Ta. Schlager et al., EFFECT OF PERIURETHRAL COLONIZATION ON THE RISK OF URINARY-TRACT INFECTION IN HEALTHY GIRLS AFTER THEIR 1ST URINARY-TRACT INFECTION, The Pediatric infectious disease journal, 12(12), 1993, pp. 988-993
We examined whether periurethral colonization with bacterial pathogens
predicts recurrent urinary tract infection (UTI) in girls at risk for
infection. Periurethral and urine cultures were obtained weekly from
each of seven healthy toilet-trained girls (3 to 6 years of age, norma
l urinary tract) during the 6 months after their first UTI, when the r
isk of UTI is 35%. Periurethral and urine isolates of Escherichia coli
were grouped into electrophoretic types (ETs) by multilocus enzyme el
ectrophoresis. Fifty-three (43%) of the 122 periurethral cultures were
positive for a pathogen (median, 6 positive cultures/patient). Two pa
tients each experienced 2 UTI. Positive periurethral cultures were as
common in the five uninfected patients as in the two infected patients
(9 of 32 vs. 44 of 90, P = 0.06). In only 1 of the 4 UTI was the infe
cting organism detected on the periurethra in the 2 weeks prior. Multi
locus enzyme electrophoresis of the 104 periurethral and urine E. coli
isolates from the 7 patients revealed 22 ETs. Such a diversity of ETs
suggests that the flora of the periurethral region is colonized by mu
ltiple E. coli strains and is constantly changing in clonal compositio
n. Five E. coli strains (ETs) associated with the initial UTI were det
ected again on the periurethra of 3 patients during surveillance but d
id not ascend to cause infection. Thus the mere presence of a pathogen
on the periurethra is not by itself a risk factor for UTI.