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V R Dowell

Publications and source records attributed to V R Dowell.

71 records · Page 4Linked to original sources
PubMed1971

Comparison of Schaedler agar and trypticase soy-yeast extract agar for the cultivation of anaerobic bacteria.

Schaedler agar (SA) and Trypticase soy-yeast extract agar (TSYEA), both supplemented with rabbit blood (5%, v/v) and menadione (0.5 mg/liter), were compared with respect to quantitative recovery, quality of growth, and rapidity of growth of selected anaerobic bacteria. The media were stored for 2 to 4 days prior to use in an anaerobic glove box, where all subsequent bacteriological procedures were performed. After 24 hr of incubation, colonies of Clostridium cadaveris (C. capitovale), C. haemolyticum, C. novyi A, and C. perfringens were larger on SA than on TSYEA, and the appearance of C. novyi B colonies on SA at 24 hr antedated their appearance on TSYEA. Quantitative recovery of C. novyi B was improved on SA; recovery of the other clostridia tested was comparable on the two media (inconclusive results were obtained with C. novyi A). Rough colonial types of some of the clostridia emerged on SA. No appreciable differences in results with the two media were noted for Bacteroides fragilis, B. melaninogenicus, or Fusobacterium fusiforme.

Agar↗
PubMed1969

Cultural characteristics and fatty acid composition of propionibacteria.

The cultural characteristics and cellular fatty acid composition of 40 strains representing 7 species of Propionibacterium and of 9 cultures of anaerobic corynebacteria were studied. The cultures were characterized by means of 23 separate cultural and biochemical tests. Cultures of the two genera differed consistently in only two reactions; the propionibacteria did not produce indole or liquefy gelatin, whereas the anaerobic corynebacteria were consistently positive with these tests. The fatty acids were extracted from whole cells and examined as methyl esters by gas-liquid chromatography. The most abundant acid in the seven Propionibacterium species was a C(15)-saturated branched-chain acid which was present in both the iso-and anteiso-form. Based on a comparison of the relative abundance of these isomers (i-C(15) and a-C(15)), the species were separated into two groups. P. freudenreichii and P. shermanii (group one) were similar and contained the a-C(15) isomer as the predominant acid. The i-C(15) isomer was the most abundant acid in the second group (P. arabinosum, P. jensenii, P. pentosaceum, P. thoenii, and P. zeae). The fatty acid profiles of the anaerobic corynebacteria were somewhat similar to those of the second group of propionibacteria, but were distinct from the profiles of P. freudenreichii and P. shermanii. The addition of branched-chain amino acids (l-leucine and l-isoleucine) to the growth medium increased the synthesis of the specific fatty acid(s) structurally related to the added amino acid.

Bacteriological Techniques↗
PubMed1967

Cultural characteristics and fatty acid composition of Corynebacterium acnes.

A detailed study of the cultural characteristics and cellular fatty acid composition of 27 isolates of Corynebacterium acnes was performed to establish the properties by which this organism may be identified and characterized. The fatty acids were extracted directly from whole cells and examined as methyl esters by gas-liquid chromatography. Each strain possessed a similar fatty acid profile which was characterized by a large percentage of C15 branched-chain acid. Uniformity in certain biochemical reactions and cultural characteristics was also observed. All strains were catalase-positive, nonmotile, and urease-negative, reduced nitrate, liquefied gelatin, failed to hydrolyze esculin and starch, and gave a positive methyl red test. Glucose, fructose, and glycerol were fermented, but not lactose, salicin, sucrose, maltose, xylose, or arabinose. Production of hydrogen sulfide and indole, fermentation of mannitol, and hemolytic activity were variable characteristics. Two species of the genus Propionibacterium were also tested and found to be similar to C. acnes both in cultural characteristics and fatty acid composition. The results strengthen previous suggestions that C. acnes should be classified in the genus Propionibacterium.

Acids↗
PubMedDate not supplied

Botulism and tetanus: selected epidemiologic and microbiologic aspects.

Botulism is rare in both developing and developed countries. During 1980 only 89 cases (18 food borne, 68 infant, 2 wound, 1 unspecified) were reported in the United States. Coproexamination is essential for laboratory confirmation of infant botulism. Botulinal antitoxins of equine origin are used for treating food-borne and wound botulism but are usually not recommended for infant cases. Tetanus is much more common in some developing countries than in developed countries. During 1980 only 95 cases of tetanus were reported in the United States; in 68 (72%) of these cases, the patient was 50 years or older, and in only two (2.1%) cases was the patient younger than one year. Tetanus neonatorum is a major problem in some developing countries. Diagnosis of tetanus is based primarily on clinical findings, but laboratory studies can be helpful, especially in epidemiologic investigations. Human hyperimmune immunoglobulin is now used in the treatment of tetanus.

Adolescent↗
PubMedDate not supplied

Bacteremia with Anaerobiospirillum succiniciproducens.

Anaerobiospirillum succiniciproducens is a motile, spiral anaerobic bacterium with bipolar tufts of flagella. Reports of clinical illness due to A. succiniciproducens are rare. In a retrospective review of anaerobic isolates referred to the Centers for Disease Control (CDC) from January 1, 1975, through January 31, 1986, isolates of A. succiniciproducens from the blood of 21 patients were identified. A single patient whose blood isolate had not been received at CDC was included in the review. These 22 patients were from 15 states. Their mean age was 58.6 years. Underlying disorders included alcoholism, atherosclerosis, malignancy, surgery, diabetes mellitus, and dental caries. Clinical features included gastrointestinal tract signs and symptoms in 17 (77%) of 22, fever greater than 38 degrees C in seven (37%) of 19, and leukocytosis of more than 10,000 cells/mm3 in 11 (58%) of 19. Although 16 patients received antimicrobial therapy, its effect on outcome was unclear. A. succiniciproducens was reported to have contributed to the deaths of seven patients. Disorders predisposing patients to anaerobic infections may put them at increased risk for A. succiniciproducens bacteremia. The presence of antecedent gastrointestinal tract signs and symptoms suggests that the gastrointestinal tract might be the primary portal of entry.

Adult↗