What is the recommended treatment for Mycoplasma hominis infections?

Treatment of Mycoplasma hominis Infections

Tetracyclines, particularly doxycycline, are the first-line treatment for Mycoplasma hominis infections due to their proven efficacy and favorable safety profile. 1, 2

First-Line Treatment Options

• Doxycycline is the drug of choice for M. hominis infections with typical dosing of 100 mg twice daily for 7-14 days 2, 3
• Minocycline is an effective alternative tetracycline that can be used when doxycycline is not available 3
• The optimal duration of antibiotic therapy for extragenital M. hominis infections is 10-14 days based on clinical experience 2

Alternative Treatment Options

• Clindamycin is the recommended alternative for patients who cannot tolerate tetracyclines or in cases of tetracycline resistance 2
• Ofloxacin has shown good activity against M. hominis and can be considered as another alternative treatment option 3
• Josamycin (a macrolide) may be effective against some strains, though tetracyclines generally show better activity 3

Treatment Considerations by Infection Type

Urogenital Infections

• For urethritis caused by M. hominis:
  • Doxycycline 100 mg twice daily orally for 7 days is the preferred regimen 1
  • Alternative: Ofloxacin 200 mg twice daily orally for 7 days 1

Extragenital Infections

• For bloodstream infections, central nervous system infections, or septic arthritis:
  • Tetracycline is generally the drug of choice 2, 4
  • Longer treatment duration (10-14 days) is typically required 2
  • Surgical drainage may be necessary in cases of abscess formation 5

Pyelonephritis

• Doxycycline has been shown to be effective in treating M. hominis pyelonephritis when conventional antibiotics fail 6
• Rapid improvement in symptoms and normalization of inflammatory markers can be expected with appropriate therapy 6

Ineffective Antibiotics

• Beta-lactam antibiotics (penicillins, cephalosporins) are ineffective due to the lack of a cell wall in M. hominis 2, 5
• Macrolides like erythromycin and azithromycin typically used for M. pneumoniae have limited activity against M. hominis 7, 2
• Sulfonamides, chloramphenicol, and aminoglycosides do not elicit a clinical response in M. hominis infections 2

Diagnostic Challenges

• M. hominis infections are often missed in routine cultures due to the organism's slow growth and special culture requirements 4, 5
• Consider M. hominis in cases of culture-negative infections, especially in:
  • Postoperative infections after urological procedures 5
  • Postpartum infections 4
  • Immunocompromised patients 4
  • Patients with persistent symptoms despite conventional antibiotic therapy 6

Monitoring and Follow-up

• Clinical improvement should be expected within 48-72 hours of appropriate antibiotic therapy 6
• Persistent symptoms suggest either resistance to the chosen antibiotic, inadequate drainage of an abscess, or an alternative diagnosis 5
• Local antimicrobial susceptibility surveillance is important to guide empiric treatment strategies 3