Detection of a cfr-positive MRSA CC398 strain in a pig farmer in Spain.

Abstract Objective To characterize one linezolid- and methicillin-resistant Staphylococcus aureus (MRSA) isolate recovered from a nasal sample of a pig farmer patient. Methods The detection of linezolid resistance mechanisms was performed by PCR and sequencing. The antimicrobial resistance and virulence profile was investigated, and the molecular typing was performed by molecular techniques. The transference of cfr gene was assessed by conjugation experiments and its genetic environment was investigated by specific PCRs. Results The linezolid-resistant MRSA isolate was typed as t011-ST398/CC398-SCCmecV-agrI and carried the cfr gene. The isolate was multidrug-resistant but lacked the virulence genes studied. The cfr gene was co-located with the fexA gene on a Tn558 variant and was successfully transferred by conjugation. Conclusion We report the first description of LA-MRSA-CC398 carrying the cfr gene in Spain. This finding highlights the importance of surveillance programmes to determine the presence and spread of the cfr gene in the livestock and clinical settings.