Helicobacter pylori from gastric biopsies: epidemiology and burden of antimicrobial resistance against first and second-line drugs

Objective: Background and Objectives: Helicobacter pylori is causing gastric ulcer and gastric cancer. The urease enzyme plays an important role in H. pylori survival and virulence by neutralizing stomach acid. The undertaken study detected antibiotic resistance signatures of H. pylori. Methods: Biopsy samples (n=2640) were collected from Tertiary Care Hospital, Peshawar, Pakistan. H. pylori were identified using culture, biochemical and PCR-based methods. The disc diffusion assay was used for antibiotic susceptibility, and multiplex PCR was incorporated for detection of antibiotic resistance genes, including 16S rRNA, pbp1, rdxA/frxA, gyrA/gyrB and 23S rRNA. Results: The PCR detection rate of H. pylori among urease positive isolates (n=489) was 43.9% (n=215). The detection rate of H. pylori was higher in gastric ulcer (n=53, 33.5%) and gastritis samples (n=46, 33.8%). On disc diffusion assay, resistance to first-line drugs, including metronidazole (n=214, 99.5%), amoxicillin (n=144, 66.9%) and clarithromycin (n=126, 58.6%) was alarmingly high among H. pylori isolates. Resistance towards second-line drugs, including levofloxacin (n=67, 31.1%) and tetracycline (n=59, 27.4%), was also documented. A significant association was documented among clarithromycin resistance, male individuals, and age group >40 years, with a prevalence of 38.8% (n=35, p=0.015) and 45.5% (n=41, p=0.002), respectively. The resistant isolates to all antibiotics were also resistant on the E-test based on MIC50 and MIC90. Molecular detection of gyrA/gyrB (for levofloxacin, n=39, 58.2%), 23S rRNA (for clarithromycin, n=69, 54.8%), frxA/rdxA (for metronidazole, n=91, 42.5%), 16S rRNA (for tetracycline, (n=28, 47.4%) and pbp1 (n=56, 38.8%) genes further confirmed the resistance signatures among H. pylori isolates. Conclusions: H. pylori detection rate was higher in gastric ulcer and gastritis samples. Multi-drug resistance was detected in almost half of the H. pylori isolates, while higher resistance rates were documented against first-line and second-line drugs.