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Staphylococcus aureus is a versatile bacterium, which can infect or colonize a variety of host species. The objective of this study was to characterize S. aureus isolates recovered from nasal swabs of 167 healthy ewes sampled from 12 farms in different areas of Tunisia during the period of 20142015. Genetic lineages, virulence factors and antibiotic resistance mechanisms were determined for recovered isolates. S. aureus was detected in 45 out of 167 tested samples (26.9%). All isolates were methicillin-susceptible (MSSA) and the majority of them were susceptible to tested antibiotics with few exceptions (% of resistance): penicillin (8.8), ciprofloxacin (4.4), and tobramycin or tetracycline (2.2, each). Twelve different spa types were detected (t15098, t15099, t1773, t3576, t1534, t5428, t3750, t5970 t254, t2883, t127 and t933), two of them were new (t15098 and t15099). S. aureus isolates were ascribed to agrI (n = 23), agrII (n = 1) and agrIII (n = 20), and one was non-typeable. According to the sequence-type (ST) determined and/or the spa-type detected, the 45 S. aureus isolates were assigned to six clonal complexes, with CC522 (44.4%) and CC130 (37.7%) being the most common lineages. Twenty-one (46.6%) and two (4.2%) isolates harbored the tst and eta genes encoding TSST-1 and ETA, respectively. In conclusion, nares of healthy ewes could be a reservoir of MSSA CC522 and CC130, lineages associated with TSST-1 and ETA that might represent a risk to human health. © 2017 Elsevier Ltd

Clin Microbiol Infect ABSTRACT: Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of healthcare-associated (HA), community-associated (CA) and livestock-associated (LA) infections. Recently, the discovery of human and bovine MRSA isolates carrying a new mecA gene homologue, mecA(LGA251) (now designated mecC), has caused concern because they are not detected by conventional, confirmatory tests for MRSA. Very little is known about their frequency, epidemiology and possible transmission between livestock and humans. In this study, the epidemiology of the mecC isolates in Denmark was investigated by screening the national collections of MRSA cases (from 1988 onwards) and S. aureus bacteraemia cases (from 1958 onwards). Isolates carrying mecC were only recovered infrequently before 2003 (n = 2) but now seem to be increasing, with 110 cases in 2003-2011. Clinical data on mecC-carrying MRSA demonstrated that mecC-MRSA were primarily community-acquired (CA-MRSA) and affected persons typically living in rural areas, being older than other CA-MRSA patients. Among 22 cases in Region Zealand, four reported contact with cattle and sheep. Two of these persons lived on farms with livestock positive for mecC-carrying MRSA, sharing spa type (t843), MLVA (MT429) and PFGE pattern with the human isolates. These observations indicate that mecC-carrying MRSA can be exchanged between humans and ruminants.

Methicillin-resistant Staphylocoocus aureus (MRSA) harboring mecA(LGA251) has been isolated from humans and ruminants. Database screening identified this MRSA variant in cats, dogs, and a guinea pig in Germany during 2008-2011. The novel MRSA variant is not restricted to ruminants or humans, and contact with companion animals might pose a zoonotic risk.