Testing for Mycoplasma genitalium in Recurrent Bacterial Vaginosis
Yes, women with recurrent bacterial vaginosis should be tested for Mycoplasma genitalium, as this emerging sexually transmitted infection is significantly more prevalent in women with BV and may be contributing to treatment failures.
The Evidence Supporting Testing
The association between BV and M. genitalium is substantial and clinically relevant:
- Women with BV have nearly double the risk of concurrent M. genitalium infection compared to those without BV (7.0% vs 3.6%, OR 1.97) 1
- Prior BV increases the odds of acquiring M. genitalium by 3.5-fold in prospective studies 2
- In women with persistent/recurrent vaginal discharge, multiplex PCR identified M. genitalium as one of the three most common organisms (along with Ureaplasma urealyticum and Gardnerella vaginalis), with an 85% detection rate for causative organisms 3
Why Standard BV Guidelines Don't Address This
The CDC guidelines you'll find 4, 5 are from 1993-2002 and predate our understanding of M. genitalium as a significant pathogen. These older guidelines mention only Mycoplasma hominis as part of the BV flora—not M. genitalium, which is a distinct organism requiring different treatment. The 2006 CDC guidelines 6 acknowledge that "standardized diagnostic tests for M. genitalium are not commercially available" at that time, but this has changed.
When to Test
Test for M. genitalium in these specific scenarios:
- Recurrent BV (multiple episodes despite appropriate treatment)
- Persistent vaginal discharge after standard BV treatment
- Cervicitis with or without BV 6, 7
- First episode of symptomatic vaginitis if you're using multiplex PCR testing 3
Do NOT test asymptomatic women without known M. genitalium exposure 7.
Testing Method
- Use FDA-approved nucleic acid amplification tests (NAATs) for M. genitalium 7
- Multiplex PCR panels (testing for 7+ organisms simultaneously) are superior to standard microscopy and culture, identifying causative organisms in 85-95% of cases 3
- Resistance testing for macrolide resistance is recommended by CDC but not widely available in the US 7
Treatment Implications
This matters because M. genitalium requires different antibiotics than BV:
- Standard BV treatment (metronidazole or clindamycin) does NOT treat M. genitalium
- CDC recommends 2-step treatment: doxycycline 100mg twice daily for 7 days, followed by either azithromycin (extended regimen) or moxifloxacin 7
- Moxifloxacin is preferred when resistance testing is unavailable or shows macrolide resistance 7
Clinical Pitfalls to Avoid
- Don't assume recurrent BV is just "treatment failure"—look for concurrent STIs, particularly M. genitalium
- Don't rely solely on Nugent scoring—it won't detect M. genitalium 8
- Don't use single-dose metronidazole for recurrent BV—it has lower efficacy (84% vs 95% for 7-day regimen) 4
- Don't test or treat asymptomatic women for M. genitalium unless they're contacts of infected partners 7
The Bottom Line
While older BV guidelines don't mention M. genitalium testing, current evidence strongly supports testing for this organism in recurrent BV cases 3, 1. The 18% prevalence in some populations 8, the strong epidemiologic association with BV 1, 2, and the availability of FDA-approved testing 7 make this a practical and evidence-based approach to managing treatment-refractory cases. Multiplex PCR testing from a single vaginal swab can simultaneously screen for M. genitalium and other common pathogens, making it an efficient diagnostic strategy 3.