M. genitalium is an established cause of sexually transmitted urethritis and cervicitis, and may cause upper tract disease in women. Detection by nucleic acid amplification tests is currently the only diagnostic method available, but no FDA approved assays are currently available, and the CE marked tests suffer from limited clinical evaluation.

In most settings, M. genitalium infections explain 15–25% of symptomatic non-gonococcal urethritis, but as diagnosis of the infection is not routinely carried out, treatment will usually be syndromic. However, only a few randomised trials have evaluated treatment of M. genitalium, and compared only doxycycline 200 mg daily for 7 days with a 1 g single dose of azithromycin. Together with results from open trials, it is obvious that doxycycline is inefficient in eradicating M. genitalium showing eradication rates around 35%. The eradication rate after azithromycin 1 g single dose is significantly better, but differs greatly between studies. Thus, older studies appear to have higher eradication rates than recent ones and a lower eradication rate is reported in studies from centres where azithromycin has been used as the primary treatment for chlamydial and idiopathic urethritis and cervicitis.

At present, the only second line antibiotic that has been shown to have a high activity against macrolide resistant M. genitalium is moxifloxacin. However, this drug is significantly more expensive and has a less favourable safety profile than macrolides, and multidrug resistant infections have emerged, primarily in patients with contact to South East Asia. Consequently, there is an urgent need for clinical trials with possible alternative drugs. Such trials should preferably also address the treatment efficacy in chlamydial and idiopathic urethritis and cervicitis as a single treatment covering these conditions would be advantageous.