Estudo de amostras de Staphylococcus spp isolados de infecÃÃo nosocomial da cidade de Recife, Pernambuco, Brasil / Study of samples of Staphylococcus spp isolated from nosocomial infection in the city of Recife, Pernambuco, Brazil

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

Staphylococcus, although present in the microflora of human skin and mucosa, behaves as an opportunistic pathogen responsible for infectious complications, especially after the implantation of prosthetic devices. Furthermore, it has an extraordinary ability to acquire resistance to antimicrobials. Nowadays, methicillin-resistant Staphylococcus (MRS) are widespread and related to infectious processes both in the hospital and community. The ability of the bacteria to adhere to and to colonize inert materials through the formation of a biofilm confers protection against host defenses and antimicrobial agents. Biofilm formation has been associated with the level of susceptibility to methicillin. In the present study, we characterized staphylococcal samples identifying genes related to the production of biofilm (icaAD) and to the regulation of resistance to methicillin (mecI and mecR1) correlating with the ability to form biofilm in vitro and with susceptibility to oxacillin, respectively. Furthermore, we determined the cassette chromosome recombinase SCCmec present in the samples and established the genetic relationship among the isolates. An analysis carried out on 46 samples of Staphylococcus obtained from nosocomial infections at a university hospital in the city of Recife, Pernambuco, Brazil showed that the ability to form biofilm is not always associated with the presence or transcription of the icaAD genes, mainly in the MRS. Hence, icaAD genes are not effective molecular markers for differentiating biofilm-producers from non-producers among isolates. Therefore, both the molecular detection of ica genes and the phenotypic determination of biofilm production are recommended. Our results demonstrate that the allele type ccrA3 is conserved both in S. aureus and in SCN, suggesting horizontal transfer among the samples. We also observed a deletion of approximately 700 bp in mecR1, suggesting a new arrangement in this region in MRSA and MRSCN not yet described in isolates of hospital origin. The assessment of the relationship among the isolates showed high genetic diversity among sensitive and resistant isolates and the prevalence of some clones within the hospital. The diversity of profiles found suggests a community origin of the samples. Knowledge of the molecular and phenotypic profile of samples of Staphylococcus obtained through our studies may help in guiding the therapeutic approach for the treatment and control of hospital infections

ASSUNTO(S)

biofilme staphylococcus sccmec sccmec ciencias biologicas biofilm staphylococcus

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