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Biomedical subjects

V R Dowell

Publications and source records attributed to V R Dowell.

At least 37 records · Page 2Linked to original sources
PubMed1981

Clinical features of types A and B food-borne botulism.

Medical records of 55 patients with type A and type B food-borne botulism reported to the Centers for Disease Control during 2 years were reviewed to assess the clinical features and severity of illness, diagnostic test results, nature of complications, amd causes of death. Some patients had features not usually associated with botulism including paresthesia (14%), asymmetric extremely weakness (17%), asymmetric ptosis (8%), slightly elevated cerebrospinal fluid protein values (14%), and positive responses to edrophonium chloride(26%). Several observation suggest that type A was more severe than type B disease. Although the case-fatality ratio was not significantly greater, patients with type A disease saw a physician earlier in the course of illness, were more likely to need ventilatory support, and were hospitalized longer. Patients who died were older than those who survived. Deaths within the first 2 weeks resulted from failure to recognized the severity of the disease or from pulmonary or systemic infection whereas the three late deaths were related to respirator malfunction.

Adult↗
PubMed1981

Diet as a coadjuvant for development of antibiotic-associated diarrhea in hamsters (Mesocricetus auratus).

During a study of the effects of nutrition on experimental tumors in hamsters, fatal diarrhea developed. To determine the role of diet in this condition and the relationship between diet and antibiotics, two diets were used, ground commercial diet and a purified diet. Two antibiotics were used, neomycin sulfate and vancomycin. Diarrhea was evident soon after the animals were given the combination of purified diet and neomycin sulfate. Vancomycin initially acted as a suppressor of diarrhea, but hamsters fed the purified diet developed diarrhea after the drug was discontinued. None of the animals fed ground commercial diet treated with neomycin sulfate developed diarrhea. Clostridium difficile was isolated from most of the sick animals; all of the isolates of Clostridium difficile were toxigenic except one. No significant differences were seen among the Clostridium difficile isolated from different animals. Clostridium sporogenes and Clostridium tertium also were isolated from some of the animals.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1980

Susceptibility of Clostridium botulinum to thirteen antimicrobial agents.

A total of 224 strains of Clostridium botulinum (including isolates from 14 patients with infant botulism and 4 with wound botulism) and 15 strains of C. sporogenes were tested by agar dilution for susceptibility to tetracycline, metronidazole, erythromycin, penicillin, rifampin, chloramphenicol, clindamycin, cephalothin, cefoxitin, vancomycin, sulfamethoxazole-trimethoprim, nalidixic acid, and gentamicin. At least 90% of the C. botulinum strains tested (except for nonproteolytic strains of toxin type F with penicillin) were susceptible to all drugs except sulfamethoxazole-trimethoprim, nalidixic acid, and gentamicin. Minimal inhibitory concentrations for strains from patients with infant and wound botulism were similar to those for other C. botulinum strains.

Anti-Bacterial Agents↗
PubMed1980

Cultural and physiological characteristics and antimicrobial susceptibility of Clostridium botulinum isolates from foodborne and infant botulism cases.

Isolates Clostridium botulinum from foodborne and infant botulism cases in the United States were compared on the basis of toxigenicity, cultural and biochemical characteristics, metabolic products, and susceptibility to antimicrobial agents. Seventy-eight strains, including 42 from foodborne and 36 from infant botulism sources, were examined. Cultures on anaerobic blood agar exhibited circular, spindle, and rhizoid (medusa head) colonies. Overall, the characteristics of isolates from foodborne and infant botulism cases were quite similar. We concluded that it was not possible to differentiate C. botulinum isolates associated with foodborne botulism from those recovered from infant botulism cases. All of the 78 strains produced an unidentified indole derivative(s), detected with paradimethylaminocinnamaldehyde reagent, and hydrocinnamic acid, detected by gas-liquid chromatography; all exhibited a high degree of resistance to cycloserine, sulfamethoxazole, and trimethoprim. These characteristics should prove to be useful in the isolation and identification of C. botulinum from mixed microbial populations.

Anti-Bacterial Agents↗
PubMed1979

Clostridium septicum bacteremia. Its clinical significance.

The medical records of 59 patients with Clostridium septicum bacteremia were reviewed; 42 (71 per cent) of these patients had malignancies. One half had hematologic malignancies, and one half had solid tumors. Of the 21 patients with solid tumors, 14 (67 per cent) had cancer of the colon. Among these patients, the cecum was the most frequent site of malignancy. The cecum and distal ileum were the most probable portals of entry for C. septicum bacteremia among the 28 patients examined at autopsy. Patients admitted to the hospital with C. septicum bacteremia usually have fulminating clinical courses and, unless the appropriate antibiotics are administered soon after admission, the outcome is fatal. The results of this study demonstrate the high association of C. septicum bacteremia and malignancy, and the need for early recognition and therapy.

