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Sørensen AIV, Hansen JE, Halasa T. A dynamic model for spread of livestock-associated methicillin-resistant Staphylococcus aureus on a pig farm, incorporating bacterial load and human exposure through air. J Theor Biol 2020; 505:110402. [PMID: 32663507 DOI: 10.1016/j.jtbi.2020.110402] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 04/11/2020] [Accepted: 07/05/2020] [Indexed: 11/28/2022]
Abstract
Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) is widely distributed in the pig population in many countries, where its presence is undesirable, because as an opportunistic human pathogen, it poses a threat to human health. At present, there is a lack of knowledge regarding successful methods for eradication of LA-MRSA on a pig farm, which does not involve emptying the farm and culling all pigs. Some studies have reported an association between levels of LA-MRSA in the barn air and LA-MRSA carriage among humans entering or working in the pig barns. Therefore, interventions that are able to reduce the amount of LA-MRSA carried by the pigs and/or the concentration of LA-MRSA in the barn air, might be highly relevant if aiming for reducing the spread of LA-MRSA into the general human population. In the present study, an existing agent-based simulation model for spread of LA-MRSA within a pig herd was extended to also include LA-MRSA load and spread through air. This makes it possible to use the model for studying the air exposure to LA-MRSA for humans entering the pig barns. The model was used for simulating various types of interventions in contaminated herds. At present quantitative data for nasal carriage of LA-MRSA in pigs are sparse, and many knowledge gaps regarding spread of LA-MRSA remain. Thus, our goal of building this model was not to provide exact values for risk reduction, but to avail a model that can be used for studying the effect of various types of interventions mechanistically, once more relevant data become available. Collection of more data on the influence of load is crucial for getting a better understanding of which possible interventions strategies, that might still have some potential in countries, where LA-MRSA has already spread to the majority of the pig population.
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Affiliation(s)
- Anna Irene Vedel Sørensen
- Department of Veterinary and Animal Sciences, Copenhagen University, Grønnegårdsvej 8, DK-1870 Frederiksberg, Denmark; National Veterinary Institute, Technical University of Denmark, Kemitorvet 204, DK-2800, Lyngby, Denmark.
| | - Julie Elvekjær Hansen
- National Veterinary Institute, Technical University of Denmark, Kemitorvet 204, DK-2800, Lyngby, Denmark; DTU Bioengineering, Technical University of Denmark, Søltofts Plads 221, DK-2800, Lyngby, Denmark
| | - Tariq Halasa
- Department of Veterinary and Animal Sciences, Copenhagen University, Grønnegårdsvej 8, DK-1870 Frederiksberg, Denmark; National Veterinary Institute, Technical University of Denmark, Kemitorvet 204, DK-2800, Lyngby, Denmark
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Abstract
Biofilm formation on indwelling medical devices represents an exclusive evasion mechanism for many pathogenic bacteria to establish chronic infections. Staphylococcus aureus is one of the major bacterial pathogens that are able to induce both animal and human infections. The continued emergence of multiple drug-resistant S. aureus, especially methicillin-resistant S. aureus, is problematic due to limited treatment options. Biofilm formation by S. aureus complicates the treatment of methicillin-resistant S. aureus infections. Therefore, elucidating the mechanisms of biofilm formation in this pathogen is important for the development of alternative therapeutic strategies. Various environmental and genetic factors contribute to biofilm formation. In this review, we address the environmental factors and discuss how they affect biofilm formation by S. aureus.
