Controlled ten-day antimicrobial therapy in asymptomatic bacteriuria of old age: relations with localization,mobility and mortality

The effectiveness of a 10-day i.m. antimicrobial therapy in eradicating bacteriuria for six months, preventing decline of physical status and reducing mortality for five years was tested in 73 ambulant, self-caring bacteriuric residents of a retirement home (16 men) compared to 264 non-bacteriuric subjects (79 men), and in 29 bacteriuric controls under no treatment (4 men), all groups having a mean age of 82.5 years. Structural abnormalities by ultrasonography were detected in 29% of 69 treated bacteriuric subjects and 18.4% of 76 non-bacteriuric controls (N.S.). Seventy-five percent of bacteriuric men and 56% of women had positive antibody coated bacteria (ABC+) in the urine. One of three agents was used: netilmicine 150 mg/d (26 subjects), ceforanide 1.0 g/d (23 subjects), and cotrimoxazole 160/800 mg/d (24 subjects). At one week post therapy 61.6% of treated subjects had negative urines vs. 27.6% of untreated controls (p<0.005); at one and six months negative urines were present in 52.2% and 44.8% of subjects treated vs. 39.3% and 40% of controls (N.S.). Netilmicine and ceforanide were more effective at one week and one month, cotrimoxazole at six months. Elimination of bacteria ACB(+) or (?) was equal but relapses were more numerous in ACB(+) strains. At 18 months “good” mobility was more frequent among subjects originally non-bacteriuric than among the treated bacteriuric subjects (61.1% vs. 38.6%, p<0.01). There were no deaths among the treated bacteriuric subjects for six months, but thereafter mortality rose fast so that at 18 months their cumulative mortality was significantly higher than in the non-bacteriuric subjects (p<0.0001). Subsequently, however, mortality accelerated in both groups, so that at 5 years cumulative mortality was equally high among originally bacteriuric and non-bacteriuric subjects. The study shows that: (a) the treatment used was moderately effective in eradicating bacteriuria, urines remaining sterile in almost half of the subjects for up to six months; (b) successful therapy did not alter the evolution of physical disability; (c) therapy delayed the onset of mortality for six months but did not reduce subsequently the high death rate of bacteriuric subjects during 18 months; (d) over the 5-year follow-up the high mortality of subjects with mean age 87.5 years conceals earlier occurring mortality differences between groups which should be assessed in younger subjects.