Methicillin-resistant Staphylococcus aureus in horses and horse personnel: An investigation of several outbreaks

Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, PO Box 80165, 3508 TD Utrecht, Utrecht University, The Netherlands.
Veterinary Microbiology (Impact Factor: 2.51). 09/2009; 141(1-2):96-102. DOI: 10.1016/j.vetmic.2009.08.009
Source: PubMed


At the Veterinary Microbiological Diagnostic Center, the Netherlands, the percentage of methicillin-resistant Staphylococcus aureus (MRSA) isolates found in equine clinical samples increased from 0% in 2002 to 37% in 2008. MRSA of spa-type t064, belonging to MLST ST8 and spa-types t011 and t2123, both belonging to the livestock-associated MLST ST398, predominated. During an outbreak of post-surgical MRSA infections in horses at a veterinary teaching hospital in 2006/2007, MRSA isolates of spa-type t2123 were cultured from 7 horses and 4/61 personnel which indicated zoonotic transmission. After intervention the outbreak stopped. However, another outbreak occurred in 2008, where 17 equine MRSA isolates of spa-type t011 (n=12), t2123 (n=4), and t064 (n=1) were found. This time, 16/170 personnel were positive for MRSA with spa-type t011 (n=11) and t2123 (n=5). Personnel in close contact with horses were more often MRSA-positive (15/106) than those without (1/64). Screening of horses upon admission showed that 9.3% were MRSA-positive predominantly with spa-type t011. Weekly cross-sectional sampling of all hospitalized horses for 5 weeks showed that 42% of the horses were MRSA-positive at least once, again predominantly with spa-type t011, which suggests that nosocomial transmission took place. Fifty-three percent of the environmental samples were MRSA-positive, including samples from students' and staff members' rooms, and all were spa-type t011. This indicates that humans contribute to spreading the organism. Culturing of samples employing high-salt pre-enrichment performed better than a comparable method without pre-enrichment. Our results show that nosocomial transmission occurs in equine clinics and suggests that personnel play a role in the transmission.

