Bacteriuria in representative population samples of persons aged 72-79 years.

Screening for bacteriuria was performed between 1984 and 1988 in persons aged 72-79 years representative of the general population in Göteborg, Sweden. The frequency of bacteriuria (greater than or equal to 10(5)/ml) at a single screening was 6% and 16% at age 72 years and 6% and 14% at age 79 years for the screened men (n = 235 and 259) and women (n = 259 and 297), respectively. By repeated screening after one month and 30 months of those previously negative at age 72 years, an additional 4% and 3% of men and 3% and 7% of women with bacteriuria were detected. Bacteriuric persons were excluded from further screening and controlled by frequent cultures during several years, with careful monitoring of clinical interventions. The persistence of untreated bacteriuria was analyzed in relation to bacterial species and number in the untreated subgroup of bacteriuric individuals. Nine of 10 Escherichia coli (E. coli) with less than 10(6)/ml and 22/22 non-E. coli strains disappeared spontaneously. In contrast, 20/26 (77%, p less than 0.01) with greater than or equal to 10(6) E. coli/ml persisted. Of 17 persons with bacteriuria persisting at least 12 months, 16 were women and 16 had E. coli. Of 201 E. coli cultures obtained from this group, 94% had greater than or equal to 10(6)/ml, and 99% had greater than or equal to 5 x 10(5)/ml. The results indicate that screening for high counts (greater than 10(6)/ml) of E. coli most effectively detects persisting bacteriuria in the general elderly population.