Bactérias relevantes na vigilância epidemiológica: contextualização da problemática dos processos envolvendo Staphylococcus aureus resistentes à meticilina (MRSA)

Abstract

The first semi-synthetic penicillin derivative, resistant to hydrolysis by staphylococcal beta-lactam methicillin was introduced into clinical practice in 1960 for the treatment of infections caused by a strain of Staphylococcus aureus resistant to penicillin. The molecular mechanism of methicillin resistant in S. aureus (MRSA) consists of purchasing a mobile genetic element called Staphylococcal Cassette Cromossome MEC (SCCmec) containing the mecA gene, responsible for the alteration of penicillin binding proteins (PBP). MRSA is a major cause of infections worldwide and a growing problem in Latin America. Epidemiological studies show a significant increase of MRSA infections in both hospital and community. Diagnosis is based on a combination of epidemiological data, clinical symptoms and characterization of the infecting strain ofMRSA. The Staphylococcus species can be identified based on a variety of conventional phenotypic characteristics. One of the most effective ways to control the spread of MRSA is by determining the genotypic characteristics of MRSA clones and the genetic relatedness of strains in different geographic regions. Fast and reliable methods for antimicrobial susceptibility are important to institute appropriate therapy. However,there is increasing resistance of MRSA to antimicrobial agents, reduced sensitivity to vancomycin and difficulty in treating severe infections caused by MRSA, even with appropriate antibiotics, and was not yet possible to find an active and passive immunization as an effective strategy. The alternative to reduce MRSA infections is increasing practices that reduce the spread of these microorganisms, which can be considered as barrier precautions or isolating contact.