Invited commentary

The bacterium Mycoplasma genitalium is frequently asymptomatic but can cause urethritis in men, and cervicitis, endometritis, pelvic inflammatory disease and infertility in women.1 2 Our understanding of this infection has rapidly expanded since it was first described at a British genitourinary medicine clinic nearly three decades ago.3 Biological and diagnostic issues have likely contributed to the blurriness surrounding this STI—it lacks a cell wall (and so is not visualised with routine Gram stain) and the fastidious organism requires 1–2 months to culture. In addition, the limited number of commercially available diagnostic tests has restricted testing and extensive epidemiological investigation. Currently, no routine serological diagnostics exist for M. genitalium and there are no US Food and Drug Administration-approved diagnostics. This daunting biology and diagnostic situation begs the question: why does detecting this pathogen matter when most empirical therapy covers the bacteria?

Two changes have sharpened the focus on M. genitalium in recent years—greater availability of nucleic acid amplification test (NAAT)-based diagnostic testing and the rise of antibiotic resistance. From a diagnostic perspective, there are now widely accessible NAAT diagnostics that can conveniently and rapidly test samples from multiple sites—first-void urine, and swabs from the anorectum, endocervix, …