Teisuke Imamura

Clostridium hiranonis sp. nov., a human intestinal bacterium with bile acid 7alpha-dehydroxylating activity

The Clostridium-like organisms TO-931T and HD-17, isolated from human faeces, have high levels of bile acid 7alpha-dehydroxylating activity. Sequencing of their 16S rDNA demonstrated that they belong to cluster XI of the genus Clostridium and that they represent a new and distinct line of descent. Clostridium bifermentans and Clostridium sordellii in cluster XI also possess bile acid 7alpha-dehydroxylating activity. DNA-DNA hybridization experiments with the isolates, TO-931T and HD-17, and C bifermentans and C. sordellii revealed that the isolates are a single species distinct from C. bifermentans and C sordellii. On the basis of phylogenetic analysis, using 16S rDNA sequences, and DNA-DNA hybridization analysis, it is concluded that strains TO-931T and HD-17 are members of a new species of the genus Clostridium, for which the name Clostridium hiranonis is proposed. The type strain is strain TO-931T (= JCM 10541T = DSM 13275T).

Assignment of Eubacterium sp. VPI 12708 and related strains with high bile acid 7alpha-dehydroxylating activity to Clostridium scindens and proposal of Clostridium hylemonae sp. nov., isolated from human faeces.

Unknown Eubacterium-like organisms VPI 12708 and five strains (Y-1113, I-10, M-18, TH-82 and 36S) had high bile acid 7alpha-dehydroxylating activity; the unknown Clostridium-like organisms TN-271T and TN-272 also had the same activity. Analysis of their 16S rDNA sequences demonstrated that all strains belong to cluster XIVa of the genus Clostridium (Collins et al., 1994). Strain VPI 12708 and five other strains (Y-1113, I-10, M-18, TH-82 and 36S) formed a single cluster and strains TN-271T and TN-272 formed another single cluster. Clostridium scindens JCM 6567T was the most closely related species for two clusters in the phylogenetic tree. Values for DNA-DNA similarities among C. scindens JCM 6567T, strain VPI 12708 and the other five strains were greater than 70%, showing that these micro-organisms were a single species. Therefore, we identified strain VPI 12708 and the five other strains as C. scindens. In addition, DNA-DNA similarities among C. scindens JCM 6567T, strain TN-271T and strain N-272 revealed that strains TN-271T and TN-272 were distinct from C. scindens JCM 6567T. On the basis of phylogenetic analysis and DNA-DNA similarity data, it was concluded that strains TN-271T and TN-272 are members of a new species of the genus Clostridium, for which the name Clostridium hylemonae is proposed. The type strain is strain TN-271T (= JCM 10539T).

The Effects of Oral RNA and Intraperitoneal Nucleoside-Nucleotide Administration on Methicillin-Resistant Staphylococcus aureus Infection in Mice

The effects of oral RNA and intraperitoneal nucleoside-nucleotide mixture administration on methicillin-resistant Staphylococcus aureus (MRSA) strain 8985N infection were studied in mice. BALB/c mice were fed a nucleic acid-free diet or nucleic acid-free diet supplemented with 0.5% or 2.5% ribonucleic acid (RNA) for 30 days. Nucleoside-nucleotide mixture or saline (control) was intraperitoneally administered daily to these rats except for the 2.5% RNA group, which received saline only. On the 10th day of this treatment, the mice were inoculated intravenously with the viable MRSA organisms. Susceptibility to the MRSA was determined by animal survival and recovery of the MRSA from the organs. The survival rates in the three groups that were administered saline were 29%, 35%, and 40% for nucleic acid-free diet, 0.5% RNA, and 2.5% RNA groups, respectively, whereas in the two groups that received the nucleoside-nucleotide mixture the rates were 69% for the nucleic acid-free diet group and 55% for 0.5% RNA group. The susceptibility of the mice to the MRSA challenge was not affected by dietary RNA, which indicates the ineffectiveness of oral RNA. The combined survival rate in the two nucleoside-nucleotide groups (64%) was statistically different (p < .01) from that in the three saline groups (34%). There was a greater reduction in viable organism recovery in the kidney and spleen of the surviving mice that had been administered the nucleoside-nucleotide mixture than in those administered saline.(ABSTRACT TRUNCATED AT 250 WORDS)

