Objective: To determine the levels of Oxalobacter formigenes and the oxalate-degrading ability in probiotic supplements (PRO-LAB from Toronto, Canada, and Oxalo from Hyderabad, India) marketed to reduce kidney stone recurrence in stone-forming patients.

Design: Prospective in-vitro study.

Methods: Probiotic supplements obtained from PRO-LAB and Oxalo were cultured in a number of different medias. Optical density was used to measure bacterial growth, while ion chromatography was used to measure loss of oxalate in media. Polymerase chain reaction (PCR) was used to determine organism species.

Results: No growth of oxalate-degrading organisms occurred. PCR showed that the PRO-LAB supplement contained Lactococcus lactisand Oxalo contained several Bacillus species and Lactobacillus plantarum.

Conclusions: Current probiotic supplements did not contain O formigenes or other oxalate-degrading organisms and are unlikely to benefit calcium oxalate kidney stone patients.

Reviewer’s Comments: Much work is being performed in an attempt to provide O formigenes as a probiotic supplement in hopes of reducing urinary oxalate excretion in calcium oxalate stone-forming patients. However, it has proven very difficult to get viable O formigenes organisms to the intended site for colonization in patients. The current marketed formulations over the Internet (PRO-LAB and Oxalo) have no resemblance to organisms containing oxalate-degrading properties. These probiotics are a waste of money for patients and they should not be recommended for use. This study reminds us to use caution in recommending or purchasing any product that is not regulated by the Food and Drug Administration since no quality measures are required for supplements and the product is often not as advertised.(Reviewer–David A. Duchene, MD).