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Affiliation(s)
- Ying Liu
- Shanghai Vocational College of Agriculture and Forestry, Shanghai, China
- Department of Veterinary Biomedical Science, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN, USA
| | - Jiang Zhang
- Shanghai Vocational College of Agriculture and Forestry, Shanghai, China
| | - Yinduo Ji
- Department of Veterinary Biomedical Science, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN, USA
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Dignard C, Leibler JH. Recent Research on Occupational Animal Exposures and Health Risks: A Narrative Review. Curr Environ Health Rep 2019; 6:236-246. [PMID: 31823248 PMCID: PMC7099379 DOI: 10.1007/s40572-019-00253-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
PURPOSE OF REVIEW In the last year, an increasing number of studies have reported on methicillin-resistant Staphylococcus aureus (MRSA) transmission in Africa and Asia and in migrant workers. We reviewed original research on occupational health and safety of animal workers published from January 1, 2018, through June 30, 2019, with a targeted focus on infectious disease studies published in these populations. RECENT FINDINGS Studies focused on occupational exposures to infectious agents, dust and allergens, pesticides, and occupational injury. Research on zoonotic MRSA used whole genome-sequencing technologies to evaluate transmission in Africa and Asia. Swine worker exposure to porcine coronavirus and emerging influenza A viruses was documented in China. 16s RNA amplicon sequencing identified distinct microbiota compositions in households with active animal farmers. Multiple bioaerosol exposures were assessed for industrial dairy workers. Occupational injury studies highlighted the struggles of Latino animal workers in the USA. These studies highlighted the global expansion of zoonotic antibiotic resistance and identified novel occupational zoonoses of concern. The integration of microbiome assessment and compound mixtures into the evaluation of dust and endotoxin exposures for animal workers marks a new direction for this work.
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Affiliation(s)
| | - Jessica H Leibler
- Department of Environmental Health, Boston University School of Public Health, 715 Albany St, Boston, MA, 02118, USA.
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Kozajda A, Jeżak K, Kapsa A. Airborne Staphylococcus aureus in different environments-a review. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:34741-34753. [PMID: 31654301 PMCID: PMC6900272 DOI: 10.1007/s11356-019-06557-1] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 09/23/2019] [Indexed: 05/22/2023]
Abstract
The aim of the literature review was to describe the environments where the presence of airborne Staphylococcus aureus was confirmed and to catalogue the most often used methods and conditions of bioaerosol sampling to identify the bacteria. The basis for searching of studies on S. aureus in the bioaerosol in different environments was PubMed database resources from the years 1990-2019 (May). The review included studies which were carried on in selected environments: hospitals and other health care facilities, large-scale animal breeding, wastewater treatment plants, residential areas, educational institutions, and other public places. The highest concentrations and genetic diversity of identified S. aureus strains, including MRSA (methicillin-resistant S. aureus), have been shown in large-scale animal breeding. The role of the airborne transmission in dissemination of infection caused by these pathogens is empirically confirmed in environmental studies. Commonly available, well-described, and relatively inexpensive methods of sampling, identification, and subtyping guarantee a high reliability of results and allow to obtain fast and verifiable outcomes in environmental studies on air transmission routes of S. aureus strains.
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Affiliation(s)
- Anna Kozajda
- Nofer Institute of Occupational Medicine, 8 Teresy Str, 91-348, Łódź, Poland.
| | - Karolina Jeżak
- Nofer Institute of Occupational Medicine, 8 Teresy Str, 91-348, Łódź, Poland
| | - Agnieszka Kapsa
- Nofer Institute of Occupational Medicine, 8 Teresy Str, 91-348, Łódź, Poland
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Abstract
The term "ag-gag" refers to state laws that intentionally limit public access to information about agricultural production practices, particularly livestock production. Originally created in the 1990s, these laws have recently experienced a resurgence in state legislatures. We discuss the recent history of ag-gag laws in the United States and question whether such ag-gag laws create a "chilling effect" on reporting and investigation of occupational health, community health, and food safety concerns related to industrial food animal production. We conclude with a discussion of the role of environmental and occupational health professionals to encourage critical evaluation of how ag-gag laws might influence the health, safety, and interests of day-to-day agricultural laborers and the public living proximal to industrial food animal production.
