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Biomedical subjects

B O Blackburn

Publications and source records attributed to B O Blackburn.

At least 19 recordsLinked to original sources
PubMed1992

Plasmid profile analysis, phage typing, and antibiotic sensitivity of Salmonella dublin from clinical isolates in the United States.

One hundred clinical isolates of Salmonella choleraesuis subsp. choleraesuis serovar dublin (Salmonella dublin) were examined for phage sensitivity, antibiotic resistance patterns, and plasmid content. Computer analysis of the lysis patterns observed by using 27 typing phages divided the S. dublin isolates into 26 groups. One lytic pattern (Designated pattern 16) contained 52% of the isolates examined whereas 16 isolates had unique patterns, and nine patterns had fewer than ten members. Although 14 antibiotic resistance patterns were observed among the 100 isolates, 79% of the isolates grouped in three major patterns. Seven plasmid groups were identified and designated A-G based on the large plasmids found in the isolates. Of the 100 isolates, 28 contained the plasmid profile of Group A, 28 were Group B, 7 were Group C, 34 were Group D, and 1 isolate each was observed in Groups E, F, and G. The strong association between antibiotic resistance pattern and plasmid type suggest that the drug resistance genes are plasmid borne.

Animals↗
PubMed1989

Paratuberculosis in cattle: a comparison of three serologic tests with results of fecal culture.

Feces and blood were collected from cattle in 13 herds known to be infected with Mycobacterium paratuberculosis to evaluate a complement-fixation (CF) test, an agar gel immunodiffusion (AGID) test and an enzyme-linked immunosorbent assay (ELISA) for the serologic diagnosis of paratuberculosis. M. paratuberculosis was isolated from the feces of 36 of 192 cattle examined. Twenty-three culture-positive animals had CF test titers regarded as suspect or positive, 10 were positive by the AGID test and 34 were suspect or positive by the ELISA. Of the 156 culture-negative animals, the CF test agreed on 136, the ELISA on 129 and the AGID on 151.

Animals↗
PubMed1988

Serologic response of Babesia equi-infected horses as measured by complement-fixation and indirect fluorescent antibody tests.

Both the complement-fixation test (CFT) and the indirect fluorescent antibody test (IFAT) were conducted on weekly serum samples from nine Arab geldings for 28 days before and 256 days after their exposure to Babesia equi of European origin. On an average the IFAT became positive 8 days before the CFT and showed higher relative serum titer increases. Both test procedures successfully detected infection and neither showed an appreciable drop in titer during this time frame, with the exception of the CFT, which showed a transient drop immediately following treatment with imidocarb. A test conducted 540 days after infection showed four of the eight surviving, and presumably infected, horses to be negative on CFT, where as all eight were still positive on IFAT. Comparisons made with the IFAT, on horse sera from B. equi infection of both European and North American origin, utilizing homologous and heterologous antigens, showed significantly higher titers with homologous antigens.

Animals↗
PubMed1986

Survey of selected diseases in wild swine in Texas.

Tissue, fecal, and serum specimens and swabs of nasal turbinates and tracheas were collected from 100 wild swine (Sus scrofa) from 10 populations in Texas and, along with 24 additional serum specimens, were evaluated for selected swine diseases. Swine positive for pseudorabies were detected in 7 populations. Brucella suis biovar 1 was isolated from 4 swine from 2 populations, but positive serologic results may indicate a more widespread distribution of the organism. All populations contained swine that were positive for leptospirosis. Trichinella spiralis was not found in the swine evaluated.

Animals↗
PubMed1984

Antibiotic resistance of members of the genus Salmonella isolated from chickens, turkeys, cattle, and swine in the United States during October 1981 through September 1982.

Members of the genus Salmonella isolated from chickens, turkeys, cattle, and swine and submitted to the National Veterinary Services Laboratories for serotyping during October 1981 through September 1982 were tested for sensitivity to 12 antibacterial drugs. A total of 3,500 isolates was tested. A high rate of drug resistance was observed. Three cultures were resistant to each of the drugs and 30% were resistant to each drug except chloramphenicol, cephalothin, and gentamicin. Multiple resistance patterns were observed for 80% of the cultures with an even higher percentage in cultures from swine.

