Probiotics are live micro-organisms that can be taken orally that can restore balance to the intestinal microflora. These bacteria or yeasts can also produce nutrients and anti-oxidants that fight bacterial endotoxin and activate the lymphoid tissue found in the intestine.

Probiotics come in a variety of forms and can cost very little or quite a lot. The simplest and cheapest forms are live culture yogurts found in the grocery store. Oral supplements are also available that are just a little more expensive. A few specialty products are available for critically ill patients that cost quite a lot.

Going along with probiotics are so-called prebiotics, which are dietary fibers that can help with fluid absorption and diarrhea, and with keeping bowel movements regular and of reasonable consistency. Use of prebiotics has been shown to decrease catheter related sepsis in ICU patients.

A newer concept is the use of probiotics when antibiotics are given for the treatment of infection. Any antibiotic can wipe out portions of the normal gut flora, leaving room for pathogenic bacteria (such as C. Diff.) to go wild. The thought is that the probiotics help recolonize the colon with “good bacteria” and avoid the development of an infectious diarrhea.

The last time I reviewed the literature on this topic, there was no clear data that probiotics reduce antibiotic associated diarrhea. There was evidence that it helped some other infectious and inflammatory conditions. Well, things have changed and new meta-analyses have been released in the last 6 months that do show a benefit. Both lactobacillus strains (found in yogurt and the usual supplements) and Saccharomyces boulardii (a yeast found only in certain supplements in this country) show statistically significant reduction in antibiotic associated diarrhea. 

Bottom line: Given the fact that these supplements are cheap and have few side effects, it is probably beneficial to administer a probiotic during and for a few days after discontinuation of antibiotics. Use should be limited to reasonably healthy, non-immunocompromised patients, since high dose Saccharomyces can cause fungemia in the critically ill. The use of prebiotics (fiber) is probably also beneficial, especially for patients on narcotic pain medications.

References:

1. Role of Lactobacillus in the prevention of antibiotic-associated diarrhea: a meta-analysis. Kale-Pradhan PB, Jassal HK, Wilhelm SM. Pharmacotherapy. 2010 Feb;30(2):119-26.
2. Systematic review and meta-analysis of Saccharomyces boulardii in adult patients. McFarland LV.World J Gastroenterol. 2010 May 14;16(18):2202-22.