title: Incidence and risk factors of urinary tract infection in very low birth weight infants.
abstract: OBJECTIVE
  To describe the incidence and associated risk factors of urinary tract infection (UTI) in very low birth weight (VLBW) infants and to determine the value of diagnostic imaging studies after the first UTI episode before discharge from the neonatal intensive care unit (NICU).
  
  
  METHODS
  VLBW infants born during 2003-2012 were reviewed for UTI. In a nested case-control study, potential risk factors of UTI were compared between infants with UTI (cases) versus birth weight and gestational age matched controls. Renal ultrasonography (USG) and voiding cystourethrography (VCUG) results were reviewed in cases.
  
  
  RESULTS
  During the study period, 54.7% of urine culture specimens were collected by sterile methods. 3% (45/1,495) of VLBW infants met the study definition for UTI. UTI was diagnosed at mean postnatal age of 33.1±22.9 days. There was no significant difference in gender, ethnicity, antenatal steroid exposure, blood culture positive sepsis, ionotropic support, respiratory support and enteral feeding practices between cases and controls. Cases had a significantly higher cholestasis compared to controls (22% vs. 9% ; p = 0.03). However, cholestasis was not a significant predictor of UTI in the adjusted analysis [adjusted OR 2.38 (95% CI 0.84 to 6.80), p = 0.11]. Cases had higher central line days, parenteral nutrition days, total mechanical ventilation days, chronic lung disease, and length of stay compared to controls. Renal USG was abnormal in 37% and VCUG was abnormal in 17% of cases.
  
  
  CONCLUSIONS
  The incidence of UTI in contemporary VLBW infants is relatively low compared to previous decades. Since no significant UTI predictors could be identified, urine culture by sterile methods is the only reliable way to exclude UTI. The majority of infants with UTI have normal renal anatomy. UTI in VLBW infants is associated with increased morbidity and length of stay.
authors.affiliation: Division of Neonatology, Department of Pediatrics, Rainbow Babies & Children's Hospital, University Hospitals, Case Western Reserve University, Cleveland, OH, USA.
authors.forename: C
authors.initials: C
authors.lastname: Ruangkit
authors.affiliation: Division of Neonatology, Department of Pediatrics, Rainbow Babies & Children's Hospital, University Hospitals, Case Western Reserve University, Cleveland, OH, USA.
authors.forename: Ankita
authors.initials: A
authors.lastname: Satpute
authors.affiliation: Division of Pediatric Nephrology, Department of Pediatrics, Rainbow Babies & Children's Hospital, University Hospitals, Case Western Reserve University, Cleveland, OH, USA.
authors.forename: B A
authors.initials: BA
authors.lastname: Vogt
authors.affiliation: Division of Pediatric Infectious Diseases, Department of Pediatrics, Rainbow Babies & Children's Hospital, University Hospitals, Case Western Reserve University, Cleveland, OH, USA.
authors.forename: C
authors.initials: C
authors.lastname: Hoyen
authors.affiliation: Division of Neonatology, Department of Pediatrics, Rainbow Babies & Children's Hospital, University Hospitals, Case Western Reserve University, Cleveland, OH, USA.
authors.forename: S
authors.initials: S
authors.lastname: Viswanathan
mesh_terms: D016022:Case-Control Studies; D055499:Catheter-Related Infections / Q000150:complications / Q000151:congenital* / Q000453:epidemiology* / Q000652:urine; D002408:Catheters, Indwelling / Q000009:adverse effects* / Q000382:microbiology; D005260:Female; D006801:Humans; D015994:Incidence; D007231:Infant, Newborn; D019102:Infant, Very Low Birth Weight; D007363:Intensive Care Units, Neonatal; D008297:Male; D011247:Pregnancy; D012189:Retrospective Studies; D012307:Risk Factors; D018805:Sepsis / Q000151:congenital* / Q000453:epidemiology* / Q000209:etiology / Q000652:urine; D014552:Urinary Tract Infections / Q000151:congenital* / Q000453:epidemiology* / Q000209:etiology / Q000652:urine
keywords: Urinary tract infection; VLBW; premature infants; renal ultrasound; urine culture; voiding cystourethrography