Histological changes in refractory Helicobacter pylori infection and its relationship with increased levels of resistance to antibiotics and therapeutic regimens: one-year follow-up.

Eradication failure of Helicobacter pylori infection could play a causal role in progression of gastric disorders. In this study, infection with H. pylori was followed in gastric biopsies of symptomatic adult patients at two phases during 1-year period. Analyses were done to show association of therapeutic regimens with the refractory infection, changes in sequence types (STs) and minimum inhibitory concentration (MIC) values, and progression of histopathological changes. Infection with H. pylori was confirmed in 32.3% (57/170) of the patients. Persistent infection with H. pylori was confirmed in 14 out of the 25 patients (56%) who participated at the second phase of the study. A difference between primary and secondary resistance rates to clarithromycin (49% vs 64.3%), metronidazole (76.36% vs 100%), and ciprofloxacin (45% vs 57.1%) was detected. Although the re-emerged strains in patients with refractory infection did not show alteration in STs, their MIC50 values showed twofold increases for clarithromycin and ciprofloxacin. While ciprofloxacin containing regimens were more successful, failure of metronidazole containing regimens was detected in 77% of the patients. Consequently, inappropriate medication has an impact on refractory H. pylori infection, which could cause to a rise in resistance levels to antibiotics and progression of pathological disorders.