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Verkola M, Takala M, Nykäsenoja S, Olkkola S, Kurittu P, Kiljunen S, Tuomala H, Järvinen A, Heikinheimo A. Low-level colonization of methicillin-resistant Staphylococcus aureus in pigs is maintained by slowly evolving, closely related strains in Finnish pig farms. Acta Vet Scand 2022; 64:34. [PMID: 36461079 PMCID: PMC9716547 DOI: 10.1186/s13028-022-00653-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 11/15/2022] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Over the past two decades, livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) has become widely prevalent in pig production in Europe. The carriage status of LA-MRSA is known to vary among individual pigs, but bacterial load in pigs has rarely been studied. We assessed the quantity of LA-MRSA in nasal and skin samples of pigs and investigated the genetic diversity of the strains together with sequenced strains from national surveillance and pathology samples from the Finnish Food Authority. On two farms with assumed MRSA-positive status, farm 1 and farm 2, 10 healthy pigs were sampled three times during 2 weeks from the nares and skin (study A). On farm 1, 54 additional pigs were sampled and from confirmed MRSA-positive animals, 10 were randomly selected and transported to a clean, controlled environment for further sampling (study B). From the samples taken on farms 1 and 2 and in the controlled environment, MRSA was isolated both by direct plating and enrichment on selective media. spa types, multilocus sequence types, staphylococcal cassette chromosome mec types, resistance and virulence genes were determined. Core genome multilocus sequence typing (cgMLST) analysis was performed, including the sequences deriving from the surveillance/pathology samples from the Finnish Food Authority. RESULTS All pigs on farm 1 carried LA-MRSA in the nares at all three time points and five pigs on farm 2 at one time point. Nasal quantity varied between 10 and 103 CFU/swab and quantity on the skin between 10 and 102 CFU/swab. In the controlled environment, MRSA was detected in at least one of the nasal samples from each animal. spa type t034 was predominant. cgMLST showed one cluster with minimum allele differences between 0 and 11. CONCLUSIONS The study shows predominantly low-level carriage (< 103 CFU/swab) of LA-MRSA on farms. In the controlled environment we observed a decline in nasal carriage but constant skin carriage. cgMLST showed that strains of spa type t034 are closely related at the national level.
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Affiliation(s)
- Marie Verkola
- grid.7737.40000 0004 0410 2071Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, P.O. Box 66, 00014 University of Helsinki Helsinki, Finland ,grid.509946.70000 0004 9290 2959Laboratory and Research Division, Microbiology Unit, Finnish Food Authority, P.O. Box 200, 00027 Finnish Food Authority Helsinki, Finland
| | - Milla Takala
- grid.7737.40000 0004 0410 2071Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, P.O. Box 66, 00014 University of Helsinki Helsinki, Finland
| | - Suvi Nykäsenoja
- grid.509946.70000 0004 9290 2959Laboratory and Research Division, Microbiology Unit, Finnish Food Authority, P.O. Box 200, 00027 Finnish Food Authority Helsinki, Finland
| | - Satu Olkkola
- grid.509946.70000 0004 9290 2959Laboratory and Research Division, Microbiology Unit, Finnish Food Authority, P.O. Box 200, 00027 Finnish Food Authority Helsinki, Finland
| | - Paula Kurittu
- grid.7737.40000 0004 0410 2071Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, P.O. Box 66, 00014 University of Helsinki Helsinki, Finland
| | - Saija Kiljunen
- grid.7737.40000 0004 0410 2071Human Microbiome Research Program, Faculty of Medicine, Helsinki University Central Hospital, University of Helsinki, P.O. Box 21, 00014 University of Helsinki Helsinki, Finland
| | - Henni Tuomala
- grid.7737.40000 0004 0410 2071Human Microbiome Research Program, Faculty of Medicine, Helsinki University Central Hospital, University of Helsinki, P.O. Box 21, 00014 University of Helsinki Helsinki, Finland
| | - Asko Järvinen
- grid.7737.40000 0004 0410 2071Department of Infectious Diseases, Inflammation Center, Helsinki University Central Hospital, University of Helsinki, P.O. Box 340, 00029 HUS Helsinki, Finland
| | - Annamari Heikinheimo
- grid.7737.40000 0004 0410 2071Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, P.O. Box 66, 00014 University of Helsinki Helsinki, Finland ,grid.509946.70000 0004 9290 2959Laboratory and Research Division, Microbiology Unit, Finnish Food Authority, P.O. Box 200, 00027 Finnish Food Authority Helsinki, Finland
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Stelder JJ, Kjær LJ, Jensen LB, Boklund AE, Denwood M, Carlsen M, Bødker R. Livestock-associated MRSA survival on house flies (Musca domestica) and stable flies (Stomoxys calcitrans) after removal from a Danish pig farm. Sci Rep 2021; 11:3527. [PMID: 33574465 PMCID: PMC7878913 DOI: 10.1038/s41598-021-83228-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 02/01/2021] [Indexed: 01/30/2023] Open
