title: Urinary tract infection in infants: the significance of low bacterial count.
abstract: BACKGROUND
  In national guidelines for urinary tract infection (UTI) in children, different cut-off levels for defining bacteriuria are used. In this study, the relationship between bacterial count in infant UTI and inflammatory parameters, frequency of vesicoureteral reflux (VUR), kidney damage, and recurrent UTI was analyzed.
  
  
  METHODS
  We conducted a population-based retrospective study of 430 infants age <1 year with symptomatic UTI diagnosed by suprapubic aspiration. Clinical and laboratory parameters, findings on voiding cystourethrography and (99m)technetium dimercapto-succinic acid scintigraphy, and frequency of recurrence were related to bacterial count at the index UTI.
  
  
  RESULTS
  Eighty-three (19%) infants had bacterial counts <100,000 colony-forming units (CFU)/ml and 347 (81%) had ≥100,000 CFU/ml. There was similar frequency of VUR (19% in both groups), kidney damage (17 and 23%, p = 0.33) and recurrent UTI (6 and 12%, p = 0.17) in the low and high bacterial group. Non-E. coli species were more prevalent (19 versus 6%, p = 0.0006) and mean C-reactive protein was lower (50 vs. 79 mg/l, p <0.0001) in the low bacteria group.
  
  
  CONCLUSIONS
  UTI with low bacterial count is common and of importance since it may be associated with VUR and renal damage. Non-E. coli species and low inflammatory response were more prevalent in UTI with low bacterial count.
authors.affiliation: Department of Pediatrics, The Queen Silvia Children's Hospital, Sahlgrenska University Hospital, Gothenburg, Sweden. svante.swerkersson@gu.se.|Pediatric Uronephrologic Center, The Queen Silvia Children's Hospital, Sahlgrenska University Hospital, 416 85, Göteborg, Sweden. svante.swerkersson@gu.se.
authors.forename: Svante
authors.initials: S
authors.lastname: Swerkersson
authors.affiliation: Department of Pediatrics, The Queen Silvia Children's Hospital, Sahlgrenska University Hospital, Gothenburg, Sweden.
authors.forename: Ulf
authors.initials: U
authors.lastname: Jodal
authors.affiliation: Department of Clinical Bacteriology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.|STRAMA, The Swedish Strategic Programme against Antibiotic Resistance, Region of Västra Götaland, Göteborg, Sweden.
authors.forename: Christina
authors.initials: C
authors.lastname: Åhrén
authors.affiliation: Pediatric Clinical Physiology, The Queen Silvia Children's Hospital, Sahlgrenska University Hospital, Gothenburg, Sweden.
authors.forename: Rune
authors.initials: R
authors.lastname: Sixt
authors.affiliation: Pediatric Radiology, The Queen Silvia Children's Hospital, Sahlgrenska University Hospital, Gothenburg, Sweden.
authors.forename: Eira
authors.initials: E
authors.lastname: Stokland
authors.affiliation: Department of Pediatrics, The Queen Silvia Children's Hospital, Sahlgrenska University Hospital, Gothenburg, Sweden.
authors.forename: Sverker
authors.initials: S
authors.lastname: Hansson
mesh_terms: D001419:Bacteria / Q000302:isolation & purification; D058491:Bacterial Load / Q000379:methods*; D015169:Colony Count, Microbial; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007674:Kidney Diseases / Q000175:diagnosis / Q000382:microbiology*; D008297:Male; D012008:Recurrence; D012189:Retrospective Studies; D019783:Technetium Tc 99m Dimercaptosuccinic Acid; D014552:Urinary Tract Infections / Q000175:diagnosis / Q000382:microbiology*; D014718:Vesico-Ureteral Reflux / Q000175:diagnosis / Q000382:microbiology*
chemical_list: D019783:Technetium Tc 99m Dimercaptosuccinic Acid
keywords: Bacterial count; Children; Infants; Kidney damage; Urinary tract infection; Vesicoureteral reflux