Animals↗
PubMed1982

Brucellosis in wild swine: a serologic and bacteriologic survey in the southeastern United States and Hawaii.

Sera from wild swine from 20 populations in 11 southeastern states and Hawaii were tested for brucellosis by the card, tube, plate, buffered plate antigen, complement-fixation, and rivanol tests. Twenty-one of 352 (6.0%) swine were considered seropositive, and these animals originated from 7 populations in 5 states: Arkansas, Florida, Georgia, Louisiana, and South Carolina. Cultural examinations for Brucella suis also were made from subsamples of the swine tested serologically. Brucella suis biotype 1 was isolated from lymph nodes or seminal vesicles from wild swine in 2 areas in Florida and 1 in Louisiana.

Animals↗
PubMed1982

Molecular epidemiology of antibiotic resistance in salmonella from animals and human beings in the United States.

We collected serotyped isolates of salmonella from reference laboratories in the United States, tested their susceptibility to antibiotics, and extracted plasmids from isolates that were resistant to a different combination of antibiotics from each of three serotypes. Restriction-endonuclease digestion showed that within each of the three groups, plasmid molecules from animal and human isolates were often identical or nearly identical. One serotype-plasmid combination appeared to be endemic in cattle in 20 states and infected 26 persons in two states. The human cases, which were not recognizably related except for their common plasmids, appeared to be clustered in time but geographically dispersed, like cases in previous outbreaks spread by food products. These findings suggest that resistance plasmids may be extensively shared between animal and human bacteria, and that spread of multiresistant strains of salmonella among animals and human beings, as observed in Britain, may have been undetected in the United States for lack of comparable surveillance.

Animals↗
PubMed1980

Three new serotypes of Salmonella.

Three new Salmonella serotypes belonging to Kauffmann's subgenus I (F. Kauffmann, The Bacteriology of Enterobacteriaceae, 1966) were identified. These serotypes were Salmonella brazos 6,14,18:a:e,n,z15, Salmonella midway 6,14,24:d:1,7, and Salmonella balboa 48a, 48b:z41:monophasic.

Salmonella↗
PubMed1978

Antibody response of horses to Mycoplasma mycoides subsp capri.

In horses given whole cultures or cells of Mycoplasma mycoides subsp capri (by subcutaneous and intravenous injections), antibody responses were measured by serologic procedures. During an immunization period of 22 weeks, horses produced an antiserum that was used to identify M mycoides subsp capri by agglutination, complement-fixation, and fluorescent antibody (FA) tests, but not by the growth-inhibition test. Horses that were injected with whole cultures of M mycoides subsp capri responded better than horses that were injected with only cells, ie, antibodies were detectable sooner by agar gel diffusion and FA tests and the serums displayed more bands of precipitation. The FA reagent was stable during lyophilization and storage at 5 C for 60 days.

Agglutination Tests↗
PubMed1976

Canine salmonellosis: A review and report of dog to child transmission of Salmonella enteritidis.

Dogs have been shown to harbor 53 salmonellae serotypes. Multiple simultaneous infections with 2 to 4 serotypes have been observed. The prevalence of canine salmonellosis may be a high as 27 per cent. Salmonella typhimurium and S. anatum are the most common etiologic agents. Dogs commonly experience a sub-clinical course of salmonellosis. Some investigators state that the dog may serve as a source of human infections. A few reports in the literature have documented this fact. The transmissions of S. enteritidis from dog to child is described in this article.

Ampicillin↗
PubMed1973

Lactose-fermenting Salmonella from dried milk and milk-drying plants.

A study of 552 salmonella cultures revealed that 86 (15.6%) of the cultures fermented lactose. These had been isolated from dried milk products and milk-drying plants. Acid and gas were produced in lactose broth. Solid media containing lactose as the key ingredient for the differential reaction were not satisfactory for recognizing salmonella colonies. No problem was encountered in selecting salmonella colonies when bismuth sulfite agar was used.

Animals↗