Emerging and Fastidious Uropathogens Were Detected by M-PCR with Similar Prevalence and Cell Density in Catheter and Midstream Voided Urine Indicating the Importance of These Microbes in Causing UTIs

Abstract

Introduction This study compared microbial compositions of midstream and catheter urine specimens from patients with suspected complicated urinary tract infections to determine if emerging and fastidious uropathogens are infecting the bladder or are contaminants. Methods Urine was collected by in-and-out catheter (n = 1000) or midstream voiding (n = 1000) from 2000 adult patients (≥60 years of age) at 17 DispatchHealth sites across 11 states. The two groups were matched by age (mean 81 years), sex (62.1% female, 37.9% male), and ICD-10-CM codes. Microbial detection was performed with multiplex polymerase chain reaction (M-PCR) with a threshold for “positive detection” ≥ 10,000 cells/mL for bacteria or any detection for yeast. Results were divided by sex. Results In females, 28 of 30 microorganisms/groups were found by both collection methods, while in males 26 of 30 were found by both. There were significant overlaps in the detection and densities of classical uropathogens including Escherichia coli, Enterococcus faecalis , and Klebsiella pneumoniae , as well as emerging uropathogens including Actinotignum schaalii and Aerococcus urinae . In females, detection rates were slightly higher in midstream voided compared to catheter-collected (p = 0.0005) urine samples, while males showed the opposite trend (p < 0.0001). More polymicrobial infections were detected in midstream voided compared to catheter-collected samples (64.4% vs 45.7%, p < 0.0001) in females but the opposite in males (35.6% vs 47.0%, p = 0.002). Discussion In-and-out catheter-collected and midstream voided urine specimens shared significant similarities in microbial detections by M-PCR, with some differences found for a small subset of organisms and between sexes. Conclusion Non-invasive midstream voided collection of urine specimens for microbial detection and identification in cases of presumed UTI does not result in significantly more contamination compared to in-and-out catheter-collected specimens. Additionally, organisms long regarded as contaminants should be reconsidered as potential uropathogens.

The Prevalence and Association of Different Uropathogens Detected by M-PCR with Infection-Associated Urine Biomarkers in Urinary Tract Infections

“…42 Other studies identified VGS and CoNS in both midstream voided and catheter-collected specimens at similar prevalence and densities, further indicating the organisms' likely pathogenic nature. 43 Therefore, the approach of detecting only classical uropathogens may result in missed cases, as emerging or less common pathogens can cause infections and pose significant health threats.…”