agar and Mycobacterium-Infections

Ten different agar media were tested for the in vitro growth of Mycobacterium genavense in primary cultures and in subcultures from BACTEC vials. These agar media were based on Middlebrook 7H9, 7H10 and 7H11, and supplemented with additives: mycobactin J, yeast extract, charcoal, or defibrinated sheep blood. Some media were acidified with phosphoric acid to a final pH of 6.2 +/- 0.2. Fourteen M. genavense strains from nude mouse organs as well as one decontaminated clinical specimen (from a bird) were tested. The optimal medium for primary cultures of M. genavense was Middlebrook 7H11 acidified to pH 6.2 +/- 0.2 and supplemented with charcoal and sheep blood: on this medium, all strains produced colonies within 6-12 weeks of incubation in numbers approaching the number of bacilli inoculated. It was also the only medium to support the growth of the decontaminated clinical specimen. Added blood and charcoal appeared not as essential for subcultures as for primary cultures. Three media supported the growth of all strains within 1 month incubation: they were acidified, and were supplemented with yeast extract or pancreatic digest of casein, and with either blood or charcoal.

Topics: Agar; AIDS-Related Opportunistic Infections; Animals; Bird Diseases; Birds; Blood; Charcoal; Culture Media; Female; Humans; Mice; Mice, Inbred BALB C; Mice, Nude; Mycobacterium; Mycobacterium Infections

Primary BACTEC 12B cultures with serpentine cords observed in Kinyoun-stained smears were tested with a probe for Mycobacterium tuberculosis complex, while cultures without cords were tested with a probe for M. avium complex. The sensitivity, specificity, and positive and negative predictive values of cording for the presumptive identification of M. tuberculosis were 95, 95, 90, and 98%, respectively. With experience, the selection of a probe for testing of primary BACTEC 12B cultures on the basis of cord formation and history of tuberculosis can provide a rapid and reliable approach to the laboratory diagnosis of tuberculosis.

Topics: Agar; Bacteriological Techniques; Culture Media; Diagnostic Errors; DNA Probes; Evaluation Studies as Topic; Humans; Molecular Probe Techniques; Mycobacterium; Mycobacterium avium Complex; Mycobacterium Infections; Mycobacterium tuberculosis; Sensitivity and Specificity; Tuberculosis

Mycobacterium avium complex-serotype 6 was isolated in pure culture on blood agar plates from inocula taken from the heart blood, lungs, liver, kidneys, and spleen of a naturally infected captive female opossum (Didelphis marsupialis virginiana). Repeat cultures from stored tissues and transfer of colonies from original blood agar plates revealed that the mycobacterium grew on tryptose, brilliant green, eosin-methylene blue. Sabouraud glucose, and mycobiotic agar plates and in Fletcher leptospira medium. The cultural, biochemical, and serological characteristics of the test isolate were compared with other mycobacteria. This is the first report to describe the primary isolation of a serotype from the M. avium complex from an animal species on blood agar or in Fletcher broth. In addition, this is the second documented report describing the isolation and identification of a mycobacterial species from the American opossum.

Topics: Agar; Animals; Blood; Female; Mycobacterium; Mycobacterium avium; Mycobacterium Infections; Opossums

Topics: Agar; Animals; Antibody Formation; Antigens; Erythrocytes; Hemagglutination Tests; In Vitro Techniques; Lung; Male; Mice; Mycobacterium Infections; Mycobacterium tuberculosis; Rabbits; Spleen