Increased carriage of macrolide-resistant fecal E. coli following mass distribution of azithromycin for trachoma control

Jessica C. Seidman, Christian L. Coles, Ellen K. Silbergeld, Joshua Levens, Harran Mkocha, Lashaunda B. Johnson, Beatriz Muñoz, Sheila K. West

Research output: Contribution to journalArticlepeer-review

30 Scopus citations


Background: Mass drug treatment with azithromycin (MDA) is part of the WHO-endorsed 'SAFE' strategy for trachoma control in endemic communities. MDA has been associated with reduced trachoma prevalence and short-term reductions in other bacterial infections, but can also lead to increased circulation of macrolide-resistant bacteria. Methods: We prospectively monitored macrolide resistance in fecal E. coli collected from young children participating in the PRET{thorn} Study in rural Tanzania. MDA was administered in four villages with >10% trachoma prevalence. Four nearby communities with lower trachoma prevalence served as controls. Rectal swabs were collected during crosssectional surveys performed at baseline, 1, 3 and 6 months after MDA. Fecal E. coli isolates were screened for macrolide susceptibility using disc diffusion and minimum inhibitory concentration methods. Cross-sectional and longitudinal differences in resistance prevalence by MDA exposure were compared using t-tests and logistic regression. Results: There was no difference in the proportion of individuals carrying azithromycinresistant E. coli at baseline (0.21 vs 0.16, P>0.05). Azithromycin resistance carriage prevalence remained stable over follow-up in non-MDA villages but increased sharply in MDA villages (0.61 at 1 month, 0.42 at 3 months and 0.31 at 6 months). MDA exposure was highly associated with azithromycin resistance carriage at 1 month post-MDA (OR 15.27, P<0.001) and subsequent surveys. Younger age and recent diarrhoea were also associated with increased odds of resistance (P<0.01). Conclusions: MDA resulted in significantly increased prevalence of macrolide resistance in E. coli. Although MDA is effective for trachoma elimination, it has costs; it is essential to monitor antimicrobial resistance following MDA.

Original languageEnglish (US)
Article numberdyu062
Pages (from-to)1105-1113
Number of pages9
JournalInternational journal of epidemiology
Issue number4
StatePublished - Aug 2014
Externally publishedYes


  • Africa
  • Antimicrobial resistance
  • Azithromycin
  • Children
  • E. Coli

ASJC Scopus subject areas

  • Epidemiology


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