Gut microbiota and fecal calprotectin levels in preterm infants with feeding intolerance and necrotizing enterocolitis: An observational study

Preterm infants with a lower gestational age have a higher risk of developing gastrointestinal (GI) pathologies, such as feeding intolerance (FI) and necrotizing enterocolitis (NEC). Infants with a very low birth weight (VLBW) and an extremely low birth weight (ELBW) are prone to pathogenic gut colonization due to prolonged periods of hospitalization in intensive care units (ICUs), maternal or infant antibiotic use, and difficulties with breastfeeding related to marked morphofunctional and immune immaturity. Despite available data on the pathogenetic role of dysbiosis and pathogenic flora in FI and NEC, consistent microbiome‑related risk factors and clear diagnostic approaches have not yet been defined, and the search for reliable noninvasive intestinal markers continues. The aim of the present study was to determine whether pathogenic intestinal colonization and elevated fecal calprotectin (FC) levels are associated with FI and NEC in preterm infants with a low birth weight. For this purpose, the present prospective cohort study compared gut microbiota composition and FC levels in preterm infants with and without FI. The present study included preterm infants with a VLBW or ELBW (birth weight, <1,500 g; age >14 days). Infants with FI formed the study group (n=57), and those without GI symptoms served as the controls (n 21). Preterm infants with a VLBW or ELBW and FI (n=57) were found to carry pathogenic flora, including Klebsiella pneumoniae (29.8%), Klebsiella oxytoca (22.8%), Enterobacter cloacae (17.6%), Enterobacter aerogenes (15.8%), Citrobacter koseri (10.5%), Acinetobacter baumannii complex (1.7%) and Candida albicans (7.0%). A total of 10 infants (17.5%) subsequently developed NEC, accompanied by an increase in the level of FC. N the whole, the present study found that underweight preterm infants with FI in the ICUs had pathogenic or potentially pathogenic microorganisms in their gut microbiota and were at risk of developing NEC. For preterm infants with a VLBW or ELBW in ICUs, the early identification of pathogenic gut colonization and elevated FC levels may help stratify the risk of FI and NEC and guide targeted preventive strategies.