Combination Therapy for Mycoplasma genitalium, and New Insights Into the Utility of parC Mutant Detection to Improve Cure

Lenka A Vodstrcil, Erica L Plummer, Michelle Doyle, Gerald L Murray, Kaveesha Bodiyabadu, Jorgen S Jensen, David Whiley, Emma Sweeney, Deborah A Williamson, Eric P F Chow, Christopher K Fairley, Catriona S Bradshaw

Research output: Contribution to journalArticlepeer-review

Abstract

BACKGROUND: Mycoplasma genitalium (MG) infection is challenging to cure because of rising antimicrobial resistance and limited treatment options.

METHODS: This was a prospective evaluation of the efficacy and tolerability of resistance-guided combination antimicrobial therapy for MG treatment at Melbourne Sexual Health Centre (August 2019-December 2020). All patients received 7 days of doxycycline before combination therapy based on the macrolide-resistant profile. Macrolide-susceptible infections received combination doxycycline + azithromycin (1 g, day 1; 500 mg, days 2-4) and macrolide-resistant infections combination doxycycline + moxifloxacin (400 mg daily for 7 days). Adherence and adverse effects were recorded at test-of-cure, recommended 14-28 days after antimicrobial completion. Sequencing was performed to determine the prevalence of single nucleotide polymorphisms (SNPs) in the parC gene and their association with moxifloxacin treatment outcomes in macrolide-resistant infections.

RESULTS: Of 100 patients with macrolide-susceptible MG treated with doxycycline + azithromycin, 93 were cured (93.0%; 95% confidence interval [CI], 86.1-97.1). Of 247 patients with macrolide-resistant MG receiving doxycycline + moxifloxacin, 210 were cured (85.0%; 95% CI, 80.0-89.2). parC sequencing was available for 164 (66%) macrolide-resistant infections; 29% had SNPs at parC S83 or D87 (23% S83I). The absence of SNPs at parC S83/D87 was associated with 98.3% cure (95% CI, 93.9-99.8) following doxycycline + moxifloxacin. The presence of the parC S83I-SNP was associated with failure in 62.5% (95% CI, 45.8-77.3). Side effects were common (40%-46%) and predominantly mild and gastrointestinal.

CONCLUSIONS: Combination doxycycline + azithromycin achieved high cure for macrolide-susceptible infections. However, in the context of a high prevalence of the parC S83I mutation (23%) in macrolide-resistant infections, doxycycline + moxifloxacin cured only 85%. Infections that were wild-type for S83/D87 experienced high cure following doxycycline + moxifloxacin, supporting the use of a parC-resistance/susceptibility testing strategy in clinical care.

Original languageEnglish
Pages (from-to)813-823
Number of pages11
JournalClinical Infectious Diseases
Volume75
Issue number5
Early online date10 Feb 2022
DOIs
Publication statusPublished - 14 Sept 2022

Keywords

  • Anti-Bacterial Agents/adverse effects
  • Azithromycin/adverse effects
  • Doxycycline/adverse effects
  • Drug Resistance, Bacterial/genetics
  • Humans
  • Macrolides/adverse effects
  • Moxifloxacin/pharmacology
  • Mycoplasma Infections/drug therapy
  • Mycoplasma genitalium/drug effects

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