinary Laboratories Ltd, Calgary, AB, Canada
| | - Tim McAllister
- Agriculture and Agri-Food Canada, Lethbridge, AB, Canada
| | - Brenda Ralston
- Alberta Ministry of Agriculture and Forestry, Airdrie, AB, Canada
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Ahmed MO, Baptiste KE. Vancomycin-Resistant Enterococci: A Review of Antimicrobial Resistance Mechanisms and Perspectives of Human and Animal Health. Microb Drug Resist 2017; 24:590-606. [PMID: 29058560 DOI: 10.1089/mdr.2017.0147] [Citation(s) in RCA: 220] [Impact Index Per Article: 31.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Vancomycin-resistant enterococci (VRE) are both of medical and public health importance associated with serious multidrug-resistant infections and persistent colonization. Enterococci are opportunistic environmental inhabitants with a remarkable adaptive capacity to evolve and transmit antimicrobial-resistant determinants. The VRE gene operons show distinct genetic variability and apparently continued evolution leading to a variety of antimicrobial resistance phenotypes and various environmental and livestock reservoirs for the most common van genes. Such complex diversity renders a number of important therapeutic options including "last resort antibiotics" ineffective and poses a particular challenge for clinical management. Enterococci resistance to glycopeptides and multidrug resistance warrants attention and continuous monitoring.
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Affiliation(s)
- Mohamed O Ahmed
- 1 Department of Microbiology and Parasitology, Faculty of Veterinary Medicine, University of Tripoli , Tripoli, Libya
| | - Keith E Baptiste
- 2 Department of Veterinary Medicine, Danish Medicines Agency , Copenhagen South, Denmark
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Allen RC, Engelstädter J, Bonhoeffer S, McDonald BA, Hall AR. Reversing resistance: different routes and common themes across pathogens. Proc Biol Sci 2017; 284:20171619. [PMID: 28954914 PMCID: PMC5627214 DOI: 10.1098/rspb.2017.1619] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 08/23/2017] [Indexed: 11/12/2022] Open
Abstract
Resistance spreads rapidly in pathogen or pest populations exposed to biocides, such as fungicides and antibiotics, and in many cases new biocides are in short supply. How can resistance be reversed in order to prolong the effectiveness of available treatments? Some key parameters affecting reversion of resistance are well known, such as the fitness cost of resistance. However, the population biological processes that actually cause resistance to persist or decline remain poorly characterized, and consequently our ability to manage reversion of resistance is limited. Where do susceptible genotypes that replace resistant lineages come from? What is the epidemiological scale of reversion? What information do we need to predict the mechanisms or likelihood of reversion? Here, we define some of the population biological processes that can drive reversion, using examples from a wide range of taxa and biocides. These processes differ primarily in the origin of revertant genotypes, but also in their sensitivity to factors such as coselection and compensatory evolution that can alter the rate of reversion, and the likelihood that resistance will re-emerge upon re-exposure to biocides. We therefore argue that discriminating among different types of reversion allows for better prediction of where resistance is most likely to persist.
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Affiliation(s)
- Richard C Allen
- Institute of Integrative Biology, ETH Zürich, CH-8092 Zurich, Switzerland
| | - Jan Engelstädter
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia
| | | | - Bruce A McDonald
- Institute of Integrative Biology, ETH Zürich, CH-8092 Zurich, Switzerland
| | - Alex R Hall
- Institute of Integrative Biology, ETH Zürich, CH-8092 Zurich, Switzerland
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14
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Hume ME, Donskey CJ. Effect of Vancomycin, Tylosin, and Chlortetracycline on Vancomycin-Resistant Enterococcus faecium Colonization of Broiler Chickens During Grow-Out. Foodborne Pathog Dis 2017; 14:231-237. [PMID: 28128649 DOI: 10.1089/fpd.2016.2217] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Broiler chickens may serve as reservoirs for human colonization by vancomycin-resistant Enterococcus (VRE). We examined the effects of vancomycin and two commonly used antimicrobial feed additives on VRE colonization in broiler chickens during grow-out. Chicks received unsupplemented feed or feed containing vancomycin, chlortetracycline, or tylosin from day of hatch to grow-out at 6 weeks. At 3 days of age, chicks received by crop gavage 107 colony-forming units (CFUs) of a human or poultry VRE isolate. Cecal contents were monitored weekly for VRE, short-chain fatty acids (SCFAs), and bacterial denaturing gradient gel electrophoresis (DGGE) profile methods. Vancomycin promoted persistent and high-level colonization with human- and poultry-derived VRE to grow-out in comparison with controls, while treatment with chlortetracycline and tylosin did not. Colonization by the poultry isolate in control, chlortetracycline, and tylosin groups persisted throughout the grow-out period with low concentrations present at 6 weeks, whereas the human isolate decreased to an undetectable level by week 6. Vancomycin resulted in significant reductions in cecal acetic acid and butyric acid in comparison with controls, but chlortetracycline and tylosin did not. DGGE profiles contained two main clusters with all vancomycin profiles in a smaller cluster and all other profiles in a larger cluster. These results demonstrate that vancomycin, but not chlortetracycline or tylosin, disrupted the indigenous microbiota and SCFA patterns of broiler chickens and promoted colonization by VRE.