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Affiliation(s)
- Caitlin A. Ceryes
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Christopher D. Heaney
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
- Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA
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6
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Wenke C, Pospiech J, Reutter T, Altmann B, Truyen U, Speck S. Impact of different supply air and recirculating air filtration systems on stable climate, animal health, and performance of fattening pigs in a commercial pig farm. PLoS One 2018; 13:e0194641. [PMID: 29558482 PMCID: PMC5860761 DOI: 10.1371/journal.pone.0194641] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 03/07/2018] [Indexed: 01/06/2023] Open
Abstract
Biosecurity is defined as the implementation of measures that reduce the risk of disease agents being introduced and/or spread. For pig production, several of these measures are routinely implemented (e.g. cleaning, disinfection, segregation). However, air as a potential vector of pathogens has long been disregarded. Filters for incoming and recirculating air were installed into an already existing ventilation plant at a fattening piggery (3,840 pigs at maximum) in Saxony, Germany. Over a period of three consecutive fattening periods, we evaluated various parameters including air quality indices, environmental and operating parameters, and pig performance. Animal data regarding respiratory diseases, presence of antibodies against influenza A viruses, PRRSV, and Actinobacillus pleuropneumoniae and lung health score at slaughter were recorded, additionally. There were no significant differences (p = 0.824) in total bacterial counts between barns with and without air filtration. Recirculating air filtration resulted in the lowest total dust concentration (0.12 mg/m3) and lung health was best in animals from the barn equipped with recirculating air filtration modules. However, there was no difference in animal performance. Antibodies against all above mentioned pathogens were detected but mostly animals were already antibody-positive at re-stocking. We demonstrated that supply air filtration as well as recirculating air filtration technique can easily be implemented in an already existing ventilation system and that recirculating air filtration resulted in enhanced lung health compared to supply air-filtered and non-filtered barns. A more prominent effect might have been obtained in a breeding facility because of the longer life span of sows and a higher biosecurity level with air filtration as an add-on measure.
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Affiliation(s)
- Cindy Wenke
- Institute of Animal Hygiene and Veterinary Public Health, University of Leipzig, Leipzig, Germany
| | - Janina Pospiech
- Institute of Animal Hygiene and Veterinary Public Health, University of Leipzig, Leipzig, Germany
| | | | - Bettina Altmann
- Institute for Medical Informatics, Statistics and Epidemiology, University of Leipzig, Leipzig, Germany
| | - Uwe Truyen
- Institute of Animal Hygiene and Veterinary Public Health, University of Leipzig, Leipzig, Germany
| | - Stephanie Speck
- Institute of Animal Hygiene and Veterinary Public Health, University of Leipzig, Leipzig, Germany
- * E-mail:
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Narvaez-Bravo C, Toufeer M, Weese S, Diarra M, Deckert A, Reid-Smith R, Aslam M. Prevalence of methicillin-resistant Staphylococcus aureus
in Canadian commercial pork processing plants. J Appl Microbiol 2016; 120:770-80. [DOI: 10.1111/jam.13024] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 11/04/2015] [Accepted: 11/24/2015] [Indexed: 12/11/2022]
Affiliation(s)
- C. Narvaez-Bravo
- Department of Food Science; University of Manitoba; Winnipeg MB Canada
| | - M. Toufeer
- Agriculture and Agri-Food Canada; Lacombe Research Centre; Lacombe AB Canada
| | - S.J. Weese
- Department of Pathobiology; University of Guelph; Guelph ON Canada
| | - M.S. Diarra
- Guelph Food Research Centre; Agriculture and Agri-Food Canada; Guelph ON Canada
| | - A.E. Deckert
- Public Health Agency of Canada; Guelph ON Canada
| | | | - M. Aslam
- Agriculture and Agri-Food Canada; Lacombe Research Centre; Lacombe AB Canada
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Leibler JH, Jordan JA, Brownstein K, Lander L, Price LB, Perry MJ. Staphylococcus aureus Nasal Carriage among Beefpacking Workers in a Midwestern United States Slaughterhouse. PLoS One 2016; 11:e0148789. [PMID: 26866374 PMCID: PMC4750916 DOI: 10.1371/journal.pone.0148789] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 01/22/2016] [Indexed: 11/19/2022] Open
Abstract
