Epidemiology and Infection

Original Papers

High prevalence of nasal MRSA carriage in slaughterhouse workers in contact with live pigs in The Netherlands

B. A. G. L. VAN CLEEFa1a2 c1, E. M. BROENSa1a3, A. VOSSa4, X. W. HUIJSDENSa1, L. ZÜCHNERa5, B. H. B. VAN BENTHEMa1, J. A. J. W. KLUYTMANSa2, M. N. MULDERSa1 and A. W. VAN DE GIESSENa1

a1 RIVM National Institute for Public Health and the Environment, Centre for Infectious Disease Control Netherlands, Bilthoven, The Netherlands

a2 VU University Medical Centre, Department of Medical Microbiology and Infection Prevention, Amsterdam, The Netherlands

a3 Quantitative Veterinary Epidemiology, Wageningen Institute of Animal Sciences (WIAS), Wageningen University, Wageningen, The Netherlands

a4 Canisius-Wilhelmina Hospital, Department of Medical Microbiology and Infection Control, Nijmegen, The Netherlands

a5 Food and Consumer Product Safety Authority (VWA) Region East, Zutphen, The Netherlands

SUMMARY

Livestock-associated MRSA has been found in various animals, livestock farmers and retail meat. This study aimed to determine the prevalence and determinants of nasal MRSA carriage in pig slaughterhouse workers. Three large pig slaughterhouses in The Netherlands were studied in 2008 using human and environmental samples. The overall prevalence of nasal MRSA carriage in employees of pig slaughterhouses was 5·6% (14/249) (95% CI 3·4–9·2) and working with live pigs was the single most important factor for being MRSA positive (OR 38·2, P<0·0001). At the start of the day MRSA was only found in environmental samples from the lairages (10/12), whereas at the end of the day MRSA was found in the lairages (11/12), the dirty (5/12) and clean (3/12) areas and green offal (1/3). The MRSA status of the environmental samples correlated well with the MRSA status of humans working in these sections (r=0·75). In conclusion, a high prevalence of nasal MRSA carriage was found in pig-slaughterhouse workers, and working with live pigs is the most important risk factor. Exact transmission routes from animals to humans remain to be elucidated in order to enable application of targeted preventive measures.

(Accepted January 15 2009)

(Online publication February 09 2010)

Correspondence:

c1 Author for correspondence: Drs B. A. G. L. van Cleef, Epidemiology and Surveillance Unit, National Institute for Public Health and the Environment, PO Box 1, 3720 BA Bilthoven, The Netherlands. (Email: brigitte.van.cleef@rivm.nl)

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