Importance of Urine Dipstick in Evaluation of Young Febrile Infants With Positive Urine Culture: A Spanish Pediatric Emergency Research Group Study.

BACKGROUND AND OBJECTIVES: Guidelines from the American Academy of Pediatrics define urinary tract infection (UTI) as the growth of greater than 50,000 ufc/mL of a single bacterium in a urine culture with a positive urine dipstick or with a urinalysis associated. Our objective was to evaluate the adequacy of this cutoff point for the diagnosis of UTI in young febrile infants. METHODS: Subanalysis of a prospective multicenter study developed in RISeuP-SPERG Network between October 11 and September 13. To carry out the study, it was performed a comparison of analytical and microbiological characteristics of patients younger than 90 days with fever without focus, taking into account the results of urine dipstick and urine culture. RESULTS: Of a total of 3333 infants younger than 90 days with fever without focus which were included in the study, 538 were classified as UTI in accordance with American Academy of Pediatrics' guidelines. These patients were similar to those who had a positive urine dipstick and a urine culture yielding of 10,000 to 50,000 ufc/mL, and they were different from those who had a normal urine dipstick and a urine culture >50,000 ufc/mL, being focused on the isolated bacteria and blood biomarkers values. Forty-five invasive bacterial infections were diagnosed (5.9% of the 756 with a urine culture >10,000 ufc/mL). Half of the infants with a normal urine dipstick diagnosed with invasive bacterial infections were younger than 15 days. CONCLUSIONS: It might be inadequate to use a threshold of 50,000 cfu/mL to consider a urine culture as positive in young febrile infants given the fact that it would misdiagnose several UTIs.

Using a urine dipstick to identify a positive urine culture in young febrile infants is as effective as in older patients.

AIM: There is limited evidence about the diagnostic value of urine dipsticks in young febrile infants. The aim of this study was to determine whether urine dipsticks would identify positive urine cultures in febrile infants of less than 90 days of age. METHODS: This study was a subanalysis of a prospective multicentre study developed in 19 Spanish paediatric emergency departments belonging to the Spanish Paediatric Emergency Research Network. It focused on febrile infants of less than 90 days of age admitted between October 2011 and September 2013. A positive urine culture was defined as the growth of ≥ 50,000 cfu/mL of a single pathogen collected by a sterile method. RESULTS: We included 3401 patients, and 176 (12.8%) female patients and 473 (23.3%) males had a positive urine culture. The leucocyte esterase test showed a mean sensitivity of 82.1% and a mean specificity of 92.4%, with a greater mean negative predictive value for females than males (97.8 versus 94.1%) and a greater mean positive predictive value for males than females (79.4% versus 58%). CONCLUSION: The leucocyte esterase test showed the same accuracy in young febrile infants as previously reported findings for older children. It predicted positive urine cultures and also revealed important gender differences.

Febrile young infants with altered urinalysis at low risk for invasive bacterial infection. a Spanish Pediatric Emergency Research Network's Study.

BACKGROUND: Urinary tract infection (UTI) is the most common serious bacterial infection (SBI) in infants younger than 90 days of age. Many physicians admit infants younger than 90 days old because of their greater risk of developing invasive bacterial infections (IBIs), secondary to UTI. The primary objective of this study was to design a prediction model to identify febrile infants younger than 90 days old with an altered urinalysis who were at low risk for IBI and suitable for outpatient management METHODS: : Prospective multicenter study included 19 hospitals that are members of the Spanish Pediatric Emergency Research Group of the Spanish Society of Pediatric Emergencies. Febrile infants younger than 90 days old with altered urinalysis were included. RESULTS: A total of 766 (22.5%) infants with altered urine dipstick were analyzed. Fifty (6.5%) of them developed IBI, 39 (78.0%) secondary to UTI. Patients were at low risk for IBI if they were well appearing at arrival to the emergency department, were older than 21 days and had procalcitonin and C-reactive protein (CRP) blood values lower than 0.5 ng/mL and 20 mg/L, respectively. These factors were used to create a prediction model for IBI secondary to UTI, with a sensitivity of 100% (95% CI: 89.3-100) and a negative predictive value of 100% (95% CI: 97.5-100). CONCLUSIONS: We have derived a highly accurate prediction model for IBI in febrile infants with altered urinalysis. Given these results, outpatient management might be suitable for 1 of each 4 infants diagnosed, with a considerable improvement in resource utilization.