Evaluation of evidence-based urinalysis reflex to culture criteria: Impact on reducing antimicrobial usage

Beyond urinalysis: evaluation of various clinical and laboratory reflex criteria to warrant urine culture collection in the emergency department

BACKGROUND

Clinical criteria are essential for diagnosing urinary tract infections (UTIs) followed by urine testing, including urinalysis (UA). No study has evaluated the potential related factors that may guide the appropriate collection of urine cultures. Therefore, we aimed to assess the factors that may guide the appropriate collection of urine cultures.

METHODS

This was a case-control study of patients for whom a urine culture and a UA were ordered in the emergency department (ED) between February 2018 and December 2022. The cases included patients with positive cultures, whereas the controls included patients without growth. Patients were excluded if they were pregnant, underwent any urological procedure, received antibiotics within 3 days before ED presentation, or before culture collection.

RESULTS

Of the 263 patients, 123 had growth and 140 did not have growth in urine cultures. In the univariate analysis, female gender, urinary symptoms, urinary white blood cell (WBC) count > 5 cells/hpf, and nitrite in urine were significantly associated with growth (P < 0.05). However, only female gender (aOR, 1.86; 95% CI, 1.06-3.24), urinary WBC count > 5 cells/hpf (aOR, 4.60; 95% CI, 2.21-9.59), and positive nitrite in urine (aOR, 21.90; 95% CI, 2.80-171.00) remained significant in the multivariable analysis. These factors also remained significant in the subgroup of patients with urinary symptoms, except for the female gender.

CONCLUSION

A high urinary WBC count and positive nitrite in UA should be utilized as a guide to collect urine culture, particularly in female patients, to limit the unnecessary ordering of urine culture in the ED. These factors can be used as evidence-based UA reflex criteria as an antimicrobial stewardship intervention.

Lack of microbiological awareness on the ward as a key factor for inappropriate use of anti-infectives: results of a point prevalence study and user satisfaction survey in a large university hospital in Austria

PURPOSE

Although diagnostic stewardship issues in clinical microbiology harbor an optimization potential for anti-infective consumption, they are only marginally addressed in antimicrobial stewardship (AMS) programs. As part of an AMS point prevalence (PPS) survey we therefore aimed to gain a more dynamic view on the microbiological awareness within therapeutic regimens. By examining whether initial microbiological sampling was performed and in which way microbiological results were incorporated into further treatment considerations we sought to find out to what extent these points determine the appropriateness of treatment regimens.

METHODS

PPS was performed at the University Hospital Salzburg (1524 beds) in May 2021. Relevant data was determined from the patient charts and the appropriateness of anti-infective use was assessed using predefined quality indicators. Six months after the PPS, a questionnaire was administered to clinicians to obtain information on the use of microbiological findings and their relevance in the clinic.

RESULTS

Lack of microbiological awareness in the clinical setting proved to be the key reason for an overall inadequate use of anti-infectives (35.4% of cases rated as inadequate), ahead of the aspects of dose (24.1%), empirical therapy (20.3%) and treatment duration (20.2%). This was particularly the case for broad-acting agents and was most evident in urinary tract infections, skin and soft tissue infections, and pneumonia. The results of the questionnaire indicate a discrepancy between the physicians surveyed and the routine clinical setting.

CONCLUSION

A high potential in improving the use of anti-infectives in hospitals seems to lie in a strong emphasis on microbiological diagnostic stewardship measures.

Impact of restrictive urinalysis reflex to culture criteria at a large community hospital

Treatment of asymptomatic bacteriuria (ASB) is a common, but often unnecessary, practice. Our objective was to determine the impact of restrictive urinalysis reflex to culture (UARC) criteria on rate of urine cultures (UC) ordered and ASB treatment. Criteria were modified from positive leukocyte esterase, positive nitrites, or white blood cells (WBC) >10 cells to only WBC >10 cells. This pre-post study evaluated UARCs ordered in the emergency department or inpatient units. The primary outcome was the proportion of reflex UCs prevented. Secondary outcomes included the frequency of repeat UARCs and stand-alone UCs, gram-negative rod (GNR) bacteremia, and ASB treatment. In the pre-intervention, there were 4761 UARCs compared to 5420 in the post-intervention; 37.9 % and 21.4 % reflexed to UCs, a 43.5 % reduction in UCs. The rate of repeat UARCs, stand-alone UCs, and GNR bacteremia in the pre- and post-interventions were similar. ASB treatment rate was numerically lower in the post-intervention.

