The number of nosocomial infection

The number of nosocomial infection experienced by preterm infants prior to the development of NEC may lead to increase risk for NEC. An increased number of infection might be due to increased use of parenteral nutrition, which has an immunosuppressive effect by impairing the phagocytosis and killing of coagulase negative staphylococci. Moreover, the risk for NEC increase when preterm infants require central venoustherapy devices that potentially could lead to more infection . This vulnerability to infection could be caused by the overutilization of antibiotics resulting in overgrowth of pathogens and antibiotic-resistant bacteria, subsequently increasing the number of infection. Although the preterm infants' bowel is usually sterile before birth (determined by the sterility of the amniotic fluid), it is rapidly colonized with bacteria within 7 to 10 days after birth. Due to medical treaments of preterm infants (e.g., antibiotic therapy, incubators, pacifiers, and hyperalimentation), the intestinal colonization process may be delayed or impaired, which can cause slower acquisition of commensal bacteria and higher susceptibility to pathogenic colonization. Therefore, preterm infants in neonatal intensive care unit are likely to have alterations in the bacteria colonization of the intestines due to treatment exposures, differences in the microbial flora (neonatal intensive care unit dependent), and antibiotic exposure. Although most investigators acknowledge that infants are at increased risk for NEC because of the presence of pathogens or possible imbalances in the intestinal microbial flora, no literature identified to date has examined the mechanism by which the number of the infections experienced by preterm infants affects their risk for developing NEC.