Detection of point mutations in the gyrA gene of Helicobacter pylori isolates in Slovenia.
OBJECTIVE
The prevalence of antibiotic-resistant H. pylori clinical isolates is a growing concern. So far, fluoroquinolones have not been used to treat H. pylori on a large scale, but recent studies have reported a high rate of quinolones-resistance in H. pylori too. The aim of our study was to asses the mechanism of resistance to ciprofloxacin in H. pylori clinical isolates from patients living in Slovenia.


METHODS
Out of 397 H. pylori clinical isolates, obtained in the period 1997 to 2004, 33 (8.3%) ciprofloxacin-resistant H. pylori isolates were recognized. DNA sequences of the gyrA gene were determined and translated into amino acid sequences.


RESULTS
Based on the results of this analysis, various point mutations in the ciprofloxacin-resistant clinical isolates were revealed. The most common mutations in H. pylori gyrA gene were found at codons corresponding to Asp91 (57.6%) and Asn87 (36.4%). Sequence analysis revealed amino acid substitutions also at codons Ala97 to Val, Ala129 to Thr and a double substitution at Asn87 to Lys and Val107 to Ile.


CONCLUSIONS
These results suggest that H. pylori resistance to ciprofloxacin is already present in the Slovenian population and that it seems to be mediated through amino acid substitutions in the gyrA gene. Furthermore, the results obtained from the study also demonstrate no significant association between the type of gyrA mutation and the ciprofloxacin MIC level.
Kese
Darja
D
Institute of Microbiology and Immunology, Medical Faculty, University of Ljubljana, Ljubljana, Slovenia. darja.kese@mf.uni-lj.si
Gubina
Marija
M
Kogoj
Rok
R
Strasek
Katja
K
Tepes
Bojan
B
D000328:Adult; D002939:Ciprofloxacin; D015331:Cohort Studies; D027081:DNA Gyrase / Q000235:genetics*; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D016481:Helicobacter Infections / Q000382:microbiology*; D016480:Helicobacter pylori / Q000235:genetics*; D006801:Humans; D008826:Microbial Sensitivity Tests; D017354:Point Mutation / Q000235:genetics*; D017524:Slovenia
D002939:Ciprofloxacin; D027081:DNA Gyrase