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Biomedical subjects

R C Good

Publications and source records attributed to R C Good.

At least 55 records · Page 3Linked to original sources
PubMed1982

Disk diffusion testing with polymyxin and amikacin for differentiation of Mycobacterium fortuitum and Mycobacterium chelonei.

Disk diffusion is one method of susceptibility testing of the Mycobacterium fortuitum complex to antibacterial agents. We utilized disks of polymyxin B (300 U), amikacin, and kanamycin to determine whether they could also be used for species identification when compared with standard biochemical methods. With the polymyxin disk, 100% of 75 M. fortuitum strains produced zones of inhibition, whereas none (0%) of 58 Mycobacterium chelonei subspecies abscessus and chelonei strains had any zone of inhibition. With the amikacin disk, 99% of M. fortuitum biovariant fortuitum had zones of greater than or equal to 30 mm compared with 6% of M. chelonei. The rare M. chelonei-like organisms gave variable results, and 42% of the unnamed "third group" biovariant of M. fortuitum exhibited an unusual but diagnostic pattern of small zone sizes to amikacin and no zone to kanamycin. The kanamycin disk was otherwise not helpful, although it resulted in larger zone sizes for M. chelonei than did amikacin. Thus, disk diffusion susceptibilities which include these disks (especially polymyxin) will provide presumptive evidence of species as well as susceptibility data.

Amikacin↗
PubMed1982

Bacteriophage types of Mycobacterium tuberculosis in the United States.

Strains of Mycobacterium tuberculosis from various geographic areas within the continental United States were typed according to their susceptibility to 4 mycobacteriophages. Of 462 wild isolates studied, 34% were phage type 1 (previously designated A0), 42% were type 2 (A1), 2.6% were type 5 (A4), 13% were type 7 (A6), and 20.1% were type 8 (B). Distribution of types was essentially unaffected by geographic location, sex, age, or ethnic origin of the patient or by resistance of the isolate to antituberculosis drugs. Major types were further divided by susceptibility of the strains to lysis by 8 auxiliary phages, 2 of which were phages newly evaluated in this study. A new numbering system is proposed for designating major phage types of M. tuberculosis.

Bacteriophage Typing↗
PubMed1982

Mycobacterium avium-intracellulare: a cause of disseminated life-threatening infection in homosexuals and drug abusers.

Five men developed disseminated infection with Mycobacterium avium-intracellulare. These patients all lived in the New York City area and presented with their illnesses between January 1981 and September 1981; four were homosexual and one was an intravenous drug abuser. Four patients died. All five patients had defects in the cell-mediated immune response. The infections were characterized histopathologically by poor or absent granulomatous tissue reaction. Clinical isolates of M. avium-intracellulare from all five patients agglutinated commonly used antimycobacterial drugs. The spectrum of opportunistic infections among populations of homosexuals and drug abusers should be expanded to include disseminated disease due to M. avium-intracellulare.

Adult↗
PubMed1981

Identification of clinically significant Mycobacterium fortuitum complex isolates.

Recent outbreaks of nosocomial infections caused by organisms identified as the Mycobacterium fortuitum complex suggest that species and subspecies identification is epidemiologically important. In a study of 170 strains, M. fortuitum was differentiated from M. chelonei by nitrate reduction and iron uptake. M. fortuitum was further divided into biovariant fortuitum, biovar peregrinum, and an unnamed third biovar by inositol and mannitol utilization. M. chelonei was further divided into subsp. chelonei, subsp. abscessus, and an unnamed subspecies by tolerance to 5% sodium chloride, utilization of mannitol and sodium citrate, and uptake of iron.

Bacteriological Techniques↗
PubMed1981

Rapid drug-susceptibility testing of Mycobacterium tuberculosis.

Three methods for rapidly determining the susceptibility of Mycobacterium Tuberculosis isolates to isoniazid, rifampin, ethambutol, streptomycin, and para-aminosalicylic acid were evaluated in a large-scale, blind study. Two of the methods measured evolution of CO2 from radio-labeled substrate (14CO2), and one method measured incorporation of 3H-uracil into ribonucleic acid. Rapid indirect drug-susceptibility test results for nearly 300 isolates were compared with those obtained using a standard modified proportion technique. The 3H-uracil uptake method proved to be unacceptable. Over-all, the results obtained using the 14CO2 methods and the standard method were similar. In general, there was greater agreement between the 14CO2 and proportion techniques with drug-susceptible strains than with drug-resistant strains. Among drug-resistant strains, both 14CO2 methods were more reliable for determining resistance to rifampin than to other drugs. This study demonstrates that large-scale, blind evaluations of new laboratory procedures are valuable. Our results indicate that methods relying o the enzymatic release of 14CO2 should be further refined and evaluated.

Aminosalicylic Acid↗
PubMed1978

Evaluation of thermal disinfection procedures for hydrophilic contact lenses.

The kinetics and efficacy of moist heat disinfection for hydrophilic contact lenses were investigated by using representative microorganisms of ophthalmic concern and several heat-resistant species. In replicate challenges, 80 degrees C for 10 min and 75 degrees C for 5 min were proven efficacious for moist-heat disinfection.

