June 24, 2019
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High urine culture rates in nursing homes linked with antibiotic use, CDI

Findings from a study conducted at nearly 600 nursing homes in Ontario found that high urine culturing rates were associated with increased total antibiotic use, Clostridiodes difficile infection and 30-day mortality, researchers reported.

“Rates of antibiotic use in nursing homes are highly variable in health care systems around the world. Very little of this variation is explained by characteristics of residents residing within homes. Instead, factors related to the prescriber and the nursing home are strongly associated with increased antibiotic use in terms of antibiotic initiation, duration, and class. The resultant inter-facility variation in antibiotic receipt is tightly linked to adverse effects in nursing home residents including Clostridiodes difficile, antibiotic resistance, and antibiotic allergic reactions,” Kevin A. Brown, PhD, an epidemiologist with Public Health Ontario, and colleagues wrote.

“Antibiotic stewardship programs are being designed in order to reduce unnecessary antibiotic prescribing and mitigate the adverse effects of antibiotic overuse, though the optimal strategies for nursing homes are not known.”

Brown and colleagues conducted a longitudinal, multilevel, retrospective cohort study based on quarterly nursing home assessments from April 2014 to January 2017. The study included 591 nursing homes and 131,218 patients, representing more than 90% of the nursing home residents in Ontario, the most populous province in Canada.

According to the study, the researchers measured nursing home urine culturing as the proportion of residents with a urine culture in the prior 14 days. The outcomes included receipt of any systemic antibiotic and any urinary antibiotic within 30 days of assessment, and C. difficile infection in the 90 days after the assessment.

Overall, Brown and colleagues found that 7.9% of resident assessments included a urine culture in the prior 14 days, with rates varying “dramatically” across the 591 nursing homes. After adjusting for resident factors associated with antibiotic use, they found that nursing home urine culturing was a “strong predictor” of total antibiotic use (adjusted risk ratio [RR] per doubling of urine culturing = 1.21; 95% CI, 1.18-1.23), urinary antibiotic use (aRR per doubling = 1.33; 95% CI, 1.28–1.38) and C. difficile infection (incidence RR per doubling = 1.18; 95% CI, 1.07–1.31).

Brown and colleagues said antimicrobial stewardship initiatives could reduce urine culturing and antibiotic use.

“This study demonstrates that variation in nursing home urine culturing is driven by facility and not resident factors. This variability significantly contributes to higher antibiotic use and C. difficile infection in facilities with more urine culturing,” they wrote. “Through antimicrobial stewardship initiatives targeted at nursing homes with high levels of urine culturing, a large portion of nursing homes could reduce urine culturing and antibiotic use, in order to reduce negative sequelae of antibiotic overuse including antibiotic resistance and C. difficile infection.” – by Caitlyn Stulpin

Disclosures: The authors report no relevant financial disclosures.