Primary and secondary antibiotic resistance of Helicobacter pylori strains isolated in central Italy during the years 1998-2002.
BACKGROUND
Antibiotic resistance of Helicobacter pylori is the most common reason for failure in its eradication.


OBJECTIVE
To determine the incidence of primary and secondary resistance to tinidazole, clarithromycin and amoxycillin in Helicobacter pylori isolates from dyspeptic patients in central Italy and to evaluate the modifications of resistance over the period from 1998 to 2002.


METHODS
H. pylori strains were isolated from antral biopsies taken during upper endoscopy in 406 dyspeptic patients with no previous therapy against H. pylori, and in 96 patients who had already undergone one or more triple therapies. Antibiotic susceptibility test was performed using the screening agar method and agar dilution method.


RESULTS
Overall primary resistance to tinidazole, clarithromycin and amoxycillin was 36.7, 23.4 and 0.2%, respectively. Secondary resistance rates were: tinidazole 69.8%, clarithromycin 82.3% and amoxycillin 1%. Resistance to clarithromycin was often associated with tinidazole resistance and was significantly higher in female patients (p<0.05). Primary and secondary antibiotic resistance did not change during the 4 years of observation.


CONCLUSIONS
The dyspeptic population with H. pylori infection in central Italy shows high levels of antibiotic resistance. Primary resistance to clarithromycin is most frequent in female patients. In patients with secondary resistance, dual resistance to clarithromycin and tinidazole is found in the majority of cases.
Internal Medicine Unit, Department of Medicine and Aging, G. d'Annunzio University, Presidio Ospedaliero Spirito Santo, Via Fonte Romana 8, 65124 Pescara, Italy.
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Toracchio
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Marzio
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000658:Amoxicillin / Q000627:therapeutic use; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D000994:Antitrichomonal Agents / Q000627:therapeutic use*; D017291:Clarithromycin / Q000627:therapeutic use; D024901:Drug Resistance, Multiple, Bacterial; D004415:Dyspepsia / Q000382:microbiology; D005260:Female; D016481:Helicobacter Infections / Q000188:drug therapy*; D016480:Helicobacter pylori / Q000302:isolation & purification; D006801:Humans; D015994:Incidence; D007558:Italy; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D012737:Sex Factors; D014011:Tinidazole / Q000627:therapeutic use; D014505:Urban Population
D000900:Anti-Bacterial Agents; D000994:Antitrichomonal Agents; D014011:Tinidazole; D000658:Amoxicillin; D017291:Clarithromycin