Antimicrobial Resistance and Genetic Lineages of Staphylococcus aureus from Wild Rodents: First Report of mecC-Positive Methicillin-Resistant S. aureus (MRSA) in Portugal

摘要

Staphylococcus aureus is present in the microbiota of both humans and some animal species, being recognized as one of the most important opportunistic human pathogens. S. aureus is responsible for causing a variety of infections. Methicillin-resistant S. aureus (MRSA) is particularly important, as it is becoming increasingly prevalent in the population. MRSA has been increasingly reported among wild free-living animals which may impose a public health concern due to its zoonotic potential. To investigate the prevalence and antimicrobial resistance of S. aureus and MRSA in wild synanthropic rodent populations, we conducted this study on 204 rodents captured in port areas in Portugal. The antimicrobial resistance was investigated in all isolates as well as virulence genes and genetic lineages. Thirty-eight S. aureus were isolated. The results showed that six MRSA were detected with particularly interesting mecC-carrying MRSA isolates which had not yet been found in Portugal. A low frequency of antibiotic resistance and virulence genes was observed among the isolates. Nevertheless, a high diversity of clonal lineages was detected among S. aureus some of which are associated with livestock.