Diagnostic stewardship to improve patient outcomes and healthcare-associated infection (HAI) metrics

Diagnostic stewardship seeks to improve ordering, collection, performance, and reporting of tests. Test results play an important role in reportable HAIs. The inclusion of HAIs in public reporting and pay for performance programs has highlighted the value of diagnostic stewardship as part of infection prevention initiatives. Inappropriate testing should be discouraged, and approaches that seek to alter testing solely to impact a reportable metric should be avoided. HAI definitions should be further adapted to new testing technologies, with focus on actionable and clinically relevant test results that will improve patient care.

Positive predictive value of urine analysis with reflex criteria at a large community hospital

INTRODUCTION AND HYPOTHESIS

Urine analysis with reflex to culture (URTC) is employed as a diagnostic aid for urinary tract infections (UTIs). Criteria utilized to determine whether a urine analysis (UA) will reflex varies owing to a lack of evidence-based guidance. Positive predictive value (PPV) of URTC varies across studies. The URTC criteria in this study included moderate or more white blood cells (> 5 high-power field [HPF]), few or more bacteria (> 1 HPF), and few or no epithelial cells (< 3 HPF). The purpose of this study was to determine the extent to which URTC predicts culture positivity.

METHODS

This study was a single-center, retrospective evaluation at a large community hospital. A report of URTC ordered in adults in October 2020 was generated from the hospital's electronic database. The primary outcome was to determine the PPV of URTC criteria. The secondary outcome was to examine the differences in microscopic UA results between culture-positive and culture-negative urine. A total of 350 patients were included for analysis. The data was analyzed through descriptive statistics, Mann-Whitney U test, and multivariate logistic regression.

RESULTS

The results showed a PPV of 58%. Variables predicting negative culture included younger patients, males, and a reason for the visit to the emergency department of a fall/syncope or other.

CONCLUSIONS

Further optimization is needed for URTC criteria and the appropriateness of ordering UAs to reduce operational laboratory costs and inappropriate antibiotic treatment.

A decade of clinical microbiology: top 10 advances in 10 years: what every infection preventionist and antimicrobial steward should know

The past 10 years have brought paradigm-shifting changes to clinical microbiology. This paper explores the top 10 transformative innovations across the diagnostic spectrum, including not only state of the art technologies but also preanalytic and post-analytic advances. Clinical decision support tools have reshaped testing practices, curbing unnecessary tests. Innovations like broad-range polymerase chain reaction and metagenomic sequencing, whole genome sequencing, multiplex molecular panels, rapid phenotypic susceptibility testing, and matrix-assisted laser desorption ionization time-of-flight mass spectrometry have all expanded our diagnostic armamentarium. Rapid home-based testing has made diagnostic testing more accessible than ever. Enhancements to clinician-laboratory interfaces allow for automated stewardship interventions and education. Laboratory restructuring and consolidation efforts are reshaping the field of microbiology, presenting both opportunities and challenges for the future of clinical microbiology laboratories. Here, we review key innovations of the last decade.

Severe Acute Respiratory Syndrome Coronavirus 2 in Infants Younger Than 90 Days Presenting to the Pediatric Emergency Department: Clinical Characteristics and Risk of Serious Bacterial Infection

OBJECTIVES

There are scant data on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in infants younger than 90 days. This study was designed to characterize COVID-19 presentation and clinical course in this age group and evaluate the risk of serious bacterial infection.

METHODS

Data on all SARS-CoV-2-polymerase chain reaction-positive infants presenting to the pediatric emergency department (PED) were retrospectively collected, followed by a case-control study comparing those infants presenting with fever (COVID group) to febrile infants presenting to the PED and found to be SARS-CoV-2 negative (control group).

