When should retesting for Mycoplasma genitalium be considered after treatment?

Mycoplasma Genitalium Retesting Recommendations

Retesting for Mycoplasma genitalium should be performed approximately 4 weeks after treatment completion to ensure eradication of the infection and identify potential treatment failures. 1, 2

General Retesting Guidelines

• A test of cure (TOC) is recommended for all patients treated for Mycoplasma genitalium infection approximately 4 weeks after treatment initiation 2
• Day-to-day fluctuations in bacterial load, especially in patients with macrolide-resistant strains, may lead to false-negative results if testing is performed too early 2
• For patients with wild-type (non-resistant) M. genitalium, TOC can be performed as early as one week after treatment initiation 2
• Patients should be retested even if symptoms have resolved, as asymptomatic infections are common 1

Rationale for Retesting

• High rates of treatment failure have been documented, particularly following azithromycin therapy, with failure rates of up to 16-44% 3, 4
• Persistent infection is strongly associated with persistent symptoms (91% of cases with persistent infection vs 17% of cases where M. genitalium was eradicated) 4
• Increasing prevalence of macrolide resistance necessitates follow-up testing to identify treatment failures 1, 5
• Pretreatment resistance testing is recommended when available to guide appropriate therapy and reduce the risk of treatment failure 1, 2

Testing Considerations

• Nucleic acid amplification testing (NAAT) is the only reliable method for detecting M. genitalium 1, 5
• If available, testing should include assays for macrolide resistance mutations to guide therapy 1
• False-negative results may occur during the first 5 weeks after treatment initiation due to fluctuations in bacterial load, particularly in patients with resistant strains 2

Management of Treatment Failure

• For patients with persistent infection after initial azithromycin treatment, moxifloxacin 400 mg daily for 7-10 days is recommended as second-line therapy 1, 5
• For persistent infection after both azithromycin and moxifloxacin:
  • Doxycycline 100 mg twice daily for 14 days may be effective in 30-70% of cases 1
  • Pristinamycin 1 g four times daily for 10 days has a cure rate of approximately 75-90% 1, 5

Prevention of Reinfection

• Patients should abstain from sexual intercourse for 7 days after single-dose therapy or until completion of a multi-day regimen 6
• Sexual abstinence should continue until all sex partners have been treated to minimize the risk of reinfection 6
• All sex partners from the previous 60 days should be referred for evaluation, testing, and treatment 6

Special Considerations

• Patients with complicated M. genitalium infection (PID, epididymitis) require longer treatment courses (moxifloxacin 400 mg daily for 14 days) and should be retested to confirm cure 1, 5
• When distinguishing between treatment failure and reinfection, consider the possibility of untreated partners as a source of reinfection 4
• Symptoms that persist after treatment should prompt retesting for M. genitalium, as persistent infection is strongly associated with persistent symptoms 4