Prevalence and molecular characteristics of methicillin-resistant Staphylococcus aureus (MRSA) among subjects working on bovine dairy farms

Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause ofhealthcare-associated infections worldwide and has recently been identified as anemerging pathogen in livestock and companion animals. Livestock-associated MRSA(LA-MRSA) may be responsible for increased rates of colonization and/or infectionamong people working on farms. We evaluated the prevalence and molecularcharacteristics of MRSA among dairy farmers in the province of Ragusa,South-Eastern Sicily, their animals and bulk tank milk samples. A surprisinglyhigh number of samples tested positive for MRSA: 36% of human nasal swabs, 61% ofbovine nasal swabs and 44% of bulk tank milk samples. MRSA carrier prevalence in humans significantly correlated with the percentage of positive cows on the farm,the number of livestock units and the presence of consensual positive bulk tankmilk samples. Prospective studies are needed to investigate MRSA transmissionbetween animals and humans and implement preventive strategies.