Use of molecular techniques for the detection of quinolone resistance in uropathogen Escherichia coli

Uropathogen E. coli is a bacteria that causes urinary tract infection and in which antibiotic resistance is a problem. In recent years, increasing resistance to antimicrobial drugs has been detected in both community acquired and nosocomial UTI caused by E. coli.The aim of this study is to detect the quinolone resistance of uropathogen E.coli strains by conventional and molecular methods.One hundred and two E.coli which were isolated from urine samples sent to our hospital were included in this study. These samples have been identified by using conventional methods. Ciprofloxacin, ofloxacin and levofloxacin suspectibility of the strains were assessed by using agar dilution method according to the recommendations of CLSI. The DNA gyrase subunit A is mostly investigated and thought to be responsible for the resistance to quinolones in E. coli. 28 E.coli strains selected from the quinolone resistant strains were analyzed molecularly by DNA sequencing of gyr A gene region.According to our data; 102 E.coli strain were detected for suspectibility to ciprofloxacin, ofloxacin and levofloxacin by agar dilution method and the results are as follows; 34 out of 102 (%33.33) E.coli strains were resistant, 6 (%5.88) strains were intermediate resistant and 62 (%60.78) strains were sensitive.Mutations in codons 83 and 87 were detected by gene sequence analysis of gyrA. According to results of the gyrA gene region sequence analysis, mutations caused by convertion of serin to leusin at codon 83, and aspartic acid to asparagin at codon 87 were found in 24 out of 28 E.coli strains (%85.71) which were resistant to ciprofloxacin, ofloxacin and levofloxacin. In 4 strains (%14.28) there were not any gyrA mutations determined.There is increasing resistance to quinolones in uropathogen E.coli so further investigation is needed to explain the resistance to antimicrobials. gyrA gene region that is mostly associated with the mutations is commonly studied. The results of our study declare the molecular profile of quinolone resistance of uropathogen E.coli. To clarify the molecular features of resistance and identify quinolone resistance by all means, gene regions, gyrB, parC and parE, that may be associated with resistance should be investigated.