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PubMed1963

Lipid metabolism of rumen ciliates and bacteria. II. Uptake of fatty acids and lipid analysis of Isotricha intestinalis and rumen bacteria with further information on Entodinium simplex.

The total lipid and free fatty acid contents of Isotricha intestinalis, Entodinium simplex, and the rumen bacterial flora of the respective protozoa were determined. Warburg manometric data showed that the sodium salts of tributyrin, oleic, and acetic acids stimulated gas production in I. intestinalis, whereas tributyrin was stimulatory with E. simplex and less active with oleic and acetic acids. Rumen bacteria provided fatty acids produced lower manometric gaseous increases when compared with the protozoa. Volatile fatty acids were produced by I. intestinalis and rumen bacteria with tributyrin, but not with tripalmitin. Sodium oleate gave little volatile fatty acid response with I. intestinalis or rumen bacteria. Washed suspensions of I. intestinalis and rumen bacteria concentrated C(14)-labeled oleic, palmitic, stearic, and linoleic acids within the cells during short incubation periods. Autoradiographs demonstrated the conversion of C(14)-labeled oleic, palmitic, stearic, linoleic, and acetic acids in the rumen protozoa and bacterial cells.

Animals↗
PubMed1964

MODIFICATIONS OF A DEVICE FOR MAINTENANCE OF THE RUMEN MICROBIAL POPULATION IN CONTINUOUS CULTURE.

An improved and simplified apparatus for maintaining the rumen microbial population in continuous culture was constructed. All components were easily obtained from commercial sources or were simple to construct. Mechanical difficulties were minimal, and little attention was needed on the part of the operator. The deoxyribonucleic acid (DNA) content of the cultures (100 to 150 mug/ml) varied little during 7 days of continuous culture, and protozoal concentration decreased from 10(5) per ml to a steady-state level of 2 x 10(3) per ml in 4 days. Volatile fatty acid and methane production followed the normal in vivo pattern for 7 days of continuous culture. DNA, protozoal concentrations, and fermentation patterns did not significantly change between 4 and 21 days of continuous culture.

Animals↗
PubMed1964

DELAYED APPEARANCE OF LACTOBACILLI IN THE INTESTINES OF CHICKS REARED IN A "NEW" ENVIRONMENT.

Male chicks (1 day old; Vantress x Arbor Acre) were fed a basal folic acid-deficient diet, a 5% uric acid-containing diet with and without 5 mg/lb (453.5 g) of bacitracin and 20 mg/lb of sodium penicillin G, the basal diet supplemented with only the antibiotics, and the basal diet plus 500 mug/lb of folic acid. The chicks were reared in a room which had not been used previously for housing chickens ("new" environment). Bacteriological analyses of the contents of the small intestine revealed a decrease in numbers of streptococci and "anaerobic" bacteria in the chicks receiving dietary antibiotics. No persistent changes were seen in the numbers of coliform bacteria. Lactobacilli were not detected in any of the groups until 3 weeks after feeding.

Animals↗
PubMed1964

SOURCE AND PORTAL OF ENTRY OF BACTERIA FOUND IN BRUISED POULTRY TISSUE.

Bacteriological studies revealed that normal tissue, air sacs, feathers, skin of birds, poultry feed, gut, and chicken droppings were sources of the predominant organisms, including staphylococci, found in bruised poultry tissue. Further investigation of normal tissue revealed that after the intramuscular injection of Staphylococcus aureus, marker strain (MS), the organism was eliminated from these tissues within 7 days. However, when these tissues were traumatized 3 days after injection, the number of the test organism increased, and the organism was present on the 7th day after inoculation. Poultry feed and fecal material contained a large number of staphylococci identical to those isolated from bruised tissue (McCarthy, Brown, and Hamdy, 1963), thereby implicating the gut as a possible portal of entry. When a pathogenic marker strain of S. aureus was established in the intestinal tract of chickens by administering an active culture of this organism either in their drinking water or by gavage, it was recovered from the traumatized tissue. The incidence of positive culture of S. aureus MS in these tissues correlated with age of bruise, reaching 22 to 33% immediately after contusion and at the early stages of healing (1 to 3 days post bruise) and decreasing thereafter from 11 to 0% on the 4th through 6th days after bruise infliction. The air sac was also found to be a site by which bacteria may enter the traumatized tissues, but to a limited extent.

Animals↗
PubMed1979

Effect of oral tetracycline, the microbial flora, and the athymic state on gastrointestinal colonization and infection of BALB/c mice with Candida albicans.

