Clinical aspects of Mycoplasma genitalium infection

Abstract

The microorganism Mycoplasma (M.) genitalium was first isolated by culture in 1980. Further attempts to culture this mycoplasma were difficult because of its slow growing nature. The development of polymerase chain reaction methods has made it possible to detect M. genitalium more readily but yet there are no commercial tests available. M. genitalium is sexually transmitted and is an independent cause of non-gonococcal urethritis in men and most likely of cervicitis in women. There is accumulating evidence that M. genitalium might play a role as an important agent causing upper genital tract infections in women with possible sequelae like those found after Chlamydia (C.) trachomatis infections. In this thesis various clinical aspects of M. genitalium infection have been elucidated in patients attending our clinic for sexually transmitted infections (STI-clinic).

Paper I: M. genitalium among male patients was found to be associated with nonchlamydial non-gonoccocal urethritis. M. genitalium positive patients also more often had a history of recurrent urethritis compared to controls.

Paper II: First void urine (FVU) specimens were found superior to urethral swab specimens in male patients to detect M. genitalium; giving a relative sensitivity of 98 % with the first test regime compared to 89 % with the latter. Among female patients the highest sensitivity was accomplished when a FVU specimen was supplemented with a cervical swab specimen.

Paper III: A patient with a unilateral conjunctivitis and a concomitant urethritis was found to be infected with M. genitalium. Identical DNA sequences were found in the eye and the genital tract. After antibiotic treatment the symptoms cleared and tests of cure became negative for M. genitalium at both sites. This is the first publication of M. genitalium associated conjunctivitis.

Paper IV: Antibiotic treatment of M. genitalium was studied. Treatment with doxycycline was found much less effective as compared to azithromycin in both men and women. The highest clearance rate was achieved when azithromycin was given in a dose of 500 mg day 1 followed by 250 mg days 2-5. This regimen is today recognized as the treatment of choice for M. genitalium infections. The clinical findings after treatment were poor predictors of successful outcome.

Paper V: The clinical findings in women infected with M. genitalium as compared to women with chlamydial infection or women uninfected with these organisms were studied. There were only minor differences in the clinical appearance between these groups regarding symptoms and signs of lower genital tract infection. A substantial number of both M. genitalium and C. trachomatis positive women were symptomless. Thus, in order to detect Mycoplasma genitalium infections in women, as is the case with C. trachomatis infections, tests should be used on wide indications.

Conclusions: We recommend a generous testing of men and women for M. genitalium regardless of signs and symptoms - if tests are available! We recommend azithromycin orally 500 mg day 1 followed by 250 mg daily for 4 days as the first line treatment of M. genitalium infection in Sweden.