Risk factors for the development of acute pyelonephritis in women with a positive urine culture

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

Background

Many emerging uropathogens are currently identified by multiplex polymerase chain reaction (M-PCR) in suspected UTI cases. Standard urine culture (SUC) has significantly lower detection rates, raising questions about whether these organisms are associated with UTIs and truly cause inflammation.

Objective

To determine if microbes detected by M-PCR were likely causative of UTI by measuring inflammatory biomarkers in the urine of symptomatic patients.

Design Setting and Participants

Midstream voided urine was collected from subjects ≥60 years presenting to urology clinics with symptoms of UTI (n = 1132) between 01/2023 and 05/2023. Microbe detection was by M-PCR and inflammation-associated biomarker (neutrophil gelatinase-associated lipocalin, interleukin 8, and interleukin 1β) was by enzyme-linked immunosorbent assay. Biomarker positivity was measured against individual and groups of organisms, E. coli and non-E. coli cases, emerging uropathogens, monomicrobial and polymicrobial cases.

Outcome Measurements and Statistical Analysis

Distributions were compared using 2-sample Wilcoxon Rank Sum test with 2-tailed p-values < 0.05 considered statistically significant.

Results and Limitations

M-PCR was positive in 823 (72.7%) specimens with 28 of 30 (93%) microorganisms/groups detected. Twenty-six of twenty-eight detected microorganisms/groups (93%) had ≥2 biomarkers positive in >66% of cases. Both non-E. coli cases and E. coli cases had significant biomarker positivity (p < 0.05). Limitations were that a few organisms had low prevalence making inferences about their individual significance difficult.

Conclusion

The majority of microorganisms identified by M-PCR were associated with active inflammation measured by biomarker positivity, indicating they are likely causative of UTIs in symptomatic patients. This includes emerging uropathogens frequently not detected by standard urine culture.

Comparison Shows that Multiplex Polymerase Chain Reaction Identifies Infection-associated Urinary Biomarker-positive Urinary Tract Infections That Are Missed by Standard Urine Culture

Background

Multiplex polymerase chain reaction (M-PCR) has increased sensitivity for microbial detection compared with standard urine culture (SUC) in cases diagnosed as urinary tract infections (UTIs), leading to questions whether detected microbes are likely causative of UTIs or are incidental findings.

Objective

To compare infection-associated biomarker levels against M-PCR and SUC results in symptomatic cases with a presumptive diagnosis of a UTI by a urologist.

Design setting and participants

Participants were ≥60 yr old and presented to urology clinics between January and April 2023 with symptoms of UTIs (n = 583). Urine microbial detection was by M-PCR and SUC. Three infection-associated biomarkers (neutrophil gelatinase-associated lipocalin, interleukin-8, and interleukin-1β) were measured by enzyme-linked immunosorbent assay. Symptomatic cases with elevated biomarkers, detection of uropathogens, and a specialist clinical diagnosis of a UTI were considered definitive UTI cases.

Outcome measurements and statistical analysis

Distributions were compared using two-sample Wilcoxon rank sum test, with two-tailed p values of <0.05 considered statistically significant.

Results and limitations

In cases with M-PCR-positive/SUC-negative results (n = 80), all median biomarker levels were significantly higher (p < 0.0001) than in cases with M-PCR-negative/SUC-negative results (n = 107). Two or more biomarkers were positive in 76% of M-PCR-positive/SUC-negative specimens. Limitation was an inability to examine associations between each individual organism and inflammation.

Conclusions

A significant number of M-PCR-positive/SUC-negative cases had elevated levels of infection-related urinary biomarkers, especially when infection was caused by organisms other than Escherichia coli. This is a strong indication that microbes detected by M-PCR, which would be missed by SUC, are associated with UTIs.

Patient summary

We compared infection-associated biomarkers in patients diagnosed with urinary tract infections (UTIs) against the detection of microorganisms by standard urine culture (SUC) and multiplex polymerase chain reaction (M-PCR). We found that most patients with microorganisms detected by M-PCR, which were missed by SUC, had elevated markers of inflammation, indicating that these organisms were likely causative of UTIs.