Occupational contact with livestock is an established risk factor for exposure to livestock-associated methicillin-resistant Staphylococcus aureus (MRSA), particularly among industrial swine workers. While S. aureus is known to infect cattle, livestock-associated S. aureus carriage among workers in the beef production chain has received limited attention. Beefpacking workers, who slaughter, butcher and process cattle, have intensified exposure to potentially infectious animal materials and may be at risk of livestock-associated S. aureus exposure. We conducted a cross-sectional study of beefpacking workers (n = 137) at an industrial slaughterhouse in the Midwestern United States to evaluate prevalence and characteristics of S. aureus nasal colonization, specifically the absence of the scn gene to identify putative association with livestock, antibiotic susceptibility, presence of Panton-Valentin leukocidin (PVL) genes lukS-PV and lukF-PV, and spa type. Overall prevalence of S. aureus nasal carriage was 27.0%. No workers carried livestock-associated MRSA. Methicillin-sensitive S. aureus isolates (MSSA) recovered from five workers (3.6%) lacked the scn gene and were considered putative livestock-associated S. aureus (pLA-SA). Among pLA-SA isolates, spa types t338, t748, t1476 and t2379 were identified. To our knowledge, these spa types have not previously been identified as associated with livestock. Prevalence of human-adapted MRSA carriage in workers was 3.6%. MRSA isolates were identified as spa types t002, t008 and t024, and four of five MRSA isolates were PVL-positive. To date, this is the first study to indicate that industrial beefpacking workers in the United States may be exposed to livestock-associated S. aureus, notably MSSA, and to spa types not previously identified in livestock and livestock workers. Occupational exposure to livestock-associated S. aureus in the beef production chain requires further epidemiologic investigation.
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Affiliation(s)
- Jessica H. Leibler
- Department of Environmental Health, Boston University School of Public Health, Boston, Massachusetts, United States of America
- * E-mail:
| | - Jeanne A. Jordan
- Department of Epidemiology and Biostatistics, Milken Institute School of Public Health, The George Washington University, Washington, District of Columbia, United States of America
| | - Kirsten Brownstein
- Department of Environmental and Occupational Health, Milken Institute School of Public Health, The George Washington University, Washington, District of Columbia, United States of America
| | - Lina Lander
- Department of Epidemiology, College of Public Health, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Lance B. Price
- Department of Environmental and Occupational Health, Milken Institute School of Public Health, The George Washington University, Washington, District of Columbia, United States of America
- Division of Pathogen Genomics, the Translational Genomics Research Institute, Flagstaff, Arizona, United States of America
| | - Melissa J. Perry
- Department of Environmental and Occupational Health, Milken Institute School of Public Health, The George Washington University, Washington, District of Columbia, United States of America
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Wan MT, Chou CC. Class 1 Integrons and the Antiseptic Resistance Gene (qacEΔ1) in Municipal and Swine Slaughterhouse Wastewater Treatment Plants and Wastewater-Associated Methicillin-Resistant Staphylococcus aureus. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2015; 12:6249-60. [PMID: 26042365 PMCID: PMC4483699 DOI: 10.3390/ijerph120606249] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 05/27/2015] [Accepted: 05/28/2015] [Indexed: 01/16/2023]
Abstract
Class 1 integrons are mobile gene elements (MGEs) containing qacEΔ1 that are resistant to quaternary ammonium compound (QAC) disinfectants. This study compared the abundances of class 1 integrons and antiseptic resistance genes in municipal (M) and swine slaughterhouse (S) wastewater treatment plants (WWTPs) and investigated the presence of class 1 integrons and antiseptic resistance genes in methicillin-resistant Staphylococcus aureus (MRSA) isolated from wastewater samples. The abundances of intI1 and qacEΔ1 genes in 96 wastewater samples were quantified using real-time quantitative polymerase chain reaction (real-time qPCR), and 113 MRSA isolates recovered from the wastewater samples were detected class 1 integrons and linked antiseptic resistance genes (qacEΔ1), and minimum inhibitory concentrations (MICs) for QAC antiseptics. The intI1 and qacEΔ1 genes were detected in all the wastewater samples, and they were more abundant in S-WWTP samples than in M-WWTP samples. A higher percentage of MRSA isolates carried qacEΔ1 in MRSA from swine wastewater samples (62.8%) than in municipal MRSA (3.7%). All the MRSA isolates showed high MICs for antiseptic agents. This study provides important evidence regarding the abundances of intI1 and qacEΔ1 genes in municipal and swine slaughterhouse wastewater, and antiseptic-resistant MRSA strains were detected in swine slaughterhouse wastewater.
