Inpatient Urine Cultures Are Frequently Performed Without Urinalysis or Microscopy: Findings From a Large Academic Medical Center

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.

Asymptomatic bacteriuria among medical inpatients: Data from an Indian teaching hospital

Studies indicate that asymptomatic bacteriuria in medical inpatients is often inappropriately treated with antibiotics. We prospectively studied the proportion of asymptomatic bacteriuria among 200 positive urine cultures which were ordered in hospitalised medical inpatients of a teaching hospital in southern India. We used pre-defined criteria to classify patients as urinary tract infection and asymptomatic bacteriuria. Median age of patients was 53.5 (42-65) years, and 51% were male. In all, 157 (78.5%) patients had urinary tract infection (131 [66.5%] definite and 26 [13%] probable) and 43 (21.5%) had asymptomatic bacteriuria. In patients with asymptomatic bacteriuria, 18 (41.8%) received urinary tract infection-directed antibiotics; broad spectrum antibiotics were used in 10 (23%). Patients with asymptomatic bacteriuria were younger, more likely to be on a urinary catheter, had higher prevalence of chronic kidney disease and congestive cardiac failure and had lower prevalence of pyuria and lower total leucocyte counts. Urine cultures should be ordered only in indicated patients. Inappropriate antibiotic treatment in patients with asymptomatic bacteriuria should be avoided.

Multimodal Intervention Approach Reduces Catheter-associated Urinary Tract Infections in a Rural Tertiary Care Center

OBJECTIVE

To compare the catheter-associated urinary tract infections (CAUTI) standardized infection rate (SIR) before and after implementation of a multimodal intervention approach in a rural tertiary hospital.

DESIGN

Before-after analysis of a multimodal intervention to evaluate primary outcomes of the incidence of inpatient CAUTI, the SIR for CAUTI, and number of urinary catheter days.

SETTING

All inpatient departments of a rural 504-bed tertiary care facility in the Midwest.

PARTICIPANTS

Patients admitted for in-patient care.

INTERVENTIONS

A multimodal intervention composed of: (a) physician and nurse education, (b) modification of progress note templates and daily provider reminders for the clinical necessity of catheters, (c) implementing established best practices for eliminating CAUTIs, (d) advocating for alternative toileting options, and (e) promoting aseptic techniques for insertion and removal of catheters. SIR, CAUTI, and the number of urinary catheter days were obtained before and after implementation of the multimodal intervention in 2015 and 2017, respectively.

RESULTS

After a one-year timeframe of intervention, CAUTI event rates decreased, and SIR for CAUTI was reduced by 60.2% (from 1.524 to 0.607) with P value<0.05. Urinary catheter days were also reduced from 16,195 in 2015 to 13,348 in 2017 (17.6% reduction) with P value <0.05.

CONCLUSIONS

Incidence of CAUTIs were significantly reduced with a team effort involving infection control, physician and nursing education, modification of progress note and templates and daily provider reminders for the clinical necessity of catheters and appropriate usage of urinary catheter with corresponding reduction in urinary catheter days.

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.

Evaluation of Acridine Orange Staining for a Semi-Automated Urinalysis Microscopic Examination at the Point-of-Care

A urinary tract infection (UTI) can be diagnosed via urinalysis, consisting of a dipstick test and manual microscopic examination. Point-of-care (POC) image-based systems have been designed to automate the microscopic examination for low-volume laboratories or low-resource clinics. In this pilot study, acridine orange (AO) was evaluated as a fluorescence-based contrast agent to aid in detecting and enumerating urine sediment specific for diagnosing a UTI. Acridine orange staining of epithelial cells, leukocytes, and bacteria provided sufficient contrast to successfully implement image segmentation techniques, which enabled the extraction of classifiable morphologic features. Surface area bounded by each cell border was used to differentiate the sediment; epithelial cells were larger than 500μm², bacteria were less than 30μm², and leukocytes in between. This image-based semi-automated technique using AO resulted in similar cell counts to the clinical results, which demonstrates the feasibility of AO as an aid for POC urinalysis systems.

Effect of changing urine testing orderables and clinician order sets on inpatient urine culture testing: Analysis from a large academic medical center

OBJECTIVE

To evaluate the impact of changes to urine testing orderables in computerized physician order entry (CPOE) system on urine culturing practices.

DESIGN

Retrospective before-and-after study.

SETTING

A 1,250-bed academic tertiary-care referral center.

PATIENTS

Hospitalized adults who had ≥1 urine culture performed during their stay.

INTERVENTION

The intervention (implemented in April 2017) consisted of notifications to providers, changes to order sets, and inclusion of the new urine culture reflex tests in commonly used order sets. We compared the urine culture rates before the intervention (January 2015 to April 2016) and after the intervention (May 2016 to August 2017), adjusting for temporal trends.

RESULTS

During the study period, 18,954 inpatients (median age, 62 years; 68.8% white and 52.3% female) had 24,569 urine cultures ordered. Overall, 6,662 urine cultures (27%) were positive. The urine culturing rate decreased significantly in the postintervention period for any specimen type (38.1 per 1,000 patient days preintervention vs 20.9 per 1,000 patient days postintervention; P &lt; .001), clean catch (30.0 vs 18.7; P &lt; .001) and catheterized urine (7.8 vs 1.9; P &lt; .001). Using an interrupted time series model, urine culture rates decreased for all specimen types (P &lt; .05).

CONCLUSIONS

Our intervention of changes to order sets and inclusion of the new urine culture reflex tests resulted in a 45% reduction in the urine cultures ordered. CPOE system format plays a vital role in reducing the burden of unnecessary urine cultures and should be implemented in combination with other efforts.