MRSA carriage in the equine community: an investigation of horse-caretaker couples

Equine methicillin-resistant Staphylococcus aureus (MRSA) carriage entails a risk of both equine and zoonotic transmission and infection. In Europe, CC398, the livestock-associated (LA-)MRSA is highly prevalent in horses and veterinary personnel at equine clinics. The extent of the MRSA reservoir created by healthy horses from the general population and associated health hazard for their daily caretakers is, however, unknown. This study aimed at screening healthy horse-caretaker couples from a broad range of home farms. At five equine gatherings, 166 couples were selected for MRSA screening in the anterior nares and participation in an epidemiologic survey. All MRSA isolates were subjected to genotyping and antimicrobial susceptibility testing. Only 4 humans (2.4%) and 2 of their horses (1.2%) tested MRSA positive. Within the 2 couples where both partners were positive, man and horse carried isolates belonging to identical, livestock-associated spa types (t011 and t2330) and demonstrating equal antimicrobial susceptibility patterns. For all LA-MRSA positive humans (n=3) and animals (n=2) regular (in)direct contact with the veterinary sector was reported. A significant association between the horses' carriage status and transportation to an event could not be demonstrated (P=1.00). In conclusion, outside equine clinics, the extent of the MRSA reservoir in horses and their caretakers was low. Travel to an equine gathering could not be withheld as a risk factor for equine MRSA carriage, whereas indications were found that contact with veterinary care may predispose both healthy horses and their handlers to carriage.