Bacteria↗
PubMed1976

Comparison of antigens in sonic and pressure cell extracts of Mycobacterium tuberculosis.

Comparisons were made of the yield, chemical content, and biological activity of filtrates and extracts obtained by sonic and pressure cell disruption of bacilli from 4- and 8-week-old Proskauer and Beck cultures of the H37Rv strain (TMC no. 102) of Mycobacterium tuberculosis. The culture filtrates were dialyzed, freeze-dried, reconstituted in saline, and sterilized by membrane filtration. The viable bacilli were washed and resuspended in distilled water and subsequently disrupted either by sonication in the cold for 15 or 30 min or by treatment at 20,000 or 40,000 lb/in2 in a pressure cell. The resulting extracts were clarified by centrifugation, concentrated, and sterilized by filtration. All preparations were adjusted to contain 10 mg of solids (dry weight)/ml and were analyzed quantitatively for protein, deoxyribonucleic acid, ribonucleic acid, polysaccharide, and lipid content. Separation patterns obtained by gradient acrylamide gel electrophoresis, as well as by one- and two-dimensional immunoelectrophoresis, provided the basis for qualitative comparisons of the culture filtrates and cell extracts. Three-point dose-response curves also were used to compare the preparations for skin test reactivity in BCG-vaccinated guinea pigs. It was concluded that, although there were no consistent differences in chemical content or biological activity between the preparations, a 15-min sonic treatment appeared to be the most suitable method for preparation of bacillary extracts based on yield of active components and ease of preparation.

Animals↗
PubMed1975

Tuberculin-induced lymphocyte transformation and skin reactivity in monkeys vaccinated or not vaccinated with Bacille Calmette-Guérin, then challenged with virulent Mycobacterium tuberculosis.

The in vitro lymphocyte transformation test was compared to the skin test at intervals after aerogenic administration of bacille Calmette-Guerin vaccine to monkeys, and also at monthly intervals after aerogenic challenge of monkeys vaccinated and not vaccinated with virulent strain H37Rv of Mycobacterium tuberculosis. Individual responses varied, but several consistent patterns of sensitivity development could be discerned. The lymphocyte transformation test was more sensitive, and often positive when the skin test was negative, doubtful, or feeble. Conversion to tuberculin reactivity was detected by lymphocyte transformation in vitro earlier in the disease or after vaccination, and persisted longer after sensitivity to the skin test had waned or after the animals had become anergic by the skin test. Monkeys not vaccinated, but challenged, developed larger in vitro skin reactions and responses than animals that were either vaccinated and challenged or only vaccinated; however, the unvaccinated, challenged monkeys developed anergy to tuberculin and progressive disease more rapidly than other groups, and their cells became less responsive to phytohemagglutinin in vitro.

Animals↗
PubMed1975

Immunoelectrophoresis of Mycobacterium tuberculosis antigens. Comparative analysis of cell extract and culture filtrate antigens.

Immunoelectrophoretic analyses were performed on a cell extract and culture filtrate of Mycobacterium tuberculosis, H37Rv strain using homologous polyvalent goat antisera. General similarity between the cell extract and culture filtrate antigens was found. Significant variation between two anti-culture filtrate antisera was observed. These antigens and antisera also differed significantly from previously described reference reagents. These findings demonstrate the necessity of using reference materials for precise identification of mycobacterial antigens in comparative studies.

Animals↗
PubMed1971

Respiratory pathogens in monkeys.

Respiratory disease in a dynamic colony of nonhuman primates during a 4-year period was due primarily to infections caused by Klebsiella pneumoniae, Diplococcus pneumoniae, Bordetella bronchiseptica, Pasteurella multocida, and Haemophilus influenzae. The principal secondary invaders were Escherichia coli, Staphylococcus aureus, and streptococci. A high fatality rate was associated with infections caused by each of the primary pathogens, and females appeared to be more susceptible than males. Incidence of respiratory disease was greatest in the fall and early winter; however, at all times newly colonized monkeys had a higher infection rate than conditioned monkeys. Infections were occasionally confined only to the lungs and were sometimes present without grossly observable lung lesions. The information given on susceptibility of 10 species of nonhuman primates to respiratory infections provides a basis for developing disease models.

Journal Article↗
PubMed1969

Enteric pathogens in monkeys.

From 1964 to 1967, 6,646 monkeys, representing 10 primate species, were examined for Shigella and Salmonella infections upon arrival at the National Center for Primate Biology. Of these animals, 12% were infected with Shigella, and 75% of the Shigella isolates were S. flexneri 4. The incidence of Salmonella infections decreased from 12 to 3% during the period of study. Epidemiological studies of animals in the colony for 90 days or more indicated no seasonal variation in the occurrence of Shigella and Salmonella. Many of the isolates from incoming monkeys as well as from laboratory-conditioned animals were resistant to chloramphenicol, dihydrostreptomycin, and tetracycline. The possible operation of drug-resistance factors in these infections is discussed.

Animals↗