Investigating risk factors for urine culture contamination in outpatient clinics: A new avenue for diagnostic stewardship

Abstract

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.

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

“…Overall, >40% of our samples grew mixed urine cultures, but this finding is consistent with rates of mixed urine cultures reported by other large academic medical centers and outpatient clinics. 7 Our data on risk factors for mixed urine cultures have been previously described, but these studies did not include data on delays in collection or transport across the health system. 7 We could not include all urinalysis orders in our analyses; instead we paired urinalysis with urine cultures ordered within a 24-hour period to replicate how clinicians and laboratories would use reflex urine cultures in real life.…”

“…7 Our data on risk factors for mixed urine cultures have been previously described, but these studies did not include data on delays in collection or transport across the health system. 7 We could not include all urinalysis orders in our analyses; instead we paired urinalysis with urine cultures ordered within a 24-hour period to replicate how clinicians and laboratories would use reflex urine cultures in real life. Lastly, we were not able to assess for ASB versus UTI, and instead used significant bacteriuria as our outcome for 2 reasons.…”

“…Mixed urine cultures were defined by Duke University Microbiology Laboratory as the presence of 2 or more organisms when all organisms were nonsignificant (not a known uropathogen) or when one of the organisms was considered a significant uropathogen but was in lesser quantity (∼10-fold fewer) than the concentration of the nonsignificant organisms (eg, 1,000 CFU/mL significant organisms compared with 10,000 CFU/mL of nonsignificant organisms). 7 Low-level pyuria on urinalysis (predictor variable of interest) was defined as WBC ≥ 5 per high-powered field (hpf). Low-level bacteriuria on urinalysis was defined as 5-50 bacteria per hpf.…”

Using the COM-B model to identify barriers to and facilitators of evidence-based nurse urine-culture practices

“… 3 , 4 In addition, poor collection techniques may lead to contaminated or false-positive results, further complicating the clinician’s ability to interpret a urine-culture result. 5 …”

“…3,4 In addition, poor collection techniques may lead to contaminated or false-positive results, further complicating the clinician's ability to interpret a urine-culture result. 5 Prior data related to nurse-driven urine-culture practices have primarily focused on assessing knowledge, with little investigation into social, environmental, and cultural barriers that influence these practices. 4,6 The Capability, Opportunity, Motivation and Behavior (COM-B) model examines the interactions among 3 components: capability, opportunity, and motivation on behavior.…”