Abstract
We caught stable- and house flies on a Danish LA-MRSA positive pig farm. Stable- and house flies were housed together and culled over time to test for the presence of live LA-MRSA bacteria at 24 h intervals to establish the length of time for which LA-MRSA can persist on flies. On average, 7% of stable flies and 27% of house flies tested positive for LA-MRSA immediately upon removal from the farm. LA-MRSA prevalence decreased over time and estimates based on a Kaplan-Meier time-to-event analysis indicated that the probability of a stable- or house fly testing positive for LA-MRSA was 5.4% and 7.8% after 24 h, 3.5% and 4.3% after 48 h, 3.1% and 2.2% after 72 h and 0.4% and 0% after 96 h of removal from the pig farm, respectively. Simultaneously, we found that caged cultivated house flies became carriers of LA-MRSA, without direct contact with pigs, in the same proportions as wild flies inside the farm. We provide distance distributions of Danish pig farms and residential addresses as well as the calculated maximum dispersal potentials of stable- and house flies, which suggest that there is a potential for stable- and house flies dispersing live LA-MRSA bacteria into the surrounding environment of a pig farm. This potential should therefore be considered when modelling the spread between farms or the risk posed to humans living in close proximity to LA-MRSA pig farm sources.
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Affiliation(s)
- Jonno Jorn Stelder
- Section for Animal Welfare and Disease Control, Department of Veterinary and Animal Sciences, Copenhagen University, Grønnegårdsvej 8, 1870, Frederiksberg C, Denmark.
| | - Lene Jung Kjær
- Section for Animal Welfare and Disease Control, Department of Veterinary and Animal Sciences, Copenhagen University, Grønnegårdsvej 8, 1870, Frederiksberg C, Denmark
| | - Lars Bogø Jensen
- National Food Institute, DTU Technical University of Denmark, Kemitorvet Building 204, 2800, Lyngby, Denmark
| | - Anette Ella Boklund
- Section for Animal Welfare and Disease Control, Department of Veterinary and Animal Sciences, Copenhagen University, Grønnegårdsvej 8, 1870, Frederiksberg C, Denmark
| | - Matt Denwood
- Section for Animal Welfare and Disease Control, Department of Veterinary and Animal Sciences, Copenhagen University, Grønnegårdsvej 8, 1870, Frederiksberg C, Denmark
| | - Margrethe Carlsen
- National Food Institute, DTU Technical University of Denmark, Kemitorvet Building 204, 2800, Lyngby, Denmark
| | - René Bødker
- Section for Animal Welfare and Disease Control, Department of Veterinary and Animal Sciences, Copenhagen University, Grønnegårdsvej 8, 1870, Frederiksberg C, Denmark
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3
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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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4
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Mou KT, Allen HK, Alt DP, Trachsel J, Hau SJ, Coetzee JF, Holman DB, Kellner S, Loving CL, Brockmeier SL. Shifts in the nasal microbiota of swine in response to different dosing regimens of oxytetracycline administration. Vet Microbiol 2019; 237:108386. [PMID: 31526488 DOI: 10.1016/j.vetmic.2019.108386] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 07/26/2019] [Accepted: 08/07/2019] [Indexed: 01/10/2023]
Abstract
The impacts of antibiotic treatment and dosing regimen of an antibiotic on the swine respiratory microbiota are poorly defined. To begin to address this, this study characterized the impact of oxytetracycline administration, given either parenterally or in feed, on the diversity of the nasal and tonsil microbiotas of post-weaned pigs over a two-week period. One group received a single intramuscular injection (IM) of oxytetracycline, the second was treated with oxytetracycline mixed in feed (IF), and the control group received non-medicated (NON) feed. Nasal samples were collected on days 0 (before start of treatment), 4, 7, 11, and 14. Tonsil tissue samples were collected from a subset of pigs selected for necropsy on days 4, 7, and 14. The results showed that the tonsil microbiota was stable regardless of antibiotic treatment. In contrast, the nasal bacterial diversity decreased for both oxytetracycline-treated groups compared to NON. The IF group also exhibited decreased diversity on more days than the IM group. The nasal bacterial community structures of the antibiotic treatment groups were significantly different from the NON group that persisted from day 4 until day 7 for the IM group, and up until day 11 for the IF group. This included relative increased abundances of Actinobacillus and Streptococcus, and relative decreased abundances of multiple commensal genera. The microbiota of the IF group was also more disturbed than the microbiota of the IM group, relative to NON. This study revealed that short-term exposure to broad-spectrum antibiotics like oxytetracycline can disturb the upper respiratory microbiota, and the dosing regimen has differential effects on the microbiota.