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Affiliation(s)
- Michael E Hume
- 1 Food and Feed Safety Research Unit, Southern Plains Agricultural Research Center , Agricultural Research Service, U.S. Department of Agriculture, College Station, Texas
| | - Curtis J Donskey
- 2 Infectious Diseases Section, Louis Stokes Cleveland Veterans Affairs Medical Center , Cleveland, Ohio
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Murphy D, Ricci A, Auce Z, Beechinor JG, Bergendahl H, Breathnach R, Bureš J, Duarte Da Silva JP, Hederová J, Hekman P, Ibrahim C, Kozhuharov E, Kulcsár G, Lander Persson E, Lenhardsson JM, Mačiulskis P, Malemis I, Markus-Cizelj L, Michaelidou-Patsia A, Nevalainen M, Pasquali P, Rouby JC, Schefferlie J, Schlumbohm W, Schmit M, Spiteri S, Srčič S, Taban L, Tiirats T, Urbain B, Vestergaard EM, Wachnik-Święcicka A, Weeks J, Zemann B, Allende A, Bolton D, Chemaly M, Fernandez Escamez PS, Girones R, Herman L, Koutsoumanis K, Lindqvist R, Nørrung B, Robertson L, Ru G, Sanaa M, Simmons M, Skandamis P, Snary E, Speybroeck N, Ter Kuile B, Wahlström H, Baptiste K, Catry B, Cocconcelli PS, Davies R, Ducrot C, Friis C, Jungersen G, More S, Muñoz Madero C, Sanders P, Bos M, Kunsagi Z, Torren Edo J, Brozzi R, Candiani D, Guerra B, Liebana E, Stella P, Threlfall J, Jukes H. EMA and EFSA Joint Scientific Opinion on measures to reduce the need to use antimicrobial agents in animal husbandry in the European Union, and the resulting impacts on food safety (RONAFA). EFSA J 2017; 15:e04666. [PMID: 32625259 PMCID: PMC7010070 DOI: 10.2903/j.efsa.2017.4666] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
EFSA and EMA have jointly reviewed measures taken in the EU to reduce the need for and use of antimicrobials in food-producing animals, and the resultant impacts on antimicrobial resistance (AMR). Reduction strategies have been implemented successfully in some Member States. Such strategies include national reduction targets, benchmarking of antimicrobial use, controls on prescribing and restrictions on use of specific critically important antimicrobials, together with improvements to animal husbandry and disease prevention and control measures. Due to the multiplicity of factors contributing to AMR, the impact of any single measure is difficult to quantify, although there is evidence of an association between reduction in antimicrobial use and reduced AMR. To minimise antimicrobial use, a multifaceted integrated approach should be implemented, adapted to local circumstances. Recommended options (non-prioritised) include: development of national strategies; harmonised systems for monitoring antimicrobial use and AMR development; establishing national targets for antimicrobial use reduction; use of on-farm health plans; increasing the responsibility of veterinarians for antimicrobial prescribing; training, education and raising public awareness; increasing the availability of rapid and reliable diagnostics; improving husbandry and management procedures for disease prevention and control; rethinking livestock production systems to reduce inherent disease risk. A limited number of studies provide robust evidence of alternatives to antimicrobials that positively influence health parameters. Possible alternatives include probiotics and prebiotics, competitive exclusion, bacteriophages, immunomodulators, organic acids and teat sealants. Development of a legislative framework that permits the use of specific products as alternatives should be considered. Further research to evaluate the potential of alternative farming systems on reducing AMR is also recommended. Animals suffering from bacterial infections should only be treated with antimicrobials based on veterinary diagnosis and prescription. Options should be reviewed to phase out most preventive use of antimicrobials and to reduce and refine metaphylaxis by applying recognised alternative measures.
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Persistence of vancomycin resistance in multiple clones of Enterococcus faecium isolated from Danish broilers 15 years after the ban of avoparcin. Antimicrob Agents Chemother 2015; 59:2926-9. [PMID: 25712360 DOI: 10.1128/aac.05072-14] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 02/16/2015] [Indexed: 12/16/2022] Open
Abstract
The occurrence and diversity of vancomycin-resistant Enterococcus faecium (VREF) were investigated in 100 Danish broiler flocks 15 years after the avoparcin ban. VREF occurred in 47 flocks at low fecal concentrations detectable only by selective enrichment. Vancomycin resistance was prevalently associated with a transferable nontypeable plasmid lineage occurring in multiple E. faecium clones. Coselection of sequence type 842 by tetracycline use only partly explained the persistence of vancomycin resistance in the absence of detectable plasmid coresistance and toxin-antitoxin systems.
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17
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Navarro-Gonzalez N, Porrero MC, Mentaberre G, Serrano E, Mateos A, Domínguez L, Lavín S. Antimicrobial resistance in indicator Escherichia coli isolates from free-ranging livestock and sympatric wild ungulates in a natural environment (Northeastern Spain). Appl Environ Microbiol 2013; 79:6184-6. [PMID: 23892753 PMCID: PMC3811374 DOI: 10.1128/aem.01745-13] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 07/17/2013] [Indexed: 11/20/2022] Open
Abstract
Antimicrobial resistance was assessed in indicator Escherichia coli isolates from free-ranging livestock and sympatric wild boar (Sus scrofa) and Iberian ibex (Capra pyrenaica) in a National Game Reserve in northeastern Spain. The frequency of antimicrobial resistance was low (0% to 7.9%). However, resistance to an extended-spectrum cephalosporin and fluoroquinolones was detected.
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Affiliation(s)
- N. Navarro-Gonzalez
- Servei d' Ecopatologia de Fauna Salvatge (SEFaS), Departament de Medicina i Cirurgia Animals, Universitat Autònoma de Barcelona (UAB), Bellaterra, Barcelona, Spain
| | - M. C. Porrero
- Centro de Vigilancia Sanitaria Veterinaria (VISAVET), Universidad Complutense (UCM), Madrid, Spain
| | - G. Mentaberre
- Servei d' Ecopatologia de Fauna Salvatge (SEFaS), Departament de Medicina i Cirurgia Animals, Universitat Autònoma de Barcelona (UAB), Bellaterra, Barcelona, Spain
| | - E. Serrano
- Servei d' Ecopatologia de Fauna Salvatge (SEFaS), Departament de Medicina i Cirurgia Animals, Universitat Autònoma de Barcelona (UAB), Bellaterra, Barcelona, Spain
- Estadística i Investigació Operativa, Departament de Matemàtica, Universitat de Lleida (UdL), Lleida, Spain
| | - A. Mateos
- Centro de Vigilancia Sanitaria Veterinaria (VISAVET), Universidad Complutense (UCM), Madrid, Spain
| | - L. Domínguez
- Centro de Vigilancia Sanitaria Veterinaria (VISAVET), Universidad Complutense (UCM), Madrid, Spain
| | - S. Lavín
- Servei d' Ecopatologia de Fauna Salvatge (SEFaS), Departament de Medicina i Cirurgia Animals, Universitat Autònoma de Barcelona (UAB), Bellaterra, Barcelona, Spain
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18
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Jansson D, Nilsson O, Lindblad J, Greko C, Bengtsson B. Inter-batch contamination and potential sources of vancomycin-resistantEnterococcus faeciumon broiler farms. Br Poult Sci 2012; 53:790-9. [DOI: 10.1080/00071668.2012.750715] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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19
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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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20
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Hume ME. Historic perspective: prebiotics, probiotics, and other alternatives to antibiotics. Poult Sci 2011; 90:2663-9. [PMID: 22010256 DOI: 10.3382/ps.2010-01030] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Applications of antimicrobials in food production and human health have found favor throughout human history. Antibiotic applications in agricultural and human medical arenas have resulted in tremendous increases in food animal production and historically unprecedented gains in human health protection. Successes attributed to widespread antibiotic use have been accompanied by the inadvertent emergence of antibiotic-resistant bacteria. A major problem associated with this emerging resistance is the crossover use of some antibiotics in agricultural settings as well as in the prevention and treatment of human disease. This outcome led to calls to restrict the use of human health-related antibiotics in food animal production. Calls for restricted antibiotic use have heightened existing searches for alternatives to antibiotics that give similar or enhanced production qualities as highly reliable as the antibiotics currently provided to food animals. Agricultural and scientific advances, mainly within the last 100 yr, have given us insights into sources, structures, and actions of materials that have found widespread application in our modern world. The purpose of this presentation is to provide a historic perspective on the search for what are generally known as antibiotics and alternative antimicrobials, probiotics, prebiotics, bacteriophages, bacteriocins, and phytotherapeutics.
