Resumo

Introduction: S. aureus is one of the leading causes of nosocomial infection in Brazil and many hospital and community-acquired infections are associated with colonization by S. aureus methicillin-resistant (MRSA). This resistance results from the acquisition of a mobile genetic element, the SCCmec. Methodology: Identification of the SCCmec complex was performed for 89 clinical isolates from different sources of infection in patients from public hospitals in Northeast Brazil, to determine if they harbored segments of SCCmec elements I to V by multiplex e uniplex PCRs. The cefoxitin disc diffusion susceptibility test was performed. Results: Of 89 isolates, 31 were considered MRSA and 58 methicillin-sensitive (MSSA) by the antibiogram. All the isolates were tested for the presence of mecA gene, mec complex (mecI and mecR1) and ccr genes. The SCCmec typing for the 31/89 (34,8%) MRSA showed that 19 isolates were SCCmecIII (mec complex A, mecA-mecR1-mecI and ccr A3B3), 11 isolates were SCCmecIV (mec complex B, mecA-mecR1, without mecI and ccr A2B2) and a single isolate was SCCmecII (mec complex A and ccr A2B2). The remaining 58/89 (65,2%) MSSA isolates were investigated to determine if they harbored segments of SCCmec. Thirty of the 58 MSSA isolates were mecA gene positive, in which 15 isolates amplified for ccr genes types 2, 3 or 5. Three isolates were mecA gene negative, although harbored mec complex type A (Sa5 and Sa21) and ccr gene type 5 (Sa56). Discussion: The data showed that the frequencies of MRSA isolates were elevated. Molecular typing tools were performed and suggest that some S. aureus isolates are circulating in all sectors of the hospitals, demonstrating a serious public health problem in our region. All the samples belonging to SCCmecIII and IV were respectively similar to the BEC clone (a pandemic HA-MRSA, disseminated and predominated in Brazilian hospitals) and to the USA800 (a paediatric clone). The SCCmecII was similar to the USA100 (New York/Japan clone). Conclusions: Our data show a high frequency of MRSA (34, 8%) isolates circulating in public hospitals units of Northeast Brazil, which can be responsible for severe nosocomial diseases. This research can aid in the monitoring of potentially pathogenic isolates, since in our region very few studies have been conducted in this area.