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Biomedical subjects

G S Nygaard

Publications and source records attributed to G S Nygaard.

7 recordsLinked to original sources

Primary plague pneumonia contracted from a domestic cat at South Lake Tahoe, Calif.

Primary plague pneumonia occurred in a 47-year-old South Lake Tahoe woman shortly after face-to-face exposure to her plague pneumonia-infected cat. Both died. Field investigation revealed a recent plague epizootic in squirrels and chipmunks around the patient's home. Control measures included active surveillance and chemoprophylaxis of 197 contacts to the victim, a community alert on methods of self- and pet protection, and application of insecticide to reduce rodent flea populations. No secondary cases occurred.

Animals↗

Less frequently reported gram-negative fermentative rods.

The clinical significance and distinguishing characteristics of less frequently reported gram-negative fermentative rods (Pasteurella, Yersinia, Vibrio, Aeromonas and Plesiomonas, Enterobacter agglomerans, and Chromobacterium) are described. Increased awareness of these organisms, a knowledge of possible sites in which they cause infection, and identification criteria which will separate them from similar bacteria will prepare the clinical microbiologist for the isolation and identification of these "unusual" organisms.

Aeromonas↗

Clostridium botulinum type F: isolation from venison jerky.

A Clostridium botulinum type F was isolated from the venison jerky responsible for the only type F botulism outbreak reported in the United States. The isolate differed from the prototype Langeland type F strain in being nonproteolytic.

Anaerobiosis↗

Laboratory identification of aeromonads from man and other animals.

Forty-eight isolates of aeromonads from clinical specimens were studied. The laboratory procedures employed and the results obtained are reported in the hope that they may be of assistance to other workers in the field of diagnostic microbiology. Capability of identifying these organisms in the laboratory will contribute to a better understanding of the role of this group of organisms in human disease as well as in diseases in other animals.

Aeromonas↗

Use of immunofluorescence and animal tests to detect growth and toxin production by Clostridum botulinum type E in food.

The appearance of Clostridium botulinum type E organisms and of toxin in experimentally inoculated packages of turkey roll was followed to study the time relationship between the presence of vegetative cells and the demonstration of toxin. The presence of vegetative cells was determined by immunofluorescence, and animal tests were used to assay toxin production. Growth initiated from detoxified spores of C. botulinum type E resulted in toxin formation within 24 hr. Presence of fluorescing vegetative cells and of toxin coincided from 1 to 14 days of incubation. Beginning with the next testing date, day 21, differences were observed. Toxin could be detected for a longer time than vegetative cells. Neither toxin nor organisms could be found after 56 days of incubation. The mouse lethal dose tests (MLD per gram of turkey roll) showed fluctuations in the amount of toxin present throughout the period of testing. Maximal amounts of toxin were present during the period when fluorescing organisms were also more numerous. The applications of immunofluorescence in the study and in the diagnosis of botulism is discussed.

Animals↗

Examination of prepared foods in plastic packages for Clostridium botulinum.

The incidence of Clostridium botulinum organisms was determined in a variety of plastic-packaged "vulnerable" foods (food requiring little or no heating prior to consumption). A total of 113 foods were examined by use of an enrichment recovery procedure followed by toxin testing in animals. Results of the survey indicate that the incidence of C. botulinum organisms in these vulnerable foods is extremely low. The ability of inoculated food products to support growth and toxigenesis of C. botulinum type E was then tested. The 64 packaged foods were inoculated with type E spores and incubated anaerobically at 30 C for 11 days. A slurry of each food was prepared, smears for fluorescent-antibody testing were made, and animal tests were performed for toxin. If the animal tests were negative, enrichment cultures were prepared from the slurry and incubated at 30 C. On direct examination of the slurries for toxin, only samples of turkey roll and soybean cake supported growth and toxigenesis by C. botulinum type E. However, the enrichment culture method was able to induce growth and toxin production in 60 of the remaining 62 samples.

Clostridium botulinum↗