A four-year follow-up of schoolgirls with untreated covert bacteriuria: bacteriological aspects.

: In 75 schoolgirls aged 5-11 with untreated covert coliform bacteriuria who were followed up to 4 years, infection cleared in 16 (21%), cleared and recurred in 37 (50%) and persisted in 22 (29%). Clearance of bacteriuria was significantly (P less than .05) more frequent in girls with normal radiological findings than in those with abnormal findings. In 31 (59%) of the 53 girls in whom bacteriuria cleared spontaneously, the urine became sterile within the first year after the discovery of the bacteriuria. Spontaneous clearance of bacteriuria was preceded by an increase of the sensitivity of the urinary pathogens to the cidal effect of human serum. Seven (10%) of the 75 untreated bacteriuric girls had shown progression of kidney damage (progression of scarring in 4 and failure of kidney growth in 3). In all of these 7 girls vesico-ureteric reflux (VUR) was present and bacteriuria was persistent, but in 6 of them from one to three changes in the serotype of Esch. coli or bacterial species were noted during follow-up. These observations suggest that changes in bacterial flora may be a risk factor in the progression of kidney damage in girls with urinary tract infection and VUR.