Resistance of Helicobacter pylori to antibiotics used to treat it has increased, exceeding 15% in most of the world, according to a recent global meta-analysis.
Researchers searched publication databases for studies that assessed rates of H. pylori resistance to clarithromycin, metronidazole, levofloxacin, amoxicillin, or tetracycline and grouped the evidence by World Health Organization (WHO) region. They found 178 studies with 66,142 H. pylori isolates from 65 countries. Results were published by Gastroenterology on July 7.
The analysis found primary and secondary resistance rates to clarithromycin, metronidazole, and levofloxacin to be at least 15%, the common threshold for choosing alternative empiric regimens, in almost all WHO regions. Exceptions were primary clarithromycin resistance in the Americas (10%; 95% CI, 4% to 16%) and Southeast Asia (10%; 95% CI, 5% to 16%) and primary levofloxacin resistance in Europe (11%; 95% CI, 9% to 13%). There was considerable heterogeneity among the analyses, but increasing antibiotic resistance was observed in most regions.
The analysis also found an increased risk of treatment failure with H. pylori resistance. In particular, resistance to clarithromycin was associated with failure of clarithromycin-containing regimens at an odds ratio of 6.97 (95% CI, 5.23 to 9.28; P<0.001). Although metronidazole resistance was the most prevalent worldwide, the association between resistance to the drug and treatment failure was lower than with the other drugs, supporting existing evidence that metronidazole resistance “can partially be overcome by increasing the dose and duration of treatment, especially when used a part of a bismuth-containing quadruple therapy,” the study authors said.
They called the levels of resistance found in the analysis “alarming” and recommended local and national surveillance to select appropriate eradication regimens for each region. The observed increases in resistance among treatment-naïve patients “can be correlated with the increasing and uncontrolled consumption of antibiotics that are commonly used in [H. pylori] empirical therapy and also used to treat other common infections in the general population (e.g., respiratory, genital, and urinary infections, parasite infestation),” the authors said.
Limitations of the study included limited prevalence data in several countries and heterogeneity between regions and countries, as well as publication bias among the included studies, the authors noted.