Diagnosis of urinary tract infections: need for a reflective rather than reflexive approach

Appropriate prescription of cytobacteriological urine examinations in older adults

Cytobacteriological urine examinations (CBEU) are frequently ordered for the older adults, sometimes without straightforward indication and with the risk of prescribing empirical antibiotics. The aim of this study was to evaluate the relevance of the CBEU prescription and empiric antibiotic therapy in our geriatric hospital. Among 129 patients (mean age 84 years, sex ratio 0.69), 229 CBEU were collected with 20.9% of inappropriate indication. Cultures were sterile in 43% (n = 99) of cases and positive in 57% (n = 130) cases. Gram-negative bacilli dominated the isolated bacteria (76.9%) followed by gram-positive cocci (17.6%). In 113 patients, probabilistic antibiotic therapy was prescribed of which 68 treatments were initiated before the CBEU. Ceftriaxone and amoxicillin plus clavulanic acid were the main therapeutic option used representing 70.8% of cases. Antibiotic therapy was re-evaluated after 3 days in 74.3% of patients. Efforts to reduce the number of useless ECBUs by training doctors to follow official guidelines are a priority.

Bacteremia From a Presumed Urinary Source in Hospitalized Adults With Asymptomatic Bacteriuria

Importance

Guidelines recommend withholding antibiotics in asymptomatic bacteriuria (ASB), including among patients with altered mental status (AMS) and no systemic signs of infection. However, ASB treatment remains common.

Objectives

To determine prevalence and factors associated with bacteremia from a presumed urinary source in inpatients with ASB with or without AMS and estimate antibiotics avoided if a 2% risk of bacteremia were used as a threshold to prompt empiric antibiotic treatment of ASB.

Design, Setting, and Participants

This cohort study assessed patients hospitalized to nonintensive care with ASB (no immune compromise or concomitant infections) in 68 Michigan hospitals from July 1, 2017, to June 30, 2022. Data were analyzed from August 2022 to January 2023.

Main Outcomes and Measures

The primary outcome was prevalence of bacteremia from a presumed urinary source (ie, positive blood culture with matching organisms within 3 days of urine culture). To determine factors associated with bacteremia, we used multivariable logistic regression models. We estimated each patient's risk of bacteremia and determined what percentage of patients empirically treated with antibiotics had less than 2% estimated risk of bacteremia.

Results

Of 11 590 hospitalized patients with ASB (median [IQR] age, 78.2 [67.7-86.6] years; 8595 female patients [74.2%]; 2235 African American or Black patients [19.3%], 184 Hispanic patients [1.6%], and 8897 White patients [76.8%]), 8364 (72.2%) received antimicrobial treatment for UTI, and 161 (1.4%) had bacteremia from a presumed urinary source. Only 17 of 2126 patients with AMS but no systemic signs of infection (0.7%) developed bacteremia. On multivariable analysis, male sex (adjusted odds ratio [aOR], 1.45; 95% CI, 1.02-2.05), hypotension (aOR, 1.86; 95% CI, 1.18-2.93), 2 or more systemic inflammatory response criteria (aOR, 1.72; 95% CI, 1.21-2.46), urinary retention (aOR, 1.87; 95% CI, 1.18-2.96), fatigue (aOR, 1.53; 95% CI, 1.08-2.17), log of serum leukocytosis (aOR, 3.38; 95% CI, 2.48-4.61), and pyuria (aOR, 3.31; 95% CI, 2.10-5.21) were associated with bacteremia. No single factor was associated with more than 2% risk of bacteremia. If 2% or higher risk of bacteremia were used as a cutoff for empiric antibiotics, antibiotic exposure would have been avoided in 78.4% (6323 of 8064) of empirically treated patients with low risk of bacteremia.

Conclusions and Relevance

In patients with ASB, bacteremia from a presumed urinary source was rare, occurring in less than 1% of patients with AMS. A personalized, risk-based approach to empiric therapy could decrease unnecessary ASB treatment.

Impact of COVID-19 pandemic on the rates of central line...associated bloodstream infection and catheter-associated urinary tract infection in an.ßintensive care setting:.ßNational experience

BACKGROUND

COVID-19 is believed to increase the risk of secondary health care...associated infections. The objective was to estimate the impact of COVID-l9 pandemic on the rates of central line...associated bloodstream infection (CLABSI) and catheter-associated urinary tract infections (CAUTIs) in the.ßMinistry of Health hospitals across Saudi Arabia.

