Contributing Factors to the Clinical and Economic Burden of Patients with Laboratory-Confirmed Carbapenem-Nonsusceptible Gram-Negative Urinary Tract Infections

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.

A single- and multiple-dose study to characterize the pharmacokinetics, safety, and tolerability of ceftolozane/tazobactam in healthy Chinese participants

Ceftolozane/tazobactam (C/T) is approved in several countries to treat complicated urinary tract infections, complicated intra-abdominal infections, and nosocomial pneumonia. There is a paucity of pharmacokinetics and safety data for C/T in Chinese participants. This study evaluated the pharmacokinetics, safety, and tolerability of C/T in 12 healthy Chinese participants after three single administrations of increasing doses (0.75 g, 1.5 g, and 3 g) and multiple administrations of 1.5 g C/T every 8 h for 3 days. After single doses, maximum concentrations of ceftolozane and tazobactam were reached by the end of the 1-h infusion and declined in a biphasic manner thereafter, with mean half-lives of 1.9-2.2 h and 0.74-0.95 h, respectively. Volume of distribution (V_d) and renal clearance (CL) were consistent across the three single-dose levels for ceftolozane (V_d, 15.8-19.5 L; CL, 5.68-6.09 L/h) and tazobactam (V_d, 23.3-28.6 L; CL, 20.8-23.5 L/h). Area under the concentration-time curve (AUC) extrapolated to infinity (ceftolozane, 88.1-328 h∙μg/mL; tazobactam, 10.7-48.0 h∙μg/mL) increased in a dose-dependent manner. After multiple doses over 3 days, AUC from time 0 to 8 h, and concentration at the end of infusion were similar to single-dose measurements (geometric mean ratios, 0.87-1.01 for both drugs). C/T was well tolerated, with no serious adverse events or discontinuations reported; all adverse events were mild. The pharmacokinetics and safety/tolerability of C/T in healthy Chinese participants was comparable to that in previous studies in other populations, supporting the use of C/T for the treatment of Chinese patients.

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.

A Phase 3, Multicenter, Double-blind, Randomized Clinical Trial to Evaluate the Efficacy and Safety of Ceftolozane/Tazobactam Plus Metronidazole Versus Meropenem in Chinese Participants With Complicated Intra-abdominal Infections

OBJECTIVE

To evaluate the efficacy and safety of ceftolozane/tazobactam plus metronidazole vs meropenem plus placebo for the treatment of complicated intra-abdominal infection (cIAI) in Chinese adult participants.

METHODS

In this phase 3 clinical trial (NCT03830333), Chinese adult participants with cIAI were randomized 1:1 to receive ceftolozane/tazobactam plus metronidazole or meropenem plus placebo. The primary objective was to assess ceftolozane/tazobactam plus metronidazole for noninferiority vs meropenem for clinical response rate at the test of cure (TOC; 28 ± 2 days after study start) visit in the clinically evaluable (CE) population. Secondary end points included clinical and microbiologic responses at the TOC and end of treatment (EOT; ≤24 hours after last dose) visits and adverse event rates.

RESULTS

Clinical cure at the TOC visit in the CE population was 95.2% and 93.1% for ceftolozane/tazobactam plus metronidazole and meropenem, respectively (between-treatment difference: 2.1% [95% CI: -4.7%, 8.8%); thus, noninferiority was met. Clinical responses at the TOC and EOT visits and microbiologic responses at the TOC visit were consistent with the primary efficacy end point. Safety was comparable between study treatment groups.

CONCLUSION

In Chinese adult participants with cIAI, ceftolozane/tazobactam plus metronidazole was noninferior to meropenem, with comparable safety.

Descriptive Epidemiology and Outcomes of Hospitalizations With Complicated Urinary Tract Infections in the United States, 2018

Background

Hospitalizations with complicated urinary tract infection (cUTI) in the United States have increased. Though most often studied as a subset of cUTI, catheter-associated UTI (CAUTI) afflicts a different population of patients and carries outcomes distinct from non-CA cUTI (nCAcUTI). We examined the epidemiology and outcomes of hospitalizations in these groups.

Methods

We conducted a cross-sectional multicenter study within the 2018 National Inpatient Sample (NIS) database, a 20% stratified sample of discharges from US community hospitals, to explore characteristics and outcomes of patients discharged with a UTI diagnosis. We divided cUTI into mutually exclusive categories of nCAcUTI and CAUTI. We applied survey methods to develop national estimates.

Results

Among 2 837 385 discharges with a UTI code, 500 400 (17.6%, 19.8% principal diagnosis [PD]) were nCAcUTI and 126 120 (4.4%, 63.8% PD) were CAUTI. Though similar in age (CAUTI, 70.1 years; and nCAcUTI, 69.7 years), patients with nCAcUTI had lower comorbidity (mean Charlson, 4.3) than those with CAUTI (mean Charlson, 4.6). Median (interquartile range [IQR]) length of stay (LOS) was 5 (3–8) days in nCAcUTI and 5 (3–9) days in CAUTI. Overall median (IQR) hospital costs were similar in nCAcUTI ($9713 [$5923–$17 423]) and CAUTI ($9711 [$5969–$17 420]). Though low in both groups, hospital mortality was lower in nCAcUTI (2.8%) than in CAUTI (3.4%). Routine discharges home were higher in nCAcUTI (41.5%) than CAUTI (22.1%).

Conclusions

There are >626 000 hospital admissions with a cUTI, comprising ~1.8% of all annual admissions in the United States; 4/5 are nCAcUTI. Because CAUTI is frequently the reason for admission, preventive efforts are needed beyond the acute care setting.

