Population-level macrolide consumption is associated with clarithromycin resistance in Helicobacter pylori: An ecological analysis.

Bystander selection has been shown to result in strong population-level correlations between the level of antimicrobial consumption in the general population and resistance to that antimicrobial or similar antimicrobials in a range of bacteria. The prevalence of clarithromycin resistance in Helicobacter pylori has been increasing rapidly resulting in increased difficulty to eradicate this infection. Using country- and WHO-world-region-level macrolide resistance data from a systematic review and macrolide consumption data from the MIDAS Quantum data base, we tested the hypothesis that the prevalence of clarithromycin resistance was correlated with macrolide consumption. At a country level, we found these variables to be positively correlated (Spearman's rho=0.49; P=0.007). Whilst positive, the correlation between macrolide consumption and primary resistance was not statistically significant at world region level (Spearman's rho=0.95; P=0.05).