Adolescent↗
PubMed1979

Antibiotic-associated colitis.

Pseudomembranous colitis, a relatively uncommon and sometimes severe diarrheal disease, recently has been linked to the administration of a number of broad-spectrum antibiotics. The cause has now been identified as a spore-forming clostridial species not previously recognized as a human pathogen. Since the organism is sensitive to moset commonly used antibiotics, its spores may be the key to the disease.

Anti-Bacterial Agents↗
PubMed1979

Serological study of trichloroacetic acid extracts of Bacteroides fragilis.

Immunodiffusion techniques were used on trichloroacetic acid extracts from 10 strains of Bacteroides fragilis in detecting precipitating antibodies against this species in immune rabbit sera. Species and even strain specificities were observed in these precipitin reactions. Multiple antigens were detected in the extracts from some strains, whereas only one precipitin band per extract developed during agar-gel diffusion tests of others. The antigen extracts were found to be both heat stable and resistant to hydrolysis by alpha-chymotrypsin. Four serological patterns were demonstrated in homologous and heterologous reactions with the B. fragilis. antigen-antibody systems used. The results showed that some strains were serologically distinct from others, indicating that the strains tested are of more than one serotype.

Animals↗
PubMed1979

Immunochemical evidence for multiple serotypes of Bacteroides fragilis.

An immunochemical comparison of outer membrane antigens obtained from five select and biochemically defined strains indicated that there are several serotypes of Bacteroides fragilis. Each strain was serologically defined by individual or by combinations of determinant groups composed of carbohydrates in the form of polysaccharides or glycoproteins. The carbohydrate constituents were tentatively identified as glucose, galactose, fucose, rhamnose, glucosamine, galactosamine, and traces of mannose. Strains were observed to have minor qualitative and major quantitative variations in carbohydrate composition.

Antigens, Bacterial↗
PubMed1979

Cultural characteristics of Yersinia enterocolitica and Yersinia pseudotuberculosis on differential media.

A study was made of the cultural characteristics of 43 strains of Yersinia enterocolitica and 49 strains of Yersinia pseudotuberculosis on media commonly used for the isolation and differentiation of enteric bacteria. Best growth of the yersinia occurred on MacConkey agar, followed by growth on SS agar; none of the strains of either species developed colonies on brilliant green agar. The Y. pseudotuberculosis strains developed only one type of colony on MacConkey, SS, EMB, Hektoen, and XLD media whereas Y. enterocolitica exhibited more than one type of colony on all of the media except MacConkey and SS agar. The 'lactose-positive' colonies of Y. enterocolitica were especially distinctive on EMB. These were quite dark, with or without a metallic sheen, and closely resembled the colonies of lactose fermenting Escherichia coli on EMB agar. Strains of both Y. enterocolitica and Y. pseudotuberculosis grew better on the differential media at 35 degrees C than at 22 degrees C but the growth of Y. pseudotuberculosis was considerably slower than that of the other species.

Agar↗
PubMed1978

Anaerobic flora of the normal human conjunctival sac.

Specimens from the conjunctival sacs of 92 healthy eyes were cultured on two separate occasions to determine the presence or absence of a persistent anaerobic flora. Aerobic bacteria and fungi were also studied for comparison. Of the 184 eye cultures, 112 (60.9%) contained at least one microorganism. Obligate anaerobes were recovered from 51.6% (95/184) of the cultures. Propionibacterium acnes, the predominant anaerobe encountered, was present in 49.5% (91/184) of the eyes. Aerobic and facultatively anaerobic bacteria, present in 32.6% of the total eye cultures, were less common than obligate anaerobes. Staphylococcus epidermidis was the most common of these. Fungi were rarely found. Our findings suggest that the conjunctival sac is either sterile or normally contains small numbers of anaerobic, aerobic, or facultatively anaerobic bacteria. As other workers have suggested, the origin of the bacteria in the eyes may be the skin of the eyelids.

Adult↗
PubMed1978

Infant botulism: new guise for an old disease.

While classic botulism is usually due to preformed toxin in improperly prepared food, the newly recognized infant syndrome occurs when spores or vegetative cells germinate in the gut of the very young and elaborate toxin there. The resulting illness may range from inapparent to fulminant, sometimes causing respiratory arrest and death. Infant botulism may also account for at least some cases of sudden infant death syndrome.

Adolescent↗
PubMed1978

Use of ethanol for selective isolation of sporeforming microorganisms.