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Affiliation(s)
- M E Hume
- USDA, Agricultural Research Service, Southern Plains Agricultural Research Center, Food and Feed Safety Research Unit, College Station, TX 77845, USA.
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Sapkota AR, Hulet RM, Zhang G, McDermott P, Kinney EL, Schwab KJ, Joseph SW. Lower prevalence of antibiotic-resistant Enterococci on U.S. conventional poultry farms that transitioned to organic practices. ENVIRONMENTAL HEALTH PERSPECTIVES 2011; 119:1622-1628. [PMID: 21827979 PMCID: PMC3226496 DOI: 10.1289/ehp.1003350] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Accepted: 08/01/2011] [Indexed: 05/29/2023]
Abstract
BACKGROUND In U.S. conventional poultry production, antimicrobials are used for therapeutic, prophylactic, and nontherapeutic purposes. Researchers have shown that this can select for antibiotic-resistant commensal and pathogenic bacteria on poultry farms and in poultry-derived products. However, no U.S. studies have investigated on-farm changes in resistance as conventional poultry farms transition to organic practices and cease using antibiotics. OBJECTIVE We investigated the prevalence of antibiotic-resistant Enterococcus on U.S. conventional poultry farms that transitioned to organic practices. METHODS Poultry litter, feed, and water samples were collected from 10 conventional and 10 newly organic poultry houses in 2008 and tested for Enterococcus. Enterococcus (n = 259) was identified using the Vitek® 2 Compact System and tested for susceptibility to 17 antimicrobials using the Sensititre™ microbroth dilution system. Data were analyzed using SAS software (version 9.2), and statistical associations were derived based on generalized linear mixed models. RESULTS Litter, feed, and water samples were Enterococcus positive. The percentages of resistant Enterococcus faecalis and resistant Enterococcus faecium were significantly lower (p < 0.05) among isolates from newly organic versus conventional poultry houses for two (erythromycin and tylosin) and five (ciprofloxacin, gentamicin, nitrofurantoin, penicillin, and tetracycline) antimicrobials, respectively. Forty-two percent of E. faecalis isolates from conventional poultry houses were multidrug resistant (MDR; resistant to three or more antimicrobial classes), compared with 10% of isolates from newly organic poultry houses (p = 0.02); 84% of E. faecium isolates from conventional poultry houses were MDR, compared with 17% of isolates from newly organic poultry houses (p < 0.001). CONCLUSIONS Our findings suggest that the voluntary removal of antibiotics from large-scale U.S. poultry farms that transition to organic practices is associated with a lower prevalence of antibiotic-resistant and MDR Enterococcus.
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Affiliation(s)
- Amy R Sapkota
- Maryland Institute for Applied Environmental Health, University of Maryland, School of Public Health, College Park, Maryland, USA.
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Barros J, Igrejas G, Andrade M, Radhouani H, López M, Torres C, Poeta P. Gilthead seabream (Sparus aurata) carrying antibiotic resistant enterococci. A potential bioindicator of marine contamination? MARINE POLLUTION BULLETIN 2011; 62:1245-1248. [PMID: 21511306 DOI: 10.1016/j.marpolbul.2011.03.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Revised: 03/07/2011] [Accepted: 03/16/2011] [Indexed: 05/30/2023]
Abstract
Antibiotic resistance in bacteria is a growing problem that is not only restricted to the clinical setting but also to other environments such as marine species that harbor antibiotic resistant bacteria and therefore may serve as reservoirs for antibiotic-resistance genetic determinants. The aim of this study was to evaluate antibiotic resistance phenotypes in enterococci isolated from fecal samples of gilthead seabream and the associated mechanisms of resistance. A collection of 118 samples were analyzed and 73 enterococci were recovered. The strains showed high percentages of resistance to erythromycin and tetracycline (58.9% and 17.8%, respectively). Lower level of resistance (<13%) was detected for quinupristin-dalfopristin, ampicillin, high-level-gentamicin, high-level-streptomycin, high-level-kanamycin, ciprofloxacin and chloramphenicol. The erm(B), tet(L) or tet(M), aac(6')-aph(2″) and aph(3')-IIIa genes were shown in isolates resistant to erythromycin, tetracycline, high-level gentamicin and high-level kanamycin, respectively. Antibiotic resistance in natural microbiota is becoming a concern of human and environmental health.
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Affiliation(s)
- Joana Barros
- Institute for Biotechnology and Bioengineering, Center of Genomics and Biotechnology, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal
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Bélanger L, Garenaux A, Harel J, Boulianne M, Nadeau E, Dozois CM. Escherichia coli from animal reservoirs as a potential source of human extraintestinal pathogenic E. coli. ACTA ACUST UNITED AC 2011; 62:1-10. [PMID: 21362060 DOI: 10.1111/j.1574-695x.2011.00797.x] [Citation(s) in RCA: 180] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Extraintestinal pathogenic Escherichia coli (ExPEC) are an important cause of urinary tract infections, neonatal meningitis and septicaemia in humans. Animals are recognized as a reservoir for human intestinal pathogenic E. coli, but whether animals are a source for human ExPEC is still a matter of debate. Pathologies caused by ExPEC are reported for many farm animals, especially for poultry, in which colibacillosis is responsible for huge losses within broiler chickens. Cases are also reported for companion animals. Commensal E. coli strains potentially carrying virulence factors involved in the development of human pathologies also colonize the intestinal tract of animals. This review focuses on the recent evidence of the zoonotic potential of ExPEC from animal origin and their potential direct or indirect transmission from animals to humans. As antimicrobials are commonly used for livestock production, infections due to antimicrobial-resistant ExPEC transferred from animals to humans could be even more difficult to treat. These findings, combined with the economic impact of ExPEC in the animal production industry, demonstrate the need for adapted measures to limit the prevalence of ExPEC in animal reservoirs while reducing the use of antimicrobials as much as possible.
