Send to

Choose Destination
Clin Infect Dis. 2019 Oct 20. pii: ciz1031. doi: 10.1093/cid/ciz1031. [Epub ahead of print]

Resistance-guided antimicrobial therapy using doxycycline-moxifloxacin and doxycycline-2.5g azithromycin for the treatment of Mycoplasma genitalium infection: efficacy and tolerability.

Author information

Central Clinical School, Monash University, Melbourne, Victoria, Australia.
Melbourne Sexual Health Centre, Alfred Health, Carlton, Victoria, Australia.
Murdoch Children's Research Institute, Parkville, Victoria, Australia.
Centre for Women's Infectious Diseases, The Royal Women's Hospital, Melbourne, Victoria, Australia.
Speedx Pty Ltd, National Innovation Centre, Eveleigh, New South Wales, Australia.



Macrolide-resistance in Mycoplasma genitalium (MG) exceeds 50% in many regions and quinolone-resistance is increasing. We recently reported that resistance-guided therapy (RGT) using doxycycline followed by sitafloxacin or 2.5g-azithromycin cured 92% and 95% of macrolide-resistant and macrolide-susceptible infections, respectively. We now present the data on RGT using doxycycline-moxifloxacin, the regimen recommended in international guidelines, and extend the data on the efficacy of doxyxycline-2.5g azithromycin and subsequent de novo macrolide-resistance.


Patients attending Melbourne Sexual Health Centre between 2017-2018 with STI-related syndromes were treated with doxycycline for 7 days and recalled if positive for MG. Macrolide-susceptible cases then received 2.5g azithromycin (1g, then 500mg daily for 3 days) and resistant cases received moxifloxacin (400 mg daily, 7 days). Test of cure (TOC) was recommended 14-28 days post-completion of antimicrobials. Adherence and adverse effects were recorded.


A total of 383 patients (81 females/106 heterosexual males/196 men-who-have-sex-with-men) were included. Microbial cure following doxycycline-azithromycin was 95.4% (95% CI 89.7-98.0) and doxycycline-moxifloxacin was 92.0%(88.1-94.6). De novo macrolide-resistance was detected in 4.6% of cases. Combining doxycycline-azithromycin data with our prior RGT study (n=186) yielded a pooled cure of 95.7% (91.6-97.8). ParC mutations implicated in moxifloxacin failure were present in 15-22% of macrolide-resistant cases at baseline.


These findings support the inclusion of moxifloxacin in resistance-guided strategies and extend the evidence for use of 2.5g azithromycin, and presumptive use of doxycycline. These data provide an evidence-base for current UK, Australian and European guidelines for the treatment of MG, an STI which is increasingly challenging to cure.


Mycoplasma genitalium ; antimicrobial resistance; moxifloxacin; sexually transmitted infections; treatment


Supplemental Content

Full text links

Icon for Silverchair Information Systems
Loading ...
Support Center