Mutational analysis of quinolone resistance in the plasmid-encoded pentapeptide repeat proteins QnrA, QnrB and QnrS
نویسندگان
چکیده
منابع مشابه
Mutational analysis of quinolone resistance in the plasmid-encoded pentapeptide repeat proteins QnrA, QnrB and QnrS.
OBJECTIVES Pentapeptide repeat proteins (PRPs) QnrA, QnrB and QnrS confer reduced susceptibility to quinolones. This study presents an in vitro analysis of the genetic evolution of quinolone resistance mediated by changes in the coding sequences and promoter regions of qnrA1, qnrS1 and qnrB1 genes. METHODS A random mutagenesis technique was used to predict the evolutionary potential of these ...
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Screening of 368 consecutive nonreplicate clinical isolates of Enterobacteriaceae resistant to nalidixic acid and at least one extended-spectrum beta-lactam revealed the presence of qnrA, qnrB, and qnrS determinants, and identified novel qnrB variants, in Citrobacter freundii isolates. This study also revealed, for the first time, the linkage of qnrB, armA, and extended-spectrum and/or AmpC-typ...
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The prevalence of three plasmid-mediated quinolone resistance determinants, QnrA, QnrB, and QnrS, among 526 nonreplicate clinical isolates of Enterobacter cloacae collected at a Taiwanese university hospital in 2004 was determined by PCR and colony hybridization, and the association of Qnr with the IMP-8 metallo-beta-lactamase was investigated. Eighty-six (16.3%) of all isolates were qnr positi...
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Sir, Quinolone resistance in Enterobacteriaceae usually results from mutations in genes coding for chromosomally encoded type II topoisomerases, efflux pumps or porin-related proteins. Recently, transferable, plasmid-borne, quinolone resistance genes—qnrA, qnrB, qnrS, cr variant of aac(60)-Ib, qepA and oxqB—have been observed in clinical isolates, more frequently among strains producing plasmid...
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strain with no parC mutations. This is consistent with previous findings that gyrA mutations are necessary for quinolone resistance, whereas parC mutations appear to be complementary, as resistant strains do not carry parC mutations alone. – 6 Some studies further suggest that additional parC mutations facilitate increasing levels of resistance, but our study did not support this. For example, ...
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ژورنال
عنوان ژورنال: Journal of Antimicrobial Chemotherapy
سال: 2009
ISSN: 1460-2091,0305-7453
DOI: 10.1093/jac/dkp111