Isolation and Characterization of Bile Acid 7-Dehydroxylating Bacteria from Human Feces

Methods for isolation of fecal 7α‐dehydroxylating bacteria are presented. A total of 219 strains were isolated from feces of healthy humans, and their ability to 7‐dehydroxylate cholic, chenodeoxycholic, and ursodeoxycholic acids were examined. Of all the isolates, 14 strains were found to be capable of eliminating the hydroxy group at C‐7α and/or C‐7β. All the isolates were strictly anaerobic, Gram‐positive rods. Thirteen isolates were non‐sporeforming bacteria showing certain saccharolytic properties with the production of acid and gas from dextrose, and were catalase‐positive but indole‐, lecithinase‐, urease‐ and oxidase‐negative. Based on the data available at present, it was concluded that they could be regarded as members of the genus Eubacterium. One strain, however was identified as Clostridium sordellii. The isolated strains capable of 7α‐dehydroxylating cholic acid and chenodeoxycholic acid were also able to oxidize the hydroxy group at C‐7α. Nine strains (10, 12, 36S, M‐2, M‐17, M‐18, Y‐98, Y‐1112, and Y‐1113) of the 7α‐dehydroxylating bacteria were confirmed to have 7β‐dehydroxylation ability, but five strains (O‐51, O‐52, O‐71, O‐72, and Y‐67) could not transform ursodeoxycholic acid to lithocholic acid.

7β-Dehydroxylation of 3, 7-Dihydroxy Bile Acids by a Eubacterium Species Strain C-25 and Stimulation of 7β-Dehydroxylation by Bacteroides distasonis Strain K-5

It is well known that the elimination of the 7ƒ¿-hydroxy group of primary bile acids, cholic acid (CA) and chenodeoxycholic acid (CDCA) occurs frequently by intestinal bacteria in vivo. Actually,7-dehydroxylated bile acids were found in more than 80% of human fecal bile acids (2). Recently microbial strains capable of 7ƒ¿-dehydroxylating bile acids have been isolated by several researchers (1, 4-6, 9, 11, 13, 14). However, all of the 7ƒ¿-dehydroxylating activity of bacteria was reported to be weak in vitro. Hirano and Masuda (7) reported that they isolated 7ƒ¿-dehydroxylating bacteria (Eubacterium sp.), the 7ƒ¿-dehydroxylation of which was clearly stimulated when cocultured with Bacteroides spp. which alone has no 7ƒ¿dehydroxylation activity. They suggested an important cooperative reaction among different microorganisms. Therefore their findings may help explain the extensive occurrence of 7ƒ¿-dehydroxylated bile acids in the human intestine. On the other hand, a little ursodeoxycholic acid (UDCA), which is a 7-epimer of CDCA, was found in human bile and feces under normal conditions. This bile acid and CDCA have been used for dissolution of cholesterol gallstones. How ever, there have been a few reports on the transformation of UDCA, particularly on 7ƒÀ-dehydroxylation in vivo and in vitro (3, 15). Our investigation was designed to test 7ƒÀ-dehydroxylation activity by a gram

Compatibility of Bricef Dry Syrup with Oral Liquids

Compatibility of Bricef Dry Syrup (cefatrizine oral suspension) with oral liquids was investigated with regard to changes in appearance, pH value and residual potency. These changes were tested immediately, and 3, 7 and 14 days after admixing at room temperature, and in some admixtures, at 6°C.At room temperature, decrease in residual potency during incubation was observed in admixture with concentrated brocin-codeine, brocin, and transamin syrup; however, the decrease was prevented at 6°C. A large decrease in pH was observed in the admixture with decreased potency. Consequently, a correlation between decrease of pH and potency may be considered. Significant change in appearance was not observed in any of the combinations tested.