Intestinal microbiota and secretory immunoglobulin A in feces of exclusively breast-fed infants with blood-streaked stools.
Episodes of blood-streaked stools are not uncommon in exclusively breast-fed infants under 6 months of age. Such bleeding is thought to be associated with food protein-induced proctocolitis, however the pathomechanism remains unclear. The aim of this study was to investigate intestinal microbiota and secretory immunoglobulin A in the feces of exclusively breast-fed infants with blood-streaked stools. Fecal specimens from 15 full-term infants with blood-streaked stools and 15 breast-fed healthy infants were studied and the results compared. All infants had been delivered vaginally and exclusively breast-fed. The fecal microbiota were investigated by phylogenetic analysis combined with culture methods for some bacterial species, and feces were assessed for the presence of fecal secretory immunoglobulin A by enzyme-linked immunosorbent assay. Phylogenetic cluster analysis revealed four major clusters of fecal bacteria, cluster A being found only in healthy infants. The Bacteroides fragilis group was observed more frequently in controls than in patients (P < 0.05). In the controls, the predominant species belonging to the Enterobacteriaceae group was Escherichia coli, whereas in the patients it was Klebsiella (P < 0.05). Concentrations of secretory immunoglobulin A were high in one third of the healthy controls. In conclusion, the pathomechanism of rectal bleeding in exclusively breast-fed infants may be related to differences in the composition of their intestinal flora.
Department of Pediatrics, Hitachiomiya Saiseikai Hospital, 3033-3 Tagouchi-cho, Hitachiomiya, Ibaraki 319-2256, Japan. h-kumagai@jichi.ac.jp
Hideki
H
Kumagai
Shun-ichi
S
Maisawa
Mamoru
M
Tanaka
Motomichi
M
Takahashi
Yuhei
Y
Takasago
Asaka
A
Nishijima
Shuhka
S
Watanabe
D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D001431:Bacteriological Techniques / Q000379:methods; D058448:Biota; D001942:Breast Feeding; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005243:Feces / Q000737:chemistry* / Q000382:microbiology*; D005260:Female; D006801:Humans; D007071:Immunoglobulin A, Secretory / Q000032:analysis*; D007223:Infant; D008297:Male; D056186:Metagenomics / Q000379:methods; D010802:Phylogeny; D011350:Proctocolitis / Q000276:immunology* / Q000382:microbiology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics
D004269:DNA, Bacterial; D007071:Immunoglobulin A, Secretory; D012336:RNA, Ribosomal, 16S