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Affiliation(s)
- Louise Bélanger
- Prevtec microbia, Saint-Hyacinthe, QC, Canada Centre de recherche en infectiologie porcine, Université de Montréal, Saint-Hyacinthe, QC, Canada
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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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Lanthier M, Scott A, Lapen DR, Zhang Y, Topp E. Frequency of virulence genes and antibiotic resistances inEnterococcusspp. isolates from wastewater and feces of domesticated mammals and birds, and wildlife. Can J Microbiol 2010; 56:715-29. [DOI: 10.1139/w10-046] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Enterococci are gastrointestinal tract residents and also an important cause of nosocomial infections. To understand which species, virulence determinants, and antibiotic resistances are prevalent in enterococci shed by various hosts groups, a total of 1460 strains isolated from 144 fecal samples obtained from wastewater, domesticated mammals and birds, and wildlife were characterized. Identification of isolates to the species level showed that Enterococcus faecalis was dominant in domesticated mammals and birds and wildlife feces, whereas Enterococcus faecium was dominant among wastewater isolates, and that no single Enterococcus species could be associated with a specific host group. The frequency of 12 virulence determinants was evaluated among isolates, but no single virulence determinant could be associated with a specific host group. Resistance to 12 antibiotics was evaluated among isolates, and it was shown that the highest frequency of resistance at breakpoint concentration was found in domesticated mammals and birds (P ≤ 0.05 for 4 antibiotics). Our results suggests that (1) species identification and virulence typing of Enterococcus spp. isolates are not useful for the identification of the host groups responsible for fecal contamination of water by microbial source tracking and that (2) antibiotic use for clinical, veterinary, or animal husbandry practices is promoting resistance.
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Affiliation(s)
- Martin Lanthier
- Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, 960 Carling Avenue, Ottawa, ON K1A 0C6, Canada
- Southern Crop Protection and Food Research Centre, Agriculture and Agri-Food Canada, 1391 Sanford Street, London, ON N5V 4T3, Canada
| | - Andrew Scott
- Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, 960 Carling Avenue, Ottawa, ON K1A 0C6, Canada
- Southern Crop Protection and Food Research Centre, Agriculture and Agri-Food Canada, 1391 Sanford Street, London, ON N5V 4T3, Canada
| | - David R. Lapen
- Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, 960 Carling Avenue, Ottawa, ON K1A 0C6, Canada
- Southern Crop Protection and Food Research Centre, Agriculture and Agri-Food Canada, 1391 Sanford Street, London, ON N5V 4T3, Canada
| | - Yun Zhang
- Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, 960 Carling Avenue, Ottawa, ON K1A 0C6, Canada
- Southern Crop Protection and Food Research Centre, Agriculture and Agri-Food Canada, 1391 Sanford Street, London, ON N5V 4T3, Canada
| | - Edward Topp
- Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, 960 Carling Avenue, Ottawa, ON K1A 0C6, Canada
- Southern Crop Protection and Food Research Centre, Agriculture and Agri-Food Canada, 1391 Sanford Street, London, ON N5V 4T3, Canada
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Pleydell E, Rogers L, Kwan E, French N. Evidence for the clustering of antibacterial resistance phenotypes of enterococci within integrated poultry companies. MICROBIAL ECOLOGY 2010; 59:678-688. [PMID: 20082072 DOI: 10.1007/s00248-009-9625-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2009] [Accepted: 11/22/2009] [Indexed: 05/28/2023]
Abstract
From July to December 2006, a panel of 401 enterococci was isolated from carcass rinse samples collected in five poultry processing plants in New Zealand. Agar diffusion assays for nine antibacterial drugs were used to obtain a resistance phenotype for each isolate. Hierarchical clustering techniques and diversity indices showed a high diversity of resistance phenotypes within each plant, with populations of Enterococcus faecalis showing greater heterogeneity than Enterococcus faecium. Bayesian modelling identified three clusters of phenotype patterns within the panel: the E. faecium isolates showed a high probability of containing two distinct clusters, whilst the E. faecalis isolates all grouped together to form the third cluster. The validity of these three clusters was examined using pairwise fixation indices and analysis of variance. Comparing the three clusters to the structure of the participating companies showed that resistance phenotypes for E. faecium isolated from processing plants that were geographically separated but were operated by the same integrated poultry company were more similar than E. faecium isolated from unconnected companies. Company-level management factors, such as the routine use of antibacterial drugs and the genetic line of birds reared, mirrored the structure of these clusters, thus indicating that company-level factors were the dominant selective pressures upon resistance phenotypes across all operating units within these integrated poultry companies.
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Affiliation(s)
- Eve Pleydell
- Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Private Bag 11 222, Palmerston North, New Zealand.
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Schwaiger K, Schmied EMV, Bauer J. Comparative Analysis on Antibiotic Resistance Characteristics ofListeriaspp. andEnterococcusspp. Isolated From Laying Hens and Eggs in Conventional and Organic Keeping Systems in Bavaria, Germany. Zoonoses Public Health 2010; 57:171-80. [DOI: 10.1111/j.1863-2378.2008.01229.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Comparison of the prevalence of bacterial enteropathogens, potentially zoonotic bacteria and bacterial resistance to antimicrobials in organic and conventional poultry, swine and beef production: a systematic review and meta-analysis. Epidemiol Infect 2009; 137:1217-32. [DOI: 10.1017/s0950268809002635] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
SUMMARYThe prevalences of zoonotic and potentially zoonotic bacteria or bacteria resistant to antimicrobials in organic and conventional poultry, swine and beef production were compared using systematic review and meta-analysis methodology. Thirty-eight articles were included in the review. The prevalence of Campylobacter was higher in organic broiler chickens at slaughter, but no difference in prevalence was observed in retail chicken. Campylobacter isolates from conventional retail chicken were more likely to be ciprofloxacin-resistant (odds ratio 9·62, 95% confidence interval 5·67–16·35). Bacteria isolated from conventional animal production exhibited a higher prevalence of resistance to antimicrobials; however, the recovery of some resistant strains was also identified in organic animal production, where there is an apparent reduced antimicrobial selection pressure. Limited or inconsistent research was identified in studies examining the prevalence of zoonotic and potentially zoonotic bacteria in other food-animal species. There is a need for further research of sufficient quality in this area.
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Gaze W, O'Neill C, Wellington E, Hawkey P. Antibiotic resistance in the environment, with particular reference to MRSA. ADVANCES IN APPLIED MICROBIOLOGY 2008; 63:249-80. [PMID: 18395130 DOI: 10.1016/s0065-2164(07)00007-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- William Gaze
- Department of Biological Sciences, University of Warwick, Coventry CV47AL, United Kingdom
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30
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Hammerum AM, Heuer OE, Lester CH, Agersø Y, Seyfarth AM, Emborg HD, Frimodt-Møller N, Monnet DL. Comment on: withdrawal of growth-promoting antibiotics in Europe and its effects in relation to human health. Int J Antimicrob Agents 2007; 30:466-8. [PMID: 17884357 DOI: 10.1016/j.ijantimicag.2007.07.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2007] [Accepted: 07/11/2007] [Indexed: 11/22/2022]
Abstract
In response to a review titled 'Withdrawal of growth-promoting antibiotics in Europe and its effects in relation to human health', published in this Journal by Ian Phillips, we hereby comment on the review. Phillips makes use of data from the Danish Integrated Antimicrobial Resistance Monitoring and Research Programme (DANMAP) reports and studies on Campylobacter and enterococci. Unfortunately, we find these data frequently misinterpreted by Phillips, leading to false conclusions such as inferences that the ban of antibiotic growth promoters should cause an increased prevalence of resistant enterococci and Campylobacter.
