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The epidemiology of urinary tract infection (UTI) in the population of Vännäs (8 000 inhabitants) was studied during one year. The annual incidence increased from 0.5% in the first decade of life to more than 10% in the age group 90-100 years. Male UTI comprised only 13% of the episodes, increased after middle age and contributed 4 0% by > 80 years of age. At 17 PHC centres (PHCCs) a prevalence study (McPHC) of mainly uncomplicated UTI was performed. Most episodes were acutely symptomatic (lower 75%, upper 5%).

Microscopy of wet-stained urinary sediment with a minimum of moderate amount of bacteria and/or 5 leukocytes per high power field (4 00 x) as breakpoint resulted in a desired high sensitivity (97%) and 86% efficacy in acutely symptomatic patients. Diagnosis of bacteriuria using Uricult dipslides yielded acceptable results with an overall efficacy of 88%. Nitrite test and Uriglox showed an unacceptable low mean sensitivity ofR56 and 69%, respectively. A positive nitrite, sediment or Uricult , when used in combination, was optimal in diagnosing UTI with a sensitivity of 98% in acutely symptomatic patients during their office visits.

The average risk of drug resistance was 17% in the Vännäs study. Sensicult satisfactorily predicted drug sensitivity (93%) but not bacterial drug resistance (50%). Using Uricult with classification of bacteriuria by Gram-grouping, lactose and catalase reactions for targeting UTI therapy, according to local guidelines, resulted in a similar low risk (6 %) of prescribing drugs to which the organisms were resistagt as when using Sensicult (7%). This development of the Uricult method is simple and can be recommended for office practice in PHC.

The spectrum of bacteria causing UTI and their drug resistance was more associated with the selection of patients, sex and age than with symptoms. The pattern of drug resistance was little influenced by UTI history and the mean pretherapy resistance for the seven drugs tested in McPHC was low (7%). Drug resistance was increased in failure (mean 24%) but not in early or repeated recurrence. In McPHC therapy resulted in 8% bacteriological failure and 12% early recurrence, irrespective of whether the bacteria were classified as sensitive or resistant in vitro to the drug given. Thus, in order to be of prognostic value for therapy of uncomplicated UTI, high-level breakpoints focusing more on peak urinary drug concentrations need to be studied.

UTI symptoms in McPHC were eradicated in only 2/3 of the bacterio- logically cured episodes and in 1/3 of the failures at control 1-3 days posttherapy showing that symptoms are an unreliable indicator of UTI.

From current literature, it seems unlikely that asymptomatic bacteriuria (ABU) plays a major role in the development of uremia due to chronic pyelonephritis. With the exception of ABU in pregnancy, therapy seems to yield no benefit. Omitting posttherapy bacteriuria controls in patients with symptoms eradicated, at least in women with uncomplicated UTI, would lead to considerable savings both for patients and the health care system.