Is there evidence for resistance of ocular Chlamydia trachomatis to azithromycin after mass treatment for trachoma control?

Sheila K. West, Jeanne Moncada, Beatriz Munoz, Harran Mkocha, Philip Storey, Justin Hardick, Charlotte A. Gaydos, Thomas C. Quinn, Julius Schachter

Research output: Contribution to journalArticlepeer-review

Abstract

Background. Trachoma, caused by repeated infections with ocular Chlamydia trachomatis, is targeted for elimination using multiple annual rounds of mass drug administration (MDA) in endemic communities. Infection rates do not decline as expected in some communities, leading to concerns about azithromycin resistance. Methods. After 3 yearly MDAs in 32 communities in Tanzania, 107 children were identified 1 year later with infection. All were provided MDA again, and 90 were seen again at 2 months, of whom 30 had infection. Chlamydia trachomatis isolates were obtained before and after MDA in 15 paired samples and were tested for antimicrobial susceptibility. The infectious load of C. trachomatis before MDA was determined in 30 children who had infection at both times and 60 whose infection cleared. Results. The median load was 8.6 genome copies per polymerase chain reaction in the consistently infected, and 8.4 in those whose infection cleared (P = .86). For the consistently infected, the average minimum inhibitory concentration was 0.26 μg/mL for azithromycin before and 0.20 μg/mL after MDA. All isolates had minimum inhibitory concentration ≤0.50 μg/mL. Conclusions. There is no evidence that continued infection after MDA was due either to resistance to azithromycin or to a heavier load of organism before treatment. Other potential causes of persistent infection need to be evaluated.

Original languageEnglish (US)
Pages (from-to)65-71
Number of pages7
JournalJournal of Infectious Diseases
Volume210
Issue number1
DOIs
StatePublished - Jul 1 2014

Keywords

  • Azithromycin
  • C. trachomatis
  • Mass drug administration
  • Resistance
  • Trachoma

ASJC Scopus subject areas

  • Immunology and Allergy
  • Infectious Diseases

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