Metabolism of primary bile acids by Clostridium perfringens.
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Bile Acids and Salts↗
Biomedical subjects
V D Bokkenheuser
Publications and source records attributed to V D Bokkenheuser.
Location of Campylobacter jejuni in infected chicken livers.
To determine whether chicken livers infected with Campylobacter jejuni are seeded in vivo or contaminated after slaughtering, 117 livers purchased in retail outlets in New York were examined for surface and tissue infections. Of 56 livers positive for C. jejuni, 36 yielded surface growth only, 18 both surface and tissue growth, and 2 tissue growth only. The scanty growth from tissue samples suggests a carry-over of organisms from the surface. It was concluded, therefore, that contamination is most likely due to unhygienic handling of offal. Infection rates of livers varied from retailer to retailer.
Animals↗
Inactivation of contraceptive steroid hormones by human intestinal clostridia.
Steroid hormones reduced in ring-A are devoid of hormonal activity. In metabolic experiments we found that human fecal flora reduced the delta 4-3-keto structure of natural progestins to 3 alpha-hydroxy, 5 beta-steroid metabolites (3 alpha,5 beta) and of synthetic progestins to a mixture of 3 alpha,5 beta and 3 beta,5 beta compounds. 3 alpha,5 beta-Reductase was synthesized by Clostridium paraputrificum and had a strong affinity for natural progestins such as progesterone. 3 beta,5 beta-Reductase was synthesized by Clostridium innoculin and had a stronger affinity for synthetic progestins. A third enzyme, 3 beta,5 alpha-reductase, was synthesized by St. Luke's strain 209 (Clostridium species "J-1") but was only observed when pure cultures were used. Ring-A reduction of synthetic progestins was 3 to 10 times slower than that of natural progestins, thus explaining the pharmacological superiority of synthetic progestins over naturally occurring analogs.
Clostridium↗
Age related susceptibility to Campylobacter jejuni infection in a high prevalance population.
In a year long prospective study of diarrhoea in children under 2 years of age in Soweto, South Africa, Campylobacter jejuni was isolated in 18 of 60 children under 9 months of age with diarrhoea, compared with 4 of 60 age matched controls. In the older children, 16 of 51 children with diarrhoea and 17 of 51 control children excreted this organism in their faeces. These results indicate a change in susceptibility to C jejuni in children over 9 months of age. Campylobacter enteritis in the young children was usually mild, without macroscopic blood in the faeces, and prolonged excretion of the organism after acute attacks was not infrequent. Breast feeding did not seem to protect against colonisation with C jejuni.
Age Factors↗
Degradation of steroids in the human gut.
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Adult↗
Fecal steroid 21-dehydroxylase, a potential marker for colorectal cancer.
Eubacterium lentum and phenotypically similar organisms synthesize a steroid 21-dehydroxylase which converts biliary tetrahydrodeoxycorticosterone to pregnanolone. Tetrahydrodeoxycorticosterone, in contrast to pregnanolone, is carcinogenic for hamster embryonic cells (HECT test). In patients with recently diagnosed, untreated sigmoidal or rectal cancer the fecal concentration of 21-dehydroxylating organisms is reduced by more than 99% as compared with age-matched controls. The lack of fecal 21-dehydroxylating organisms, therefore, is a potential marker for the disorder. The role of steroid 21-dehydroxylase in the pathogenesis of colorectal cancer is unknown.
Adult↗
16 alpha-dehydration of corticoids by bacteria isolated from rat fecal flora.
Two strains (No. 144 and No. 146) of rat intestinal anaerobic bacteria, phenotypically similar to Eubacterium lentum, were isolated and found capable of 16 alpha-dehydrating corticoids. The initial step in the 16 alpha-dehydration of 16 alpha-hydroxyprogesterone was dehydration at the C-16 and C-17 position with the accumulation of 16-dehydroprogesterone. This step required the side chain at C-17. In bacterial cultures the 16-dehydroprogesterone was then slowly reduced to iso-progesterone. 16 alpha-Hydroxypregnanolone was also converted to iso-pregnanolone by these bacteria. 16 alpha-Dehydratase was easily demonstrated in cell fractions of strain No. 144 incubated either aerobically or anaerobically. The same extracts did not convert 16-dehydroprogesterone to iso-progesterone under similar assay conditions. 16 alpha-Dehydration occurred at all substrate concentrations tested (20 to 200 micrograms/ml) provided the pH of the growth medium was between 6 abd 8 and the Eh below -130 mV. Strain No. 146 had both 16 alpha-dehydration and 21-dehydroxylation activities. The two enzymes functioned independently. A role for intestinal bacteria in the biotransformation of biliary 16 alpha-hydroxylated steroids and subsequent excretion in the urine is proposed.