Scanning electron microscopy, light microscopy, and quantitative culture of microorganisms in intestinal contents were used to determine the effects of oral tetracycline, the bacterial flora of conventionally reared animals (conventional), and thymus-dependent immune competency on the capacity of Candida albicans to colonize and infect the gastrointestinal tract of four groups of mice: thymus-intact conventional mice, conventional athymic mice, flora-defined athymic mice, and thymus-intact bacteria-free mice. Thymus-intact conventional mice without antibiotic treatment began to shed C. albicans less than 48 h after oral yeast challenge and were devoid of detectable yeast by day 16. Tetracycline altered the bacterial flora qualitatively and quantitatively, allowing C. albicans to colonize in less than 48 h and to persist in the gut tract for 32 days. Only 2 of 72 of these conventional mice developed candidiasis (hyphal infection). Although tetracycline altered the bacterial flora of conventional athymic (nude) mice, it was not required to allow C. albicans to colonize their gut tract to levels significantly higher than those in thymus-intact conventional mice. All conventional nude mice were consistently colonized and 14 of 24 animals showed an increased yeast colonization of the keratinized stomach, but only 3 of 24 developed gastric candidiasis. Flora-defined athymic (nude) mice had significantly lower aerobic bacterial levels and significantly higher C. albicans levels in the gut contents than conventional athymic mice. The flora-defined nude mice, however, developed gastric candidiasis by day 5. Thymus-intact bacteria-free mice were uniformly colonized and infected with C. albicans less than 48 h after oral challenge regardless of tetracycline treatment. Populations of C. albicans in the gut of bacteria-free mice were significantly higher than in the gut tract of the thymus-intact conventional or athymic mice. Gastric mycelial infection was detected in 8 of 10 bacteria-free animals 2 days after oral challenge. By 32 days, 45 of 50 mice of both tetracycline-treated and control bacteria-free groups were infected with C. albicans. These data indicate that a competive bacteria flora is more effective than an intact immune system in preventing gastric candidiasis and that an immune deficiency may allow increased yeast colonization of the keratinized and glandular stomach epithelium. Tetracycline did not appear to enhance the invasiveness or pathogenicity of C. albicans in mice even though it facilitates yeast-phase gut colonization in conventionally reared mice.

Animals↗
PubMed1962

Some nutritional characteristics of predominant culturable ruminal bacteria.

Bryant, M. P. (U.S. Department of Agriculture, Beltsville, Md.) and I. M. Robinson. Some nutritional characteristics of predominant culturable ruminal bacteria. J. Bacteriol. 84:605-614. 1962.-The effect of enzymatic hydrolysate of casein, NH(4) (+), a mixture of volatile fatty acids (acetic, n-valeric, isovaleric, 2-methylbutyric, and isobutyric), hemin, and ruminal fluid on growth of 89 freshly isolated strains of predominant culturable ruminal bacteria was studied, using basal media containing glucose, cellobiose, or maltose as energy source, minerals, cysteine, and S(=) as reducing agents, and H(2)CO(3)-HCO(3) (-) buffer. Of these strains, 13% (four morphological groups) grew poorly or not at all in defined medium plus casein hydrolysate; 6% (one morphological group) required casein hydrolysate; 56% (four morphological groups) grew with either NH(4) (+) or casein hydrolysate as the main source of nitrogen; and NH(4) (+), but not casein hydrolysate, was essential for 25% of the strains (five morphological groups). The volatile fatty acid mixture excluding acetate was essential for 19% of the strains (five morphological groups), and this mixture and acetate were necessary for good growth of 23% of the strains (one morphological group) when casein hydrolysate was excluded from the medium; 30% of the strains (one morphological group) required hemin. Similar studies are reported on 35 old laboratory strains of ruminal bacteria, most of which were previously identified. The results indicate that most strains of ruminal bacteria can be grown in defined media, and suggest the relative importance of NH(4) (+) and volatile fatty acids and the relative lack of importance of organic nitrogen compounds such as amino acids in the nutrition of these bacteria.

Amino Acids↗
PubMed1963

NORMAL FLORA OF THE NOSE, THROAT, AND LOWER INTESTINE OF DOGS.

