The association of the intestinal oxalate degrading bacteria with recurrent calcium kidney stone formation and hyperoxaluria: a case-control study.

To investigate the potential oxalate degrading bacteria, including Oxalobacter formigenes (O.f), Lactobacillus (Lac) and Bifidobacterium (Bif) genera, and Oxalyl-CoA decarboxylase (oxc) encoding Lac (LX) and Bif (BX) species in recurrent calcium kidney stone patients and their correlation with 24-hour urine oxalate.

Stool and 24-hour urine samples were collected from 58 patients with urolithiasis, (29 cases with and 29 cases without hyperoxaluria) and 29 healthy controls. Absolute quantitation and relative abundance of the bacteria were measured by real-time PCR. The relationship between investigated bacteria and 24-hour urine oxalate were assessed statistically.

The count/gr stool and relative abundance of O.f, Lac, Bif, LX and BX and the number of patients carrying O.f, LX and BX bacteria were not significantly different between groups. However, the relative abundance of O.f in stone-formers was lower than healthy controls (p= 0.035). More healthy controls were O.f positive compared with stone formers (p= 0.052). The results of linear regression model, including all study participants, showed that O.f presence could decrease 24-h urine oxalate (β = -8.4, p= 0.047). Neither Lac and Bif genera nor LX and BX species had correlation with calcium stone or urine oxalate.

These results emphasize the role of O.f in kidney stone formation and its role in hyperoxaluria, which may be independent of kidney stone disease. Moreover, our results suggest that although some Lac and Bif strains have oxalate degrading potential, they may not be among the major oxalate degrading bacteria of the gut microbiome. This article is protected by copyright. All rights reserved.

BJU international. 2019 May 30 [Epub ahead of print]

Sanaz Tavasoli, Masoud Alebouyeh, Mohammad Naji, Ghazaleh Shakiba Majd, Maryam Shabani Nashtaei, Nasrin Broumandnia, Abbas Basiri

Urology and Nephrology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, I.R. Iran., Pediatric Infections Research Center, Research Institute for Children's Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran., Department of anatomy, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.