What is the treatment for Lactobacillus overgrowth (Lactobacilosis)?

Treatment for Lactobacillus Overgrowth (Lactobacilosis)

Antibiotic therapy with metronidazole is the first-line treatment for Lactobacillus overgrowth (lactobacilosis), as Lactobacillus species are generally resistant to metronidazole but susceptible to penicillin and vancomycin. 1

Understanding Lactobacilosis

• Lactobacilli are normally part of the human gastrointestinal and vaginal flora but can occasionally become pathogenic when overgrowth occurs 1
• Lactobacillus species are taxonomically complex with over 170 species that often require molecular identification for accurate diagnosis 1
• While lactobacilli are generally considered beneficial and are used in probiotics, overgrowth can lead to clinical symptoms requiring treatment 2

First-Line Treatment Options

• Metronidazole: Most Lactobacillus species (including L. rhamnosus and L. casei) are resistant to metronidazole, making it an ineffective treatment for lactobacilosis 1
• Penicillin: L. acidophilus is susceptible to penicillin, making it an effective first-line treatment 1
• Vancomycin: L. acidophilus shows susceptibility to vancomycin, while L. rhamnosus and L. casei are resistant 1

Antibiotic Susceptibility Profile

• Lactobacilli are generally resistant to:

  • Aminoglycosides (amikacin, gentamicin, kanamycin, streptomycin) 3
  • Quinolones (ciprofloxacin, norfloxacin, nalidixic acid) 3
  • Sulfonamides (sulphamethoxazole, trimethoprim, co-trimoxazole) 3
  • Cell membrane disruptors (polymyxin B, colistin sulphate) 3

• Lactobacilli are generally susceptible to:

  • Tetracycline 3
  • Chloramphenicol 3
  • Rifampicin 3

Treatment Algorithm

1. Confirm diagnosis: Molecular identification is often necessary due to taxonomic complexity 1

2. First-line treatment:

   • For L. acidophilus overgrowth: Penicillin or vancomycin 1
   • For other Lactobacillus species: Tetracycline, chloramphenicol, or rifampicin 3

3. Alternative treatments if first-line fails:

   • Consider combination therapy with antibiotics that target cell wall synthesis 3
   • Evaluate for underlying conditions that may predispose to lactobacilosis 2

Special Considerations

• Antibiotic selection should consider the specific Lactobacillus species involved, as susceptibility patterns vary 1
• Some Lactobacillus strains (particularly L. plantarum and L. oris) may express resistance to tetracycline and/or doxycycline 4
• Beta-lactam resistance in lactobacilli appears to be due to cell wall impermeability rather than beta-lactamase production 3

Monitoring and Follow-up

• Monitor for clinical response within 48-72 hours of initiating antibiotic therapy 1
• Consider environmental modifications to prevent recurrence after successful treatment 5
• For recurrent cases, consider longer treatment courses or combination therapy 3

Important Caveats

• Avoid using probiotics containing the same Lactobacillus species causing the overgrowth during treatment 6
• In immunocompromised patients, lactobacilosis treatment requires more aggressive management due to increased risk of bacteremia 2
• The natural resistance of lactobacilli to many antibiotics can make treatment challenging and may require targeted therapy based on susceptibility testing 3