Association between Cephalexin Administration and Emergence of Methicillin-resistant Coagulase-positive Staphylococci (MRCoPS) in Dogs

The potential transmission of methicillin-resistant coagulase-positive staphylococci (MRCoPS) between dogs and human has been noted as of potential public health concern. The current study aimed to determine the emergence of methicillin-resistant coagulase-positive staphylococci (MRCoPS) in dogs after oral administration of cephalexin. Skin swabs from 38 dogs without a history of antibiotic exposure were collected before drug administration (pre-treatment dogs) and during drug administration within one month (treatment dogs). A total of 196 CoPS were isolated from the nose, perineum and skin lesions. Fewer MRCoPS were isolated from the pre-treatment dogs (7.89%) than from the treatment dogs (p<0.001). Methicillin-resistant Staphylococcus (S.) schleiferi subsp. coagulans (MRSSc) were only recovered from the treatment dogs, whereas methicillin-resistant S. pseudintermedius (MRSP) were found in both groups. Overall, a high incidence of MRSP was found since the first week after administration. The nose and perineum were confirmed as the most common site of carriage of MRCoPS rather than the skin lesions. In conclusion, the oral cephalexin administration was associated with the emergence of MRCoPS on dog skin, a potential source of contamination to humans.