High prevalence of "livestock-associated" meticillin-resistant Staphylococcus aureus ST398 in swine and pig farmers in Belgium

Abstract number: O508

Denis O., Suetens C., Hallin M., Ramboer I., Catry B., Gordts B., Butaye P., Struelens M.J.

Backgrounds: Meticillin-resistant Staphylococcus aureus (MRSA) is a major pathogen in hospitals and in the community. Recently, a novel MRSA genotype has been reported among livestock animals, farmers and veterinarians in the Netherlands and neighboring countries. These animal associated strains are resistant to SmaI macrorestriction and belong to sequence type (ST) 398 by MLST. The objectives of this study were to determine the prevalence and risk factors for MRSA carriage in farmers and their household contacts in Belgian swine farms and characterise these stains genotypically and phenotypically.

Methods: Farmers and household contacts residing on 49 swine farms were screened for MRSA carriage by culturing nasal swabs onto selective agars. MRSA identification were confirmed by PCR and genotyped by pulsed field gel electrophoresis (PFGE) after SmaI macrorestriction, staphylococcal cassette chromosome mec (SCCmec) typing, spa sequence typing and MLST. Susceptibility to 18 antimicrobials was determined by the disk diffusion method. Demographic data, animal exposure and medical history were recorded to determine risk factors of MRSA carrier status in this population.

Results: Of 127 farmers screened, 48 (38%) were positive for MRSA. Carriers were found in 25 farms from seven provinces of Flanders and Wallonia. The prevalence was independently associated with porcine MRSA carriage and the frequent contact with pigs, horses and dogs. MRSA carriage was associated with higher levels of personal protection and hygiene. By molecular typing, all isolates were resistant to SmaI digestion and belonged to ST398 with spa types t011 or t034 with SCCmec type IV or type V. MRSA strains were resistant to tetracycline (100%), trimethoprim (100%), MLS (>50%), aminoglycosides (>40%) and ciprofloxacin (32%). The MRSA strains from human shared the same characteristics as those found in pigs.

Conclusions: A high prevalence of MRSA carriage was found (38%) in swine farmers and family members. Risk factors for MRSA colonisation included frequent contact with pigs and other farm animals and higher levels of protection and hygiene. MRSA strains from farmers and pigs belonged to the ST398 "animal MRSA clone" which has been reported in livestock animals, farmers and veterinarians in Europe.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Location: Barcelona, Spain
Presentation type:
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