In vitro antimicrobial activity of azithromycin against Mycoplasma genitalium and the bacteriological efficacy in male M. genitalium-positive non-gonococcal urethritis

Abstract number: 1733_621

Yasuda M., Hagiwara N., Ito M., Ishihara S., Maeda S., Ito S., Narita H., Deguchi T.

Objectives: Many studies have shown Mycoplasma genitalium to be a pathogen responsible for non-gonococcal urethritis (NGU). However, there are no published guidelines or recommendations for treating M. genitalium-positive NGU. So dosing regimens of antimicrobial agents active against Chlamydia trachomatis are usually used to treat M. genitalium-positive NGU. In the CDC and EAU guidelines, azithromycin or doxycycline treatment is recommended for management of patients with NGU. Thus we investigated the minimal inhibitory concentration (MIC)s of azithromycin and other antimicrobial agents for M. genitalium and whether azithromycin are clinically efficacious as antibacterial therapy against M. genitalium.

Methods: Seven strains of M. genitalium were obtained from the American Type Culture Collection. Susceptibility testing was performed by the broth microdilution method in 96-well microtiter plates with SP-4 medium. We then enrolled a total of 19 men with M. genitalium-positive NGU who were treated with azithromycin 1,000 mg orally as single dose. PCR-based assay was performed to evaluate the microbiological efficacy of eradication therapy in these patients.

Results: Azithromycin (MIC range: 0.004–0.008 mg/L) and clarithromycin (MIC range: 0.008–0.015 mg/L) were very active against M. genitalium. Doxycycline (MIC range: 0.06–0.125 mg/L) and minocycline (MIC range: 0.06–0.125 mg/L) had a moderate activities against M. genitalium-positive non-gonococcal urethritis. Gatifloxacin (MIC range: 0.125–0.25 mg/L) and sparfloxacin (MIC: 0.25 mg/L) were more active than levofloxacin (MIC: 1.0 mg/L). In 17 of 19 (89.5%) patients treated with azithromycin, M. genitalium was eradicated from the urethra.

Conclusions: Susceptibility testing suggests that azithromycin are suitable for treating M. genitalium-positive NGU. Clinical results suggest that azithromycin given orally at 1,000 mg as single dose is useful in treating M. genitalium-positive NGU.

Session Details

Date: 31/03/2007
Time: 00:00-00:00
Session name: European Society of Clinical Microbiology and Infectious Diseases
Location: ICC, Munich, Germany
Presentation type:
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