Source: BioDrugs  |  Posted 8 years ago

Azithromycin is effective at eradicating []Mycoplasma genitalium[]; however tetracycline treatment, commonly used to treat urethritis caused by []Chlamydia trachomatis[], was not effective in patients with urethritis or cervicitis as a result of []M. genitalium[], according to a recent Swedish study.

[]Chlamydia trachomatis[] is the leading cause of non-gonococcal urethritis (NGU). In addition, []Mycoplasma genitalium[] has been shown to cause non-chlamydial-nongonococcal urethritis (NCNGU) and/or cervicitis.

No clinical data are available that evaluate whether standard treatments for NGU such as tetracyclines or macrolides are also effective in treating NCNGU. []in vitro[] experiments have suggested that []M. genitalium[] is sensitive to azithromycin, but not to doxycycline and ciprofloxacin.(1)

Lars Falk and colleagues at Orebro University Hospital, Sweden, and Statens Serum Institut, Copenhagen, Denmark, analysed the efficacy of tetracyclines and azithromycin in 31 men and 26 women with []M. genitalium[] infection.

Patients with urethritis or cervicitis were treated with doxycycline (200 mg first day, 100 mg following 8 days) or lymecycline (300 mg twice daily for 10 days). Patients who had not already received initial antibiotic treatment were given azithromycin (500 mg first day, 250 mg following 4 days).

Follow-up analysis was conducted 4 to 5 weeks after treatment and patients given tetracycline who were still []M. genitalium[] positive at follow up were offered azithromycin treatment.

At follow up, 71% of women and 63% of men who were treated with tetracyclines were still infected with []M. genitalium[]. Those patients with concomitant []C. trachomatis[] infection did show elimination of []C. trachomatis[].

In contrast to tetracycline therapy, the []M. genitalium[] infection was cleared in all patients given azithromycin. Furthermore, all []M. genitalium[] positive patients who received azithromycin after tetracycline failure were []M. genitalium[] negative at 5 week re-evaluation.

The authors note that "treatment [of] urethritis and cervicitis with tetracyclines does not appear to be sufficient to eradicate []M. genitalium[] and this should be considered in treatment guidelines." They furthermore advocate the need for "a randomised controlled treatment to evaluate the efficacy of azithromycin at different dosages."

Reference:

1- Hannan PC. "Comparative susceptibilities of various AIDS-associated and human urogenital tract mycoplasmas and strains of Mycoplasma pneumoniae to 10 classes of antimicrobial agent in vitro." J Med Microbiol 1998;47:1115-22.