Treatment of Mycoplasma hominis Infection
Doxycycline 100 mg orally twice daily for 10-14 days is the best medication for Mycoplasma hominis infection, with clindamycin as the primary alternative for patients who cannot tolerate tetracyclines. 1, 2
First-Line Treatment
- Doxycycline 100 mg orally twice daily for 10-14 days is the drug of choice for M. hominis infections based on consistent clinical efficacy and maintained susceptibility 1, 2
- Minocycline 100 mg orally twice daily for 10-14 days is an equally effective tetracycline alternative with similar activity against M. hominis 2
- The 10-14 day duration is recommended based on clinical experience with extragenital M. hominis infections, though optimal duration has not been definitively established 1
Alternative Treatment Options
- Clindamycin is the primary alternative for patients who cannot tolerate tetracyclines, though specific dosing for M. hominis is not well-established in the literature 1
- Ofloxacin demonstrates potent activity against M. hominis and can be considered as an alternative fluoroquinolone option 2, 3
- Moxifloxacin 400 mg orally daily shows excellent in vitro activity (MIC ≤1 mg/L for 90% of isolates) and bactericidal activity against M. hominis 4
- Levofloxacin has low resistance rates (5.3%) and can be used as first-choice fluoroquinolone therapy 3
Critical Resistance Considerations
- M. hominis is intrinsically resistant to all macrolides (including azithromycin and clarithromycin), making these agents completely ineffective despite their utility against other mycoplasma species 1
- M. hominis is also resistant to beta-lactam antibiotics, chloramphenicol, aminoglycosides, and sulfonamides—these agents do not elicit clinical response 1
- Ciprofloxacin resistance is high (59.8%) and this agent should be avoided 3
- Fluoroquinolone resistance rates are increasing over time across all agents, though newer fluoroquinolones (levofloxacin, moxifloxacin) maintain better activity 3
Clinical Context for Treatment Decisions
- Transient M. hominis bacteremia in postpartum fever or febrile abortion is often self-limiting and does not require antibiotic treatment 1
- Treatment is mandatory for invasive extragenital infections including bloodstream invasion with urologic disease/trauma, central nervous system infections, septic arthritis, and other metastatic sites 1
- For complicated infections (meningitis, septic arthritis), consider extending treatment duration beyond 14 days based on clinical response 1
Common Pitfalls to Avoid
- Do not prescribe azithromycin or other macrolides—M. hominis lacks the target site for macrolide activity and will not respond 1
- Do not use ciprofloxacin as first-line therapy given high resistance rates (59.8%) 3
- Do not assume all mycoplasma species respond to the same antibiotics—M. hominis has distinctly different susceptibility patterns compared to M. pneumoniae and M. genitalium 1, 2
- Avoid treating asymptomatic colonization or transient bacteremia in postpartum settings where spontaneous resolution is expected 1