When to perform urine cultures in respiratory syncytial virus-positive febrile older infants?

TLDR: Febrile older infants who are RSV positive have a clinically significant rate of UTIs, and Circum circumcised boys are at a decreased risk of UTI, compared with uncircumcised boys.

Abstract: Background Respiratory syncytial virus (RSV) infections are associated with clinically significant rate of urinary tract infections (UTIs) in young infants. Previous research investigating RSV infections and UTIs has been performed mainly in infants younger than 2 to 3 months and has not focused on the risk of UTI in infants 3 to 12 months. Objective This study aimed to assess the rate of UTIs in febrile RSV-positive older infants admitted as inpatients and identify predictors of UTI in febrile RSV-positive older infants. Methods This is a retrospective comparative study of febrile RSV-positive infants 0 to 12 months of age admitted to the inpatient pediatric unit of Lincoln Medical and Mental Health Center, Bronx, from September through April 2006 to 2012. Infants 3 to 12 months were considered the cases, and infants 0 to 3 months were the comparative group. The rate of UTIs between the 2 groups was compared. Univariate tests and multiple logistic regression were used to identify demographic/clinical factors associated with UTI in febrile RSV-positive older infants. Results A total of 414 RSV-positive febrile infants were enrolled including 297 infants 3 to 12 months of age. The rate of UTI in older infants was 6.1% compared with 6.8% in infants younger than 3 months. Positive urinalysis finding was an independent predictor of UTI (P = 0.003) in older infants. All 11 boys with UTI were uncircumcised, and none of the 51 circumcised boys had UTI. Demographic (race, sex, and age) and clinical factors (temperature, white blood cell count, and absolute neutrophil count) were not associated with UTI. Conclusions Febrile older infants who are RSV positive have a clinically significant rate of UTIs. It seems prudent to examine the urine of these older infants. Positive urinalysis finding was a predictive factor of UTI. Circumcised boys are at a decreased risk of UTI, compared with uncircumcised boys.