INTRODUCTION
Mass azithromycin administration has been shown to reduce mortality by up to 25% for preschool children in several African communitiesThe cluster-randomized MORDOR trial provides an opportunity to quantify the emergence of antibiotic resistance after villages in Niger were cluster randomized to receive either twice-yearly azithromycin or placebo for children aged 1 to 59 months for 2 years. Macrolide and nonmacrolide resistance in nasopharyngeal To characterize the temporal dynamics and persistence of phenotypic resistance, we examined macrolide and nonmacrolide resistance from the MORDOR trial in children’s nasopharyngeal samples from azithromycin and placebo villages 36 months after trial initiation. Our primary intention was to determine whether resistance rates remained higher at 36 months in azithromycin villages than in placebo villages and whether resistance rates continued to increase beyond the 12- and 24-month prevalence values reported by Doan et al.