Impact of mass drug administration with azithromycin for trachoma elimination on prevalence and azithromycin resistance of genital Mycoplasma genitalium infection

Background: Mass Drug Administration (MDA) of 20mg/kg (to a maximum 1g in adults) azithromycin for ocular Chlamydia trachomatis (CT) infection is a key component of the WHO trachoma elimination strategy. However, this dose is known to be sub-optimal for the treatment of genital Mycoplasma genitalium infection and may encourage emergence of antimicrobial resistance (AMR) to azithromycin in M. genitalium. Methods: Pre-MDA, and 10 months post-MDA, CT-negative vulvovaginal swabs from women attending three outpatient antenatal clinics (Honiara, Solomon Islands) were tested for M. genitalium infection using Fast Track Diagnostics Urethritis Plus nucleic acid amplification assay. M. genitalium positive samples were subsequently tested for azithromycin resistance by sequencing domain V of the 23S rRNA DNA region of M. genitalium and underwent phylogenetic analysis by dual locus strain typing.Results: M. genitalium prevalence was 11.9% (28/236) in women pre-MDA and 10.9% (28/256) 10 months post-MDA (p=0.7467). 22 M. genitalium positives from each of the pre-MDA and post-MDA samples were sequenced, all showing a macrolide susceptible genotype. Strain typing showed that sequence types diverged into two lineages, with a suggestion of strain replacement post-MDA.Conclusion: A single round of azithromycin MDA in an island population with high baseline M. genitalium prevalence did not impact on either prevalence or azithromycin resistance, in contrast to reported decreased genital CT prevalence in the same population. Further investigation of the impact of multiple rounds of MDA on M. genitalium azithromycin AMR in antibiotic experienced and naïve populations is warranted.