John S. Chapman

The Ecology of the Atypical Mycobacteria

In this paper an effort has been undertaken to view the family Mycobacteriaceae from the standpoint of general biology, evolution, and ecology at the microscopic level. By their range of tolerances for a variety of adverse environments, by their association with geographic and unknown soil and climatic factors, by their ability to survive and reproduce in sparse media, the atypical mycobacteria seem to possess characteristics of free-living organisms, whose contact with and importance to man results from overlapping niches, well-defined in the case of most mycobacteria, but less so in the case of Mycobacterium kansasii. In contrast, the human tubercle bacillus appears as a highly specialized organism with its niche restricted to mammalian tissue.

Pneumoconiosis Among Activated-Carbon Workers

The prevalence of respiratory symptoms and chest radiographic and spirometric abnormalities was assessed among 397 employees of an activated carbon plant. Definite radiographic findings of pneumoconiosis, consisting of p-type, rounded opacities in the lower lung fields without firbosis or coalescence, were present in 9.6% of men and were related to cumulative dust exposure. Lesser degrees of radiographic abnormality suggesting pneumoconiosis were present in 11% of men and 2% of women. Spirometric values were substantially lower in blacks than in whites. However, cumulative dust exposure was not an important determinant of pulmonary function in either race. Review of lung biopsy speciments that had been obtained previously in two employees revealed extensive carbon depositiion but minimal associated fibrosis. Prolonged inhalation of activated carbon dust leads to pulmonary deposition of carbon and raciographic signs of pneumoconiosis; such deposition has little, if any, effect on respiratory symptoms or pulmonary function.

A serological reaction associated with sarcoidosis.

Conclusions 1. A serological reaction has been obtained between sera of patients with sarcoidosis and antigens from anonymous mycobacteria, using agar diffusion technic. 2. The reaction has occurred in sera of 28 of 32 patients, 3 of which changed from negative to positive as lesions improved. 3. The data permit no conclusion as to specificity of this reaction, but suggest its value as an additional diagnostic method in sarcoidosis. The author expresses gratitude to Dr. M. M. Cummings, Oklahoma City; Dr. Helen Dickie, Madison, Wis.; Dr. Edwin Kendig, Richmond, Va.; and Dr. Howard Buechner, New Orleans, for assistance in obtaining sera from their several areas. The author wishes to express his great obligation to Miss Maro Speight, whose untiring and enthusiastic efforts have made this study possible, and to Dr. Lloyd Hirshberger, San Angelo, Texas, for providing sera and information on the sanatorium patients.

Effect of solvents on eosinophile-stimulating substance of erythrocyte stroma.

Summary 1. A series of experiments with variously treated RBC stroma injected intra-peritoneally into mice clearly demonstrates that an eosinophile-stimulating substance previously noted is not a lipid. 2. The experiments further establish that the substance is either a protein or a protein-carbohydrate compound. 3. The possibility is raised that the physical state of material (gel or insoluble suspension) may determine the eosinophilic response.

Mycobacterium kansasii (Hauduroy)

This organism was first fully described as a distinct mycobacterium by Hauduroy, and it is now fully accepted as a species.450 Bonicke’s amidase tests reveal enzymes effective only against urea and nicotinamide,33 a finding fully verified by others.162,366 A distinctive set of lipases,366 serotyping,167 and phage typing167 further establish the organism as a distinct species. For other bacteriological characteristics, see Table 2-1.

Mycobacterium marinum (balnei)

In 1954, Linell and Norden first isolated and identified M. marinum as the specific agent for a characteristic disease of the skin that was associated with swimming pools. They established the source of the infection as bacterial colonies in rough cement and described a specific response in animals as well as the histological and immunological results of human infection.229

Mycobacterium fortuitum (with M. chelonei, M. borstelense, and M. abscessus)

These several organisms are considered under the same heading both for convenience and as a result of uncertainty. Bacteriologists have not reached complete agreement as to the exact relationship among them. Clinical studies and reports often antedate the separation of M. abscessus but present infections that seem clearly to result from the organism now known by that name. Mycobacterium borstelense and M. chelonei appear as organisms in a number of reports but are thought (see below) to be identical with M. abscessus.

The Avium-Battey Complex

In 1967313 and again in 1971,314 Runyon stated succinctly the problem that mycobacteriologists have almost unanimously recognized: “M. intracellulare and M. avium so much intergrade that reference is better made to the avium complex.” In spite of this statement, it is generally accepted that M. intracellulare is a species, and it is so described. However, it is a species with a very broad range of characters. At one end of the range resemblance to M. avium is striking, at the other it seems to merge with organisms of the soil that possess no pathogenicity.

Pathology and Pathogenesis

Detailed and specific descriptions of gross pathology have been relatively rare. Much of the available material has consisted of resected pulmonary tissue, and post mortem examinations have most often dealt with severe disseminated disease in compromised hosts. In consequence, detailed description of the gross appearance of unmodified disease is lacking.

Early History of the Atypical Mycobacteria

Almost a hundred years ago Koch described the human strain of Mycobacterium tuberculosis. Within a short time, the bovine tubercle bacillus had been identified as a separate, specific organism, and within a few years, the avian mycobacterium had also been isolated and described. By 1895, not only were these organisms well known to bacteriologists, but in the course of their work, they had encountered many strains that did not coincide with descriptions of the original specific acid-fast bacilli. Investigators of the period undertook the same examinations of problems of origin, mutation, transmissibility, infectivity, and pathogenesis that their successors were to take up 50 years later. It will be evident from the account that follows that bacteriologists turned at once to the environment, not only as a source for the various strains but also as an intermediate habitat of tubercle bacilli.