Catheter-obtained, Enterococcus and Proteus positive urine cultures may
represent mostly contamination or asymptomatic bacteriuria in Infants

Background: Urinary tract infection (UTI) diagnosis in neonates and young infants is
often made by a positive result of urine culture obtained through suprapubic aspiration
(SPA) or catheterization, regardless of urine dipstick findings.
Aim: To assess parameters that may impact positive urine culture results
interpretation in infants obtainment (SPA vs. catheterization), bacteria type, presence of fever, age, and
laboratory results.
Methods: A retrospective, cohort study. Infants dipstick and culture obtained through SPA or catheter, 2015-2016, were included.
Results: Overall, 19% (129/678) of cultures were positive. The dipstick sensitivity
was 51% for any positive culture; 66%, 47%, 15% and 10% for Escherichia Coli
(n=71), Klebsiella (n=19), Enterococcus (n=34) and Proteus (n=10) species,
respectively (p < .001).
Sensitivity rates were higher in SPA vs. catheter for overall positive cultures (67% vs.
43%); E. coli (78% vs. 59%); and Klebsiella (88% vs. 18%) episodes. For
Enterococcus, dipstick sensitivity rates were low in both SPA and catheter (0-16%).
All Proteus episodes were obtained by catheter.
Positive culture episodes with negative dipstick result and Enterococcus episodes
were characterized by lower levels of C-reactive protein, and higher proportions of
mixed infection (two species isolated in a single culture) compared with positive
dipstick and E. coli episodes.
Conclusions: Urine cultures in infants catheter-obtained, Enterococcus and Proteus positive cultures may represent mostly
contamination or asymptomatic bacteriuria, rather than true UTI.