Improving Patient Outcomes While Reducing Empirical Treatment with Multiplex-Polymerase-Chain-Reaction/Pooled-Antibiotic-Susceptibility-Testing Assay for Complicated and Recurrent Urinary Tract Infections

This study compared rates of empirical-therapy use and negative patient outcomes between complicated and recurrent urinary tract infection (r/cUTI) cases diagnosed with a multiplex polymerase chain reaction or pooled antibiotic susceptibility testing (M-PCR/P-AST) vs. standard urine culture (SUC). Subjects were 577 symptomatic adults (n = 207 males and n = 370 females) presenting to urology/urogynecology clinics between 03/30/2022 and 05/24/2023. Treatment and outcomes were recorded by the clinician and patient surveys. The M-PCR/P-AST (n = 252) and SUC (n = 146) arms were compared after patient matching for confounding factors. The chi-square and Fisher's exact tests were used to analyze demographics and clinical outcomes between study arms. Reduced empirical-treatment use (28.7% vs. 66.7%), lower composite negative events (34.5% vs. 46.6%, p = 0.018), and fewer individual negative outcomes of UTI-related medical provider visits and UTI-related visits for hospitalization/an urgent care center/an emergency room (p < 0.05) were observed in the M-PCR/P-AST arm compared with the SUC arm. A reduction in UTI symptom recurrence in patients ≥ 60 years old was observed in the M-PCR/P-AST arm (p < 0.05). Study results indicate that use of the M-PCR/P-AST test reduces empirical antibiotic treatment and negative patient outcomes in r/cUTI cases.

Electromechanically Functionalized Ureteral Stents for Wireless Obstruction Monitoring

While millions of ureteral stents are placed in patients with urinary tract issues around the world every year, hydronephrosis still poses great danger to these patients as a common complication. In the present work, an intelligent double-J ureteral stent equipped with a micro pressure sensor and antenna circuitry is investigated and prototyped toward enabling continuous wireless monitoring of kidney pressure to detect a ureteral obstruction and the resultant hydronephrosis via the indwelling stent. This electromechanically functionalized "intelligent" ureteral stent acts as a radiofrequency resonator with a pressure-sensitive resonant frequency that can be interrogated using an external antenna to track the local pressure. The prototype passes mechanical bending tests of up to 15 cm radius of curvature and shows wireless sensing with a sensitivity of 3.1 kHz/mmHg in artificial urine, which represents 25× enhancement over the preceding design, using an in vitro model with test tissue layers and a pressure range that functions within the conditions found in hydronephrotic conditions. These promising results are expected to propel intelligent ureteral stent technology into further clinical research.

A Diagnostic Test Combining Molecular Testing with Phenotypic Pooled Antibiotic Susceptibility Improved the Clinical Outcomes of Patients with Non-E. coli or Polymicrobial Complicated Urinary Tract Infections

Purpose

Complicated UTIs (cUTIs) cause significant morbidity and healthcare resource utilization and cost. Standard urine culture has limitations in detecting polymicrobial and non-E. coli infections, resulting in the under-diagnosis and under-treatment of cUTIs. In this study, patient-reported outcomes were compared between treated and untreated patients when an advanced diagnostic test combining multiplex-polymerase chain reaction (M-PCR) with a pooled antibiotic susceptibility method (P-AST) was incorporated into the patients' clinical management.

Methods

Patients who had symptoms typical of cUTI and positive M-PCR/P-AST test results were recruited from urology clinics. Symptom reduction and clinical cure rates were measured from day 0 through day 14 using the American English Acute Cystitis Symptom Score (ACSS) Questionnaire. Clinical cure was defined based on the sum of the scores of four US Food and Drug Administration (FDA) symptoms and the absence of visible blood in the urine.

Results

Of 264 patients with suspected cUTI, 146 (55.4%) had exclusively non-E. coli infections (115 treated and 31 untreated) and 190 (72%) had polymicrobial infections (162 treated and 28 untreated). Treated patients exhibited greater symptom reduction compared to untreated ones on day 14 for those with exclusively non-E. coli organisms (3.18 vs 1.64, p = 0.006) and polymicrobial infections (3.52 vs 1.41, p = 0.002), respectively. A higher percentage of treated patients than of untreated patients achieved clinical cure for polymicrobial infections on day 14 (58.7% vs 36.4%, p = 0.049).

Conclusion

Patients with cUTIs treated based on the M-PCR/P-AST diagnostic test had significantly improved symptom reduction and clinical cure rates compared to untreated patients among those with non-E. coli or polymicrobial infections.