The newly described mecA homologue, mecA_LGA251, is present in methicillin-resistant Staphylococcus aureus isolates from a diverse range of host species

Objectives: A previously unidentified mecA homologue, mecA_LGA251, has recently been described in methicillin-resistant Staphylococcus aureus (MRSA) from humans and dairy cattle. The origin and epidemiology of this novel homologue are unclear. The objective of this study was to provide basic descriptive information of MRSA isolates harbouring mecA_LGA251 from a range of host animal species. Methods: A number of S. aureus isolates from historical animal isolate collections were chosen for investigation based on their similarity to known mecA_LGA251 MRSA isolates. The presence of mecA_LGA251 was determined using a multiplex PCR and antimicrobial susceptibility testing performed by disc diffusion. Results: MRSA harbouring mecA_LGA251 were found in isolates from a domestic dog, brown rats, a rabbit, a common seal, sheep and a chaffinch. All of the isolates were phenotypically MRSA, although this depended on which test was used; some isolates would be considered susceptible with certain assays. All isolates were susceptible to linezolid, rifampicin, kanamycin, norfloxacin, erythromycin, clindamycin, fusidic acid, tetracycline, trimethoprim/sulfamethoxazole and mupirocin. Five multilocus sequence types were represented (2273, 130, 425, 1764 and 1245) and six spa types (t208, t6293, t742, t6594, t7914 and t843). Conclusions: The discovery of MRSA isolates possessing mecA_LGA251 from a diverse range of host species, including different taxonomic classes, has important implications for the diagnosis of MRSA in these species and our understanding of the epidemiology of this novel mecA homologue.