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Affiliation(s)
- Min Tao Wan
- School of Veterinary Medicine, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei 106, Taiwan.
- Biodiversity Research Center, Academia Sinica, 128 Academia Road, Section 2, Taipei 115, Taiwan.
| | - Chin Cheng Chou
- School of Veterinary Medicine, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei 106, Taiwan.
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Wan MT, Chou CC. Spreading of β-lactam resistance gene (mecA) and methicillin-resistant Staphylococcus aureus through municipal and swine slaughterhouse wastewaters. WATER RESEARCH 2014; 64:288-295. [PMID: 25086302 DOI: 10.1016/j.watres.2014.07.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Revised: 06/30/2014] [Accepted: 07/09/2014] [Indexed: 05/23/2023]
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is a potential zoonotic agent. Municipal wastewater treatment plants (WWTPs) can be reservoirs for MRSA dissemination. It is unclear, however, whether MRSA and its β-lactam resistance gene (mecA) can be spread from WWTPs that treat the wastewater of swine auction markets. The aims of the study were to compare (1) the abundance of the mecA gene in one municipal (M-) and one swine (S-) WWTP and (2) the genotypic and phenotypic characteristics of MRSA isolates from these two types of WWTPs. The concentrations of mecA gene from 96 wastewater samples were quantified using real-time quantitative polymerase chain reaction (real-time qPCR). One hundred and thirteen MRSA isolates were recovered and were characterized by antimicrobial susceptibility testing, minimum inhibitory concentrations (MICs), and staphylococcal cassette chromosome mec (SCCmec) typing. The mecA gene could be detected in all the wastewater samples. A high abundance of recovered mecA gene (2.6 × 10(1) to 1.9 × 10(4) gene copies μg(-1) of total DNA) in swine slaughterhouse wastewater implied a correspondingly high transferring/receiving potential. All MRSA isolates were multidrug resistant (MDR) and showed high MICs to different antimicrobials. The M-WWTP MRSA isolates harbored SCCmec II-IV and VII, whereas those from the S-WWTP harbored SCCmec V and IX. In conclusion, wastewater from swine slaughterhouses can make these slaughterhouses potential hotspots for the dissemination of mecA gene and MRSA, and the high MICs of MRSA from both WWTP origins may pose a health risk not only to workers but also to the general public.
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Affiliation(s)
- Min Tao Wan
- School of Veterinary Medicine, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei 106, Taiwan
| | - Chin Cheng Chou
- School of Veterinary Medicine, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei 106, Taiwan.
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Occurrence of livestock-associated methicillin-resistant Staphylococcus aureus in Turkey and broiler barns and contamination of air and soil surfaces in their vicinity. Appl Environ Microbiol 2013; 79:2759-66. [PMID: 23417001 DOI: 10.1128/aem.03939-12] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The emission of microorganisms, especially resistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA), from poultry farms is of public interest, and its occurrence and relevance are controversially discussed. So far, there are limited data on this issue. In this study, we investigated the occurrence of livestock-associated (LA)-MRSA inside and outside previously tested MRSA-positive poultry barns in Germany. In total, five turkey and two broiler fattening farms were investigated four and three times, respectively. In a longitudinal study during one fattening period, samples were collected from animals, the animals' environment inside the barn, including the air, and the barns' surroundings, such as ambient air and boot swabs of ground surfaces at different distances from the barn. Moreover, a cross-sectional study was carried out once inside the barns on five turkey and four broiler farms during the last third of the fatting period. In the cross-sectional study, LA-MRSA was detected in the air of most barns (7 of 9, 77.8%), as well as in many samples originating from animals, with detections levels of 50 to 54% in broiler and 62 to 77% in turkey farms. In the longitudinal study, LA-MRSA was found in the ambient air outside two turkey barns and on the ground surface on the downwind side of many (44.4%) turkey and broiler farms. The same spa types of isolates were observed inside and outside the barns. Transmission of MRSA within poultry farms, as well as emission via the airborne route, seems to be possible.