Adrenal Cortex Hormones↗
Formation of 20 beta-dihydrosteroids by anaerobic bacteria.
Cortisol was metabolized to a variety of products, among them small amounts of cortol by fecal flora of humans and rats. A microorganism, Bifidobacterium adolescentis, isolated from both sources, synthesized a 20-hydroxysteroid dehydrogenase which reduced cortisol to 20 beta-dihydrocortisol. The metabolite was reduced to cortol by Clostridium paraputrificum. The 20-hydroxysteroid dehydrogenase showed a wide substrate specificity; it was independent of the 4-ene and the configuration at C3, C-11, C-17 and C-21. Cortol was resistant to any further alteration by human fecal flora, i.e. it is a metabolic end product. As expected, B. adolescentis effectively prevented 21-dehydroxylation of cortisol by Eubacterium lentum.
Adrenal Cortex Hormones↗
Primary isolation of Campylobacter fetus subspecies jejuni.
Primary isolation of Campylobacter fetus ss. jejuni following selective filtration can be achieved equally well on a Columbia agar supplemented with sheep blood (5%), horse blood (5-10%), or heat-treated horse blood (chocolate agar). Larger, but not more, colonies were formed at 42C. However, the higher temperature inhibits C. fetus ss. Intestinalis. Reduced oxygen tension (5%) was advantageous for cultures on media supplemented with sheep blood. All other media tested did equally well as long as the atmosphere was enriched with 5-10% CO2.
Animals↗
Biotransformation of 16 alpha-hydroxyprogesterone by Eubacterium sp. 144: non-enzymatic addition of L-cysteine to delta 16-progesterone.
Eubacterium sp. 144 dehydroxylated 16 alpha-hydroxy-progesterone; however, the expected intermediate, delta 16-progesterone, did not accumulate to significant concentrations in the culture medium. Moreover, the final end product of this biotransformation, 17 alpha-progesterone, was produced at a very slow rate. It was discovered that, under our culture conditions, delta 16-progesterone reacted chemically with L-cysteine to form a highly water-soluble derivative. The ability of delta 16-progesterone to react with L-cysteine in culture media was considerably reduced when L-cysteine was autoclaved in the presence of complex medium components. delta 16-Progesterone also reacted chemically with D-cysteine, L-homocysteine, glutathione, and 2-mercaptoethylamine. The reaction was favored by alkaline pH (greater than or equal to pH 8.0) and required both an unhindered thiol group and a proximal amino group on the mercapto compound. Chromatography of the putative delta 16-progesterone L-[U-14C]-cysteine reaction product by HPLC showed a single UV-absorbing, radioactive peak (RT 4.31 min).
Biotransformation↗
Side-chain cleavage of cortisol by fecal flora.
The side chain of certain C-21 steroids may be removed by an enzyme, desmolase, synthesized by intestinal bacteria. With a view to isolate these organisms we examined the conditions required for their multiplication and function. The model substrate, cortisol (11 beta, 17 alpha, 21-trihydroxy-4-pregnene-3,20-dione), was metabolized by mixed fecal flora of humans and rats to a number of C-21 and C-19 compounds. The major C-21 metabolites were 21-deoxycortisol, tetrahydro-21-deoxycortisol, and tetrahydrocortisol. The C-19 metabolites obtained were identified as 5 beta-androstane-3 alpha, 11 beta-triol and 5 xi-androstane-3 alpha, 11 beta-diol-17-one. The prevalence of converting microorganisms was approximately 10(6)/g feces in both humans and rats. Conversion required an Eh below -130 mV, and an initial pH of 7.0. Optimal yield of C-19 products occurred with a fecal dilution of 10(5), though C-19 metabolites were evident from 10(1) through 10(8) fecal dilutions. Preliminary investigation indicates that the ability of converting organisms to form colonies varied with the composition of the media and the gaseous environment.
