Epidemiologia molecular de Staphylococcus aureus resistentes a oxacilina isoladas de pacientes do Hospital das Clinicas

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

Nosocomial infections caused by MRSA represent a serious medical and nosocomial problem around the world and have been the cause of epidemics and outbreaks with a high mortality rate mainly in University Hospitals and large and medium sized hospitals. The use of discriminatory techniques through DNA analysis of strains involved in nosocomial infections is an extremely valuable resource to confirm the efficacy of control measures related to the causing agents of nosocomial infections. This study has analyzed the genomical diversity of MRSA strains isolated from nosocomial infection carriers hospitalized at the Hospital das Clínicas da Universidade Estadual de Campinas, from 1995 to 2001, comparing them with the genomical profiles obtained from 1991 to February 1993. Two molecular typing methods were applied: - RAPD-PCR genomical DNA analysis in two periods of time and the DNA profile by PFGE. 117 MRSA strains were studied-obtained from carriers hospitalized from 1995 to 2001. Through PFGE, it has been observed that 80 (68.4%) strains had the same genomic profile A, 18 (15.4%) strains had a closely-related genomic profile AM, 18 (15.4%) strains had a possibly-related genomic profile AP and only 1 (0,8%) strain presented an unrelated profile. In the period from 1991 to 1993, 73 strains presented five distinctive DNA profiles: A, B, C, D and E. Profile A was the most frequent DNA pattern and was identified 55 (75.3%) strains; three closely-related and four possibly related profiles were also identified. The genomic profiles A, AM and AP identified in the period from 1995-2001 were identical to those obtained from 1991 to 1993, demonstrating the presence, the clonal dissemination and the persistence of an endemic strain in a nosocomial environment within a ten-year period. The computer analysis of the endemic profile A identified in period 1991-1993 and profile A from period 1995-2001 showed a 96% of similarity and they were considered to be the same profile A and they came from the common MRSA clone widely recognized in Sao Paulo and other Brazilians hospitals. Two different cluster patterns have been identified through RAPD; the profie a was represented by 43 (36.7%) strains and there was a variation from 8 to 10 fragments while profile b was represented by 74 (53.3%) strains and there was a variation from 5 to 7 fragments. Cluster analysis showed an 86% coefficient of similarity. A better understanding of the epidemiological behavior of MRSA strains at Hospital de Clínicas da Unicamp has been achieved with the application of molecular biology methods. The persistence of the same genomic profile within a ten-year period has shown a high probability of a crossed transmission of such pathogen.

ASSUNTO(S)

staphylococcus aureus epidemiologia molecular infecção hospitalar

ACESSO AO ARTIGO

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