Estudo de perfil de sensibilidade / ResistÃncia de cepas de Staphylococcus aureus MRSA do Hospital das ClÃnicas de Pernambuco

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

The appearance of Staphylococcus aureus strains MRSA during the seventies increased rapidly throughout the world. These multiresistant strains are responsable for nosocomial and community infections of difficult treatment. The resistance to meticilin is caused by the modification of a protein bound to penicilins (PBP), PBP2ÂÂ codified as mecA. Abou 40 to 60% of S. aureus strains isolated at large hospitals present resistance to metecilin and. According to the literature, those infections are besides associated to specific epidemic clones of multiresistant Staphylococcus aureus, which are very often only susceptible to the glicopeptideo vancomicin. In Brazil, since 1992, an epidemic clone had been detected and indicated as Brazilian Epidemic Clone (BEC) which is widely disseminated in hospitals of different regions in Brazil and other Latin American countries and is Europe. On the other hand, the heterogeneity of resistance presented by many of these clones, which occasionally have led to treatment failures, justifies the necessity urgence to reveal its presence. In Recife, systematic studies of the resistance of Staphylococcus aureus have so far not yet been undertaken. At the present work different technics to determine the resistance to meticilin and studies based on molecular biology to determine the presence of the mecA gene have been developed and the existence of the epidemic clone has been detected. During the period of january 2002 and July 2003, a total of two hunderd forty-one clinical isolates of Staphylococcus aureus of different origins have been collected at the University Hospital (Hospital das Clinicas) in Recife- Pernambuco. In order to determine the susceptibility/resistance profile of the adequately identified strains, a uniform antibiogram was programmed with eight antibiotics; ciprofloxacin, vancomicin, oxacilin, gentamicin, penicilin, sulfametropim, tetraciclin and eritromicin. The resistance to meticilin was confirmed by the oxacilin Agar screen test and sidewise by determination of the minimun inhibitory concentration (MCI) for oxacilin through a Steers multiinoculator and by the Etest technigue. The presence of the mecA gene, was determined by PCR amplification. From the results, fifty-seven strains (72%) of the seventy-nine mutiresistant obtained Staphylococcus aureus MRSA were susceptible only to the antibiotic Vancomicin. Forty-seven strains of multiresistant Staphylococcus aureus MRSA, choosen by their fenotypical resistance patterns were studied by the DNA electrophoresis method in alternating fields (PFGE). It was determined that twenty-six isolates were subclones of the Brazilian Epidemic Clone. On the other hand, the presence of eight isolated subclones of Pediatric Clone was confirmed. Among them a Staphylococcus aureus MRSA AM824, initially considered related to the New York clone, was classified as Pediatric Clone by the determination of the mec element, SCC mec (type IV). Besides, nine isolates related to Sporadic Epidemic Clones were detected. The proven results, principally in relation to BEC have confirmed the data cited in literature with respect to hospital centers, in Brasil, in latin american coutries, in Argentine and Uruguay, as well as in european countries

ASSUNTO(S)

antibiograma padrÃo farmacia agar âscreenâ de oxacilina meticilina cepas staphylococcus aureus clone epidÃmico brasileiro

ACESSO AO ARTIGO

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