The ethanol extracts from Japanese green tea from the leaf of Camellia sinensis (Japanese green tea) contained polyphenol compounds as major components. By liquid and gas chromatographic analysis, 5 catechin compounds were detected. The tea extracts (Deochon 13189-B, Deochon 30 EX and Camellia 50 EX) were found to effectively inhibit the growth of canine oral bacteria. Minimum inhibitory concentration (MIC) was different among genus, species and strains of the bacteria. Canine periodontal pathogens such as Porphyromonas assacharolytica were sensitive to the tea extracts. Similar result was obtained by using human oral bacteria including periodontal pathogens. These results suggest that the tea extracts would be useful as anti-periodontitis agent and/or flora control agent in dogs.

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The adherence to human buccal epithelial cells was compared between non-fimbriated and fimbriated strains of Porphyromonas gingivalis. The non-fimbriated strain was isolated from P. gingivalis 381 fimbriated strain by culturing the bacteria with the monoclonal antibody which was specific against the fimbriae of strain 381. The non-fimbriated strain did not agglutinate with the monoclonal antibody or anti-fimbriae antiserum, while it agglutinated with antiserum to whole P. gingivalis 381 cells. Fimbriae were not detected on the surface of non-fimbriated strain by electron microscopy. The adherence of the non-fimbriated strain to epithelial cells was significantly reduced in comparison to that of the original fimbriated strain 381. The mean number of bacteria adhering to epithelial cells was only 9.0± 12.0/buccal cell in the non-fimbriated strain and 92.9± 38.7 in the original strain 381. The hemagglutinating ability was not affected by loss of fimbriae. Additionally, fimbriae did not show hemagglutinating activity. The results indicated that the fimbriae of P. gingivalis 381 are largely responsible for the bacterial adherence to epithelial cells but were not essential for hemagglutinating ability of the organism.

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The fecal specimens from eight laboratory-bred male beagle dogs reared under similar conditions were analyzed for the individual variation and the seasonal variation in the composition of fecal microflora. Statistically significant differences in numbers of bacteroides, bifidobacteria, lecithinase-negative clostridia, lactobacilli, enterobacteria and enterococci were observed among individual animals. Megasphaera elsdenii was isolated from two of eight dogs. The microbial populations of bacteroides, clostridia, bifidobacteria, and peptostreptococci were associated with each other bacterial group. The seasonal variation in numbers of lecithinasenegative clostridia, Clostridium perfringensi, peptostreptococci, enterococci, eubacteria, bifidobacteria, and lactobacilli, and in the incidences of staphylococci, bacilli, and yeasts were noted. The results of this study showed that apparent variations with individuals and season occurred on the fecal microflora of individual beagle dogs reared under similar conditions.

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The β-glucuronidase activity of Escherichia coli isolated from the feces of 10 healthy humans was examined for 178 days. In these human fecal samples, β-glucuronidase-positive E. coliz was not always isolated for long term. This finding shows that the E. coli in human intestine is constantly changed by the various factors.

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