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    • "Methicillin-resistant S. aureus infections have also been reported in horses [7] [8] and have been associated with metritis, dermatitis, wound-penetrating infections, and surgical-site infections [9] [10] [11] [12] [13]. Although MRSA infections have been considered more severe than methicillinsensitive S. aureus (MSSA) infections in horses, there is insufficient information to support this assumption [9] [13]. "
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    ABSTRACT: The aims of this study were (1) to evaluate the antibacterial effects of equine platelet concentrates (PCs) and other blood-derived preparations on methicillin-resistant Staphylococcus aureus (MRSA); (2) to determine the effect of MRSA on the concentration of transforming growth factor beta 1 and platelet-derived growth factor BB over time; and (3) to determine the correlations between MRSA growth and blood cell counts (platelets and leukocytes), as well as growth factor (GF) concentrations, in PCs and other blood-derived preparations. Blood from 14 clinically healthy horses was used to prepare the different blood-derived preparations. Bacterial growth was significantly inhibited by the different PCs and the cell-free plasma products, mainly during the first 8 hours. Growth factor concentrations were not significantly affected by the presence of bacteria. No correlation between MRSA growth inhibition and blood cells and/or GFs was found. The in vitro bacteriostatic effect of PCs on MRSA could be predominantly attributed to the plasma complement.
    Journal of Equine Veterinary Science 03/2015; 35(3). DOI:10.1016/j.jevs.2015.01.001 · 0.87 Impact Factor
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    • "In veterinary medicine, recent data suggest an increase in MRSA infections especially for companion animals such as dogs, cats and horses (Leonard and Markey, 2008; Strommenger et al., 2006; van Duijkeren et al., 2010; Vincze et al., 2014; Walther et al., 2008). "
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    ABSTRACT: Increasing numbers of companion animals suffering from infections with methicillin-resistant Staphylococcus aureus (MRSA) have been reported in the recent past. These infections are of particular concern because of the limited treatment options for MRSA and their transferability to humans. Since MRSA lineages isolated from infected companion animals often mirror typical human epidemic strains circulating in the same region, successful strategies to combat MRSA need strong and coordinated efforts from both, the human and the veterinary field according to the “One Health” concept. Hence, to identify potential risk factors related to MRSA infections in dogs, cats and horses, a case-control study was conducted, including data on 106 MRSA-infected animal patients as cases and 102 MSSA-infected animals as controls, originating from 155 different veterinary settings within Germany. Demographic data on animal patients, patient history and administration of antibiotics as well as practice/clinic specific parameters were assessed as putative risk factors. Multivariable logistic regression identified the following variables as risk factors for MRSA infection compared to MSSA infection: number of employees working at the veterinary setting (n > 10; p < 0.001), antibiotic treatment prior to sampling (systemic: p = 0.002; local: p = 0.049, both: p = 0.011) and surgical site infection (p < 0.001). Spa typing revealed predominantly clonal complexes well-known for hospital-associated lineages spreading in human health-care settings in Germany (CC5 and CC22) for isolates of dog and cat origin. CC398-MRSA dominated among equine isolates, a CC that was described as a nosocomial pathogen in equine clinical settings before.
    International Journal of Medical Microbiology 10/2014; 304(7). DOI:10.1016/j.ijmm.2014.07.007 · 3.61 Impact Factor
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    • "Staphylococcus aureus is a common facultative pathogenic bacterium that has long been recognized as a burden in both human and veterinary medicine. Indeed, S. aureus has been shown to be responsible of various infections such as clinical and subclinical bovine mastitis [1,2], wound infections in horses [3-5], dogs [6] and wild animals such as hedgehogs [7]. Furthermore, S. aureus is well known to harbour resistance to antimicrobial agents which may lead to complications in the treatment of its infections [8] and increase the cost of treatments [9]. "
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    ABSTRACT: Background Staphylococcus aureus is a common bacterium usually found on skin and mucous membranes of warm blooded animals. Resistance in S. aureus has been increasingly reported though depending on the clonal lineage. Indeed, while hospital acquired (HA)-methicillin resistant S. aureus (MRSA) are typically multi-resistant, community associated (CA)-MRSA are by large more susceptible to many antibiotics. Although S. aureus isolated from animals are often susceptible to most antibiotics, multi-resistant livestock associated (LA)-MRSA have been recovered from bovine mastitis. In this study, we investigated the prevalence and types of MRSA present in the nose of healthy bovines of different age groups and rearing practices. Since no validated methods for MRSA isolation from nasal swabs were available, we compared two isolation methods. Molecular characterization was performed by means of spa-typing, MLST, SCCmec typing and microarray analysis for the detection of antimicrobial resistance and virulence genes. Results MRSA between herd prevalence in bovines was estimated at 19.8%. There was a marked difference between rearing practices with 9.9%, 10.2% and 46.1% of the dairy, beef and veal calve farms respectively being MRSA positive. No significant difference was observed between both isolation methods tested. Most isolates were ST398 spa type t011 or closely related spa types. Few ST239 spa type t037 and t388 and ST8 spa type t121 were also found. SCCmec types carried by these strains were mainly type IV(2B), IV(2B&5) and type V. Type III and non-typeable SCCmec were recovered to a lesser extent. All isolates were multi-resistant to at least two antimicrobials in addition to the expected cefoxitin and penicillin resistance, with an average of resistance to 9.5 different antimicrobials. Isolates selected for microarray analysis carried a broad range of antimicrobial resistance and virulence genes. Conclusion MRSA were mainly present in veal farms, compared to the lower prevalence in dairy or beef farms. Multi-resistance in these strains was high. Though mainly CC398 spa t011 was found, the genetic diversity was higher than what was found for pigs in Belgium. CC8 strains, a typically human lineage but also recently found also in association with bovines, has been retrieved here also.
    BMC Veterinary Research 07/2014; 10(1):153. DOI:10.1186/1746-6148-10-153 · 1.78 Impact Factor
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