Clapper, W. E. (The Lovelace Foundation for Medical Education and Research, Albuquerque, N.M.) and G. H. Meade. Normal flora of the nose, throat, and lower intestine of dogs. J. Bacteriol. 85:643-648. 1963.-An attempt was made to isolate and identify the complete normal flora of the rectum, nose, and throat of beagles. For primary isolation, 12 different kinds of media were used. Incubation of blood agar plates and slants anaerobically, and of thioglycolate broth aerobically, allowed the growth of obligate anaerobes. From the rectal specimens, 20 species of bacteria and 10 species of fungi were isolated and identified. The organisms were similar to those found in the human intestine. Escherichia coli, Streptococcus mitis, enterococci, S. lactis, Bacillus species, and coliforms other than E. coli were most frequently encountered. The frequency of occurrence was approximately the same at both samplings in more commonly cultured bacteria. Pathogenic E. coli were isolated from nearly one-third of the first specimens. These were the only human pathogens observed. In the throat cultures, 29 species of bacteria and 2 species of yeasts were identified, and 27 species of bacteria were identified from the nasal cultures. S. mitis, Neisseria, and coagulase-negative Staphylococcus were most often isolated. The flora was similar to that found in human nose and throat cultures, except that more Haemophilus and pneumococcus and fewer coliforms are generally found in human throats. Organisms resembling human pathogens were group A streptococci and coagulase-positive staphylococci. These were isolated infrequently. It appears that this kind of examination would reveal any significant changes in normal flora that might be related to the health of the animal.

Animals↗
PubMed1964

UNUSUAL BACTEROIDES-LIKE ORGANISM.

Goldberg, Herbert S. (University of Missouri, Columbia), Ella M. Barnes, and Anthony B. Charles. Unusual Bacteroides-like organism. J. Bacteriol. 87:737-742. 1964.-An organism is described which appears to be a new species of gram-negative, anaerobic, nonsporulating rod. It was isolated from poultry caeca at levels of 10(7) to 10(8) per g. It is primarily distinguished from related organisms by its unusual size (2.0 by 10.0 mu). It is biochemically differentiated from known species of Bacteroides, Fusobacterium, Sphaerophorous, and other accepted related genera. Its presence in large numbers in the gut of poultry, and its high metabolic activity would seem to indicate an important intestinal organism.

Animals↗
PubMed1964

TRANSFER OF DRUG RESISTANCE BETWEEN ENTERIC BACTERIA INDUCED IN THE MOUSE INTESTINE.

Kasuya, Morimasa (Nagoya University School of Medicine, Nagoya, Japan). Transfer of drug resistance between enteric bacteria induced in the mouse intestine. J. Bacteriol. 88:322-328. 1964.-Transfer of multiple drug resistance in the intestines of germ-free and conventional mice was studied with strains of Shigella, Escherichia, and Klebsiella. The transfer experiment was carried out under antibiotic-free conditions to eliminate the production of drug-resistant bacteria by antibiotics. All resistance factors (chloramphenicol, streptomycin, tetracycline, and sulfathiazole) were transferred with ease in the intestinal tracts of mice, when donors and recipients multiplied freely, and acquired resistance was further transferred to other sensitive enteric bacteria in the intestinal tract. Bacteria to which resistance factors were transferred showed, in most of the experiments, exactly the same level and pattern of resistance as the donors. Based on the above, a hypothesis that the same process may possibly occur in the human intestine is presented.

Animals↗
PubMed1964

INTERNAL STRUCTURES OF A EUBACTERIUM SP. DEMONSTRATED BY THE NEGATIVE STAINING TECHNIQUE.

Bladen, Howard A. (National Institute of Dental Research, Bethesda, Md.), Marie U. Nylen, and Robert J. Fitzgerald. Internal structures of a Eubacterium sp. demonstrated by the negative staining technique. J. Bacteriol. 88:763-770. 1964.-Thin sections as well as negatively stained whole cells of a Eubacterium sp. isolated from the rat cecum were examined in a Siemens Elmiskop I electron microscope. The cell wall usually appeared in thin sections as a single dense layer about 130 A thick; however, occasionally it was demonstrated to be composed of three layers. The plasma membrane was approximately 130 A wide, and was composed of a denselight-dense arrangement. Intracytoplasmic membranous elements continuous with the plasma membrane were also observed in thin sections. When whole cells were negatively stained with phosphotungstic acid, the cell wall became transparent, and structures comparable in morphology to intracytoplasmic membranous elements were observed. These were demonstrated by stereomicroscopy to be in the interior environment of the cell, and appeared in many cases continuous with the cell wall. Frequently, they seemed to open to the exterior of the cell through what may be termed a pore. Small stalked structures similar to those described in mitochondria were observed along the periphery of the cell and occasionally along the walls of the internal elements.

Cecum↗
PubMed1964

ISOLATION AND IDENTIFICATION OF ENTEROCOCCI FROM THE INTESTINAL TRACT OF THE RAT.