METHODS

A retrospective analysis of prospectively collected CLABSI and CAUTI data over a period of 3 years (2019-2021) was done. The data were obtained from the Saudi Health Electronic Surveillance Network. All adult intensive care units in 78 Ministry of Health hospitals that contributed CLABSI or CAUTI data before (2019) and during (2020-2021).ßthe pandemic were included.

RESULTS

During the study, 1440 CLABSI events and 1119 CAUTI events were identified. CLABSI rates significantly increased in 2020-2021 compared with 2019 (2.50 versus 2.16 per 1000 central line days, P.ß=.ß.010). CAUTI rates significantly decreased in 2020-2021 compared with 2019 (0.96 versus 1.54 per 1000 urinary catheter days, P.ß<.ß.001).

CONCLUSIONS

COVID-19 pandemic is.ßassociated with increased CLABSI rates and reduced CAUTI rates. It.ßis believed to have negative impacts on several infection control practices and surveillance accuracy. The opposite impacts of COVID-19 on CLABSI and CAUTI probably reflect.ßthe nature of their case definitions.

A Statewide Quality Initiative to Reduce Unnecessary Antibiotic Treatment of Asymptomatic Bacteriuria

Importance

Hospitalized patients with asymptomatic bacteriuria (ASB) often receive unnecessary antibiotic treatment, which increases antibiotic resistance and adverse events.

Objective

To determine whether diagnostic stewardship (avoiding unnecessary urine cultures) or antibiotic stewardship (reducing unnecessary antibiotic treatment after an unnecessary culture) is associated with better outcomes in reducing antibiotic use for ASB.

Design, Setting, and Participants

This 3-year, prospective quality improvement study included hospitalized general care medicine patients with a positive urine culture among 46 hospitals participating in a collaborative quality initiative, the Michigan Hospital Medicine Safety Consortium. Data were collected from July 1, 2017, through March 31, 2020, and analyzed from February to October 2022.

Exposure

Participation in the Michigan Hospital Medicine Safety Consortium with antibiotic and diagnostic stewardship strategies at hospital discretion.

Main Outcomes and Measures

Overall improvement in ASB-related antibiotic use was estimated as change in percentage of patients treated with antibiotics who had ASB. Effect of diagnostic stewardship was estimated as change in percentage of patients with a positive urine culture who had ASB. Effect of antibiotic stewardship was estimated as change in percentage of patients with ASB who received antibiotics and antibiotic duration.

Results

Of the 14 572 patients with a positive urine culture included in the study (median [IQR] age, 75.8 [64.2-85.1] years; 70.5% female); 28.4% (n = 4134) had ASB, of whom 76.8% (n = 3175) received antibiotics. Over the study period, the percentage of patients treated with antibiotics who had ASB (overall ASB-related antibiotic use) declined from 29.1% (95% CI, 26.2%-32.2%) to 17.1% (95% CI, 14.3%-20.2%) (adjusted odds ratio [aOR], 0.94 per quarter; 95% CI, 0.92-0.96). The percentage of patients with a positive urine culture who had ASB (diagnostic stewardship metric) declined from 34.1% (95% CI, 31.0%-37.3%) to 22.5% (95% CI, 19.7%-25.6%) (aOR, 0.95 per quarter; 95% CI, 0.93-0.97). The percentage of patients with ASB who received antibiotics (antibiotic stewardship metric) remained stable, from 82.0% (95% CI, 77.7%-85.6%) to 76.3% (95% CI, 68.5%-82.6%) (aOR, 0.97 per quarter; 95% CI, 0.94-1.01), as did adjusted mean antibiotic duration, from 6.38 (95% CI, 6.00-6.78) days to 5.93 (95% CI, 5.54-6.35) days (adjusted incidence rate ratio, 0.99 per quarter; 95% CI, 0.99-1.00).

Conclusions and Relevance

This quality improvement study showed that over 3 years, ASB-related antibiotic use decreased and was associated with a decline in unnecessary urine cultures. Hospitals should prioritize reducing unnecessary urine cultures (ie, diagnostic stewardship) to reduce antibiotic treatment related to ASB.

Optimizing reflex urine cultures: Using a population-specific approach to diagnostic stewardship

BACKGROUND

Clinicians and laboratories routinely use urinalysis (UA) parameters to determine whether antimicrobial treatment and/or urine cultures are needed. Yet the performance of individual UA parameters and common thresholds for action are not well defined and may vary across different patient populations.

METHODS

In this retrospective cohort study, we included all encounters with UAs ordered 24 hours prior to a urine culture between 2015 and 2020 at 3 North Carolina hospitals. We evaluated the performance of relevant UA parameters as potential outcome predictors, including sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV). We also combined 18 different UA criteria and used receiver operating curves to identify the 5 best-performing models for predicting significant bacteriuria (≥100,000 colony-forming units of bacteria/mL).

