Navegando por Palavras-chave "qnr"

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    Evaluation of the Susceptibility profiles, genetic similarity and presence of qnr gene in Escherichia coli resistant to ciprofloxacin isolated in Brazilian hospitals
    (Brazilian Society of Infectious Diseases, 2007-02-01) Pereira, Andrea dos Santos [UNIFESP]; Andrade, Soraya Sgambatti [UNIFESP]; Monteiro, Jussimara [UNIFESP]; Sader, Helio Silva [UNIFESP]; Pignatari, Antonio Carlos Campos [UNIFESP]; Gales, Ana Cristina [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); JMI Laboratories
    Increasing quinolone resistance has been reported worldwide, mainly among clinical isolates of Escherichia coli. The objectives of this study were to determine the susceptibility profile, the genetic relatedness, and the prevalence of the qnr gene among ciprofloxacin-resistant Escherichia coli isolated from distinct Brazilian hospitals. A total of 144 ciprofloxacin-resistant Escherichia coli were isolated from 17 Brazilian hospitals between January/2002 and June/2003. The antimicrobial susceptibility testing was performed by microdilution according to NCCLS. The presence of the qnr gene was initially screened by colony blotting, and then confirmed by PCR followed by DNA sequencing. Ninety-five urinary ciprofloxacin-resistant Escherichia coli were further selected for molecular typing by pulsed-field gel electrophoresis (PFGE). Imipenem and meropenem showed the highest susceptibility rates (100.0% for both compounds) followed by amikacin (91.0%) and piperacillin/tazobactan (84.8%). A single ciprofloxacin-resistant Escherichia coli isolate was positive for qnr among the 144 ciprofloxacin-resistant Escherichia coli. Forty-six PFGE patterns were observed among the 95 ciprofloxacin-resistant Escherichia coli type. This study shows that therapeutic options are limited for treatment of ciprofloxacin-resistant Escherichia coli due to the presence of additional mechanisms of antimicrobial resistance, such as ESBL production. The qnr gene was uncommon among ciprofloxacin-resistant Escherichia coli clinical isolates, but its identification might indicate the emergence of this mechanism of quinolone resistance in Brazil. The great genomic variability found among the ciprofloxacin-resistant Escherichia coli highlights the importance of the appropriate use of quinolone to restrict the selection of resistant isolates.
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    Prevalência dos genes qnr, aac (6’)Ib-cr e qepA entre isolados clínicos de enterobactérias
    (Universidade Federal de São Paulo (UNIFESP), 2011-04-27) Barbosa, Paula Ignez Pilar Lemos [UNIFESP]; Gales, Ana Cristina [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    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.