When mixed cultures containing sporeforming bacteria were treated with heat or with ethanol, the latter consistently resulted in better recovery of Clostridium and Bacillus species. Both techniques were effective in eliminating vegetative cells. An ethanol concentration greater than 25% and exposure for 45 min or longer were necessary to kill all vegetative cells in mixed-culture samples. Ethanol treatment (50% ethanol for 1 h) was effective for isolating sporeforming bacteria from intestinal specimens. Seven different species of Clostridium were the only bacteria isolated from the ethanol-treated specimen of intestinal contents from the large bowel of a patient. It was concluded that treatment with ethanol for 1 h is an effective technique for selective isolation of sporeforming bacteria from mixed cultures and certain types of clinical specimens.

Bacillus↗
PubMed1978

Evaluation of Port-A-Cul transport system for protection of anaerobic bacteria.

The protection of anaerobes in Port-A-Cul (PAC) transport system (Bioquest, Div. of Becton, Dickinson &Co., Cockeysville, Md.) tubes and vials was studied. Ten species of obligately anaerobic bacteria commonly isolated from clinical specimens were used to prepare simulated swab and fluid specimens in high and low concentrations. Samples in PAC tubes and vials were held for 2, 24, and 48 h at ambient temperature and in a refrigerator. In addition, samples of the simulated specimens were exposed to controlled anaerobic and aerobic conditions in vented tubes and vials, with and without PAC medium, at ambient and refrigerator temperatures. Viable bacterial colony counts from specimens in PAC tubes and vials used as recommended by the manufacturer were consistently greater than those from specimens exposed to the different controlled conditions. The protection in PAC was about equal for specimens with either high or low concentrations of bacteria. Protection of the anaerobes in PAC was more obvious with swab than with fluid specimens. Quantitative recovery of anaerobes from refrigerated PAC samples, with few exceptions, was comparable to that from PAC samples held at ambient temperature.

Anaerobiosis↗
PubMed1978

Alternative procedures for identification of anaerobic bacteria.

Recognizing the need for practical inexpensive procedures which allow identification of anaerobes commonly encountered in clinical laboratories, a number of investigators have in recent years proposed various alternatives to the expensive, time-consuming techniques presently recommended by reference anaerobe laboratories. Some of these techniques are potentially good alternatives. In this paper we review some of the more promising approaches and present a detailed description of two commercial microbiochemical systems for characterization of anaerobes. When used in conjunction with other available tests, the microsystems are useful and convenient methods for identification of anaerobic bacteria at a reasonable cost.

Anaerobiosis↗
PubMed1977

Coproexamination for botulinal toxin and clostridium botulinum. A new procedure for laboratory diagnosis of botulism.

Stool or serum specimens or both from 318 persons pertaining to 165 botulism investigations over a three-year period were examined. Botulinal toxin was detected in stools of 19 of 56 patients and in sera of 20 of 60 patients with clinical botulism; it was not detected in specimens from 246 persons with an illness other than botulism or well contacts of patients. Clostridium botulinum was identified in stools of 36 of 60 clinical botulism patients and in four of 27 asymptomatic contacts of patients with botulism victims, but not in stools of 65 persons not associated with confirmed botulism. When stool and serum samples were examined, confirmatory evidence was obtained for 72.9% of the botulism cases. Detection of botulinal toxin or C botulinum in the stool of a persons should be considered evidence supporting the clinical diagnosis of botulism.

Bacteriological Techniques↗
PubMed1977

Type A and type B botulism in the North: first reported cases due to toxin other than type E in Alaskan Inuit.

Botulism outbreaks shown to be due to type A and type B toxin occurred in Alaska, a region previously known for only type E botulism. The outbreak due to type A toxin involved three people, two of whom died. The outbreak due to type B toxin involved nine people, none of whom died. Both outbreaks were in Inuit villages, and native foods were incriminated. The occurrence of these outbreaks strongly suggests that Clostridium botulinum, types A and B are indigenous to Alaska. The outbreaks underscore the need for initial treatment of patients with antitoxin that is trivalent (ABE), even in Arctic regions.

Adolescent↗
PubMed1977

Type B botulism outbreak caused by a commercial food product. West Virginia and Pennsylvania, 1973.

In the week of May 7, 1973, seven persons contracted botulism after eating together. The most common symptoms were vomiting, constipation, dry mouth, dysphagia, and dysphonia. All were treated with trivalent botulinal antitoxin, and none died. Serum specimens obtained from all seven patients were negative for botulinal toxin, but stool specimens from three patients were positive for type B toxin. Electromyographic studies performed on five patients documented the neurophysiologic abnormalities of botulism. Commercially canned peppers in oil were implicated epidemiologically, and type B toxin was identified in leftover peppers. The processor voluntarily recalled the pepper product, and no further cases were reported.

Botulinum Antitoxin↗