Urinary Microbiota Diversity Associated with Protection from Infection in Catheterized Patients
Background: Bladders of chronically catheterized persons are usually colonized with potentially pathogenic organisms, yet such patients are often asymptomatic. We characterized the microbiome through Next Generation sequencing in such patients who did/did not develop symptomatic urinary tract infections.
Methods: Adults over age 50 and with indwelling catheters and baseline bacteriuria were enrolled in a clinical trial of urinary catheters pre-coated with potentially probiotic E. coli HU2117. Serial urine cultures were collected after insertion of a study catheter. Urine specimens were split for traditional microbiology methods and 16S rRNA gene profiling. Subjects with E. coli HU2117 in their urine were classified as colonized with E. coli HU2117, while subjects who developed fever related to the urinary tract were classified as infected with a UTI.
Results: 10 subjects received a study catheter, 9 males and 1 female. We performed paired microbiological/genomic analysis on 17 urine samples from 4 subjects, including 2 colonized with E. coli HU2117 and 2 infected with UTI. All 4 subjects had other organisms in their urine detected by standard microbiology methods throughout the course of the study. 100% of organisms detected by microbiology were also detected by sequencing, but only 11 of 30 (37%) of the genera identified by sequencing in abundance of ≥0.5% were also identified by microbiology. Frequently missed organisms included Actinobaculum, Aerococcus, Lactobacillus, and Prevotella; 12 of the 19 missed organisms were anaerobes. Subjects who developed an infection had significantly lower urinary bacterial diversity than subjects who did not develop an infection (Figure 1, p=0.001). Bacterial diversity did not differ by colonization status with E. coli HU2117 (p=0.43), nor did rates of UTI differ before, during and after colonization in all 10 subjects (p=0.5).
Conclusion: Bladder colonization with E. coli HU2117 did not protect against symptomatic infection, nor did colonization impact bladder bacterial diversity. The role of anaerobes in bladder health may be underappreciated. The bacterial diversity of the bladder microbiota may play a role in protection from invasive disease.
A. C. Mapes, None
N. J. Ajami, None
J. F. Petrosino, None
B. W. Trautner, None