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Affiliation(s)
- Kathy T Mou
- Oak Ridge Institute for Science and Education, P.O. Box 117, Oak Ridge, TN, 37831, USA; USDA, ARS, National Animal Disease Center, 1920 Dayton Ave., Ames, IA, 50010, USA
| | - Heather K Allen
- USDA, ARS, National Animal Disease Center, 1920 Dayton Ave., Ames, IA, 50010, USA
| | - David P Alt
- USDA, ARS, National Animal Disease Center, 1920 Dayton Ave., Ames, IA, 50010, USA
| | - Julian Trachsel
- USDA, ARS, National Animal Disease Center, 1920 Dayton Ave., Ames, IA, 50010, USA
| | - Samantha J Hau
- Oak Ridge Institute for Science and Education, P.O. Box 117, Oak Ridge, TN, 37831, USA; USDA, ARS, National Animal Disease Center, 1920 Dayton Ave., Ames, IA, 50010, USA
| | - Johann F Coetzee
- Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State University, 228 Coles Hall, Manhattan, KS, 66506, USA
| | - Devin B Holman
- Lacombe Research and Development Centre, Agriculture and Agri-Food Canada, 6000 C and E Trail, Lacombe, Alberta T4L 1W1, Canada
| | - Steven Kellner
- USDA, ARS, National Animal Disease Center, 1920 Dayton Ave., Ames, IA, 50010, USA
| | - Crystal L Loving
- USDA, ARS, National Animal Disease Center, 1920 Dayton Ave., Ames, IA, 50010, USA
| | - Susan L Brockmeier
- USDA, ARS, National Animal Disease Center, 1920 Dayton Ave., Ames, IA, 50010, USA.
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5
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Davis MF, Pisanic N, Rhodes SM, Brown A, Keller H, Nadimpalli M, Christ A, Ludwig S, Ordak C, Spicer K, Love DC, Larsen J, Wright A, Blacklin S, Flowers B, Stewart J, Sexton KG, Rule AM, Heaney CD. Occurrence of Staphylococcus aureus in swine and swine workplace environments on industrial and antibiotic-free hog operations in North Carolina, USA: A One Health pilot study. ENVIRONMENTAL RESEARCH 2018; 163:88-96. [PMID: 29428885 PMCID: PMC6292733 DOI: 10.1016/j.envres.2017.12.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 11/27/2017] [Accepted: 12/12/2017] [Indexed: 05/06/2023]
Abstract
Occupational exposure to swine has been associated with increased Staphylococcus aureus carriage, including antimicrobial-resistant strains, and increased risk of infections. To characterize animal and environmental routes of worker exposure, we optimized methods to identify S. aureus on operations that raise swine in confinement with antibiotics (industrial hog operation: IHO) versus on pasture without antibiotics (antibiotic-free hog operation: AFHO). We associated findings from tested swine and environmental samples with those from personal inhalable air samplers on worker surrogates at one IHO and three AFHOs in North Carolina using a new One Health approach. We determined swine S. aureus carriage status by collecting swab samples from multiple anatomical sites, and we determined environmental positivity for airborne bioaerosols with inhalable and impinger samplers and a single-stage impactor (ambient air) cross-sectionally. All samples were analyzed for S. aureus, and isolates were tested for antimicrobial susceptibility, absence of scn (livestock marker), and spa type. Seventeen of twenty (85%) swine sampled at the one IHO carried S. aureus at >1 anatomical sites compared to none of 30 (0%) swine sampled at the three AFHOs. All S. aureus isolates recovered from IHO swine and air samples were scn negative and spa type t337; almost all isolates (62/63) were multidrug resistant. S. aureus was recovered from eight of 14 (67%) ambient air and two (100%) worker surrogate personal air samples at the one IHO, whereas no S. aureus isolates were recovered from 19 ambient and six personal air samples at the three AFHOs. Personal worker surrogate inhalable sample findings were consistent with both swine and ambient air data, indicating the potential for workplace exposure. IHO swine and the one IHO environment could be a source of potential pathogen exposure to workers, as supported by the detection of multidrug-resistant S. aureus (MDRSA) with livestock-associated spa type t337 among swine, worker surrogate personal air samplers and environmental air samples at the one IHO but none of the three AFHOs sampled in this study. Concurrent sampling of swine, personal swine worker surrogate air, and ambient airborne dust demonstrated that IHO workers may be exposed through both direct (animal contact) and indirect (airborne) routes of transmission. Investigation of the effectiveness of contact and respiratory protections is warranted to prevent IHO worker exposure to multidrug-resistant livestock-associated S. aureus and other pathogens.