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Masclaux FG, Sakwinska O, Charrière N, Semaani E, Oppliger A. Concentration of airborne Staphylococcus aureus (MRSA and MSSA), total bacteria, and endotoxins in pig farms. ACTA ACUST UNITED AC 2013; 57:550-7. [PMID: 23293050 DOI: 10.1093/annhyg/mes098] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Pigs are very often colonized by Staphylococcus aureus and transmission of such pig-associated S. aureus to humans can cause serious medical, hygiene, and economic problems. The transmission route of zoonotic pathogens colonizing farm animals to humans is not well established and bioaerosols could play an important role. The aim of this study was to assess the potential occupational risk of working with S. aureus-colonized pigs in Switzerland. We estimated the airborne contamination by S. aureus in 37 pig farms (20 nursery and 17 fattening units; 25 in summer, 12 in winter). Quantification of total airborne bacterial DNA, airborne Staphylococcus sp. DNA, fungi, and airborne endotoxins was also performed. In this experiment, the presence of cultivable airborne methicillin-resistant S. aureus (MRSA) CC398 in a pig farm in Switzerland was reported for the first time. Airborne methicillin-sensitive S. aureus (MSSA) was found in ~30% of farms. The average airborne concentration of DNA copy number of total bacteria and Staphylococcus sp. measured by quantitative polymerase chain reaction was very high, respectively reaching values of 75 (± 28) × 10(7) and 35 (± 9.8) × 10(5) copy numbers m(-3) in summer and 96 (± 19) × 10(8) and 40 (± 12) × 10(6) copy numbers m(-3) in winter. Total mean airborne concentrations of endotoxins (1298 units of endotoxin m(-3)) and fungi (5707 colony-forming units m(-3)) exceeded the Swiss recommended values and were higher in winter than in summer. In conclusion, Swiss pig farmers will have to tackle a new emerging occupational risk, which could also have a strong impact on public health. The need to inform pig farmers about biological occupational risks is therefore crucial.
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Affiliation(s)
- Frederic G Masclaux
- Institut universitaire romand de Santé au Travail, (Institute for Work and Health), University of Lausanne and Geneva, rue du Bugnon 21, CH-1011 Lausanne, Switzerland
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13
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Molecular characterization and clonal genetic diversity of methicillin-resistant Staphylococcus aureus of pig origin in Taiwan. Comp Immunol Microbiol Infect Dis 2012; 35:513-21. [DOI: 10.1016/j.cimid.2012.05.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Revised: 04/08/2012] [Accepted: 05/01/2012] [Indexed: 12/22/2022]
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Wendlandt S, Schwarz S, Silley P. Methicillin-resistant Staphylococcus aureus: a food-borne pathogen? Annu Rev Food Sci Technol 2012. [PMID: 23190141 DOI: 10.1146/annurev-food-030212-182653] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Prior to the 1990s, most methicillin-resistant Staphylococcus aureus (MRSA) was hospital-associated (HA-MRSA); community-associated MRSA (CA-MRSA) then began to cause infections outside the health-care environment. The third significant emergence of MRSA has been in livestock animals [livestock-associated MRSA (LA-MRSA)]. The widespread and rapid growth in CA-MRSA and LA-MRSA has raised the question as to whether MRSA is indeed a food-borne pathogen. The observations on animal-to-animal and animal-to-human transfer of LA-MRSA have prompted research examining the origin of LA-MRSA and its capacity to cause zoonotic disease in humans. This review summarizes the current knowledge about MRSA from food-producing animals and foods with respect to the role of these organisms to act as food-borne pathogens and considers the available tools to track the spread of these organisms. It is clear that LA-MRSA and CA-MRSA and even HA-MRSA can be present in/on food intended for human consumption, but we conclude on the basis of the published literature that this does not equate to MRSA being considered a food-borne pathogen.
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Affiliation(s)
- Sarah Wendlandt
- Institute of Farm Animal Genetics, Friedrich-Loeffler-Institut, Neustadt-Mariensee, Germany.