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Affiliation(s)
- Anette M Hammerum
- National Center for Antimicrobials and Infection Control, Statens Serum Institut, Artillerivej 5, DK-2300 Copenhagen S, Denmark.
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31
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Singer RS, Ward MP, Maldonado G. Can landscape ecology untangle the complexity of antibiotic resistance? Nat Rev Microbiol 2006; 4:943-52. [PMID: 17109031 DOI: 10.1038/nrmicro1553] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Bacterial resistance to antibiotics continues to pose a serious threat to human and animal health. Given the considerable spatial and temporal heterogeneity in the distribution of resistance and the factors that affect its evolution, dissemination and persistence, we argue that antibiotic resistance must be viewed as an ecological problem. A fundamental difficulty in assessing the causal relationship between antibiotic use and resistance is the confounding influence of geography: the co-localization of resistant bacterial species with antibiotic use does not necessarily imply causation and could represent the presence of environmental conditions and factors that have independently contributed to the occurrence of resistance. Here, we show how landscape ecology, which links the biotic and abiotic factors of an ecosystem, might help to untangle the complexity of antibiotic resistance and improve the interpretation of ecological studies.
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Affiliation(s)
- Randall S Singer
- Division of Environmental Health Sciences, School of Public Health, University of Minnesota, Minneapolis, Minnesota 55455 USA.
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32
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Pleydell EJ, Brown PE, Woodward MJ, Davies RH, French NP. Sources of variation in the ampicillin-resistant Escherichia coli concentration in the feces of organic broiler chickens. Appl Environ Microbiol 2006; 73:203-10. [PMID: 17085693 PMCID: PMC1797143 DOI: 10.1128/aem.01482-06] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Currently, there are limited published data for the population dynamics of antimicrobial-resistant commensal bacteria. This study was designed to evaluate both the proportions of the Escherichia coli populations that are resistant to ampicillin at the level of the individual chicken on commercial broiler farms and the feasibility of obtaining repeated measures of fecal E. coli concentrations. Short-term temporal variation in the concentration of fecal E. coli was investigated, and a preliminary assessment was made of potential factors involved in the shedding of high numbers of ampicillin-resistant E. coli by growing birds in the absence of the use of antimicrobial drugs. Multilevel linear regression modeling revealed that the largest component of random variation in log-transformed fecal E. coli concentrations was seen between sampling occasions for individual birds. The incorporation of fixed effects into the model demonstrated that the older, heavier birds in the study were significantly more likely (P = 0.0003) to shed higher numbers of ampicillin-resistant E. coli. This association between increasing weight and high shedding was not seen for the total fecal E. coli population (P = 0.71). This implies that, in the absence of the administration of antimicrobial drugs, the proportion of fecal E. coli that was resistant to ampicillin increased as the birds grew. This study has shown that it is possible to collect quantitative microbiological data on broiler farms and that such data could make valuable contributions to risk assessments concerning the transfer of resistant bacteria between animal and human populations.
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Affiliation(s)
- E J Pleydell
- Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Private Bag 11 222, Palmerston North 4442, New Zealand.
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33
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Abstract
The ways in which antibiotics are used in poultry production have changed considerably during the past decade, mainly because of concerns about potential negative human health consequences caused by these uses. Human health improvements directly attributable to these antibiotic-use changes are difficult to demonstrate. Given that some antibiotics will continue to be used in the poultry industry, methods are needed for estimating the causal relationship between these antibiotic uses and actual animal and human health impacts. This is a challenging task because of the numerous factors that are able to select for the emergence, dissemination, and persistence of antibiotic resistance. Managing the potential impacts of antibiotic use in poultry requires more than a simple estimation of the risks that can be attributed to the use of antibiotics in poultry. Risk models and empirical studies that evaluate interventions that are capable of minimizing the negative consequences associated with specific antibiotic uses are desperately needed.
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Affiliation(s)
- Randall S Singer
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St Paul 55108, USA
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Lim SK, Kim TS, Lee HS, Nam HM, Joo YS, Koh HB. Persistence ofvanA-TypeEnterococcus faeciumin Korean Livestock After Ban on Avoparcin. Microb Drug Resist 2006; 12:136-9. [PMID: 16922630 DOI: 10.1089/mdr.2006.12.136] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Prevalence of vancomycin-resistant enterococci (VRE) was investigated in Korean livestock 4 years after the ban of avoparcin in feed additives. VRE were isolated from approximately 16.7% of the chicken samples (57 strains from 342 meat samples) and 1.9% of the pig samples (4 from 214 fecal samples). No VRE, however, was isolated from 110 bovine fecal samples. All the 61 VRE isolates were vanA-type Enterococcus faecium expressing a high-level resistance to vancomycin, and showed resistance to teicoplanin as well except two poultry isolates. In addition, the VRE isolates had heterogeneous pulsed-field gel electrophoresis (PFGE) patterns of SmaI-digested DNA, although identical or closely related profiles were observed among strains isolated from the same farm. Although the chicken isolates were all poultry type with G at position 8,234 of the vanX gene, the pig isolates were all swine type with T at position 8,234 of the vanX gene.
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Affiliation(s)
- Suk-Kyung Lim
- National Veterinary Research and Quarantine Service, Anyang, Republic of Korea
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Abstract
During the past century the excitement of discovering antibiotics as a treatment of infectious diseases has given way to a sense of complacency and acceptance that when faced with antimicrobial resistance there will always be new and better antimicrobial agents to use. Now, with clear indications of a decline in pharmaceutical company interest in anti-infective research, at the same time when multi-drug resistant micro-organisms continue to be reported, it is very important to review the prudent use of the available agents to fight these micro-organisms. Injudicious use of antibiotics is a global problem with some countries more affected than others. There is no dearth of interest in this subject with scores of scholarly articles written about it. While over the counter access to antibiotics is mentioned as an important contributor towards injudicious antibiotic use in developing nations, as shown in a number of studies, there are many provider, practice and patient characteristics which drive antibiotic overuse in developed nations such as the United States. Recognizing that a thorough review of this subject goes far and beyond the page limitations of a review article we provide a summary of some of the salient aspects of this global problem with a focus towards readers practicing in developing nations.
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Affiliation(s)
- Aditya H Gaur
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee 38105-2794, USA.
