Tomotari Mitsuoka

The intestinal microflora of infants: composition of fecal flora in breast-fed and bottle-fed infants.

The fecal flora of 35 breast‐fed and 35 bottle‐fed babies was determined. Bifidobacteria were the predominant fecal bacteria in both groups. Conversely, the counts of most of the other bacteria, such as bacteroides, eubacteria, peptococci, veillonella, clostridia, enterobacteria, streptococci, and bacilli in the bottle‐fed group were significantly higher than those in the breast‐fed group. The frequencies of occurrence of lecithinase positive Clostridia, clostridia‐others, pseudomonas and bacilli in the bottle‐fed group were significantly higher than those in the breast‐fed group. Twenty‐one genera and 103 species or biovars of microorganisms were isolated from the feces of the breast‐fed group and 20 genera and 97 species or biovars from the bottle‐fed group. The organism that showed the highest number and the highest frequency of occurrence in both groups was Bifidobacterium breve. Bifidobacterium infantis, which was formerly the most prevalent Bifidobacterium species in baby feces, was never isolated in this study. Further, the counts and incidences of Clostridium paraputrificum, C. perfringens, and Bacillus subtilis, the counts of C. clostridiiforme, Bacteroides vulgatus, Veillonella parvula, Lactobacillus acidophilus, Escherichia coli, Streptococcus bovis, S. faecalis, and S. faecium and the incidences of C. difficile, C. tertium, and Pseudomonas aeruginosa in the bottle‐fed infants were significantly higher than those in the breast‐fed infants.

Bifidobacteria and their role in human health

SummaryThere is a growing consensus on the beneficial effects of bifidobacteria in human health. It is now clear that bifidobacteria that exist in the large intestine are helpful for maintenance of human health and are far more important thanLactobacillus acidophilus as beneficial intestinal bacteria throughout human life. In other words, the reduction or disappearance of bifidobacteria in the human intestine would indicate an “unhealthy” state. Oral administration of bifidobacteria may be effective for the improvement of intestinal flora and intestinal environment, for the therapy of enteric and hepatic disorders, for stimulation of the immune response, and possibly for the prevention of cancer and slowing the aging process. However, for consistent and positive results further well-controlled studies are urgently needed.

Effect of a probiotic formula on intestinal immunoglobulin A production in healthy children

The anti-infectious effect of probiotics has recently been reported and one mechanism may be the non-specific stimulation of immunity. This study was performed to elucidate the influence of a probiotic formula on intestinal microflora and local immunity in healthy children. A follow-up formula containing viable bifidobacteria was given to seven healthy Japanese children (15 to 31 months old) for 21 days. During intake of the formula, the administered strain was detected in feces from five subjects (71%) and total fecal bifidobacteria slightly increased. Fecal levels of total IgA and anti-poliovirus IgA during intake of the formula were significantly higher than those before intake (P < 0.05). The increase in local IgA levels resulting from ingestion of the probiotic formula may contribute to enhancement of the mucosal resistance against gastrointestinal infections.

The Human Gastrointestinal Tract

The concept of the group name ‘lactic acid bacteria’ was created for bacteria causing fermentation and coagulation in milk, and defined as those which produce lactic acid from lactose. The family name Lactobacteriaceae was applied by Orla-Jensen (1919) to a physiological group of Gram-positive rods and cocci that ferment carbohydrates either to lactic acid alone or to lactic and acetic acids, alcohol and carbon dioxide. Today, lactic acid bacteria are regarded as synonymous by and large with the family Lactobacillaceae (Breed et al.,1957), which is now recognised as consisting of Gram-positive, non-sporing, carbohydrate-fermenting lactic acid producers, acid tolerant, of non-aerobic habit and catalase negative; typically they are non-motile and do not reduce nitrate. They are sub-divided into four genera Streptococcus, Leuconostoc, Pediococcus, and Lactobacillus.

Taxonomic Study of the Lactobacillus acidophilus Group, with Recognition of Lactobacillus gallinarum sp. nov. and Lactobacillus johnsonii sp. nov. and Synonymy of Lactobacillus acidophilus Group A3 (Johnson et al. 1980) with the Type Strain of Lactobacillus amylovorus (Nakamura 1981)

Biochemical properties and DNA-DNA reassociation studies of Lactobacillus acidophilus strains isolated from humans and animals indicate that these include six genomospecies. Two new species can be differentiated from the established species of the genus Lactobacillus: L. gallinarum sp. nov. (type strain, ATCC 33199) and L. johnsonii sp. nov. (type strain, ATCC 33200). Furthermore, it was clarified that L. acidophilus group A3 (Johnson et al. 1980) is synonymous with L. amylovorus.

Impact of Bifidobacterium longum on Human Fecal Microflora

The effects of the Bifidobacterium longum feedings for five weeks on the fecal microflora, water contents, pH values, ammonia concentration, and β‐glucuronidase activity were investigated in five healthy human volunteers. Although numbers of major bacterial groups of the fecal microflora were not changed by the bifidobacteria feedings, a remarkably decreasing number of lecithinase‐negative clostridia was observed. The percentage of lecithinase‐negative clostridia and bacteroides to the total bacterial numbers isolated were decreased during the feedings and numbers of C. paraputrificum and C. innocuum were reduced. A significant reduction of fecal pH values for the last week of the feeding was observed. Ammonia concentration and β‐glucuronidase activity in the feces during the feedings were significantly lower than those before or after the feedings. The oral supplement of B. longum may be introduced to improve the fecal properties such as fecal ammonia concentration and β‐glucuronidase activity, but not the composition of fecal flora.