RESULTS

Of the 96 PCR-positive SARS-CoV-2 infants who met the inclusion criteria, the most common presenting symptom was fever (74/96, 77.1%) followed by upper respiratory tract infection symptoms (42/96, 43.8%). Four (4.2%) presented with symptoms consistent with brief resolved unexplained event (4.2%).Among the febrile infants, the presenting symptoms and vital signs were similar in the COVID and control groups, with the exception of irritability, which was more common in the control group (8% and 26%; P < 0.01). The SARS-CoV-2-positive infants had decreased inflammatory markers including: C-reactive protein (0.6 ± 1 mg/dL vs 2.1 ± 2.7 mg/dL; P < 0.0001), white blood cell count (9.3 ± 3.4 × 10 9 /L vs 11.8 ± 5.1 × 10 9 /L; P < 0.001), and absolute neutrophils count (3.4 ± 2.4 × 10 9 /L vs 5.1 ± 3.7 × 10 9 /L; P < 0.001). The rate of invasive bacterial infection was similar between groups (1.4% and 0%; P = 0.31). No mortality was recorded. Although not significantly different, urinary tract infections were less common in the COVID group (7% and 16%; P = 0.07).

CONCLUSIONS

The SARS-CoV-2 infection in infants aged 0 to 90 days who present to the PED seems to be mostly mild and self-limiting, with no increased risk of serious bacterial infection.

Improving antimicrobial use through better diagnosis: The relationship between diagnostic stewardship and antimicrobial stewardship

Antimicrobial stewardship programs (ASPs) exist to optimize antibiotic use, reduce selection for antimicrobial-resistant microorganisms, and improve patient outcomes. Rapid and accurate diagnosis is essential to optimal antibiotic use. Because diagnostic testing plays a significant role in diagnosing patients, it has one of the strongest influences on clinician antibiotic prescribing behaviors. Diagnostic stewardship, consequently, has emerged to improve clinician diagnostic testing and test result interpretation. Antimicrobial stewardship and diagnostic stewardship share common goals and are synergistic when used together. Although ASP requires a relationship with clinicians and focuses on person-to-person communication, diagnostic stewardship centers on a relationship with the laboratory and hardwiring testing changes into laboratory processes and the electronic health record. Here, we discuss how diagnostic stewardship can optimize the "Four Moments of Antibiotic Decision Making" created by the Agency for Healthcare Research and Quality and work synergistically with ASPs.

[Diagnostic Stewardship - The right test for the right patient with the right consequences]

In 2023, the Society for Healthcare Epidemiology of America (SHEA) Task Force issued a practice recommendation on the integration of diagnostic stewardship into antibiotic stewardship (ABS) programs, which focuses on optimizing sample collection, processing, and reporting to ensure a correct test result on the one hand, and on the justifying indication to perform diagnostics on the other.Unnecessary microbiological or serological tests produce results that can then lead to unnecessary further tests for clarification or unnecessary antibiotic administration. A classic example is "routine" urine cultures before non-urological, surgical interventions, which often lead to the treatment of asymptomatic bacteriuria. Every microbiological diagnosis must therefore be preceded by a specific question, whereby screening examinations from epidemiological questions must be clearly distinguished from clinical requirements. A particular problem is the distinction between contamination, colonization and infection, especially when samples are taken from catheters or drains. These materials should always be evaluated with extreme caution and may only be accepted at all if the clinical question is clear and subject to this very reservation. This article summarizes the existing evidence on diagnostic stewardship interventions and recommendations on their implementation, extrapolating the international literature to the specifications of the German health care system.

Leveraging diagnostic stewardship within antimicrobial stewardship programmes

Novel diagnostic stewardship in infectious disease consists of interventions that modify ordering, processing, and reporting of diagnostic tests to provide the right test for the right patient, prompting the right action. The interventions work upstream and synergistically with traditional antimicrobial stewardship efforts. As diagnostic stewardship continues to gain public attention, it is critical that antimicrobial stewardship programmes not only learn how to effectively leverage diagnostic testing to improve antimicrobial use but also ensure that they are stakeholders and leaders in developing new diagnostic stewardship interventions within their institutions. This review will discuss the need for diagnostic and antimicrobial stewardship, the interplay of diagnostic and antimicrobial stewardship, evidence of benefit to antimicrobial stewardship programmes, and considerations for successfully engaging in diagnostic stewardship interventions. This article is part of the Antibiotic stewardship Special Issue: https://www.drugsincontext.com/special_issues/antimicrobial-stewardship-a-focus-on-the-need-for-moderation.

Effecting the culture: Impact of changing urinalysis with reflex to culture criteria on culture rates and outcomes

OBJECTIVE

To evaluate the impact of changes to urinalysis with reflex to culture (UARC) reflex criteria on culture performance and clinical decision outcomes.

