Urinary tract infection in infants: the significance of low bacterial count
Svante Swerkersson1,2, Ulf Jodal3, Christina Åhrén4,5
1Department of Pediatrics, The Queen Silvia Children's Hospital, Sahlgrenska University Hospital, Gothenburg, Sweden. svante.swerkersson@gu.se.
Insights
Urinary tract infections (UTIs) in infants with low bacterial counts are common and may indicate vesicoureteral reflux (VUR) and kidney damage. Non-E. coli species and reduced inflammation were more frequent in these cases.
Area of Science:
- Pediatric Nephrology
- Infectious Diseases
- Urology
Background:
- National guidelines for pediatric urinary tract infection (UTI) use varying cut-off levels for bacteriuria.
- This variability impacts the diagnosis and management of UTIs in infants.
Purpose of the Study:
- To analyze the relationship between bacterial count in infant UTIs and key clinical outcomes.
- Investigated associations with inflammatory markers, vesicoureteral reflux (VUR), kidney damage, and recurrent UTIs.
Main Methods:
- Population-based retrospective study of 430 infants under 1 year with symptomatic UTI.
- Diagnosis confirmed via suprapubic aspiration.
- Clinical data, laboratory parameters, voiding cystourethrography, and scintigraphy findings were correlated with bacterial counts.
Main Results:
- 19% of infants had low bacterial counts (<100,000 CFU/ml), while 81% had high counts (≥100,000 CFU/ml).
- Similar frequencies of VUR (19%), kidney damage (17% vs. 23%), and recurrent UTIs (6% vs. 12%) were observed in both groups.
- Non-E. coli species were more prevalent (19% vs. 6%) and C-reactive protein levels were lower (50 mg/l vs. 79 mg/l) in the low bacterial count group.
Conclusions:
- Infant UTIs with low bacterial counts are significant and can be associated with VUR and renal damage.
- Low bacterial counts in infant UTIs are linked to a higher prevalence of non-E. coli species and a diminished inflammatory response.
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.
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