Login to Access Video or Poster Abstract: MP12-14
Sources of Funding: NIH P20-DK-100863 (TC), NIH R21-DK-109433 (TC), and NIH K12-DK-07-006: Multidisciplinary K12 Urologic Research Career Development Program (TC)_x000D_

Introduction

Microbiomes refer to the collective microorganisms resident in a particular environment. They are found in all exposed tissues of the human body including the gastrointestinal, respiratory and urogenital tract. Microbiomes play a critical role in the maintenance of health and development of disease. However, the upper urinary tract microbiome has not been explored. Our objective was to define the upper urinary tract microbiome for urinary stone patients and examine its association with patient characteristics.

Methods

After institutional IRB approval was obtained, urine and renal stone fragments were prospectively collected from nephrolithiasis patients who underwent endoscopic stone removal at our institution. Patients were excluded who had a history of antibiotic or steroid medication exposure within 6 months prior to surgery. Specimens were immediately preserved with RNAlater solution and stored at -80°C. For analysis, specimens were homogenized and underwent DNA extraction and PCR amplification. 16S ribosomal RNA sequencing with Illumina NextSeq (Illumina Inc.) targeted at the V4 hypervariable region was used for microbiome identification. Resultant microbiome colonization patterns were then expressed in operation taxonomic units.

Results

6 urinary stone patients enrolled into this study consisted of 5 males and 1 female, with a mean age of 55.8±14.4 years and a mean BMI of 29.3±3.6 kg/m². 30 from 33 patient specimens (91%) demonstrated DNA quality above the threshold for extraction and were included in the analysis. A distinct microbiome was associated with kidney specimens and mainly consisted of Proteobacteria, Firmicutes, Bacteroides, and Actinobacteria. Microbial community differences were most strongly associated with patient age (p <0.05). A significant trend of alpha diversity stratifying bladder urine and stone fragment specimens between calcium oxalate versus uric acid stone formers was also seen. _x000D_

Conclusions

This pilot study confirmed the presence of microbiome communities in the upper urinary tract for nephrolithiasis patients. Differences in these microbial communities exist and are associated with patient age and stone type. Larger scale analyses are ongoing to validate these findings and verify how the microbiome plays a role in stone formation.

Funding

NIH P20-DK-100863 (TC), NIH R21-DK-109433 (TC), and NIH K12-DK-07-006: Multidisciplinary K12 Urologic Research Career Development Program (TC)_x000D_