Rogers, C. G. (Department of National Health and Welfare, Ottawa, Ontario, Canada), and W. B. Sarles. Isolation and identification of enterococci from the intestinal tract of the rat. J. Bacteriol. 88:965-973. 1964.-Surface inoculation was employed in a comparison of three selective media, M-enterococcus (M) agar, thallium acetate-glucose (TITG) agar, and KF-streptococcus (KF) agar, for enumeration and isolation of enterococci from contents of the digestive tract of the rat. Similar yields of enterococcus colonies were obtained with M, TITG, and KF agar. When cecal contents were examined, species identification of 120 isolates, 40 from each medium, revealed only minor differences in selective activity. Streptococcus faecalis and its variety zymogenes represented 55 to 63% of the isolates from each medium; the remaining strains resembled S. durans or S. faecium. More than 99% of the isolates failed to survive the heat-tellurite tolerance test. Periodic analyses of intestinal contents from young rats indicated that enterococci became established in the gut from 10 to 14 days after birth. The species isolated most frequently on M agar was S. faecalis var. zymogenes. When rats were fed a purified diet with casein as the source of nitrogen, S. faecalis var. zymogenes predominated among isolates from contents of the small intestine plated on M agar. This species was largely replaced by others resembling S. durans or S. faecium when mixtures of l-amino acids provided the dietary nitrogen. Nineteen enterococcus isolates, representing all that met the Sherman criteria, required arginine, glutamic acid, histidine, isoleucine, leucine, methionine, tryptophan, and valine; of these, two strains required in addition threonine, glycine, and lysine; four required threonine and glycine; two, threonine and lysine; and one, threonine.

Agar↗
PubMed1964

BACTEROIDES ORALIS, PROPOSED NEW SPECIES ISOLATED FROM THE ORAL CAVITY OF MAN.

Loesche, W. J. (Forsyth Dental Center and Harvard School of Dental Medicine, Boston, Mass.), S. S. Socransky, and R. J. Gibbons. Bacteroides oralis, proposed new species isolated from the oral cavity of man. J. Bacteriol. 88:1329-1337. 1964.-Twenty-seven strains of oral bacteroides were characterized and compared with a National Collection of Type Cultures strain of Bacteroides fragilis as well as strains of intestinal bacteroides. A combination of acid end products, gas production, pentose fermentation, and 10% bile tolerance afforded a basis for separation of oral strains from intestinal strains. The oral strains produced succinic, lactic, acetic, and formic acids but no gas. They were inhibited by 10% bile, and did not ferment xylose and arabinose. Intestinal strains consistent with the description for B. fragilis produced succinic, formic, acetic, and propionic acids and gas, with a few strains forming lactic acid. They were stimulated by 10% beef bile, and fermented xylose and arabinose. The oral strains are sufficiently different from intestinal strains of the B. fragilis type, so that they appear to constitute a separate species. It is proposed that they be recognized as B. oralis, sp. n.

Acetates↗
PubMed1965

EFFECT OF HIGH FAT DIETS ON INTESTINAL MICROFLORA AND SERUM CHOLESTEROL IN RATS.

Graber, C. D. (Baylor University College of Medicine, Houston, Tex.), R. M. O'Neal, and E. R. Rabin. Effect of high fat diets on intestinal microflora and serum cholesterol in rats. J. Bacteriol. 89:47-51. 1965.-Differential bacterial counts of feces and total plasma cholesterol determinations were performed on 60 Wistar rats fed several high lipid diets for a period of approximately 6 months. Fecal flora remained relatively stable irrespective of diet, but cholesterol levels rose in animals fed butter and sodium cholate. The six most commonly cultured organisms in all diets were enterococci, Proteus, lactobacilli, Escherichia coli, Staphylococcus aureus, and other micrococci. No enteric pathogens which did not ferment lactose or fermented it slowly were grown. Fungi and yeasts were rare. Aerobes generally outnumbered anaerobes in proportions which were sometimes as high as 300:1. Clostridium perfringens isolations were consistently high in animals given the butter diets, particularly when sodium cholate was added. Evidence is reviewed which indicates that this organism may play a role in bile salt and cholesterol metabolism. This experiment would seem to demonstrate that differences in plasma-cholesterol levels among the various dietary groups of rats were the result of dietary factors rather than alteration in intestinal flora.

Animals↗
PubMed1965

NORMAL INTESTINAL FLORA OF CATTLE FED HIGH-ROUGHAGE RATIONS.

Maki, Leroy R. (University of Wyoming, Laramie), and Kay Picard. Normal intestinal flora of cattle fed high-roughage rations. J. Bacteriol. 89:1244-1249. 1965.-Intestinal bacteria were isolated from 15 cattle. Approximately 600 isolates were studied, and their presence and numbers in the duodenum, ileum, cecum, and colon were noted. Bacteria most frequently isolated from all parts of the intestinal tract included Escherichia coli, Streptococcus bovis, and species of Bacillus. Several groups of gram-positive rods could not be classified according to Bergey's Manual. Direct counts of intestinal contents indicated that 1 to 10% of the bacteria present were recovered.

Animals↗