engleski

Serum calprotectin is a novel predictor of bacterial urinary tract infection in a febrile child

Although self-limiting viral infections are the principal cause of fever in the majority of cases, it is estimated that 5% of febrile children younger than three years of age would have a urinary tract infection (UTI). Despite the increased availability of laboratory testing and development of various clinical scores, there is still no reliable predictor of UTI in children. Recent advancements in the understanding of inflammatory process have highlighted the role of S100 proteins, with many studies suggesting their clinical value as a biomarker of inflammation. This research aims to investigate the possible role of serum calprotectin (sCAL), a heterodimer consisting of S100A8 and S100A9 proteins from S100 family, as a biomarker for bacterial urinary tract infection in children. Patients aged 0-36 months who came to Pediatric Emergency Department of Sestre milosrdnice University Hospital Center with fever ≥38°C, lasting <72h, positive urine leukocyte esterase and no history of chronic illness or ongoing antibiotic use, were enrolled. In every patient, sCAL was measured with Quantum Blu rapid test, along with urine culture analysis and testing of standard inflammatory markers. Patients with bacterial count of ≥10^5 CFU/mL in urine culture were defined as having UTI, while patients with negative culture, absent signs of other bacterial infection, positive influenza, adenovirus, and/or respiratory syncytial virus test, and/or characteristic symptoms were diagnosed with viral acute respiratory infection (ARI). Among 52 patients included in the study (median age 6 months, IQR 3, 1 – 13, 8), 30 were diagnosed with ARI and 22 with UTI. In patients with UTI, the median value of sCAL was 5, 6 ug/mL (IQR 3, 9 – 6, 3), which was significantly higher (p<0, 0001) than in patients with ARI, whose median value of sCAL was 2, 6ug/mL (IQR 1, 7 – 3, 5). There was a moderate positive correlation of sCAL with WBC (r=0, 64 ; p<0, 01) and CRP (r=0, 55 ; p<0, 01). The sCAL had area under curve (AUC) of 0.93 (95% CI 0.85 – 100) for predicting UTI, and with the optimal cut-off (3, 95ug/mL), sensitivity was 93, 1% (95% CI 78, 0 – 98, 8%), specificity 76, 19% (95% CI 54, 9 – 89, 4%) and positive likelihood ratio was 3, 91. The results of this study have shown that sCAL is a good predictor of bacterial UTI in a febrile child presenting to an emergency department. Besides, the correlation of sCAL with duration of fever and inflammatory markers standardly used to infer the presence of bacterial infection was only moderate or insignificant, suggesting the potential differences in their dynamics. Hence, the sCAL concentration in febrile children could add to timely and accurate diagnosis of UTI, which is essential to reduce treatment delay and improve treatment outcomes.

calprotectin ; urinary tract infection ; child

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