Primary antibiotic resistance in Helicobacter pylori strains isolated in Northern and Central Italy

Background: Helicobacter pylori resistance to antibiotics is increasing worldwide, and it reduces the efficacy of therapy. Aim: To assess current primary antibiotic resistance in H. pylori strains isolated in Italy.Methods:Between June 2004 and June 2006, H. pylori strains were isolated consecutively in the two participating centres (Bologna, northern Italy; Rome, central Italy) from patients never previously treated for the infection. Isolated strains were tested for primary clarithromycin, metronidazole and levofloxacin resistance using as break point the minimal inhibitory concentration ‡1, ‡8 and ‡1 mg⁄ L for the three antibiotics, respectively. Results: Overall, 255 H. pylori strains were evaluated. The resistance rate was 16.9% for clarithromycin, 29.4% for metronidazole and 19.1% for levofloxacin. Clarithromycin resistance was significantly higher in non-ulcer dyspepsia than in peptic ulcer patients (19.1% vs. 0%, P = 0.02), metronidazole resistance was higher in foreign than Italian patients (50% vs. 22.9%, P = 0.0004) and levofloxacin resistance was higher in old than younger patients (28.4% vs. 14.4%, P = 0.048). Levofloxacin resistance was also more frequent in those strains with either clarithromycin or metronidazole resistance. Conclusion: A very high rate of primary resistance towards the tested antibiotics was detected in our study.