DNA relatedness among Erysipelothrix rhusiopathiae strains representing all twenty-three serovars and Erysipelothrix tonsillarum.

The levels of relatedness among strains of Erysipelothrix rhusiopathiae (serovars 1 through 23 and type N) were estimated by performing DNA-DNA hybridization experiments with the type strains of E. rhusiopathiae and Erysipelothrix tonsillarum, which are the two Erysipelothrix species that have been described. Two distinct DNA relatedness groups were identified. The group 1 strains, representing serovars 1, 2, 4 through 6, 8, 9, 11, 12, 15 through 17, 19, and 21 and type N, exhibited more than 73% hybridization with the type strain of E. rhusiopathiae but less than 24% hybridization with the type strain of E. tonsillarum. Group 2 included serovar 3, 7, 10, 14, 20, 22, and 23 strains, and these strains exhibited more than 66% hybridization with the type strain of E. tonsillarum but less than 27% hybridization with the type strain of E. rhusiopathiae. Strains representing serovars 13 and 18 exhibited low levels of hybridization (16 to 47%) with both of the type strains, indicating that these serovars may be members of a new genomic species. The members of the E. rhusiopathiae and E. tonsillarum groups resembled each other in many phenotypic characteristics, but differed in their ability to produce acid from saccharose and in their pathogenicity for swine. Our results confirm that the genus Erysipelothrix contains two main genomic species, E. rhusiopathiae and E. tonsillarum, which can be differentiated into serovars.

Comparison of the Fecal Microflora in Rural Japanese and Urban Canadians

The fecal microflora of nine rural healthy Japanese and eight urban healthy Canadians was examined. The two populations ate typical Japanese and western diets, respectively. The numbers of eubacteria (P<0.01), bifidobacteria (P<0.05), bacilli (P<0.01), lactobacilli and veillonellae and the frequency of occurrence of bifidobacteria were higher in the Japanese than in the Canadians. Higher numbers of bacteroides and lecithinase‐negative Clostridia were found in the Canadians. Twenty‐three genera and over 75 species or biovars were isolated from the feces of Japanese and 18 genera and over 66 species or biovars from the Canadians. The numbers of Bacteroides vulgatus (P<0.05), Clostridium coccides (P<0.001), and C. tertium (P<0.05) and the incidence of B. uniformis (P<0.01), C. innocuum (P<0.05), and Bacillus spp. (P<0.01) were significantly lower in the Japanese than in the Canadians. In contrast, the numbers of Eubacterium aerofaciens (P<0.001), and the incidence of Bifidobacterium adolescentis biovar b (P<0.01) and Bacillus subtilis (P<0.01) were significantly higher in the Japanese than in the Canadians. These findings suggest that significant reductions in anaerobic grampositive bacilli and increased numbers of bacteroides and Clostridia in the feces were induced by the intake of a western diet.

Staphylococcus schleiferi subsp. coagulans subsp. nov., isolated from the external auditory meatus of dogs with external ear otitis.

A new subspecies, Staphylococcus schleiferi subsp. coagulans, was isolated from the external auditory meatus of dogs suffering from external ear otitis and is described on the basis of studies of 21 strains. Phenotypic studies showed that these strains are more closely related to Staphylococcus intermedius than to other staphylococci, but DNA hybridization studies indicated that they are closely related to Staphylococcus schleiferi N850274T. On the basis of biochemical distinctiveness (positive test tube coagulase test and different carbohydrate reactions) and the etiological importance (frequent isolation from otitis specimens from dogs) of these strains, we propose to classify them as a subspecies of S. schleiferi. The strains of this new subspecies are coagulase tube test, beta-hemolysin, and heat-stable nuclease positive but clumping factor negative. A simple scheme for the differentiation of S. schleiferi subsp. coagulans from the other coagulase-positive staphylococci is presented. The type strain is GA211 (= JCM 7470).

Proposal of two subspecies of Fusobacterium necrophorum (Flügge) Moore and Holdeman: Fusobacterium necrophorum subsp. necrophorum subsp. nov., nom. rev. (ex Flügge 1886), and Fusobacterium necrophorum subsp. funduliforme subsp. nov., nom. rev. (ex Hallé 1898).

The biological and biochemical properties, DNA base compositions, and levels of DNA-DNA homology of two biovars of Fusobacterium necrophorum were examined. Some differences were found between the two biovars in biological and biochemical properties. The G + C contents of DNAs from biovar A strains VPI 2891T (T = type strain), NCTC 10576, N167, Fn47, and Fn43, were 32, 30, 29, 28, and 31 mol%, respectively. The G + C contents of DNAs from biovar B strains Fn524T, 606, Fn49, Fn45, and 1260 were 30, 31, 27, 31, and 30 mol%, respectively. Labeled DNA from biovar A strain VPI 2891T exhibited 100 to 80% relatedness to DNAs from biovar A strains and 59 to 51% relatedness to DNAs from biovar B strains. Labeled DNA from biovar B strain Fn524T exhibited 100 to 81% relatedness to DNAs from biovar B strains and 71 to 60% relatedness to DNAs from biovar A strains. Therefore, the names Fusobacterium necrophorum subsp. necrophorum subsp. nov., nom. rev. (ex Flügge 1886), and Fusobacterium necrophorum subsp. funduliforme subsp. nov., nom. rev. (ex Hallé 1898), are proposed for Fusobacterium necrophorum biovars A and B, respectively. The type strain of F. necrophorum subsp. necrophorum is strain VPI 2891 (= JCM 3718 = ATCC 25286), and the type strain of F. necrophorum subsp. funduliforme is strain Fn524 (= JCM 3724).