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Affiliation(s)
- Meghan F Davis
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA; Department of Molecular and Comparative Pathobiology, Johns Hopkins School of Medicine, Baltimore, Maryland, USA.
| | - Nora Pisanic
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Sarah M Rhodes
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, NC, USA
| | - Alexis Brown
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Haley Keller
- North Carolina State University, Raleigh, NC, USA
| | - Maya Nadimpalli
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, NC, USA
| | - Andrea Christ
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Shanna Ludwig
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Carly Ordak
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Kristoffer Spicer
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - David C Love
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA; Johns Hopkins Center for a Livable Future, Baltimore, Maryland, USA
| | - Jesper Larsen
- Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
| | - Asher Wright
- NC Choices, North Carolina State University Cooperative Extension and NC A&T State University, NC, USA
| | - Sarah Blacklin
- NC Choices, North Carolina State University Cooperative Extension and NC A&T State University, NC, USA
| | | | - Jill Stewart
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, NC, USA
| | - Kenneth G Sexton
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, NC, USA
| | - Ana M Rule
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Christopher D Heaney
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA; Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA; Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA.
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6
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Emaneini M, Jabalameli F, Rahdar H, Leeuwen WBV, Beigverdi R. Nasal carriage rate of methicillin resistant Staphylococcus aureus among Iranian healthcare workers: a systematic review and meta-analysis. Rev Soc Bras Med Trop 2017; 50:590-597. [PMID: 29160504 DOI: 10.1590/0037-8682-0534-2016] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 06/05/2017] [Indexed: 01/25/2023] Open
Abstract
Globally, methicillin-resistant Staphylococcus aureus (MRSA) remains a major cause of healthcare-associated infections. Healthcare workers (HCWs), patients and the environment may act as reservoirs for the spread of MRSA to patients and other HCWs. Screening and eradication of MRSA colonization is an effective method of reducing the MRSA infection rate. There are limited data on the prevalence of MRSA among Iranian HCWs. We performed a systematic search by using different electronic databases including Medline (via PubMed), Embase, Web of Science, and Iranian Databases (from January 2000 to July 2016). Meta-analysis was performed using the Comprehensive Meta-Analysis (Biostat V2.2) software. The meta-analyses showed that the prevalence of S. aureus and MRSA among HCWs were 22.7% [95% confidence interval (CI): 19.3-26.6] and 32.8% (95% CI: 26.0-40.4) respectively. The high rate of nasal MRSA carriage among Iranian HCWs has been attributed to poor compliance to hand hygiene, injudicious use of antibiotics, and ineffective infection control and prevention measures. The rational use of antibiotics plus strict infection control are the main pillars for controlling multidrug resistant microorganisms such as MRSA in the hospital setting. These measurements should be applied nationally.
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Affiliation(s)
- Mohammad Emaneini
- Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Fereshteh Jabalameli
- Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Hosseinali Rahdar
- Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Willem B van Leeuwen
- Department of Innovative Molecular Diagnostics, Faculty of Science & Technology, University of Applied Sciences. Leiden. Netherlands
| | - Reza Beigverdi
- Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
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7
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Sørensen AIV, Toft N, Boklund A, Espinosa-Gongora C, Græsbøll K, Larsen J, Halasa T. A mechanistic model for spread of livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) within a pig herd. PLoS One 2017; 12:e0188429. [PMID: 29182655 PMCID: PMC5705068 DOI: 10.1371/journal.pone.0188429] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 11/07/2017] [Indexed: 12/18/2022] Open
Abstract
Before an efficient control strategy for livestock-associated methicillin resistant Staphylococcus aureus (LA-MRSA) in pigs can be decided upon, it is necessary to obtain a better understanding of how LA-MRSA spreads and persists within a pig herd, once it is introduced. We here present a mechanistic stochastic discrete-event simulation model for spread of LA-MRSA within a farrow-to-finish sow herd to aid in this. The model was individual-based and included three different disease compartments: susceptible, intermittent or persistent shedder of MRSA. The model was used for studying transmission dynamics and within-farm prevalence after different introductions of LA-MRSA into a farm. The spread of LA-MRSA throughout the farm mainly followed the movement of pigs. After spread of LA-MRSA had reached equilibrium, the prevalence of LA-MRSA shedders was predicted to be highest in the farrowing unit, independent of how LA-MRSA was introduced. LA-MRSA took longer to spread to the whole herd if introduced in the finisher stable, rather than by gilts in the mating stable. The more LA-MRSA positive animals introduced, the shorter time before the prevalence in the herd stabilised. Introduction of a low number of intermittently shedding pigs was predicted to frequently result in LA-MRSA fading out. The model is a potential decision support tool for assessments of short and long term consequences of proposed intervention strategies or surveillance options for LA-MRSA within pig herds.
