Based on our results, for newborns suspected of having early-onset bacterial infections, using a cut-off value of the 95th percentile in the reference curve for preterm infants or a combination of PCT level, CRP level, WBC count, and/or IgM level for term infants would lead to the appropriate use of antimicrobial drugs and prevent antimicrobial resistance [22]. This evidence concerns the gene CALCA and bacterial infectious disease.