A total of 463 respiratory specimens, all smear positive for acid-fast bacteria, were inoculated onto routine solid media and into BACTEC 7H12 Middlebrook medium for detection of mycobacterial growth. Conventional drug susceptibility testing (1% proportion method) was performed on Middlebrook 7H10/7H11 medium, and radiometric susceptibility testing was performed on BACTEC 7H12 medium. The average detection times for BACTEC-positive cultures were 8.3 days for Mycobacterium tuberculosis and 5.2 days for mycobacteria other than tuberculosis; by conventional methods, they were 19.4 and 17.8 days, respectively. These detection times do not include time required for identification, which was done by the conventional method only. There was an excellent correlation in the recovery rates of mycobacteria by the two methods. Drug susceptibility test results of M. tuberculosis isolates by the two methods showed 95.1 to 100% overall agreement. The average reporting time for drug susceptibility results ranged from 4.2 to 6.9 days for the BACTEC method and 13.7 to 21 days for the conventional methods. An average of 18 days was required by the BACTEC method for complete recovery and drug susceptibility testing of M. tuberculosis, as compared with 38.5 days for the conventional methods.

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This study was undertaken to evaluate the potential of a cryptococcal culture filtrate antigen, cryptococcin C184, for detecting delayed hypersensitivity in Cryptococcus neoformans-injected animals. The antigen was tested on guinea pigs which had received saline or C. neoformans and on animals sensitized to Histoplasma capsulatum, Blastomyces dermatitidis, Candida albicans, or Sporothrix schenckii. A delayed-type hypersensitivity response was elicited by cryptococcin C184 in C. neoformans-injected guinea pigs, whereas no indurations or erythemas were seen at 48 h after skin testing of saline controls or heterologously sensitized guinea pigs. Besides being specific for Cryptococcus, the antigen showed a high degree of sensitivity and was reproducible. Footpad tests were conducted with the antigen on mice which had previously received either 105 viable C. neoformans cells or saline. Delayed hypersensitivity was indicated in the C. neoformans-injected mice by the increase in thickness of antigen-injected footpads when compared with the saline-injected footpads. In control mice, antigen-and saline-injected footpads were comparable in thickness 24 h after injection. Mice sensitized to B. dermatitidis were footpad tested with C184, and no cross-reactivity was demonstrated. MATERIAL AND METHODS Animals. Hartley strain guinea pigs of both sexes weighing 700 to 900 g were used. Mice used for sensitization and footpad testing were six-week-old CBA/J inbred strain. All animals were born and raised in the animal facilities of the

At that time he gave a history of pleuritic type chest pain, cough, and blood-streaked sputum. Physical examination revealed bilateral crepitations in the lungs, and his chest radiograph showed dense fibrotic infiltration over the entire right lung field with evidence of cavitation in the right upper lobe. On the left there were scattered, less dense infiltrations in the lower two-thfirds. Sputum smears for acid-fast bacilli initially were reported as Gaffky VI. Subsequent sputa were negative. No cultures were made. A diagnosis of far advanced, pulmonary tuberculosis was made, and treatment consisted of repeated artificial pneumothoraces on the right. After one year he was discharged as improved.The patient remained well for two years, but was readmitted in 1941 because of shortness of breath, cough, and one episode of haemoptysis: at that time he received several additional artificial pneumothorax treatments. Sputum smears were negative for acid-fast bacilli.His third admission was in 1948 for 10 days, and once more he was given a pneumothorax on the right.The patient then felt well enough to do light work as a carpenter and as a farmer. He was admitted for the fourth time in November 1965 because of bloodstreaking in the sputum. His chest radiograph showed dense infiltration in the upper two-thirds of the right lung with cavity formation, while the left lung was 722 on 10 May 2018 by guest. Protected by copyright.