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15
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Occurrence of MRSA in air and housing environment of pig barns. Vet Microbiol 2012; 158:129-35. [PMID: 22386671 DOI: 10.1016/j.vetmic.2012.01.019] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Revised: 01/17/2012] [Accepted: 01/19/2012] [Indexed: 01/26/2023]
Abstract
A high prevalence of MRSA among farm animals, especially pigs, has been observed for some time. However, knowledge on transmission routes of MRSA in livestock production is still scarce. Therefore, the aim of this study was to determine the occurrence of MRSA in pig house air as well as in samples from pigs and their housing environment in 27 MRSA positive pig barns of different sizes and production types. In 85.2% of all barns MRSA was detected in the animal house air. Impingement turned out to be a more sensitive sampling technique than filtration. Other environmental samples such as boot swabs or faeces showed prevalences of MRSA from 55.6% to 85.2% at sample level. The level of MRSA was 88.3% for pooled and 82.1% for single nasal swabs, in skin swabs the one was 87.7%, the others was 78.7%. Spa typing of isolates from air and nasal swabs showed predominantly spa types t011 and t034. MRSA prevalences in pigs as well as in various environmental samples were significantly higher in fattening farms than in breeding farms. This study provides good reference that there could be an airborne transmission of MRSA within pig herds indicating a potential contamination of the environment of barns.
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Colonization kinetics of different methicillin-resistant Staphylococcus aureus sequence types in pigs and host susceptibilities. Appl Environ Microbiol 2011; 78:541-8. [PMID: 22081568 DOI: 10.1128/aem.05327-11] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In this study we investigated the kinetics of colonization, the host susceptibility and transmissibility of methicillin-resistant Staphylococcus aureus (MRSA) after nasal treatment of pigs with three different MRSA strains of distinctive clonal lineages (sequence type 398 [ST398], ST8, and ST9), and origin in weaning piglets. The colonization dose of 5.0 × 10(8) CFU/animal was determined in preliminary animal studies. A total of 57 piglets were randomly divided into four test groups and one control group. Each of three test groups was inoculated intranasally with either MRSA ST8, MRSA ST9, or MRSA ST398. The fourth group was a mixture of animals inoculated with MRSA ST398 and noninoculated "sentinel" animals. Clinical signs, the nasal, conjunctival, and skin colonization of MRSA, fecal excretion, and organ distribution of MRSA, as well as different environmental samples were examined. After nasal inoculation with MRSA piglets of all four test groups showed no clinical signs of an MRSA infection. MRSA was present on the nasal mucosa, skin, and conjunctiva in all four test groups, including sentinel animals. Likewise, fecal excretion and internal colonization of MRSA ST8, ST9, and ST398 could be shown in each group. However, fecal excretion and the colonization rate of the nasal mucosa with MRSA ST9 were significantly lower in the first days after infection than in test groups infected with ST8 and ST398. The results of this study suggest differences in colonization potential of the different MRSA types in pigs. Furthermore, colonization of lymph nodes (e.g., the ileocecal lymph node) with MRSA of the clonal lineage ST398 was demonstrated.
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Experimental colonization of pigs with methicillin-resistant Staphylococcus aureus (MRSA): insights into the colonization and transmission of livestock-associated MRSA. Epidemiol Infect 2010; 139:1594-600. [PMID: 21156101 DOI: 10.1017/s0950268810002888] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Two models were used for colonizing pigs under experimental conditions. In the first model, six 5-week old piglets were challenged by nasal and gastrointestinal inoculation with a mixture of four strains representing the most prevalent methicillin-resistant Staphylococcus aureus (MRSA) sequence types (ST398, ST9) and spa types (t08, t011, t034, t899) associated with pig farming. In the second model, the vagina of a pregnant sow was inoculated with the same MRSA mixture shortly before farrowing. While MRSA carriage was unstable following nasal-gastrointestinal inoculation of piglets, vaginal inoculation of the sow resulted in persistent carriage of t011-ST398 and t899-ST9 in all newborn piglets. The results from the two models provide evidence that livestock-associated MRSA can efficiently spread by vertical perinatal transmission and that direct colonization of weaned piglets is hampered by unknown host, bacterial or environmental factors. The vaginal inoculation model described in this study represents a useful tool for studying MRSA-host interactions in pigs having the same genetic background.
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