Prevalence of primary fluoroquinolone resistance among clinical isolates of Helicobacter pylori at a University Hospital in Southern Taiwan.
BACKGROUND
Fluoroquinolone-containing therapy is effective in eradicating Helicobacter pylori. However, the resistance rate of H. pylori to fluoroquinolones in Taiwan has not yet been reported. In this study, we aimed to investigate the susceptibility to antibiotics commonly used in eradication schedules and fluoroquinolones in H. pylori.


METHODS
A total of 210 clinical isolates of H. pylori were collected from April 1998 to September 2007 from patients in southern Taiwan. The in vitro activities of six antimicrobial agents were determined by the agar dilution method and Etest. The mutations in quinolone resistance-determining regions of gyrA and gyrB were investigated by direct sequencing.


RESULTS
Overall, 5.7% of the isolates were resistant to ciprofloxacin and levofloxacin. The resistance rate to amoxicillin, clarithromycin, metronidazole, and tetracycline was 1.0% (two of 210), 9.5% (20 of 210), 27.6% (58 of 210), and 0.5% (one of 210), respectively. The resistance rate to either ciprofloxacin or to levofloxacin increased from 2.8% (1998-2003) to 11.8% (2004-2007). The mutations in gyrA at N87 or D91 had an impact on primary fluoroquinolone resistance in H. pylori. Garenoxacin, but not moxifloxacin, had a good in vitro inhibitory effect against ciprofloxacin/levofloxacin-resistant strains compared with objective minimal inhibitory concentration values.


CONCLUSIONS
Drug resistance to ciprofloxacin and levofloxacin in H. pylori collected from 2004 to 2007 increased significantly compared with resistance level observed during 1998-2003. The continuous surveillance of quinolone resistance among H. pylori is important in this area.
Hung
Kuei-Hsiang
KH
Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
Sheu
Bor-Shyang
BS
Chang
Wei-Lun
WL
Wu
Hsiu-Mei
HM
Liu
Chin-Cheng
CC
Wu
Jiunn-Jong
JJ
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics; D027081:DNA Gyrase / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial; D005260:Female; D024841:Fluoroquinolones / Q000494:pharmacology*; D016481:Helicobacter Infections / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology*; D016480:Helicobacter pylori / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D006785:Hospitals, University; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D009154:Mutation; D015995:Prevalence; D013624:Taiwan / Q000453:epidemiology
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D024841:Fluoroquinolones; D027081:DNA Gyrase