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36
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Lester CH, Frimodt-Møller N, Sørensen TL, Monnet DL, Hammerum AM. In vivo transfer of the vanA resistance gene from an Enterococcus faecium isolate of animal origin to an E. faecium isolate of human origin in the intestines of human volunteers. Antimicrob Agents Chemother 2006; 50:596-9. [PMID: 16436715 PMCID: PMC1366888 DOI: 10.1128/aac.50.2.596-599.2006] [Citation(s) in RCA: 168] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Transient colonization by vancomycin-resistant enterococci of animal origin has been documented in the intestines of humans. However, little is known about whether transfer of the vanA gene occurs in the human intestine. Six volunteers ingested a vancomycin-resistant Enterococcus faecium isolate of chicken origin, together with a vancomycin-susceptible E. faecium recipient of human origin. Transconjugants were recovered in three of six volunteers. In one volunteer, not only was vancomycin resistance transferred, but also quinupristin-dalfopristin resistance. This study shows that transfer of the vanA gene from an E. faecium isolate of animal origin to an E. faecium isolate of human origin can occur in the intestines of humans. It suggests that transient intestinal colonization by enterococci carrying mobile elements with resistance genes represents a risk for spread of resistance genes to other enterococci that are part of the human indigenous flora, which can be responsible for infections in certain groups of patients, e.g., immunocompromised patients.
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Affiliation(s)
- Camilla H Lester
- National Center for Antimicrobials and Infection Control, Statens Serum Institut, 5 Artillerivej, DK-2300 Copenhagen S, Denmark.
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Sørum M, Johnsen PJ, Aasnes B, Rosvoll T, Kruse H, Sundsfjord A, Simonsen GS. Prevalence, persistence, and molecular characterization of glycopeptide-resistant enterococci in Norwegian poultry and poultry farmers 3 to 8 years after the ban on avoparcin. Appl Environ Microbiol 2006; 72:516-21. [PMID: 16391086 PMCID: PMC1352202 DOI: 10.1128/aem.72.1.516-521.2006] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2005] [Accepted: 10/20/2005] [Indexed: 11/20/2022] Open
Abstract
Environmental reservoirs of glycopeptide-resistant enterococci (GRE) in Norway have been linked to former growth promoting use of the glycopeptide avoparcin in poultry production. We have examined the prevalence of fecal GRE in poultry and poultry farmers 3 to 8 years after the Norwegian avoparcin ban in 1995 and performed molecular analyses of the GRE population. Fecal samples from poultry farmers and their flocks on 29 previously avoparcin-exposed farms were collected on five occasions during the study period (1998 to 2003). All flocks (100%) were GRE positive in 1998. Throughout the study period, 78.5% of the poultry samples were GRE positive. Glycopeptide-resistant Enterococcus faecium (GREF) was isolated from 27.6% of the farmer samples in 1998 and from 27.8% of the samples collected between 1998 and 2003. The prevalence of fecal GRE in poultry declined significantly during the study period, but prevalence in samples from the farmers did not decline. PCR analysis revealed a specific Tn1546-plasmid junction fragment in 93.9% of E. faecium isolates. A putative postsegregation killing (PSK) system linked to Tn1546 was detected in 97.1% of the isolates examined. Multilocus sequence typing of glycopeptide-susceptible (n = 10) and -resistant (n = 10) E. faecium isolates from humans (n = 10) and poultry (n = 10) on two farms displayed 17 different sequence types. The study confirms the continuing persistence of a widespread common plasmid-mediated vanA-pRE25-PSK element within a heterogeneous GRE population on Norwegian poultry farms 8 years after the avoparcin ban. Moreover, it suggests an important role of PSK systems in the maintenance of antimicrobial resistance determinants in reservoirs without apparent antimicrobial selection.
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Affiliation(s)
- M Sørum
- Department of Microbiology and Virology, Faculty of Medicine, University and University Hospital of North Norway, Tromsø, Norway.
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Eisner A, Feierl G, Gorkiewicz G, Dieber F, Kessler HH, Marth E, Köfer J. High prevalence of VanA-type vancomycin-resistant Enterococci in Austrian poultry. Appl Environ Microbiol 2005; 71:6407-9. [PMID: 16204568 PMCID: PMC1266017 DOI: 10.1128/aem.71.10.6407-6409.2005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Fecal samples from humans and food-producing animals were analyzed for the presence of vancomycin-resistant enterococci (VRE). The VRE carriage rate in humans was 6%, and there was a predominance of VanC-type resistance. Enterococcus faecium with vanA-mediated resistance was frequent in broiler chickens (42%) but rare in cattle and pig samples.
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Affiliation(s)
- Alexandra Eisner
- Institute of Hygiene, Medical University of Graz, Universitätsplatz 4, A-8010 Graz, Austria.
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Mascini EM, Bonten MJM. Vancomycin-resistant enterococci: consequences for therapy and infection control. Clin Microbiol Infect 2005; 11 Suppl 4:43-56. [PMID: 15953021 DOI: 10.1111/j.1469-0691.2005.01164.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Vancomycin-resistant enterococci (VRE) have emerged as important nosocomial pathogens, initially in the USA, but now also in Europe, where hospital outbreaks are being reported with increasing frequency, although the incidence of VRE infections remains extremely low in most European countries. The recently demonstrated in-human transmission of vancomycin resistance from VRE to methicillin-resistant Staphylococcus aureus (MRSA) in two American patients underscores the potential danger of a coexisting reservoir of both pathogens. As MRSA is already endemic in many European hospital settings, prevention of endemicity with VRE seems relevant, but should be balanced against the costs associated with the implementation of effective strategies. The presence of a large community reservoir of VRE in Europe could hamper the feasibility of infection control strategies. Although the prevalence of colonisation amongst healthy subjects has apparently decreased after the ban on avoparcin use in the agricultural industry, a large proportion of admitted patients are still potential sources of VRE transmission. With no risk profile available to identify these carriers, effective screening, followed by barrier precautions for carriers, seems to be impossible. Recent studies, however, have suggested that hospital outbreaks are almost exclusively caused by specific genogroups of VRE that can be characterised phenotypically and genotypically (e.g., co-resistance to ampicillin and the presence of the variant esp gene). Based on our own experience, we propose that VRE infection control programmes should be restricted to patients colonised with these VRE strains. If such a strain is cultured from a clinical sample, surveillance amongst contact patients is recommended and barrier precautions should be implemented in the case of documented spread.
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Affiliation(s)
- E M Mascini
- Eijkman-Winkler Institute for Medical Microbiology, Infectious Diseases and Inflammation, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
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40
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Abstract
The problems associated with antibiotic resistance have led to several agency and governmental reports since 1998, along with many sets of usage guidelines. These documents stress the desirability of reducing antimicrobial prescribing, which has subsequently fallen in several countries, including the UK. However, the evidence for any contingent reduction in resistance is scanty, and several pathogens--notably Escherichia coli--are becoming markedly more resistant. Thus, rather than being overly optimistic about the benefits of reducing antimicrobial prescriptions, we must also emphasise the use of those antibiotics that prove less prone to select resistance. Furthermore, we must be careful that guidelines are not so narrow as to rail-road prescribing and its contingent selection pressure in single directions--as happened with gonorrhoea--and to consider the likelihood that limited diverse prescribing may have the least detrimental effect upon the resistance ecology. Last, there is a need to re-invigorate antimicrobial development, which has been downgraded by many major pharmaceutical houses.
