New best practice guidance encourages stewardship of urine culture orders

New guidance offered recommendations for diagnostic stewardship of urine cultures in both inpatient and outpatient settings.

A multidisciplinary expert panel assessed best practices for urine culture diagnostic stewardship, defined as a set of procedures that modifies test ordering, processing, and reporting with the aim of optimizing diagnosis and downstream treatment. Fifteen experts reviewed clinical questions grouped into three categories (ordering, processing, reporting) in emergency, inpatient, ambulatory, and long-term care practice settings, ranking each recommendation on a nine-point Likert scale. The panel reached agreement on 104 of 165 questions, producing 18 overarching guidance statements that were published by Clinical Infectious Diseases on Nov. 29.

For diagnostic stewardship of urine culture ordering, the panel recommended requiring documentation of urinary tract infection (UTI) signs or symptoms (e.g., dysuria, flank pain), using alerts to discourage ordering in their absence, and canceling repeat cultures within five days of a positive culture during the same hospital admission. The panel also recommended replacing stand-alone urine culture orders with conditional reflex urine cultures, defined as cultures that, although ordered by a clinician, are only performed after specific criteria are met on urinalysis (e.g., white blood cell count >10/hpf), except in patients undergoing urological procedures. Clinicians should not order urine cultures in response to a change in urine characteristics, and urine cultures should not be included in standard order sets for hospital admission, inpatient pre-op, or assessment of altered mental status, the guidance said.

The panel recommended the following practices for urine culture processing in patients with UTI symptoms: using elevated urine white blood cell count as a criterion to reflex to urine culture when a clinician orders a urine culture in any health care setting and requiring documentation of collection site method (e.g., clean catch) prior to processing cultures. An inappropriate practice would be to automatically reflex routine urinalyses to urine cultures for abnormal findings in cases when a urine culture was not specifically requested by the ordering clinician, according to the guidance.

For urine culture reporting, the panel recommended that urine culture reports differentiate typical uropathogens versus contaminants, nudge clinicians to avoid treating asymptomatic bacteriuria or mixed flora, and inform clinicians that even high colony counts (e.g., >100,000 CFU) may not represent true infection in the absence of symptoms or signs. Due to expert disagreement, these recommendations do not extend to those undergoing a urological procedure. The panel also recommended selective reporting of antibiotics, withholding culture results in the presence of more than two unique bacterial strains, and withholding fluoroquinolone susceptibilities unless there is resistance to preferred oral antibiotics. Inappropriate reporting practices included nudging clinicians not to treat if there are less than 100,000 CFU of bacteria.

“These recommendations are the first expert-based guidance to formally examine these interventions with the aim of standardizing diagnostic stewardship practices to improve testing and treatment of UTIs,” the authors concluded. “These recommendations can optimize use of this non-specific test for better patient outcomes.”