Intestinal flora and infection of neonates

Abstract

Systemic bacterial infection during the neonatal period is often severe and difficult to treat. The intestinal bacterial flora is thought one of the major sources of the causative agents. Generally no bacteria can be found in the feces of newborn infants immediately after birth. This study was designed to clarify the relationship between bacterial infection and the process of intestinal flora formation.First the intestinal flora of twelve neonates was analyzed. Another ten neonates were administered Bifidobacterium breve, which is non-pathogenic and is found in the feces of many healthy nursing infants. Neonates with abnormal proliferation of specific pathogenic bacteria in the intestinal tract were administered B. breve orally.The following results were obtained.1) The formation of the intestinal flora was divided into three types. One type is that in which only intestinal bacteria were detected from the beginning. Another type is that in which some bacteria, such as Acinetobacter or Bacillus, other than intestinal ones were detected transiently. The third type is that in which only certain specific bacteria, for example Pseudomonas aeruginosa or Serratia marcescens colonized continuously and abundantly, causing bacterial infection.2) Orally administered B. breve could colonize in the gastrointestinal tract of newborn infants when given right after birth.3) When the neonates with abnormal proliferation of specific bacteria were administered B. breve orally, the B. breve colonized and the specific bacteria disappeared from the digestive tract.