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O28 Treatment of mycoplasma genitalium with azithromycin 1 g is less efficacious and associated with induction of macrolide resistance compared to a 5 day regimen
  1. Patrick Horner1,2,
  2. Suzanne Ingle1,
  3. Karla Blee2,
  4. Peter Muir3,
  5. Harald Moi4
  1. 1University of Brsitol, Bristol, UK
  2. 2University Hospitals Bristol NHS Trust, Bristol, UK
  3. 3Public Health England, Bristol, UK
  4. 4Oslo University Hospital, Oslo, UK


Background Mycoplasma genitalium (MG) is an emerging important STI. Failure rates with azithromycin 1 g appear to be increasing. This may be due to the emergence of macrolide antimicrobial resistance as a consequence of extensive use of azithromycin 1 g. An extended regimen of azithromycin 500 mgs on day one then 250 mgs daily for 4 days (5 day regimen) was introduced in the 1990s for treatment of MG and has high efficacy rates (if no pre-existing macrolide resistance) and is less associated with induction of macrolide resistance. There are no comparative trials of the two regimens.

Abstract O28 Table 1

Treatment of Mycoplasma genitalium

Aim To undertake a meta-analysis of MG treatment studies using the two azithromycin regimens to determine which is more effective.

Methods MG treatment studies were included if: patients were initially assessed for macrolide resistance genetic mutations, were treated with azithromycin 1 g or 5 days, and those who failed were again resistance genotyped. Sensitivity analyses included only patients without prior treatment.

Results Five studies were identified. Compared to the 5 day regimen, azithromycin 1 g had higher failure risk (difference: 11.8%, 95% CI: 7.3%, 16.2%) and more developed macrolide resistance (risk difference: 11.8% (8.3%, 15.3%)). The 5 day regimen included 52 patients with prior doxycycline treatment. Sensitivity analysis showed a failure risk difference of 9.2% (0.9%, 17.5%). Resistance risk did not change.

Conclusion Azithromycin 1 g is more likely to result in treatment failure and the development of macrolide antimicrobial resistance than 500 mgs on day one then 250 mgs daily for 4 days.

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