Causative organisms and antimicrobial susceptibility in jaundiced infants with significant bacteriuria

Background: Jaundice may be one of the first signs of urinary tract infection (UTI) in infants. The most common pathogen is Escherichia coli. Currently recommended antibiotic treatment for neonatal UTI is ampicillin and an aminoglycoside. Recently, increasing ampicillin and gentamicin resistance in strains of E. coli has been isolated. The aim of this study was to determine causative organisms and antimicrobial susceptibility in jaundiced infants with significant bacteriuria (SB). Methods: We evaluated admitted afebrile, asymptomatic infants younger than 1-month old with hyperbilirubinemia (total bilirubin >15 mg/dl) requiring phototherapy between January 2011 and December 2015. A total of 615 asymptomatic jaundiced infants were enrolled. Urinalysis and urine cultures were performed on all jaundiced infants. A urine culture was defined as SB if a single pathogen with more than 10(5)-colony forming units per milliliter (CFU/ml) by sterile urinary collection bag or 10(4) CFU/ml by catheterization was isolated. Results: A total of 88 (14.3%) of 615 asymptomatic jaundiced infants had positive urinary culture. E coli was the most common cultured bacteria (40 cases, [45.5%]). Enterococcus faecalis was the second most common bacteria (17 cases, [19.3%]). Seven cases (8.0%) of Streptococcus agalactiae and six cases (6.8%) of Klebsiella pneumoniae were also identified. Ampicillin sensitivity was found in 22.5% of E. coli infections, gentamicin sensitivity was found in 84.2%, and extended-spectrum beta-lactamases were found in 7.5%. Conclusion: E. coli was the most common causative organism for infants with SB. We suggest modifying current empiric antibiotics by changing gentamicin to amikacin for neonatal Gram-negative bacterial infections.

Automated summary

This study found that Escherichia coli is the most common causative organism in jaundiced infants with significant bacteriuria. Current recommended antibiotic treatment for neonatal urinary tract infection with E. coli shows low sensitivity to ampicillin but high sensitivity to gentamicin. It is suggested to modify the empiric antibiotic treatment for Gram-negative bacterial infections in neonates by changing gentamicin to amikacin.