The new quinolones are antibacterial agents recently introduced in the treatment of infectious diseases. The increase in quinolone resistance among isolates of pathogens, has stimulated the research of the mechanisms of resistance to these compounds. In \i E. coli\i0 and other bacteria, quinolone resistance is related to certain base-pair substitutions in the "quinolone resistance-determining region" (QRDR) of the \i gyrA\i0 gene, resulting in a DNA gyrase resistant to these antimicrobial agents. In this work, we propose to develop a rapid method ro identify quinolone resistant strains, based on colony hybridization with a set of oligonucleotides, able to detect each one of these point mutilations. Using this methodology, resistant strains isolated, will be analyzed. To gain more information about other mutilations, not identified by probing analysis, regions of the \i gyrA\i0 of \i E. coli\i0 resistant strains will be sequenced. Furthermore, additional mutations in the \i gyrB, parC \i0 and \i marR\i0 genes will be detected by probing analysis of resistant isolates of \i E. coli\i0 . The relationship among the presence of mutations, the level of resistance to several quinolones of the strains analyzed (MICs) and their susceptibility to non related antimicrobial agents will be studied. This work will offer a set of useful probes to identify quinolone resistant strains of the three species studied.
|Effective start/end date||1/07/98 → 1/07/01|
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