engleski

Primary resistance of Helicobacter pylori to macrolides and metronidazole in the northern part of Croatia

Objectives: The aim of this study was to assess primary antibiotic resistance rates In Helicobacter pylori isolates over a period of 12 years (1995–2011). Methods: A total of 962 H. pylori were isolated from gastric biopsies taken from ppatients visiting CHC Zagreb and CHC Merkur in Zagreb, Croatia. Isolates from 1995 to 2011 were included in the study. From each patient four gastric biopsies were taken for histology and two were sent to the Department for Clinical and Molecular Microbiology CHC Zagreb for culture and determination of antibiotic activity against H. pylori by means of agar dilution. Susceptibility to clarithromycin, azithromycin, metronidazol, tetracycline and amoxicillin was determined. Primary resistance was assessed in H. pylori strains isolated before the first eradication therapy. Results: Resistance of H. pylori to amoxicillin and tetracycline was not detected. Clarithromycin and azithromycin showed a common resistance pattern in all tested isolates. Primary resistance to macrolides was detected in 98 (10.2%) strains and 274 (29.9%) strains were resistant to metronidazole out of 962 pretreatment isolates. From 1994 to 1999 resistance to macrolides was 7% (43/618) ; metronidazole 32% (183/572). From 2000 to 2006 for macrolides there were 14.6% resistant strains (44 /301)and metronidazole 23.6% (71/301 strain). From 2007 to 2011 there were 43 pretreatment isolates ; 25.6% (11) resistant to macrolides and 46.5% (20) resistant to metronidazole. Conclusions: The resistance rates to metronidazole and macrolides are high in H. pylori from northern Croatia. There is increase in resistance to macrolides and metronidazole among pretherapy isolates in observed period.

Helicobacter pylori; primary resistance; macrolides; metronidazole

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