RESULTS

In 221,933 encounters during the 6-year study period, no single UA parameter had both high sensitivity and high specificity in predicting bacteriuria. Absence of leukocyte esterase and pyuria had a high NPV for significant bacteriuria. Combined UA parameters did not perform better than pyuria alone with regard to NPV. The high NPV ≥0.90 of pyuria was maintained among most patient subgroups except females aged ≥65 years and patients with indwelling catheters.

CONCLUSION

When used as a part of a diagnostic workup, UA parameters should be leveraged for their NPV instead of sensitivity. Because many laboratories and hospitals use reflex urine culture algorithms, their workflow should include clinical decision support and or education to target symptomatic patients and focus on populations where absence of pyuria has high NPV.

Recommendations for change in infection prevention programs and practice

Fifty years of evolution in infection prevention and control programs have involved significant accomplishments related to clinical practices, methodologies, and technology. However, regulatory mandates, and resource and research limitations, coupled with emerging infection threats such as the COVID-19 pandemic, present considerable challenges for infection preventionists. This article provides guidance and recommendations in 14 key areas. These interventions should be considered for implementation by United States health care facilities in the near future.

Investigating Risk Factors for Urine Culture Contamination in Outpatient Clinics: A New Avenue for Diagnostic Stewardship

Mixed flora in urine cultures usually occur due to preanalytic contamination. In our outpatient urology clinic, we detected a high prevalence of mixed flora (46.2%), which was associated with female sex and older age. Patient education did not influence the rate of mixed flora. Future efforts should target high-risk patients.

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.

Deconstructing the urinalysis: A novel approach to diagnostic and antimicrobial stewardship

The extensive use of the urinalysis for screening and monitoring in diverse clinical settings usually identifies abnormal urinalysis parameters in patients with no suspicion of urinary tract infection, which in turn triggers urine cultures, inappropriate antimicrobial use, and associated harms like Clostridioides difficile infection. We highlight how urinalysis is misused, and suggest deconstructing it to better align with evolving patterns of clinical use and the differential diagnosis being targeted. Reclassifying the urinalysis components into infectious and non-infectious panels and interpreting urinalysis results in the context of individual patient’s pretest probability of disease is a novel approach to promote proper urine testing and antimicrobial stewardship, and achieve better outcomes.

Quality Improvement Interventions and Implementation Strategies for Urine Culture Stewardship in the Acute Care Setting: Advances and Challenges

PURPOSE OF REVIEW

The goal of this article is to highlight how and why urinalyses and urine cultures are misused, review quality improvement interventions to optimize urine culture utilization, and highlight how to implement successful, sustainable interventions to improve urine culture practices in the acute care setting.

RECENT FINDINGS

Quality improvement initiatives aimed at reducing inappropriate treatment of asymptomatic bacteriuria often focus on optimizing urine test utilization (i.e., urine culture stewardship). Urine culture stewardship interventions in acute care hospitals span the spectrum of quality improvement initiatives, ranging from strong systems-based interventions like suppression of urine culture results to weaker interventions that focus on clinician education alone. While most urine culture stewardship interventions have met with some success, overall results are mixed, and implementation strategies to improve sustainability are not well understood.

SUMMARY

Successful diagnostic stewardship interventions are based on an assessment of underlying key drivers and focus on multifaceted and complementary approaches. Individual intervention components have varying impacts on effectiveness, provider autonomy, and sustainability. The best urine culture stewardship strategies ultimately include both technical and socio-adaptive components with long-term, iterative feedback required for sustainability.

Coronavirus disease 2019 (COVID-19) pandemic, central-line-associated bloodstream infection (CLABSI), and catheter-associated urinary tract infection (CAUTI): The urgent need to refocus on hardwiring prevention efforts

BACKGROUND

The coronavirus disease 2019 (COVID-19) pandemic has had a considerable impact on US hospitalizations, affecting processes and patient population.

OBJECTIVE

To evaluate the impact of COVID-19 pandemic on central-line-associated bloodstream infections (CLABSIs) and catheter associated urinary tract infections (CAUTIs) in hospitals.

METHODS

We performed a retrospective study of CLABSIs and CAUTIs in 78 US 12 months before COVID-19 and 6 months during COVID-19 pandemic.

