background staphylococcus aureus is a significant pathogen that can colonize the nares of different animals, causing a wide range of infections in various hosts. objectives we intended to determine the prevalence of s. aureus in the nasal cavity of healthy ruminants and also to investigate the presence of antibiotic resistance genes. materials and methods in the present study, healthy cattle (n...

We evaluated the performance of several methods for the detection of methicillin resistance in Staphylococcus aureus using 101 clinical S. aureus isolates from pediatric patients in a tertiary hospital in Brazil; 50 isolates were mecA-positive and 51 were mecA-negative. The Etest and oxacillin agar screening plates were 100% sensitive and specific for mecA presence. Oxacillin and cefoxitin disk...

OBJECTIVES This study focused on the correlation between geno- and phenotypic tests in the correct assessment of mecA-mediated methicillin resistance among coagulase-negative staphylococci (CoNS) and the further characterization of mecA-positive isolates. METHODS A total of 121 CoNS from cases of bovine mastitis were investigated for oxacillin susceptibility by disc diffusion and broth microd...

Methicillin-resistant staphylococci (MRS), and methicillin-resistant Staphylococcus aureus (MRSA) in particular, have become a public and veterinary health concern. The search for MRS reservoirs outside human hospitals is needed in order to understand the reasons for their persistence and to control their spread. MRS have been isolated from rats, but little is known about their occurrence in fo...

The aim of this study was to compare a real-time PCR assay, with a conventional culture/PCR method, to detect S. aureus, mecA and Panton-Valentine Leukocidin (PVL) genes in animals and retail meat, using a two-step selective enrichment protocol. A total of 234 samples were examined (77 animal nasal swabs, 112 retail raw meat, and 45 deli meat). The multiplex real-time PCR targeted the genes: nu...

Methicillin-resistant Staphylococcus aureus (MRSA) is an important human pathogen, which is cross-resistant to virtually all β-lactam antibiotics. MRSA strains are defined by the presence of mecA gene. The transcription of mecA can be regulated by a sensor-inducer (MecR1) and a repressor (MecI), involving a unique series of proteolytic steps. The induction of mecA by MecR1 has been described as...

Staphylococci that acquire the mecA gene are usually resistant to beta-lactam antibiotics (methicillin or oxacillin resistance). mecA encodes a penicillin-binding protein (PBP 2a) that has a reduced affinity for beta-lactams. In some isolates with methicillin or oxacillin resistance, only a small proportion (< or =0.1%) of the population expresses resistance to > or =10 microg of oxacillin per ...