DESIGN

Retrospective study utilizing interrupted time series analysis from December 2018 to November 2020. Primary outcomes were measures of culture performance. Secondary outcomes were rates of antimicrobial prescription for suspected urinary tract infection (UTI) and catheter-associated urinary tract infection (CAUTI). We also assessed harmful events related to antimicrobial prescription for all causes and UTI, UTI symptoms, and sepsis.

SETTING

A 415-bed, academic, tertiary-care, medical center.

PATIENTS

Hospitalized adult patients with urine testing performed.

INTERVENTION

UARC reflex criteria were changed on October 22, 2019, from ≥5×109/L white blood cells (WBCs) or trace leukocyte esterase or positive nitrite units on urinalysis to only ≥15×109/L WBCs.

RESULTS

The study included 11,322 unique UARC tests. We detected a significant decrease in the rate of urine cultures performed from UARC after the intervention (32.5-8.7 cultures per 1,000 patient days; P < .001), with improved diagnostic efficacy (ie, culture positivity increased from 34.8% to 62.1%). CAUTI rates did not change. We detected a significant decrease in antimicrobial prescription rates (P = .05), this was primarily driven by preintervention changes. One case of sepsis occurred secondary to a missed UTI, and UTIs were rarely missed after the intervention.

CONCLUSIONS

Implementation of a stricter UARC reflex criterion was associated with a decrease in culture rates with improved diagnostic efficacy without significant adverse events. Continued education is needed to change antimicrobial prescribing practices.

Can Electronic Clinical Decision Support Systems Improve the Diagnosis of Urinary Tract Infections? A Systematic Review and Meta-Analysis

Background

Urinary tract infection (UTI) is a commonly misdiagnosed infectious syndrome. Diagnostic stewardship interventions can reduce rates of asymptomatic bacteriuria treatment but are often labor intensive, and thus an automated means of reducing unnecessary urine testing is preferred. In this systematic review and meta-analysis, we sought to identify studies describing interventions utilizing clinical decision support (CDS) to optimize UTI diagnosis and to characterize the effectiveness of these interventions.

Methods

We conducted a comprehensive electronic search and manual reference list review for peer-reviewed articles published before July 2, 2021. Publications describing an intervention intending to enhance UTI diagnosis via CDS were included. The primary outcome was urine culture test rate.

Results

The electronic search identified 5013 studies for screening. After screening and full-text review, 9 studies met criteria for inclusion, and a manual reference list review identified 5 additional studies, yielding a total of 14 studies included in the systematic review. The most common CDS intervention was urinalysis with reflex to urine culture based on prespecified urinalysis parameters. All 9 studies that provided statistical comparisons reported a decreased urine culture rate postintervention, 8 of which were statistically significant. A meta-analysis including 4 studies identified a pooled urine culture incidence rate ratio of 0.56 (95% confidence interval, .52-.60) favoring the postintervention versus preintervention group.

Conclusions

In this systematic review and meta-analysis, CDS appeared to be effective in decreasing urine culture rates. Prospective trials are needed to confirm these findings and to evaluate their impact on antimicrobial prescribing, patient-relevant outcomes, and potential adverse effects.

Asymptomatic Bacteriuria: Prevalence, Diagnosis, Management, and Current Antimicrobial Stewardship Implementations

Asymptomatic bacteriuria is a common clinical condition that often leads to unnecessary treatment. It has been shown that incidence of asymptomatic bacteriuria increases with age and are more prominent in women than men. In older women, the incidence of asymptomatic bacteriuria is recorded to be more than 15%. This number increased up to 50% for those who reside in long-term care facilities. In most scenarios, asymptomatic bacteriuria does not lead to urinary tract infections, and therefore, antibiotic treatment of asymptomatic bacteriuria has not been shown to improve patient outcomes. In 2019, the Infectious Disease Society of America (IDSA) updated its asymptomatic bacteriuria management guidelines, which emphasized on the risks and benefits of treating the condition. Women who are pregnant should be screened for asymptomatic bacteriuria in the first trimester and treated, if positive. Individuals who are undergoing endoscopic urologic procedures should be screened and treated appropriately for asymptomatic bacteriuria as well. Treating asymptomatic bacteriuria in individuals with diabetes, neutropenia, spinal cord injuries, indwelling urinary catheters, and so on has not been found to improve clinical outcomes. Furthermore, unnecessary treatment is often associated with unwanted consequences including but not limited to increased antimicrobial resistance, Clostridioides difficile infection, and increased health care cost. As a result, multiple antibiotic stewardship programs around the US have implemented protocols to appropriately reduce unnecessary treatment of asymptomatic bacteriuria. It is important to appropriately screen and treat asymptomatic bacteriuria only when there is evidence of potential benefit.

