Diagnostic stewardship of urine cultures

Background

Asymptomatic bacteriuria is common, but positive urine cultures are still often inappropriately treated
The process of inappropriately treating asymptomatic bacteriuria can be interrupted at the culture collection stage

The following practices are recommended:
- Require documentation of signs or symptoms of UTI to obtain a urine culture, including dysuria or flank pain
  - Patients without urinary catheters
    - Appropriate signs and symptoms include dysuria, suprapubic pain, flank pain, CVA tenderness, or septic shock
    - Signs and symptoms of uncertain appropriateness include fever or leukocytosis with unknown cause
    - Inappropriate signs and symptoms include altered mental status or change in urine characteristics
  - Patients with urinary catheters are as above, except that delirium is of uncertain appropriateness
- Replace stand-alone urine culture orders with conditional reflex urine cultures
  - Direct urine culture may still need to be available to urology and obstetrics
  - Criteria for reflex culture is not standardized; elevated WBC count ≥10-50 is appropriate, but unclear whether leukocyte esterase or urine nitrate was appropriate
- Implement best practice alerts to discourage ordering urine cultures in the abscence of signs or symptoms of UTI
- Automatically cancel repeat urine cultures within 5 days of a positive culture (during the same hospital admission and 7 days for long-term care residents)
As well, urine cultures should not be included in any standardized order sets except for septic shock
Urine cultures should not be collected in response to a change in urine characteristics

The following practices are recommended:
- Use elevated urine WBC as a criterion to reflex process a urine culture when the clinician orders a urine culture
  - See section above for further detail
- Require documentation of collection site and method (e.g. clean catch) prior to processing urine culture
Reflex urine cultures should not be done on a urinalysis where the clinician did not specifically request culture

The following practices are recommended:
- Report that even high colony counts may not represent true infection in the absence of signs or symptoms
- Nudge clinicians to not treat asymptomatic bacteriuria or mixed flora
- Differentiate typical uropathogens from contaminants
- Without urine culture results when there are more than 2 unique bacterial strains in culture
- Report only recommended antibiotics if the organism is susceptible
- Withhold fluoroquinolone susceptibilities unless there is resistance to preferred oral antibiotics
The reports should not nudge clinicians to not treat based on low colony counts, either
Reports should not withhold information about organism identification or antibiotics susceptibilities unless the clinician calls the microbiology lab