Asymptomatic bacteriuria and antibiotic Use in nursing homes

Background: Overuse of antibiotics is a longstanding concern in nursing homes. As part of a project on antibiotic stewardship, we investigated the use of antibiotics to treat asymptomatic bacteriuria (ASB) among nursing home residents with a suspected urinary tract infection (UTI). Methods: In 4 central Texas nursing homes with bed sizes ranging from 48 - 222 beds, episodes of treatment for suspected UTI were identified from facility logs. Symptoms and resident characteristics were abstracted from residents' records. Using a multi-level multivariate model, we evaluated resident and facility characteristics associated with antibiotic use despite the absence of symptoms and signs suggesting need to treat a UTI. The dependent variable in our analyses was a binary variable reflecting the presence or absence of any signs or symptoms associated with a symptomatic UTI based on previously published consensus criteria by Loeb et al.(Infect Control Hosp Epidemiol 2001). Results: Over 6 months, clinicians ordered antibiotics for suspected UTI 227 times among 167 residents; 89% had urine studies. Half (114) of the antibiotic prescriptions occurred in the absence of any symptoms or signs. In multivariate analyses, resident characteristics did not differentiate between treated residents with or without symptoms or signs; however, in the same model, 2 of the 4 facilities exhibited less treatment of asymptomatic residents (odd ratios and 95% confidence intervals, 0.28 [0.09,0.88] and 0.34 [0.15,0.74]). Conclusions: This research confirms frequent use of antibiotics for ASB in nursing homes. Antibiotic stewardship in nursing homes must address treatment that seems to be based solely on urine findings. Clinicians' prescribing behavior was clearly associated with the nursing homes in which they practiced and may be related to, or may create, the facility's clinical culture.