Urine Culture Testing in Community Nursing Homes: Gateway to Antibiotic Overprescribing

Abstract

OBJECTIVE To describe current practice around urine testing and identify factors leading to overtreatment of asymptomatic bacteriuria in community nursing homes (NHs) DESIGN Observational study of a stratified random sample of NH patients who had urine cultures ordered in NHs within a 1-month study period SETTING 31 NHs in North Carolina PARTICIPANTS 254 NH residents who had a urine culture ordered within the 1-month study period METHODS We conducted an NH record audit of clinical and laboratory information during the 2 days before and 7 days after a urine culture was ordered. We compared these results with the urine antibiogram from the 31 NHs. RESULTS Empirical treatment was started in 30% of cases. When cultures were reported, previously untreated cases received antibiotics 89% of the time for colony counts of ≥100,000 CFU/mL and in 35% of cases with colony counts of 10,000-99,000 CFU/mL. Due to the high rate of prescribing when culture results returned, 74% of these patients ultimately received a full course of antibiotics. Treated and untreated patients did not significantly differ in temperature, frequency of urinary signs and symptoms, or presence of Loeb criteria for antibiotic initiation. Factors most commonly associated with urine culture ordering were acute mental status changes (32%); change in the urine color, odor, or sediment (17%); and dysuria (15%). CONCLUSIONS Urine cultures play a significant role in antibiotic overprescribing. Antibiotic stewardship efforts in NHs should include reduction in culture ordering for factors not associated with infection-related morbidity as well as more scrutiny of patient condition when results become available. Infect Control Hosp Epidemiol 2017;38:524-531.

Urinary Tract Infection and Asymptomatic Bacteriuria in Older Adults

“…A prospective study in five nursing included 397 suspected episodes of UTI and did not find an association between falls and the presence of bacteriuria plus pyuria [54]. Urine turbidity, sediment color and odor do not reliably correlate with the presence of infection and are not in themselves symptoms of UTI; they are, however, associated with antibiotic overprescribing [55–57]. Such changes in urine may suggest a need for increased oral hydration, reflecting a decreased thirst response in older adults, or may be due to their medications ( e.g ., multivitamins) or diet ( e.g ., asparagus).…”

“…In patients who lack pyuria, attention should be turned away from UTI and toward other diagnostic considerations, except in rare cases where neutropenia or other conditions may prevent pyuria. This algorithmic approach combining the urinalysis and urine culture offers both excellent sensitivity and specificity for UTI, with the reflex criteria averting inappropriate urine culture orders, a primary driver of unnecessary antibiotic prescription in patients with ASB [57–58]. …”

The Urine-culturing Cascade: Variation in Nursing Home Urine Culturing and Association With Antibiotic Use and Clostridiodes difficile Infection

“…In this case, residing in a high urine culturing facility results in an increased likelihood of receiving a urine culture, an increased likelihood of receiving an antibiotic, and ultimately, an increased likelihood of C. difficile infection. Because a urine culture order often triggers an antibiotic prescription, urine culturing has been termed a "gateway" to antibiotic use overuse [18]. Interventions that address the appropriateness of urine culturing in nursing homes are important quality improvement initiatives that can prevent unnecessary antibiotic use, and antibiotic associated adverse events including C. difficile infection [26,27].…”

“…When asked, nurses and physicians often list collection of urine culture as the first diagnostic step in the evaluation of a suspected urinary tract infection, and indicate they would treat asymptomatic bacteriuria [16]. It follows that a large portion (69%) of antibiotic prescribing for presumed urinary tract infection is inappropriate [17,18]. Despite this, little is known about the extent of variation in urine culturing practices in nursing homes, and their association with antibiotic use.…”

Progress and Challenges in the Management of Nursing Home Infections

“…However, overculturing or misinterpretation of culture results can lead to antibiotic misuse and contribute to the development of MDROs. 37 Therefore, appropriate use of microbial cultures is important in optimizing antibiotic use and often involves policy and practice changes such as removing policies that promote automatic culturing, introducing diagnostic algorithms, and creating alternative order sets promoting close monitoring over antibiotic prescribing when cultures are positive but patients are not ill. 38 This issue of JAMDA contains 2 articles that add to this knowledge baseda study documenting that hospital and nursing home cultures may differ markedly within the same geographic region 39 and a report indicating that microbial culture rates in US Veterans Affairs nursing homes have declined, likely in response to initiatives aimed at decreasing unnecessary cultures 15 dplus an editorial that provides guidance for nursing homes on best practices regarding antibiograms. 40…”