What is the treatment for Lactobacillus (lactic acid bacteria) infection?

Treatment of Lactobacillus Infection

Lactobacillus species are typically considered non-pathogenic organisms when found in urine cultures and generally do not require treatment unless there is evidence of invasive infection. 1

Clinical Significance and Evaluation

• Lactobacillus is generally considered part of normal flora and is not typically treated as a urinary pathogen when found in urine samples 1
• The American Academy of Pediatrics guidelines indicate that Lactobacillus species are not considered clinically relevant urine isolates for otherwise healthy individuals 1
• When evaluating the significance of Lactobacillus in specimens, consider patient symptoms and the presence of pyuria (white blood cells) 1

Treatment Algorithm for Lactobacillus Infections

1. Asymptomatic Bacteriuria

• No treatment is recommended for asymptomatic bacteriuria with Lactobacillus 1
• Treating asymptomatic bacteriuria may be harmful and can increase antimicrobial resistance 1

2. Symptomatic Urinary Tract Infection

• If a patient has persistent urinary symptoms with only Lactobacillus in culture, repeat urine culture to assess for other pathogens 1
• Only treat with antibiotics if a true uropathogen is identified alongside Lactobacillus 1

3. Invasive Lactobacillus Infections (Bacteremia/Endocarditis)

• For confirmed invasive infections, antimicrobial susceptibility testing should guide therapy 2
• First-line treatment options include:
  • Penicillin or ampicillin plus gentamicin (synergistic combination) 3, 2
  • Piperacillin-tazobactam (consistently shows low MICs against Lactobacillus) 2
  • Imipenem (consistently shows low MICs against Lactobacillus) 2
• Alternative options with good activity include:
  • Erythromycin 2
  • Clindamycin 2

Important Considerations

• Lactobacillus species are intrinsically resistant to vancomycin (except L. gasseri and L. jensenii) 2
• Antimicrobial susceptibility is species-dependent, so identification to species level is important 2
• Cephalosporin activity varies; cefuroxime demonstrates higher activity than ceftriaxone 2
• Combination therapy with penicillin and an aminoglycoside has shown synergistic activity and clinical effectiveness 3

Special Populations

• Patients with prosthetic heart valves or native valve disease who develop Lactobacillus bacteremia require careful evaluation for endocarditis 4, 5
• Immunocompromised patients, those with cancer, diabetes, or recent surgery are at higher risk for clinically significant Lactobacillus infections 6
• Blood cultures positive for Lactobacillus should not be dismissed as contamination, especially in high-risk patients 6, 5

Clinical Pearls and Pitfalls

• Misidentification of Lactobacillus as other gram-positive bacilli (e.g., Corynebacterium) can lead to inappropriate treatment and persistent bacteremia 4
• Lactobacillus bacteremia has a reported mortality rate of approximately 14%, with only a small percentage directly attributed to Lactobacillus sepsis 6
• Intravenous catheter infections are not commonly associated with Lactobacillus bacteremia, unlike other organisms 6
• Source control (such as removal of infected teeth or drainage of abscesses) is an important component of treatment for invasive Lactobacillus infections 4