Aerobiosis↗
In vitro susceptibility of Campylobacter fetus subsp. jejuni to N-formimidoyl thienamycin, rosaramicin, cefoperazone, and other antimicrobial agents.
The activities of 11 antimicrobial agents against 36 strains of Campylobacter fetus subsp. jejuni were studied by a broth microdilution method. All strains were susceptible to 7 of the 11 antimicrobial agents. Of the newer agents tested N-formimidoyl thienamycin (MK0787) and rosaramicin had very good activity, whereas cefotaxime, moxalactam, and cefoperazone had poorer activity.
Animals↗
Long-term infections with Campylobacter fetus subsp. jejuni.
Seventy-three apparently healthy, rural South African schoolchildren 6 to 8 or 13 to 16 years of age were examined five times over a 16-month period for fecal pathogens. Nine were positive for Campylobacter fetus subsp. jejuni. The organism was isolated intermittently from six children for at least 9 months and from three children for more than 1 year. Five of the long-term infections occurred among the 46 children aged 6 to 8 years (10.9%) versus one long-term infection among the 27 children aged 13 to 16 years (3.7%). It is not possible with present microbiological techniques to make a clear-cut distinction between reinfected subjects and chronic carriers.
Adolescent↗
Campylobacter fetus jejuni enteritis; in New York City.
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Adolescent↗
Dehydroxylation of 16 alpha-hydroxyprogesterone by fecal flora of man and rat.
16 alpha-Hydroxyprogesterone, precursor of biliary 16 alpha-hydroxypregnanolone, was incubated with mixed fecal flora of humans and rats. The major steroid metabolite formed in both systems was 3 alpha-hydroxy-17 alpha-pregnan-20-one. These results demonstrated that the fecal flora reduced the delta 4-3 keto structure, removed the hydroxy group at C-16 and isomerized the side chain from the beta to the alpha configuration. Ring-A reduction of the substrate resulted in a 5 beta-compound with human flora and a 5 alpha-product with rat bacteria. The prevalence of 16 alpha-dehydroxylating organisms varied considerably in human fecal flora and was approximately 10(5)/g of feces in the three rats tested. Rat fecal flora dehydroxylated 16 alpha-hydroxyprogesterone after 4-5 days incubation at 37 degrees C, at pH 6.5-7.5, and with a substrate concentration of 20-80 microgram/ml (optimal condition). Preliminary evidence suggests that 16 alpha-dehydroxylase is exclusively of bacterial origin and is synthesized by an obligate anaerobe.
Adult↗
Biotransformation of steroid hormones by gut bacteria.
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Animals↗
Isolation and characterization of fecal bacteria capable of 16 alpha-dehydroxylating corticoids.
For more than a decade it has been known that the fecal flora of humans and rats includes organisms capable of 16 alpha-dehydroxylating corticoids, but their identity has remained unknown. To isolate these organisms, Mueller-Hinton agar plates were seeded with fresh feces from Proteus-free rats and incubated anaerobically. On an average, 1 of every 35 colonies consisted of organisms synthesizing 16 alpha-dehydroxylase. Isolation of the individual colonies yielded two obligate anerobes, strains 144 and 146, which elaborated the enzyme. The steroid transformation could be attained by the microbial culture alone in prereduced media or in aerobic media in the presence of Escherichia coli. Although both strains were phenotypically similar to Eubacterium lentum, they differed between themselves in their enzymatic equipment.
Adrenal Cortex Hormones↗
Broiler chickens as potential source of Campylobacter infections in humans.
Of 46 broiler chickens from a live poultry market in New York City, 38 (83%) harbored Campylobacter fetus subsp. jejuni in their rectal flora. The observed mean number of C. fetus per g of feces was 4.4 x 10(6). The organisms survived in the feces for at least 96 h at 4 degrees C whether stored in the gut or transferred to a vial. The best survival medium for pure cultures of C. fetus subsp.jejuni was heart infusion broth supplemented with sterile blood and kept in a microaerophilic atmosphere.
Animals↗