Low bacterial count urinary tract infections in infants and young children

Area of Science:

• Pediatrics
• Infectious Diseases
• Microbiology

Background:

• Urinary tract infections (UTIs) are common in infants and children.
• Bacterial counts in urine cultures can vary, potentially influencing clinical presentation and outcomes.
• Understanding differences between high and low bacterial count UTIs is crucial for diagnosis and management.

Purpose of the Study:

• To compare bacterial species, clinical, laboratory, and imaging findings in infants and children with high versus low bacterial counts during their first UTI.
• To identify potential differences in causative pathogens and disease severity based on bacterial load.

Main Methods:

• A retrospective study of 419 symptomatic children aged <=54 months with a first UTI and no prior antibiotic treatment.
• Urine samples were collected via catheterization or suprapubic aspiration for quantitative cultures.
• Patients were categorized into high (>/=10(5) CFU/ml), intermediate, and low (

Main Results:

• Escherichia coli was the most common pathogen (75.2%), followed by other gram-negative bacteria (21.7%).
• Low bacterial count UTIs (Group C) were more frequently associated with gram-negative bacteria other than E. coli compared to high bacterial count UTIs (Group A) (P <0.0001).
• No significant differences were observed in clinical symptoms, laboratory findings (leukocyte count, CRP, ESR), or prevalence of pyelonephritis, reflux, or urological malformations between high and low bacterial count groups.

Conclusions:

• Low bacterial count UTIs predominantly affect infants and young children.
• Gram-negative bacteria other than E. coli are common causative agents in low bacterial count UTIs.
• Clinical presentation and diagnostic findings are similar for both high and low bacterial count UTIs, suggesting similar underlying pathology despite differing bacterial loads.