According to study, researchers determine that probiotics are effective for preventing Clostridium difficile infection (CDI) in patients treated with antibiotics. Probiotics are considerably more effective in settings where the risk for Clostridium difficile infection is moderate to high. The study was published in Infection Control.

Current clinical practice guidelines on CDI prevention focus on core strategies (e.g., staff education, patient isolation, antimicrobial stewardship and utilization of disinfectants), but none recommend probiotics for prophylaxis. Researchers conducted a meta-analysis using data from 6,851 individual participants in 18 trials to determine whether adding probiotics to an antibiotic regimen reduces the incidence of CDI among children and adults when adjusting for a variety of factors.

The incidence of CDI was 1.1% in the intervention groups and 2.5% in the control groups of the 18 studies. Probiotic prophylaxis reduced the odds of CDI by 63% in unadjusted analyses (P<0.0001). The reduction was slightly greater, 65%, in the 13 studies included in the analysis that adjusted for other factors.

The use of two or more antibiotics increased the odds of CDI 2.20-fold, whereas age, sex, hospitalization status and high-risk antibiotic exposure did not. Multispecies probiotics significantly reduced the odds of CDI, whereas there was a nonsignificant reduction with single-species probiotics. Probiotic doses below 1 billion colony forming units per day did not reduce substantially CDI risk.

"Moderate-certainty evidence suggests that probiotic prophylaxis is a useful and safe Clostridium difficile infection prevention strategy," Dr. Johnston said. "Based on a recent systematic review we conducted on prophylactic strategies for Clostridium difficile, probiotics offer the highest certainty of evidence among the existing strategies that are typically considered during Clostridium difficile outbreaks."

In related work, published simultaneously in the same journal, Dr. William E. Trick from Cook County Health and Hospitals System in Chicago and colleagues examined the effectiveness of their quality-improvement intervention of probiotics for primary prevention of CDI at a 694-bed teaching hospital. "The delayed effect is consistent with the prior literature and may have been related to poor fidelity to the protocol for probiotic administration and a delayed gradual reduction in environmental contamination," the researchers note.

Just because a product lists itself as a 'probiotic' does not mean it is useful for the specific purpose you want to use it for. The efficacy of probiotics is both strain-specific and disease-specific. Not every probiotic is created equal.

In a case-control study of 68 matched pairs of patients, however, there was no protective effect from probiotics. Many patients are at risk for complications due to exposure to antibiotics, and these should only be given when necessary," Dr. Trick said. Probiotics are one such option, but will not be completely effective without hand washing and good environmental cleaning-especially in rooms that previously housed a patient with C. difficile infection.

"Probiotics fill in a niche that standard infection-control practices don't cover," said Dr. McFarland. "They help the normally protective intestinal microflora recover and have ways to fight the pathogen while this recovery of microflora occurs. It takes 6-8 weeks for this recovery to be complete!"