Metronidazole and clarithromycin susceptibility and the subtypes of VacA of Helicobacter pylori isolates in Estonia

The prevalence of metronidazole and clarithromycin resistance of Helicobact er pylori strains under different growth conditions (microaerophilic or ana erobic preincubation) was tested in 56 patients suffering from gastritis an d peptic ulcer. vacA subtypes were detected in 46 H. pylori strains and wer e subsequently compared with the antibiotic resistance pattern. From 56 iso lates, 26 proved resistant and 30 sensitive to metronidazole, The patients with peptic ulcer and gastritis were infected sith both metronidazole-sensi tive and metronidazole-resistant strains. In anaerobic preincubation all th e strains mere sensitive to metronidazole (MIC < 8 mg/l). All the strains w ere clarithromycin-sensitive (MIC < 2 mg/l), In the patients with gastritis and peptic ulcer s1 was the predominant vacA subtype. Comparison of vacA s ubtypes with the diagnoses revealed no correlation; different virulence fac tors such as vacA subtypes and antibiotic resistance to metronidazole in a microaerophilic milieu proved unrelated.