Optimization of differential diagnosis of viral and bacterial acute intestinal infections

Objective. Determination of optimal differential diagnostic markers of acute intestinal infections (AII) of viral and bacterial etiology.

Materials and methods. Determination of the fecal calprotectin (FCP) level by ELISA was performed in 105 hospitalized patients with AII aged from 1 year to 40 years. Statistical analysis was performed by Statistica 12.0 (Stat Soft, USA). Multivariate ANOVA with the Kruskal-Wallis test was performed, and the Spearman direct linear correlation coefficient (r) was determined. The relative risk of an event (RR (CI)) was calculated using four-field tables.

Results. The relative risk of bacterial AII in adults was 3 times higher than in children. The presence of leukocytosis, neutrophilia, and left shift, changes in the coprogram, and the maximum level of increase in body temperature did not allow for a differential diagnosis between viral and bacterial AII. The CRP level was significantly (p < 0.05) higher in bacterial AII (15.9 [12.2–39.96] mg/l) than in viral AII (7.04 [1.9–14.17] mg/l). At the CRP level > 12 mg/l, bacterial AII were recorded more often than viral ones (RR = 4.34 (95% CI 1.03–18.17)). In the case of viral AII, the FCP level was 477.7 [355.9–600] μg/g, and in the case of bacterial ones – 1472.0 [584.0–1571.0] μg/g (p < 0.05). At the FCP level > 600 μg/g, the probability of bacterial AII was 45 times higher than viral one (RR = 45.0 (6.19–326.9)), sensitivity 90%, specificity 92%. At the FCP level > 600 μg/g, hemorrhagic gastropathy, liver dysfunction, and later admission to hospital were recorded more often (p < 0.05). A strong direct correlation was established between the CRP and FCP values (r = 0.7).

Conclusion. FCP is a useful non-invasive, easily and quickly measured laboratory test for differentiating bacterial and viral AII and can become an objective criterion for prescribing antibacterial therapy for AII.