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Affiliation(s)
| | - Nils Toft
- National Veterinary Institute, Technical University of Denmark, Lyngby, Denmark
| | - Anette Boklund
- National Veterinary Institute, Technical University of Denmark, Lyngby, Denmark
| | | | - Kaare Græsbøll
- National Veterinary Institute, Technical University of Denmark, Lyngby, Denmark
| | - Jesper Larsen
- Microbiology and Infection Control, Statens Serum Institute, Copenhagen, Denmark
| | - Tariq Halasa
- National Veterinary Institute, Technical University of Denmark, Lyngby, Denmark
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8
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Differential Analysis of the Nasal Microbiome of Pig Carriers or Non-Carriers of Staphylococcus aureus. PLoS One 2016; 11:e0160331. [PMID: 27509169 PMCID: PMC4980049 DOI: 10.1371/journal.pone.0160331] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 07/18/2016] [Indexed: 12/17/2022] Open
Abstract
Staphylococcus aureus is presently regarded as an emerging zoonotic agent due to the spread of specific methicillin-resistant S. aureus (MRSA) clones in pig farms. Studying the microbiota can be useful for the identification of bacteria that antagonize such opportunistic veterinary and zoonotic pathogen in animal carriers. The aim of this study was to determine whether the nasal microbiome of pig S. aureus carriers differs from that of non-carriers. The V3-V5 region of the 16S rRNA gene was sequenced from nasal swabs of 44 S. aureus carriers and 56 non-carriers using the 454 GS FLX titanium system. Carriers and non-carriers were selected on the basis of quantitative longitudinal data on S. aureus carriage in 600 pigs sampled at 20 Danish herds included in two previous studies in Denmark. Raw sequences were analysed with the BION meta package and the resulting abundance matrix was analysed using the DESeq2 package in R to identify operational taxonomic units (OTUs) with differential abundance between S. aureus carriers and non-carriers. Twenty OTUs were significantly associated to non-carriers, including species with known probiotic potential and antimicrobial effect such as lactic acid-producing isolates described among Leuconostoc spp. and some members of the Lachnospiraceae family, which is known for butyrate production. Further 5 OTUs were significantly associated to carriage, including known pathogenic bacteria such as Pasteurella multocida and Klebsiella spp. Our results show that the nasal microbiome of pigs that are not colonized with S. aureus harbours several species/taxa that are significantly less abundant in pig carriers, suggesting that the nasal microbiota may play a role in the individual predisposition to S. aureus nasal carriage in pigs. Further research is warranted to isolate these bacteria and assess their possible antagonistic effect on S. aureus for the pursuit of new strategies to control MRSA in pig farming.
