Identification of Urinary CD44 and Prosaposin as Specific Biomarkers of Urinary Tract Infections in Children With Neurogenic Bladders

Forster, Catherine S; Haffey, Wendy D; Bennett, Michael; Greis, Kenneth D; Devarajan, Prasad

Children with neurogenic bladders frequently have positive urine cultures. However, determining when a positive urine culture represents at urinary tract infection (UTI) as opposed to urinary tract colonization (UTC) can be difficult. 1 Indeed, as more than half of urine cultures from children with neurogenic bladders are positive in the absence of symptoms, 2 a positive urine culture is not diagnostic of a UTI in these children. Furthermore, there is no widely accepted definition of UTI in children with neurogenic bladders, 3 which contributes to the significant variability in the way that clinicians both diagnose and treat suspected UTIs in this population. [3] [4] [5] As there is no defintion of UTI in these children, clinicians rely on their assessment of symptoms to diagnose a UTI. However, while the combination of some symptoms is generally considered diagnostic of a UTI, such as fever, abdominal pain, and vomiting in the absence of another source, other symptoms, such as increased incontinence or discomfort with catheterization, are less clear. Indeed, in a series of adults with neurogenic bladder, symptoms were found to be non-specific for UTI. 6 There is an absence of accurate biomarkers that have good predictive accuracy for UTI in children with neurogenic bladders. While specific urinalysis (UA) parameters have good sensitivity and specificity for the diagnosis of UTI in the general pediatrics population, 7, 8 UA results are less useful in diagnosing UTIs in patients with neurogenic bladders. 9 This is likely related to the fact that components of the UA are either markers of inflammation (ie, pyuria, leukocyte esterase) or indicative of the presence of an organism (eg, nitrites) and are not specific for UTI in this population. A more accurate and objective method to diagnose UTIs in this population is needed. Indeed, there is a rapidly rising trend in antibioticresistant organisms cultured from urine in children with neurogenic bladders. 10 Although this is multifactorial, one reason behind trend is the large number of antibiotics that these children receive. Identification of a biomarker that is both sensitive and specific for UTIs in this urologically complex patient population would improve the ability to appropriately prescribe antibiotics.