Uropathogens and Pyuria in Children with Neurogenic Bladders - Beyond the Abstract

Children with neurogenic bladders frequently have bacteriuria, which may reflect either a urinary tract infection (UTI) or asymptomatic bacteriuria. As a result of the prevalence of positive urine cultures in these children, clinicians may make the decision to obtain a urine culture based on urinalysis (UA) results. Given that these children have increased rates of UTIs with antibiotic-resistant organisms, the decision to selectively obtain urine cultures has the potential to decrease antibiotic overuse in this population. However, a recent report in the general pediatrics population demonstrated that UTIs due to Enterococcus had decreased odds of both pyuria and leukocyte esterase on the UA. Children with neurogenic bladders frequently have pyuria at baseline pyuria, suggesting that this relationship between Enterococcus and pyuria may not be seen in children with neurogenic bladders. Therefore, we sought to determine if this association between pyuria and leukocyte esterase and growth of Enterococcus on urine culture persisted in children with neurogenic bladder.

We analyzed a database of 2420 urine cultures from all children with neurogenic bladder who performed clean-intermittent catheterization at a single center from 2008-2014. We exclude urine cultures that had no bacterial growth, growth of mixed organisms, or growth of a fungus, and cultures without a concurrent UA. On the bivariate analysis, we found male gender, bladder exstrophy, presence of a Mitrofanoff, and vesicoureteral reflux (VUR) were all positively associated with pyuria. Multivariate analysis showed that growth of Enterococcus was associated with significantly lower odds of pyuria (Odds ratio: 0.66 (0.47-0.91) for cultures with more than 10,000 colony-forming units per milliliter (CFU/mL); 0.44 (0.30-0.64) for cultures with more than 100,000 CFU/mL) while controlling for age, gender, etiology of neurogenic bladder, presence of a Mitrofanoff, presence of hydronephrosis, and VUR. We also found that hydronephrosis and VUR were both associated with significantly increased odds of pyuria in both analyses, while cloacal malformation, tethered cord, and growth of Proteus were all associated with increased odds of pyuria only in the analysis that included cultures with >100,000 CFU/mL.

This data suggests that the presence of Enterococcus in the urine is associated with a decreased odd of pyuria in children with neurogenic bladders. However, it is important to note that we did not attempt to differentiate between UTI and asymptomatic bacteriuria in this study. While pyuria lacks specificity for the diagnosis of UTI in children with neurogenic bladders, it is possible that the lack of differentiation between UTI and asymptomatic bacteriuria in this work is confounding the results. Further, the clinical applicability of these results is difficult to ascertain. While we do not want to advocate for routine urine cultures in every patient with a neurogenic bladder, as over testing will likely lead to overtreatment, especially with clinicians who have less experience in managing this patient population. However, in patients in whom there is a high degree of suspicion for UTI, but have a UA without pyuria, we would suggest obtaining a urine culture to assess for the presence of Enterococcus.

Written by: Catherine S. Forster, MD, MS, Pediatric Hospitalist, Children's National Medical Center

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