Intestinal floras of populations that have a high risk of colon cancer

Abstract

The fecal floras of polyp patients, Japanese-Hawaiians, North American Caucasians, rural native Japanese, and rural native Africans were compared. The polyp patients and Japanese-Hawaiians were considered to be groups at high risk of colon cancer, and the rural native Japanese and rural native Africans were considered to be groups at low risk. The North American Caucasians were found to have a flora composition intermediate between these two groups. Fifteen bacterial taxa from the human fecal flora were significantly associated with high risk of colon cancer, and five were significantly associated with low risk of colon cancer. Total concentrations of Bacteroides species and, surprisingly, Bifidobacterium species were generally positively associated with increased risk of colon cancer. Some Lactobacillus species and Eubacterium aerofaciens, which also produces major amounts of lactic acid, showed closest associations with low risk of colon cancer.

Environmental factors in inflammatory bowel disease: A co-twin control study of a Swedish-Danish twin population

“…1 Colonization of the gastrointestinal tract starts immediately after birth 11 and is of great importance for the composition of the permanent flora in adults. 23 Furthermore, the intestinal microflora affects the gut-associated lymphoid tissue, and their interaction appears to be essential for development of appropriate regulatory circuits of the immune response. 11 Environmental factors influencing the intestinal microflora include infections, diet, and antibiotics.…”

Diversity of the human gastrointestinal tract microbiota revisited

“…Molecular studies showed that members of the phylum Cyanobacteria (one phylotype) can be found in the human gastrointestinal samples (Eckburg et al, 2005), even though isolates from this group have not been reported. Furthermore, six phylotypes of the subphylum of a-Proteobacteria were detected by SSU rRNA gene sequencing, while there is only one known a-proteobacterial gastrointestinal isolate -Gemmiger formicilis (Holdeman et al, 1976;Benno et al, 1986;Moore and Moore, 1995;Macfarlane et al, 2004). Unfortunately, no 16S rRNA gene sequence is available for this species.…”

The microbiology of butyrate formation in the human colon

“…Extensive past surveys of the cultivable human intestinal micro£ora [25,26] showed that the colon harbours signi¢cant populations of genera, such as Clostridium, Eubacterium and Fusobacterium that include butyrate-producing species. The relationships of these bacteria are, however, currently undergoing rapid revision in the light of information from 16S rRNA sequencing (e.g.…”