Defining and Detecting Bacterial Consortia Within Urine Samples of Patients with Symptomatic Urinary Tract Infection
Journal of Urology
INTRODUCTION AND OBJECTIVE:
Consortia are non-random patterns of bacterial communities that work synergistically to provide growth and survival advantages. In this study, we aim to characterize bacterial consortia identified by multiplex polymerase chain reaction (M-PCR) in patients with symptomatic polymicrobial urinary tract infections (UTI).
We performed a retrospective analysis of 2493 urine specimens sent for M-PCR from patients over 60 years presenting to 37 different urology clinics with possible UTI. M-PCR was performed to detect 24 different bacterial species. A cutoff of 10 detections was used to distinguish a consortium from a random association of bacteria in a polymicrobial specimen.
M-PCR detected bacteria in 68.8% (1710/2493) of specimens. 60.1% (1027/1710) were polymicrobial. Of these, bacterial consortia were found in 42.2% (433/1027). Eight bacteria formed 18 unique consortia, Table 1. All consortia contained Gram-positive bacteria. Half of consortia contained Gram-negative bacteria. No consortium had more than one Gram-negative species. A. Schaalii and A. urinae were most commonly detected, 73.0% and 67.7%, respectively. A. Schaalii and A. urinae were found together in 55.9% of consortia polymicrobial specimens, but in only 33% of non-consortia polymicrobial specimens. In contrast, some bacteria, such as P. aeruginosa and S. aureus, were detected in polymicrobial infections but not in any consortia.
The balance of bacteria in consortia is shifted not only toward Gram-positive bacteria but also toward specific Gram-positive bacteria. The high prevalence of A. schaalii or A. urinae in the consortia suggests that these organisms could be keystone bacteria in formation of pathogenic consortia. More data is needed to determine clinical significance of consortia.
Vollstedt, A, Wang D, Luke N, Baunoch D, Wojno KJ, Gaines N, Korman H, et al. Defining and detecting bacterial consortia within urine samples of patients with symptomatic urinary tract infection. J Urol. 2021 Sep;206(3 suppl):e457.