Non-Multidrug-Resistant, Methicillin-Resistant Staphylococcus aureus Causing Infection in Health-care Facilities in Southern Brazil

Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is usually susceptible to a variety of non-beta-lactam drugs. These isolates commonly display SCCmecIV and are associated with community-acquired infections. More recently, CA-MRSA has been isolated from health-care-associated diseases. We categorize isolates resistant only to oxacillin or oxacillin plus no more than 3 non-beta-lactam antibiotics according to clinical and epidemiological characteristics, from a hospital in Porto Alegre, and performed a combination of molecular techniques including mecA, SCCmec, Panton-Valentine leukocidin (PVL) detection and Pulsed-field gel electrophoresis (PFGE). A total of twenty-five patients with non-multidrug-resistant MRSA were studied. Nineteen (76%) came from skin and soft tissue infections. All isolates presented SCCmec type IV (being 19/25 IVc) whereas the PFGE profile most frequently found was OSCP-like (15/25). The presence of international clones USA400, USA300 was also verified. Comparing the results of clonal type with source, origin, type of SCCmec, presence the PVL gene and antimicrobial resistance we observed that OSCP-like PFGE profile was associated with skin and soft tissue infections (P=0.0012) and that this clonal group was strongly associated with the presence of PVL gene (P<0.001). This study shows a clonal diversity of CA-MRSA and strengths the concept that these isolates emerged globally from different backgrounds.