Methicillin-resistant Staphylococcus aureus (MRSA) ST398 in a farmer with skin lesions and in pigs of his farm: clonal relationship and detection of lnu(A) gene

Skin infection associated with methicillin-resistant Staphylococcus aureus (MRSA)-ST398 was detected in a pig-farmer, and MRSA-ST398 isolates were also detected in nasal samples of the patient and of 11/12 pigs on his farm. Twelve MRSA isolates were obtained from skin lesions (n = 6) and nasal samples (n = 6) of the patient in two sampling moments and 11 MRSA isolates from nasal samples of pigs. They were typed as t011-SCCmecIVa-agrI and t108-SCCmecV-agrI (patient and pigs) and t588-SCCmecV-agrI (patient). The following resistance genes were detected (number isolates): tet(K) (1), tet(L) (23), tet(M) (13), erm(A) (13), erm(C) (13), msr(A) (11), lnu(A) (21), aph(2″)-acc(6′) (3), ant(4′) (13), aph(3′) (12), dfrS1 (15) and dfrK (22). Seventeen human and animal MRSA-ST398 isolates showed indistinguishable PFGE patterns (A1-spa-t011 or B2-spa-t108) and similar phenotypic-genotypic characteristics, including the presence of the lnu(A) gene, associated with lincomycin resistance. Potential pig-to-human transference of ST398 is suggested in this study. The first detection of the lnu(A) gene in MRSA-ST398 is reported.