Asymptomatic bacteriuria in older adults: the most fragile women are prone to long-term colonization.

The diagnosis of urinary tract infections (UTIs) in institutionalized older adults is often based on vague symptoms and a positive culture. The high prevalence of asymptomatic bacteriuria (ABU), which cannot be easily discriminated from an acute infection in this population, is frequently neglected, leading to a vast over-prescription of antibiotics. This study aimed to identify subpopulations predisposed to transient or long-term ABU.

Residents in a long-term care facility were screened for ABU. Mid-stream urine samples were collected during two sampling rounds, separated by 10 weeks, each consisting of an initial and a confirmative follow-up sample.

ABU occurred in approximately 40% of the participants and was mostly caused by Escherichia coli. Long-term ABU (> 3 months) was found in 30% of the subjects. The frailest women with urinary incontinence and dementia had drastically increased rates of ABU and especially long-term ABU. ABU was best predicted by a scale describing the functional independence of older adults.

Institutionalized women with incontinence have ABU prevalence rates of about 80% and are often persistent carriers. Such prevalence rates should be considered in clinical decision making as they devalue the meaning of a positive urine culture as a criterion to diagnose UTIs. Diagnostic strategies are urgently needed to avoid antibiotic overuse and to identify patients at risk to develop upper UTI.

BMC geriatrics. 2019 Jun 21*** epublish ***

Michael Biggel, Stefan Heytens, Katrien Latour, Robin Bruyndonckx, Herman Goossens, Pieter Moons

Laboratory of Medical Microbiology, University of Antwerp, Universiteitsplein 1, building S, 2610 Wilrijk, Antwerp, Belgium., Department of Family Medicine and Primary Health Care, Ghent University, Ghent, Belgium., Operational Directorate Epidemiology & Public Health, Sciensano, Brussels, Belgium., Interuniversity Institute for Biostatistics and Statistical Bioinformatics (I-BIOSTAT), Hasselt University, Hasselt, Belgium., Laboratory of Medical Microbiology, University of Antwerp, Universiteitsplein 1, building S, 2610 Wilrijk, Antwerp, Belgium. .

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