RESULTS

During the 2 study periods, there were 795,022 central-line days and 817,267 urinary catheter days. Compared to the period before the COVID-19 pandemic, CLABSI rates increased by 51.0% during the pandemic period from 0.56 to 0.85 per 1,000 line days (P < .001) and by 62.9% from 1.00 to 1.64 per 10,000 patient days (P < .001). Hospitals with monthly COVID-19 patients representing >10% of admissions had a National Health Safety Network (NHSN) device standardized infection ratio for CLABSI that was 2.38 times higher than hospitals with <5% prevalence during the pandemic period (P = .004). Coagulase-negative Staphylococcus CLABSIs increased by 130% from 0.07 to 0.17 events per 1,000 line days (P < .001), and Candida spp by 56.9% from 0.14 to 0.21 per 1,000 line days (P = .01). In contrast, no significant changes were identified for CAUTI (0.86 vs 0.77 per 1,000 catheter days; P = .19).

CONCLUSIONS

The COVID-19 pandemic was associated with substantial increases in CLABSIs but not CAUTIs. Our findings underscore the importance of hardwiring processes for optimal line care and regular feedback on performance to maintain a safe environment.

Incidence and Diagnostic Yield of Repeat Urine Culture in Hospitalized Patients: an Opportunity for Diagnostic Stewardship

There is limited knowledge on the incidence, diagnostic yield, and cost associated with inappropriate repeat urine cultures. The factors that affect repeat urine culturing practices are not well understood. We conducted a retrospective study of adult inpatients who had ≥1 urine culture performed during their hospitalization between January 2015 and February 2018. We analyzed the proportion of inappropriate repeat urine cultures performed <48 h after the index culture. We defined an inappropriate repeat urine culture to be a repeat urine culture performed following a negative index culture or a repeat urine specimen obtained from the same urinary catheter. Overall, 28,141 urine cultures were performed on 21,306 patients. There were 2,060 (7.3%) urine cultures repeated in <48 h. Of these, 1,120 (54.4%) urine cultures were inappropriate. Predictors for inappropriate repeat urine cultures included collection of the initial urine sample for culture in the emergency department (adjusted odds ratio [aOR], 5.65; 95% confidence interval [CI], 4.70 to 6.78), male gender (aOR, 1.61; 95% CI, 1.42 to 1.84), congestive heart failure (aOR, 1.20; 95% CI, 1.03 to 1.38), and a longer hospital stay (aOR, 1.01 per day; 95% CI, 1.00 to 1.01). A patient with an index urine culture obtained from an indwelling catheter (aOR, 0.65; 95% CI, 0.53 to 0.80) was less likely to have an inappropriate repeat culture. Among 1,120 negative index urine cultures, only 4.7% of repeat cultures were positive for bacteriuria. The estimated laboratory charges for inappropriate repeat urine cultures were $16,800 over the study period. Among inpatients, over half of all urine cultures repeated in <48 h were inappropriate. This offers an opportunity for diagnostic stewardship and optimization of antimicrobial use.

Knowledge and Practices of Physicians and Nurses Related to Urine Cultures in Catheterized Patients: An Assessment of Adherence to IDSA Guidelines

Background

A positive urine culture often drives initiation of antimicrobials even in the absence of symptoms. Our objectives were to evaluate the knowledge and practice patterns related to ordering urine cultures in patients with indwelling urinary catheters.

Methods

We performed chart reviews of catheter-associated urinary tract infections (CAUTIs) at our academic health care system between October 1, 2015, and September 30, 2017, to assess practice patterns related to the assessment of potential CAUTIs. Following this, we surveyed physicians and nurses about indications for ordering urine cultures in catheterized patients between January 11, 2018, and April 17, 2018. The accuracy of these indications was assessed based on Infectious Diseases Society of America CAUTI and asymptomatic bacteriuria guidelines.

Results

On chart review, we identified 184 CAUTIs in 2 years. In 159 episodes (86%), urine cultures were ordered inappropriately. In 114 episodes (62%), CAUTI criteria were met by “pan-culturing” rather than symptom-directed testing. Twenty cases (11%) experienced partial or delayed management of other infections, drug adverse events, and Clostridioides difficile infections (CDIs). On our survey, we received 405 responses, for a response rate of 45.3%. Mean scores varied by occupation and level of training. Nurses were more likely than physicians to consider change in appearance (61% vs 23%; P < .05) and odor (74% vs 42%; P < .05) of urine as indications to order urine cultures.

Conclusions

Our data reveal specific knowledge gaps among physicians and nurses related to ordering urine cultures in catheterized patients. The practice of pan-culturing and inappropriate urine culture orders may contribute to overdiagnosis of surveillance CAUTIs, delay in diagnosis of alternative infections, and excess CDIs.