Molecular epidemiology of asymptomatic bacteriuria in the elderly

Objectives: To determine the incidence and the dynamics of asymptomatic bacteriuria in ambulatory nursing home residents, and to characterise bacteria according to their phenotype and genotype. Design: An 18 months prospective longitudinal study. Subjects: 42 nursing home residents (31 female, 11 males) without indwelling catheters. Methods: Urine was sampled every 3 months. Antibiograms, biotyping and ribotyping were performed. Results: The cumulative percent of infection for females and males was 75% and 27% respectively. Osteoporosis was associated with bacteriuria. Ribotypes of consecutive Escherichia coli isolates indicated that each patient harboured a different strain. Conclusions: Asymptomatic bacteriuria in the elderly is a dynamic and transient phenomenon. Osteoporosis is common among this population. Ribotyping is a powerful tool in the elucidation of the epidemiology of this bacteriuria.