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Affiliation(s)
- David M Livermore
- Antibiotic Resistance Monitoring and Reference Laboratory, Centre for Infections, Health Protection Agency, London NW9 5HT, UK.
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41
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Price LB, Johnson E, Vailes R, Silbergeld E. Fluoroquinolone-resistant Campylobacter isolates from conventional and antibiotic-free chicken products. ENVIRONMENTAL HEALTH PERSPECTIVES 2005; 113:557-60. [PMID: 15866763 PMCID: PMC1257547 DOI: 10.1289/ehp.7647] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The use of fluoroquinolones (FQs) in poultry production is an important issue in public health today. In February 2002, two prominent U.S. poultry companies pledged to stop using FQs for flock-wide treatment. One year later, we began a survey of Campylobacter isolates on chicken products from these two companies and from two producers claiming total abstention from antibiotic use. Using both standard isolation methods and new methods modified to enhance detection of FQ-resistant Campylobacter, we compared rates of FQ-resistant Campylobacter among these products. Four major findings were drawn from this study: a) antibiotic-free brands were not more likely to be contaminated with Campylobacter; b) a high percentage of products from the two conventional brands were contaminated with FQ-resistant Campylobacter (43 and 96%); c) these conventional brands had significantly higher odds of carrying resistant strains compared with antibiotic-free products; and d) supplementing media with FQs increased the sensitivity of detecting FQ-resistant strains among mixed populations of Campylobacter, thus reducing a bias toward underestimating the prevalence of FQ-resistant Campylobacter on samples. These results suggest that FQ resistance may persist in the commercial poultry environment in the absence of FQ-selective pressure and that these strains contaminate a larger proportion of foods than reported previously.
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Affiliation(s)
- Lance B Price
- Johns Hopkins University, Bloomberg School of Public Health, 615 N. Wolfe Street, Suite W6114, Baltimore, MD 21205, USA.
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Cox LA. Potential human health benefits of antibiotics used in food animals: a case study of virginiamycin. ENVIRONMENT INTERNATIONAL 2005; 31:549-63. [PMID: 15871160 DOI: 10.1016/j.envint.2004.10.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Risk management of food-animal antibiotics has reached a crucial juncture for public health officials worldwide. While withdrawals of animal antibiotics previously used to control animal bacterial illnesses are being encouraged in many countries, the human health impacts of such withdrawals are only starting to be understood. Increases in animal and human bacterial illness rates and antibiotic resistance levels in humans in Europe despite bans on animal antibiotics there have raised questions about how animal antibiotic use affects human health. This paper presents a quantitative human health risk and benefits assessment for virginiamycin (VM), a streptogramin antibiotic recommended for withdrawal from use in food animals in several countries. It applies a new quantitative Rapid Risk Rating Technique (RRRT) that estimates and multiplies data-driven exposure, dose-response, and consequence factors, as suggested by WHO (2003) to estimate human health impacts from withdrawing virginiamycin. Increased human health risks from more pathogens reaching consumers if VM use is terminated (6660 estimated excess campylobacteriosis cases per year in the base case) are predicted to far outweigh benefits from reduced streptogramin-resistant vancomycin-resistant Enterococcus faecium (VREF) infections in human patients (0.27 estimated excess cases per year in the base case). While lack of information about impacts of VM withdrawal on average human illnesses-per-serving of food animal meat precludes a deterministic conclusion, it appears very probable that such a withdrawal would cause many times more human illnesses than it would prevent. This qualitative conclusion appears to be robust to several scientific and modeling uncertainties.
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Affiliation(s)
- Louis Anthony Cox
- Cox Associates and University of Colorado, Denver 80218, United States.
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Abstract
In the production of food animals, large amounts of antimicrobial agents are used for therapy and prophylaxis of bacterial infections and in feed to promote growth. There are large variations in the amounts of antimicrobial agents used to produce the same amount of meat among the different European countries, which leaves room for considerable reductions in some countries. The emergence of resistant bacteria and resistance genes due to the use of antimicrobial agents are well documented. In Denmark it has been possible to reduce the usage of antimicrobial agents for food animals significantly and in general decreases in resistance have followed. Guidelines for prudent use of antimicrobial agents may help to slow down the selection for resistance and should be based on knowledge regarding the normal susceptibility patterns of the causative agents and take into account the potential problems for human health. Current knowledge regarding the occurrence of antimicrobial resistance in food animals, the quantitative impact of the use of different antimicrobial agents on selection of resistance and the most appropriate treatment regimes to limit the development of resistance is incomplete. Programmes monitoring the occurrence and development of resistance and consumption of antimicrobial agents are strongly desirable, as is research into the most appropriate ways to use antimicrobial agents in veterinary medicine.
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Affiliation(s)
- Frank M Aarestrup
- Danish Institute for Food and Veterinary Research, Copenhagen V, Denmark.
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Johnsen PJ, Østerhus JI, Sletvold H, Sørum M, Kruse H, Nielsen K, Simonsen GS, Sundsfjord A. Persistence of animal and human glycopeptide-resistant enterococci on two Norwegian poultry farms formerly exposed to avoparcin is associated with a widespread plasmid-mediated vanA element within a polyclonal enterococcus faecium population. Appl Environ Microbiol 2005; 71:159-68. [PMID: 15640183 PMCID: PMC544227 DOI: 10.1128/aem.71.1.159-168.2005] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2004] [Accepted: 08/23/2004] [Indexed: 11/20/2022] Open
Abstract
The evolutionary processes responsible for the long-term persistence of glycopeptide-resistant Enterococcus faecium (GREF) in nonselective environments were addressed by genetic analyses of E. faecium populations in animals and humans on two Norwegian poultry farms that were previously exposed to avoparcin. A total of 222 fecal GREF (n = 136) and glycopeptide-susceptible (n = 86) E. faecium (GSEF) isolates were obtained from farmers and poultry on three separate occasions in 1998 and 1999. Pulsed-field gel electrophoresis (PFGE) and plasmid DNA analyses discerned 22 GREF and 32 GSEF PFGE types within shifting polyclonal animal and human E. faecium populations and indicated the presence of transferable plasmid-mediated vanA resistance, respectively. Examples of dominant, persistent GREF PFGE types supported the notion that environmentally well-adapted GREF types may counteract the reversal of resistance. PFGE analyses, sequencing of the purK housekeeping gene, and partial typing of vanA-containing Tn1546 suggested a common animal and human reservoir of glycopeptide resistance. Inverse PCR amplification and sequence analyses targeting the right end of the Tn1546-plasmid junction fragment strongly indicated the presence of a common single Tn1546-plasmid-mediated element in 20 of 22 GREF PFGE types. This observation was further strengthened by vanY-vanZ hybridization analyses of plasmid DNAs as well as the finding of a physical linkage between Tn1546 and a putative postsegregation killing system for seven GREF PFGE types. In conclusion, our observations suggest that the molecular unit of persistence of glycopeptide resistance is a common mobile plasmid-mediated vanA-containing element within a polyclonal GREF population that changes over time. In addition, we propose that "plasmid addiction systems" may contribute to the persistence of GREF in nonselective environments.
