Prevalência dos genes qnr, aac (6)Ib-cr e qepA entre isolados clínicos de enterobactérias. / Prevalence of qnr, aac (6)Ib-cr and qepA genes in clinical isolates of Enterobacteriaceae.

AUTOR(ES)

Paula Ignez Pilar Lemos Barbosa

FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

27/04/2011

RESUMO

The aim of this study was evaluated the frequency of the plasmid mediated quinolone resistance genes qnr, aac(6)Ib-cr and qepA. Were evaluated 231 Enterobacteriaceae isolated during the June of 2008 by the Central Laboratory of the São Paulo Hospital. Were analyzed by multiplex PCR followed by sequencing of the respective amplicons determinants qnrA, qnrB, qnrS, qnrC, qepA and aac(6)Ib. Into all the 231 enterobacterial isolates analyzed, nine had 99% homology with qnr genes described in the literature, among them, one E. aerogenes showed identical sequence to the gene qnrS1, three K. pneumoniae isolates showed sequences identical to qnrS1 and qnrB2, one E. cloacae showed sequence identical with qnrS1 and three E. coli presents sequence identical with qnrB19 and qnrS1. The qepA genes were not found by the PCR methodology. The aac(6)Ib gene was found in 14 samples and the sequence of the amplicons demonstrated that five samples showed the variant aac(6)Ib-cr, among them, two E. coli, two K.pneumoniae and one E.cloacae. In analyzing the transfer of qnr determinants by conjugation technique, samples of E. aerogenes carrier determinant qnrS1, K. pneumoniae and E. coli carrier qnrS1 had transferred its determinants in the recipient cell. The transfer of genes contained in conjugative plasmids was confirmed by PCR technique. The analysis of genetic similarity among isolates positives for the qnr determinants by the methodology of PFGE profiles showed clonal and related determinants qnr different. However we can conclude that the frequency of the determinants qnr and aac(6)ib-cr was low (3,46% and 2,16% respectively), the determinant qepA was not found; qnrS the determinant was more prevalent among the enterobacterial studied and was the first report of this gene in Brazilian samples and in E. aerogenes species. The determinant qnrB2 and qnrS1 was conjugated to recipient cells indicate that may be contained in conjugative plasmids, but more studies are needed to characterize the genetic context. The analysis of genetic similarity revealed that samples with the same genetic profile qnr genes are different, indicating that they were probably contained in mobile elements.

ASSUNTO(S)

qnr, aac(6)-ib-cr, qepa, enterobactérias imunologia

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