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9
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Fetsch A, Roesler U, Kraushaar B, Friese A. Co-colonization and clonal diversity of methicillin-sensitive and methicillin-resistant Staphylococcus aureus in sows. Vet Microbiol 2016; 185:7-14. [PMID: 26931385 DOI: 10.1016/j.vetmic.2016.01.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 01/07/2016] [Accepted: 01/16/2016] [Indexed: 11/19/2022]
Abstract
Methicillin-susceptible Staphylococcus (S.) aureus (MSSA) and methicillin-resistant S. aureus (MRSA) are colonizers of skin and mucosa. In humans, MSSA and MRSA compete for colonization space in the anterior nares of pig farmers; however, it was also shown that MSSA/MRSA co-colonization is common and one clone can be found rather than differing types of MSSA and MRSA. We investigated the colonization and clonality of both, MSSA and MRSA in pigs over a longer time. Eighteen sows were nasally sampled three times every ten weeks. Additionally, environmental samples were taken. Samples were investigated for MSSA and MRSA, respectively. The spa type was defined from up to five MRSA and MSSA isolates found per sample and sampling time; selected isolates were further investigated by microarray. Three sows (16.7%) were completely negative for MSSA and MRSA. Twelve pigs (66.7%) were irregularly positive for both, MSSA and MRSA over the time, whereas seven out of them (38.9%) were simultaneously colonized. CC398 (t034, t011) MRSA and CC9 (t337, t1430, and t13816) MSSA associated spa types were exclusively found. In 44.4% (n=8) of sows up to two different types of MSSA were present at the same time and sample. Strains of the same clonal lineage showed a high genetic identity despite their origin. Highly identic clones were present in sows and their environment. As conclusion, MSSA/MRSA may not exclude each other in the anterior nares of pigs. Pigs may also carry different clones at the same time.
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Affiliation(s)
- Alexandra Fetsch
- National Reference Laboratory for Coagulase-positive Staphylococci Incl. Staphylococcus aureus, Federal Institute for Risk Assessment, Max-Dohrn-Str. 8-10, 10589 Berlin, Germany.
| | - Uwe Roesler
- Institute for Animal Hygiene and Environmental Health, Freie Universität Berlin, Robert-von Ostertag-Straße 7-13, 14163 Berlin, Germany
| | - Britta Kraushaar
- National Reference Laboratory for Coagulase-positive Staphylococci Incl. Staphylococcus aureus, Federal Institute for Risk Assessment, Max-Dohrn-Str. 8-10, 10589 Berlin, Germany
| | - Anika Friese
- Institute for Animal Hygiene and Environmental Health, Freie Universität Berlin, Robert-von Ostertag-Straße 7-13, 14163 Berlin, Germany
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Skallerup P, Espinosa-Gongora C, Jørgensen CB, Guardabassi L, Fredholm M. Genome-wide association study reveals a locus for nasal carriage of Staphylococcus aureus in Danish crossbred pigs. BMC Vet Res 2015; 11:290. [PMID: 26612358 PMCID: PMC4662016 DOI: 10.1186/s12917-015-0599-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 11/18/2015] [Indexed: 11/25/2022] Open
Abstract
Background Staphylococcus aureus is an important human opportunistic pathogen residing on skin and mucosae of healthy people. Pigs have been identified as a source of human colonization and infection with methicillin-resistant Staphylococcus aureus (MRSA) and novel measures are needed to control zoonotic transmission. A recent longitudinal study indicated that a minority of pigs characterized by high nasal load and stable carriage may be responsible for the maintenance of S. aureus within farms. The primary objective of the present study was to detect genetic loci associated with nasal carriage of S. aureus in Danish crossbred pigs (Danish Landrace/Yorkshire/Duroc). Results Fifty-six persistent carriers and 65 non-carriers selected from 15 farms surveyed in the previous longitudinal study were genotyped using Illumina’s Porcine SNP60 beadchip. In addition, spa typing was performed on 126 S. aureus isolates from 37 pigs to investigate possible relationships between host and S. aureus genotypes. A single SNP (MARC0099960) on chromosome 12 was found to be associated with nasal carriage of S. aureus at a genome-wide level after permutation testing (p = 0.0497) whereas the association of a neighboring SNP was found to be borderline (p = 0.114). Typing of S. aureus isolates led to detection of 11 spa types belonging to the three main S. aureus clonal complexes (CC) previously described in pigs (CC9, CC30 and CC398). Individual carriers often harbored multiple S. aureus genotypes and the host-pathogen interaction seems to be independent of S. aureus genotype. Conclusion Our results suggest it may be possible to select pigs genetically resistant to S. aureus nasal colonization as a tool to control transmission of livestock-associated MRSA to humans. Electronic supplementary material The online version of this article (doi:10.1186/s12917-015-0599-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Per Skallerup
- Department of Veterinary Clinical and Animal Sciences, University of Copenhagen, Frederiksberg, Denmark.
| | | | - Claus B Jørgensen
- Department of Veterinary Clinical and Animal Sciences, University of Copenhagen, Frederiksberg, Denmark.
| | - Luca Guardabassi
- Department of Veterinary Disease Biology, University of Copenhagen, Frederiksberg, Denmark.
| | - Merete Fredholm
- Department of Veterinary Clinical and Animal Sciences, University of Copenhagen, Frederiksberg, Denmark.
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