Antibiotic Resistance of Helicobacter pylori Among Male United States Veterans

Abstract

Background & aims: The most recent information published on resistance of Helicobacter pylori to antibiotics in a large population in the United States is more than 10 years old. We assessed the susceptibility of H pylori to antibiotics among patients in a large metropolitan hospital, as well as demographic, clinical, and lifestyle factors associated with antimicrobial resistance.

Methods: We performed a cross-sectional study of a random sample of 656 patients (90.2% men) from a cohort of 1559 undergoing esophagogastroduodenoscopy with collection of gastric biopsies from 2009 through 2013 at the Houston Veterans Affairs Medical Center. We performed culture analyses of gastric tissues to detect H pylori. The minimum inhibitory concentrations of amoxicillin, clarithromycin, metronidazole, levofloxacin, and tetracycline were determined by the Epsilometer test. Logistic regression analysis was performed to estimate the association between risk factors and antimicrobial resistance.

Results: Biopsies from 135 subjects (20.6%) tested positive for H pylori; 128 of these were from men (94.8%). Only 65 strains were susceptible to all 5 antibiotics. The prevalence of resistance to levofloxacin was 31.3% (95% confidence interval [CI], 23.1%-39.4%), to metronidazole it was 20.3% (95% CI, 13.2%-27.4%), to clarithromycin it was 16.4% (95% CI, 9.9%-22.9%), and to tetracycline it was 0.8% (95% CI, 0.0%-2.3%). No isolate was resistant to amoxicillin. Clarithromycin resistance increased from 9.1% in 2009-2010 to 24.2% in 2011-2013. In multivariate analysis, prior treatment of H pylori infection and use of fluoroquinolones were significantly associated with clarithromycin and levofloxacin resistance, respectively.

Conclusions: H pylori resistance to clarithromycin increased between 2009 and 2013; resistance to metronidazole remains high in infected men in the United States. The high frequency of resistance to levofloxacin is a new and concerning finding.

Keywords: Bacterial Resistance; Drug; Eradication Therapy; Gastritis.

Figure 1.

Distribution of MIC for each antibiotic: (A) clarithromycin, (B) metronidazole, and (C) levofloxacin.