Can probiotics prevent Clostridioides difficile (C. Diff) infections?

Probiotics for Prevention of Clostridioides difficile Infection

Specific probiotic strains can reduce the risk of C. difficile infection in adults and children on antibiotic treatment, but the evidence is of low quality and benefits are primarily seen in high-risk populations. 1

Recommended Probiotic Strains for C. difficile Prevention

The American Gastroenterological Association (AGA) conditionally recommends the following specific probiotic strains for prevention of C. difficile infection in patients receiving antibiotics:

• Saccharomyces boulardii - reduces risk by 59% (RR, 0.41; 95% CI, 0.22-0.79) 1
• Two-strain combination of Lactobacillus acidophilus CL1285 and Lactobacillus casei LBC80R - reduces risk by 78% (RR, 0.22; 95% CI, 0.11-0.42) 1, 2
• Three-strain combination of L. acidophilus, L. delbrueckii subsp bulgaricus, and Bifidobacterium bifidum - reduces risk by 65% (RR, 0.35; 95% CI, 0.15-0.85) 1, 2
• Four-strain combination of L. acidophilus, L. delbrueckii subsp bulgaricus, B. bifidum, and Streptococcus salivarius subsp thermophilus - reduces risk by 72% (RR, 0.28; 95% CI, 0.11-0.67) 1, 2

Evidence Quality and Limitations

• The overall quality of evidence supporting probiotic use for C. difficile prevention is rated as low 1
• A Cochrane review of 39 studies with 9,955 patients found probiotics reduced overall risk of C. difficile infection vs placebo (RR, 0.40; 95% CI, 0.30-0.52) 1
• The beneficial effect was primarily observed in high-risk populations (>15% baseline risk), with no significant effects in low-risk patients 1
• Publication bias is a concern, as many registered trial protocols were not associated with subsequent peer-reviewed publications 1, 2

Patient Selection and Risk Factors

Probiotics for C. difficile prevention should be considered for:

• Patients at high risk of developing C. difficile infection (>15% baseline risk) 1, 2
• Hospitalized patients receiving broad-spectrum antibiotics 2, 3
• Patients with previous history of C. difficile infection 2, 4
• Elderly patients or those with prolonged hospitalization 2, 3

Administration Guidelines

• Start probiotics at the beginning of antibiotic therapy 2, 5
• Continue throughout the entire course of antibiotic treatment 2, 4
• Consider continuing for 1-2 weeks after antibiotics are completed 2

Important Cautions and Contraindications

• Probiotics are contraindicated in immunocompromised patients due to risk of bacteremia or fungemia 2, 6
• Patients with severe illness may be at higher risk of adverse events 1
• The benefit-risk profile may not favor probiotic use in outpatient settings with low C. difficile risk 1

Gaps in Current Evidence

• Limited data on probiotics for treatment of established C. difficile infection 1
• Heterogeneity in study populations, probiotic strains, and outcome measures 1, 3
• Inconsistent reporting of potential harms across studies 1
• Need for more standardized study designs and larger patient populations 1, 3

Clinical Decision Algorithm

1. Assess patient's risk for C. difficile infection (high risk: elderly, prolonged hospitalization, previous C. difficile infection) 2, 3
2. Evaluate contraindications (immunocompromised status, severe illness) 2, 1
3. For high-risk patients without contraindications, select one of the recommended probiotic formulations 1, 2
4. Start probiotic at the beginning of antibiotic therapy and continue throughout the course 2, 4
5. Monitor for adverse effects and C. difficile symptoms 1, 6

While probiotics show promise for C. difficile prevention in high-risk populations, the low quality of evidence and potential risks in certain patient groups warrant careful consideration of their use on a case-by-case basis.