Louis M. Bell, MD reviewing Milcent K et al. JAMA Pediatr 2016 Jan. Kupperman N and Mahajan P. JAMA Pediatr 2016 Jan.
The prevalence of bacterial infections in febrile infants younger than 90 days is 5%–15%. Urinary tract infections (UTIs) are the most common, but invasive bacterial infections (IBIs) such as bacteremia and meningitis are the most concerning and are difficult to diagnose because of the lack of reliable clinical signs and symptoms in young infants. Therefore, combining clinical observations with select laboratory screening tests is the best method for identifying infants at risk for UTIs or IBIs.
In a 3-year prospective multicenter study, investigators in France analyzed test results for 2047 admitted febrile infants (age range, 7–91 days; temperature ≥38°). Infants who had received antibiotics were excluded.
Among 1258 infants with blood culture results, 9% had UTIs and 1% had bacteremia. Escherichia coli was the pathogen most often isolated from blood cultures. C-reactive protein (CRP) and serum procalcitonin (PCT) measurements with cutoffs of 20 mg/L and 0.3 ng/mL, respectively, were equally predictive of UTI, bacteremia, and meningitis. The probability of a negative CRP or PCT in an infant with UTI, bacteremia, or meningitis was 30% (negative likelihood ratio, 0.3). Further, PCT was significantly better than CRP in predicting bacteremia or meningitis (negative likelihood ratio, 0.1 vs. 0.3, respectively).
This new information about the predictive value of serum procalcitonin could help us more accurately identify young febrile infants at risk for invasive bacterial disease. Combining a careful exam with laboratory evaluation is still the best practice. Editorialists note that rapid diagnostic techniques to detect molecular signatures of pathogens in the blood and cerebrospinal fluid or detection of reliable host responses to bacterial pathogens are needed to improve the care of young at-risk febrile infants. Stay tuned.
Milcent K et al. Use of procalcitonin assays to predict serious bacterial infection in young febrile infants. JAMA Pediatr 2016 Jan; 170:62. (http://dx.doi.org/10.1001/jamapediatrics.2015.3210)
Kupperman N and Mahajan P.Role of serum procalcitonin in identifying young febrile infants with invasive bacterial infections: One step closer to the Holy Grail? JAMA Pediatr 2016 Jan; 170:17. (http://dx.doi.org/10.1001/jamapediatrics.2015.3267)