PCR Testing Linked to Better Outcomes in Complicated UTI than Culture/Sensitivity-Guided Treatment

PCR-based molecular testing was associated with better clinical outcomes in complicated urinary tract infection (cUTI) than traditional culture-sensitivity in a randomized controlled trial, attributed by the investigators to enabling earlier targeted, rather than empiric treatment.¹

"Our findings demonstrate a significantly faster turnaround time with molecular testing compared to C&S," remarked study coordinator and lead author Frank Spangler, CEO, Soft Cell Laboratories, St George, Utah, and colleagues.

"This highlights the efficiency advantage of PCR over conventional C&S methods in clinical practice, signifying its ability to streamline diagnostic workflows and subsequent patient care," Spangler and colleagues enthused.

The investigators identified 773 patients with cUTI at multiple treatment centers to receive urine sample testing by PCR and C&S, then randomizing them on 1:1 ratio to treating clinicians blinded to results of the comparator testing.UTI was classified as complicated if patients had underlying anatomic or functional abnormalities of the genitourinary tract, which predispose to more serious infections.

The study cohort ultimately comprised 362 patients for which all study procedures and analyses were completed; 193 in the PCR arm and 169 in the C&S arm. The cohort included patients with a range of risk factors, recurrent infections, or multiple signs and symptoms. Study participants were followed for 28-days.

The trial primary endpoint was favorable clinical outcomes at the end of study visit; defined as resolution of at least one symptom of cUTI present at baseline, absence of new cUTI symptoms, and/or avoidance of parenteral antibiotic therapy following randomization. Clinical cure corresponded to complete resolution of all acute signs and symptoms of cUTI present at baseline; with no further antimicrobial therapy required.

Secondary measures included the percentage of patients in each group with microbiological eradication at end of study. In addition, a questionnaire was provided to the treating clinicians to ascertain their satisfaction with the utility of the respective testing regimen.

Spangler and colleagues reported treatments guided by PCR results were associated with significantly better clinical outcomes compared to treatments guided by conventional C&S (88.08% vs 78.11%, p=0.011), with a significantly shorter turnaround time (49.68 hours vs 104.4 hours, p<0.0001).The advantage of PCR-testing was particularly prominent, as was higher cure rate, in elderly patients (>65years), female patients, and in those with polymicrobial infection.

The overall microbial eradication efficiency was slightly, but not statistically significantly better with PCR-guided testing than with C&S (62.18% vs 56.2%), p=0.24). Clinician satisfaction scores with aspects of testing such as ease of use, timely availability, and usefulness in clinical decision making were somewhat higher with PCR-testing than traditional C&S (average 23.95 ± 1.96 vs 20.64 ± 4.12).

Spangler and colleagues acknowledge several limitation of the study, including different parameters of the PCR panels for microbial pathogen selection, and difficulty in differentiating commensal microorganisms from pathogenic species. Some patients assigned to a study arm tested negative, indicating either a discordant result or a lack of microbiological evidence of cUTI.

"Consequently, there is a pressing need for additional investigation into discordant results between PCR and C&S tests, along with further microbiological-level analysis," the investigators indicated, noting their intent to do so in a part 2 analysis of the data.

Reference

1. Spangler FL, Williams C, Aberger ME, et al. Clinical utility of PCR compared to conventional culture and sensitivity testing for the management of complicated urinary tract infections in adults: Part 1. Assessment of clinical outcomes, investigator satisfaction scores and turnaround times. Diagn Microbiol Infect Dis 2024, online November 7. https//doi.org/10.1016/j.diagmicrobio.2024.116601. Accessed December 20, 2024.