Susceptibility of hospital-acquired uropathogens to first-line antimicrobial agents at a tertiary health-care hospital, Saudi Arabia

Context

Management of urinary tract infections (UTIs) is caused by antibiotic resistance uropathogens.

Aim

This study aimed to determine the important uropathogens and their resistance to first-line urinary tract antimicrobial agents.

Settings and Design

The region of Aseer, Southern Saudi Arabia, between 2013 and 2016.

Materials and Methods

A total of 1506 isolates were recovered from the urine samples of patients that were identified and tested against nine first-line UTI antimicrobial agents. Laboratory analysis was done as per the standard methods. Confirmation of bacterial identity and antimicrobial susceptibility assay was achieved by the VITEK 2 automated system.

Statistical Analysis Used

Statistical Package for the Social Sciences software version 21.0 was used for the statistical analysis.

Results

The dominant uropathogens were Escherichia coli (E. coli) 507 (33.7%); Klebsiella pneumoniae (K. pneumoniae), 229 (15.21%); Pseudomonas aeruginosa, 153 (10.2%); Acinetobacter baumannii, 80 (5.3%); Enterococcus faecalis, 71 (4.7%); and Proteus mirabilis, 61 (4.1%). Of all culture-positive uropathogens, 51.5% were resistant to the 39 agents, whereas 48.5% were sensitive (P = 0.7969). Regarding the susceptibility to the first-line agent, the most effective against the dominant (in vitro) agents against E. coli were fosfomycin and nitrofurantoin (93.5%) and (85.4%), respectively. Whereas those worked well against K. pneumoniae were cefoxitin (57.1).

Conclusions

The present study recommends the use of fosfomycin, cefoxitin, nitrofurantoin, and amoxicillin/clavulanate as the first choice UTIs treatment given their relatively high in vitro activity against major uropathogens. Knowledge of the bacterial species and their antimicrobial sensitivity patterns are always necessary to serve as a base for selecting the empirical treatment of UTIs as resistance rates vary geographically and with time.

Imipenem/Cilastatin/Relebactam: A Review in Gram-Negative Bacterial Infections

Imipenem/cilastatin/relebactam (Recarbrio™) is an intravenously administered combination of the carbapenem imipenem, the renal dehydropeptidase-I inhibitor cilastatin, and the novel β-lactamase inhibitor relebactam. Relebactam is a potent inhibitor of class A and class C β-lactamases, conferring imipenem activity against many imipenem-nonsusceptible strains. Imipenem/cilastatin/relebactam is approved in the USA and EU for the treatment of hospital-acquired bacterial pneumonia (HABP) and ventilator-associated bacterial pneumonia (VABP) in adults and other gram-negative infections, including complicated urinary tract infections (cUTIs) [including pyelonephritis] and complicated intra-abdominal infections (cIAIs), in adults with limited or no alternative treatment options. In pivotal phase II and III trials, imipenem/cilastatin/relebactam was noninferior to piperacillin/tazobactam in patients with HABP/VABP and to imipenem/cilastatin in patients with cUTIs and cIAIs. It was also effective in imipenem-nonsusceptible infections. Imipenem/cilastatin/relebactam was generally well tolerated, with a safety profile consistent with that of imipenem/cilastatin. Available evidence indicates that imipenem/cilastatin/relebactam is an effective and generally well tolerated option for gram-negative infections in adults, including critically ill and/or high-risk patients, and a potential therapy for infections caused by carbapenem-resistant pathogens.

Contributing Factors to the Clinical and Economic Burden of Patients with Laboratory-Confirmed Carbapenem-Nonsusceptible Gram-Negative Urinary Tract Infections

PURPOSE

We explored patient- and hospital-level predictor variables for worse clinical and economic outcomes in carbapenem-nonsusceptible urinary tract infections (UTIs).

PATIENTS AND METHODS

We used electronic data (January 2013-September 2015; 78 US hospitals) from a large multicenter clinical database. Nonduplicate gram-negative isolates were considered carbapenem-nonsusceptible if they had resistant/intermediate susceptibility. Potential predictors of outcomes (mortality, 30-day readmissions, length of stay [LOS], hospital total cost, and net gain/loss per case) were examined using generalized linear mixed models. Significant predictors were identified based on statistical significance and model goodness-of-fit criteria.

RESULTS

A total of 1439 carbapenem-nonsusceptible urine cases were identified. The mortality rate was 5.5%; the hospital readmission rate was 25.0%. Mean (standard deviation [SD]) LOS, total cost, and loss per case were 12 (14) days, $21,502 ($37,172), and $5828 ($26,540), respectively. Hospital-onset (vs community-onset) infection significantly impacted all outcomes: mortality (odds ratio [OR], 2.21; 95% confidence interval [CI], 1.19-4.11; P=.01), 30-day readmissions (OR, 2.35; 95% CI, 1.49-3.71; P<.001), LOS (25.7 vs 10.2 days; P<.001), hospital total cost ($67,810 vs $22,141; P<.001), and loss per case (-$28,054 vs -$10,809; P<.001). Mechanical ventilation/intensive care unit status, neoplasms, and other underlying diseases were also common predictors for worse outcomes overall; polymicrobial infection was significantly associated with worse economic outcomes. Other key predictors were >1 prior hospitalization for 30-day readmissions, high Acute Laboratory Risk of Mortality Score for mortality, LOS, cost, and hospital teaching status for cost.

CONCLUSION

Hospital-onset infections, polymicrobial infections, higher clinical severity, and underlying diseases are key predictors for worsened overall burden of carbapenem-nonsusceptible gram-negative UTIs.