Background: Infants ≤ 60 days of age with a urinary tract infection (UTI) represent a challenging population without clear guidelines for diagnostic evaluation or antibiotic therapy. UTI represents a significant percentage of serious bacterial infection in this age group and is a common management dilemma for pediatricians. Our study examined patterns of UTI management in infants ≤ 60 days of age at a tertiary care Children’s Hospital.
Methods: We used chart review to identify infants age ≤ 60 days with diagnostic codes of UTI or fever hospitalized from 1/2013-1/2017. Inclusion criteria were urine culture obtained and documentation of a final diagnosis of UTI. Exclusion criteria were treatment of a separate source of infection, comorbid chronic conditions, genitourinary manipulation or surgical intervention within 7 days prior to admission, or a final diagnosis of hospital-acquired UTI. Variables were abstracted by clinical record review. The primary outcome was duration of antibiotic therapy. Secondary outcomes were readmission rate, length of stay and imaging evaluation. Associations between demographic and clinical variables and these outcomes were evaluated by the Mann-Whitney test and Chi-square test. Data are reported as proportions or median (Q1, Q3).
Results: 134 infants met inclusion criteria. The median age at hospital admission was 37 days (22, 48). The median duration of intravenous (IV) antibiotics was 59 hours (44, 117). The median total duration of antibiotics was 12 days (9, 14). The median length of stay was 72 hours (58, 125). 95 infants (71%) had growth of ≥50,000 CFU of a single organism. Infants ≤28 days received significantly longer IV therapy compared to those 29-60 days (89 vs 55 hours, p=0.0005) without a significant difference in total antibiotic duration. Infants with duration of fever ≥24 hours received significantly longer IV therapy compared to those with fever <24 hours (76 vs 56 hours, p=0.039). Infants with bacteremia had significantly longer IV therapy compared to those without bacteremia (126 vs 55 hours, p<0.0001). There was no association between age and either the presence of bacteremia or duration of fever. Length of stay was significantly longer for infants ≤28 days (100 vs 67 hours, p=0.0026). There were 4 readmissions for UTI recurrence. There was no significant difference in either age or duration of IV therapy in those infants readmitted. There was no significant difference by age in rates of inpatient renal ultrasounds (overall rate 95%), however infants ≤28 days were significantly more likely than those 29-60 days to have an inpatient voiding cystourethrogram (VCUG) performed (32% vs 12%, p=0.0062).
Conclusions: In this retrospective study of young hospitalized infants with a UTI, infants ≤28 days received longer IV antibiotic therapy, a finding which cannot be explained by either longer duration of fever or more concomitant bacteremia in this age group. These findings instead likely reflect a more conservative management approach in infants ≤28 days compared to those 29-60 days. Both age and duration of antibiotic therapy were not predictive of readmission for UTI, supporting the idea that shorter IV antibiotic courses are appropriate in many infants ≤60 days, but further studies are needed.