Impact of provider-selected indication requirement on urine test utilization and positivity

OBJECTIVE

To evaluate the impact of the addition of an indication specification requirement to isolated urine-culture ordering on testing utilization.

DESIGN

Retrospective study utilizing interrupted time series analysis with negative binomial regression. The preintervention period was October 1, 2018-November 11, 2019, and the postintervention period was November 12, 2019-October 31, 2020. The primary outcome was isolated culture rate per 1,000 patient days. Secondary outcomes were the proportion of all urine tests ordered as isolated urine culture and culture positivity. An exploratory analysis assessed the appropriateness of selected testing indications.

SETTING

A 415-bed, urban, academic medical center.

PATIENTS

Adult patients with urine testing performed during hospital admission. In total, 1,494 unique isolated urine-culture orders were included in the analysis.

INTERVENTIONS

On November 12, 2019, the laboratory order interface was changed to require the ordering provider to select an indication for isolated urine culture.

RESULTS

Isolated urine-culture rates did not significantly change after the intervention (11.2-7.8 cultures per 1,000 patient days; P = .17) nor did culture positivity (26.9% vs 26.8%). Most ordering providers left the indication for testing blank, and of those charts reviewed, 67% did not have a documented condition for which isolated urine culture was the most appropriate initial test.

CONCLUSIONS

The addition of an order-specification requirement for isolated urine-culture testing did not significantly affect ordering practices. The test remains overused as the initial diagnostic evaluation for a suspected urinary tract infection. Further provider education and continued changes in provider workflow are needed to achieve lasting change in practice.

Optimal Urine Culture Diagnostic Stewardship Practice- Results from an Expert Modified-Delphi Procedure

BACKGROUND

Urine cultures are nonspecific for infection and often lead to misdiagnosis of urinary tract infection and unnecessary antibiotics. Diagnostic stewardship is a set of procedures that modifies test ordering, processing, and reporting in order to optimize diagnosis and downstream treatment. This study aimed to develop expert guidance on best practices for urine culture diagnostic stewardship.

METHODS

A RAND-modified Delphi approach with a multidisciplinary expert panel was used to ascertain diagnostic stewardship best practices. Clinical questions to guide recommendations were grouped in three thematic areas (ordering, processing, reporting) in practice settings of emergency department, inpatient, ambulatory, and long-term care. Fifteen experts ranked recommendations on a 9-point Likert scale. Recommendations on which the panel did not reach agreement were discussed in a virtual meeting, and a then second round of ranking by email was completed. After secondary review of results and panel discussion, a series of guidance statements was developed.

RESULTS

165 questions were reviewed with the panel reaching agreement on 104, leading to 18 overarching guidance statements. The following strategies were recommended to optimize ordering urine cultures: requiring documentation of symptoms, alerts to discourage ordering in the absence of symptoms, and cancelling repeat cultures. For urine culture processing, conditional reflex urine cultures and urine white blood cell as criteria were supported. For urine culture reporting, appropriate practices included nudges to discourage treatment under specific conditions and selective reporting of antibiotics to guide therapy decisions.

CONCLUSIONS

These 18 guidance statements can optimize use of the imperfect urine culture for better patient outcomes.

Revisiting approaches to and considerations for urinalysis and urine culture reflexive testing

Urinalysis is considered the world's oldest laboratory test. Today, many laboratories use macroscopic urinalysis as a screening tool to determine when to subject urine samples for a microscopic urinalysis and/or bacterial culture. While reflexive urine microscopy has been practiced for decades, and reflexive urine culture, more recently, evidence-based guidelines regarding optimal reflexive criteria and workflows are lacking. Standard approaches are hindered, in part, by a lack of harmonization of urinalysis and urine culture practices, heterogeneity in patient populations that are studied, and lack of provider adherence to recommended practices. This review summarizes studies that have evaluated the performance of reflexive urine microscopy and reflexive urine culture, particularly in the context of urinary tract infections. It also examines reported clinical outcomes from reflexive urinalysis interventions and their impact on antibiotic stewardship efforts. Finally, it discusses laboratory operational considerations for the implementation of reflexive algorithms.