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Affiliation(s)
- P J Johnsen
- Department of Microbiology and Virology, Faculty of Medicine, University of Tromsø, N-9037 Tromsø, Norway.
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Manson JM, Smith JMB, Cook GM. Persistence of vancomycin-resistant enterococci in New Zealand broilers after discontinuation of avoparcin use. Appl Environ Microbiol 2004; 70:5764-8. [PMID: 15466512 PMCID: PMC522085 DOI: 10.1128/aem.70.10.5764-5768.2004] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Large amounts of tylosin, zinc-bacitracin, and avilamycin are currently used as prophylactics in New Zealand broiler production. Avoparcin was also used from 1977 to 2000. A total of 382 enterococci were isolated from 213 fecal samples (147 individual poultry farms) using enrichment broths plated on m-Enterococcus agar lacking antimicrobials. These isolates were then examined to determine the prevalence of antimicrobial resistance. Of the 382 isolates, 5.8% (22 isolates) were resistant to vancomycin, and 64.7% were resistant to erythromycin. The bacitracin MIC was > or =256 microg/ml for 98.7% of isolates, and the avilamycin MIC was > or =8 microg/ml for 14.9% of isolates. No resistance to ampicillin or gentamicin was detected. Of the 22 vancomycin-resistant enterococci (VRE) isolates, 18 (81.8%) were Enterococcus faecalis, 3 were Enterococcus faecium, and 1 was Enterococcus durans. However, when the 213 fecal enrichment broths were plated on m-Enterococcus agar containing vancomycin, 86 VRE were recovered; 66% of these isolates were E. faecium and the remainder were E. faecalis. Vancomycin-resistant E. faecium isolates were found to have heterogenous pulsed-field gel electrophoresis (PFGE) patterns of SmaI-digested DNA, whereas the PFGE patterns of vancomycin-resistant E. faecalis isolates were identical or closely related, suggesting that this VRE clone is widespread throughout New Zealand. These data demonstrate that vancomycin-resistant E. faecalis persists in the absence and presence of vancomycin-selective pressure, thus explaining the dominance of this VRE clone even in the absence of avoparcin.
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Affiliation(s)
- Janet M Manson
- Department of Microbiology, Otago School of Medical Sciences, University of Otago, P.O. Box 56, Dunedin, New Zealand
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Hayes JR, English LL, Carter PJ, Proescholdt T, Lee KY, Wagner DD, White DG. Prevalence and antimicrobial resistance of enterococcus species isolated from retail meats. Appl Environ Microbiol 2003; 69:7153-60. [PMID: 14660361 PMCID: PMC309953 DOI: 10.1128/aem.69.12.7153-7160.2003] [Citation(s) in RCA: 152] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2003] [Accepted: 09/10/2003] [Indexed: 11/20/2022] Open
Abstract
From March 2001 to June 2002, a total of 981 samples of retail raw meats (chicken, turkey, pork, and beef) were randomly obtained from 263 grocery stores in Iowa and cultured for the presence of Enterococcus spp. A total of 1,357 enterococcal isolates were recovered from the samples, with contamination rates ranging from 97% of pork samples to 100% of ground beef samples. Enterococcus faecium was the predominant species recovered (61%), followed by E. faecalis (29%), and E. hirae (5.7%). E. faecium was the predominant species recovered from ground turkey (60%), ground beef (65%), and chicken breast (79%), while E. faecalis was the predominant species recovered from pork chops (54%). The incidence of resistance to many production and therapeutic antimicrobials differed among enterococci recovered from retail meat samples. Resistance to quinupristin-dalfopristin, a human analogue of the production drug virginiamycin, was observed in 54, 27, 9, and 18% of E. faecium isolates from turkey, chicken, pork, and beef samples, respectively. No resistance to linezolid or vancomycin was observed, but high-level gentamicin resistance was observed in 4% of enterococci, the majority of which were recovered from poultry retail meats. Results indicate that Enterococcus spp. commonly contaminate retail meats and that dissimilarities in antimicrobial resistance patterns among enterococci recovered from different meat types may reflect the use of approved antimicrobial agents in each food animal production class.
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Affiliation(s)
- Joshua R Hayes
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742, USA
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Heuer OE, Pedersen K, Jensen LB, Madsen M, Olsen JE. Persistence of vancomycin-resistant enterococci (VRE) in broiler houses after the avoparcin ban. Microb Drug Resist 2003; 8:355-61. [PMID: 12523633 DOI: 10.1089/10766290260469624] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The glycopeptide growth promoter avoparcin was banned from animal production in the EU in 1997 due to concern for the spread of vancomycin-resistant enterococci (VRE) from food animals to humans. In recent Norwegian and Danish studies, extensive occurrence of VRE on broiler farms and in broiler flocks after the avoparcin ban has been reported. The present study was undertaken to investigate the epidemiology of VRE on broiler farms in the absence of the selective pressure exerted by avoparcin. Environmental samples were obtained from five broiler houses after depopulation, cleaning, and disinfection of the houses between rotations, and two consecutive broiler flocks from each house were sampled by taking cloacal swabs from the broilers at the time of slaughter. A total of 69 vancomycin-resistant Enterococcus faecium isolates obtained from broiler flocks and broiler houses were subjected to molecular typing by pulsed-field gel electrophoresis (PFGE). Forty-one PFGE-profiles were observed. VRE with indistinguishable or highly similar PFGE profiles were isolated from consecutive broiler flocks and from environmental samples from the houses in which the flocks were reared, whereas VRE-isolates from different broiler houses and from flocks reared in different houses appeared to be genetically unrelated. These findings indicated that VRE was transmitted between consecutive broiler flocks by clones of resistant bacteria surviving in the broiler houses despite cleaning and disinfection between rotations. Thus, the extensive occurrence of VRE in broiler flocks after the avoparcin ban may be explained by persistence of VRE in the broiler house environment.
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Affiliation(s)
- O E Heuer
- Danish Veterinary Institute, Department of Poultry, Fish and Fur Animals, DK-8200, Arhus N, Denmark.
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