Isolation of Mycobacterium avium complex from sputum specimens in association with the appearance of a new cavitary (or infiltrative) lesion was studied in 299 patients from whom the organism was ...isolated one or more times. Of the patients studied, 114 showed only single isolation. Of these 114, only two patients (2 percent) had association with appearance of a cavitary lesion. Of 29 patients who showed two isolations, 26 (90 percent) had the association. Of 40 patients who showed three isolations, 39 (98 percent) had the association. All 116 patients who showed four or more isolations had the association with appearance of a cavitary lesion. Accordingly, of a total of 185 patients who showed two or more isolations, 181 (98 percent) had the association. Of these 181, 176 (97 percent) showed two or more isolations in the sputum examinations made in the initial three days. Therefore, the sputum examination in the first three days after onset of disease is most important for the diagnosis of disease caused by Mycobacterium avium complex. Since the probability that casual isolation of the organism occurs twice is extremely low, we can make the diagnosis of pulmonary infection caused by this organism by evidence of two or more isolations of the organism in the first few days after the onset of disease, which is associated with appearance of a new cavitary (or infiltrative) lesion. Moreover, theoretical consideration made in this study has led us to conclude that patients who have had a single isolation of the organism together with a new cavitary lesion should be regarded as having an infection. (Chest 1991; 99:667–69)
Mycobacterium avium and Mycobacterium intracellulare are differentiated from each other by thin-layer chromatography of lipid fraction extracted after incubation with 35Smethionine. The former ...contained a petroleum ether-soluble sulfolipid and the latter did not.
Previously, it was difficult to isolate the Mycobacterium avium complex from soil, water, and dusts, because rapidly growing mycobacteria always overgrew slowly growing ones. We used Ogawa egg medium ...containing both ethambutol and ofloxacin, which inhibit the nonpathogenic slowly growing mycobacteria and most rapidly growing mycobacteria, respectively, as an aid to screen for pathogenic slowly growing mycobacteria; we could thereby isolate a number of the M. avium complex and M. scrofulaceum strains from soil, water, and dusts in this country.
DL-8280 is a new antibacterial agent and has the following chemical structure: 9-fluoro-3-methyl-10-(4-methyl-1-piperazinyl)-7-oxo-2,3-dihydro-7H -pyrido(1,2,3-de)1,4-benzoxazine-6-carboxylic acid ...(molecular weight, 361.37; C sub(18)H sub(20)FN sub(3)O sub(4)). It is under clinical investigation for diseases other than mycobacteriosis. In the present study, it has been shown that the agent has a strong in vitro antimycobacterial activity and the test for DL-8280 susceptibility is useful for differentiating between the species of some important mycobacteria.
The growth of the type strain of Mycobacterium aurum was compared between flask and tube, both of which contained the same concentration of bacteria in synthetic media and had the same air-contact ...dimension but had different dimensions of the glass wall of vessels contacting the medium. Much better growth occurred in the flask, which had a smaller dimension of the glass wall contacting the medium, than in the tube, which had a larger dimension. The finding shows that the growth of bacteria is influenced by the dimension of the glass wall of vessels. It was considered that a high chance of the attack shock for bacteria given by the Brownian movement lowers the multiplication of bacteria.
Although mycobacteria grow in Dubos liquid medium showing an arithmetic linear growth, the initial few days of growth were found to correspond to an ‘induction’ period. In this period, rapid increase ...of the amount of growth occurred, whereas increase of the number of colony-forming units remained at a low level. This finding shows that the rapid increase of the amount of growth is accompanied by rapid death of multiplied bacteria. In a successive period, which was considered to correspond to the logarithmic growth phase, a 1:1 correspondence existed between the amount of growth and the number of colony-forming units. The induction period is not considered to be a lag phase, in which the bacteria grow slowly, but a period of unbalanced relationship between the growth and the viability. Even when we inoculated different sizes of bacteria, the amounts of growth became similar in both inoculations after several days of incubation. However, the number of colony-forming units remained always smaller in the use of small inocula than in the use of large inocula. In the use of small inocula, much more rapid increase of the amount of growth occurred. However, this rapid increase gave rise to rapid death of bacteria.
Numerical classification of 280 strains of slowly growing mycobacteria was carried out by testing each strain for 76 characters. The following fourteen clusters were observed: 1. M. tuberculosis, M. ...bovis, M. africanum, and M. microti; 2. M. haemophilum; 3. M. ulcerans; 4. M. xenopi; 5. M. kansasii; 6. M. szulgai; 7. M. gordonae; 8. M gastri; 9. M. avium, M. intracellulare, M. scrofulaceum, and M. asiaticum; 10. M. marinum; 11. M. simiae; 12. M. nonchromogenicum, "M. novum," M. terrae, and M. triviale; 13 M. malmoense; 14. M. shimoidei. The clusters composed of M. tuberculosis, M. bovis, M. africanum, and M. microti, of M. avium, M. intracellulare, M. scrofulaceum, and M. asiaticum, and of M. nonchromogenicum, "M. novum," M. terrae, and M. triviale appeared to be reduced to a single species each. The names having priority for each species should be M. tuberculosis, M. avium, and M nonchromogenicum, respectively. However, the clusters may, in practice, be called the M. tuberculosis series (complex), the M. avium series (complex), and the M. nonchromogenicum series (complex). The type species of these series are M. tuberculosis, M. avium, and M. nonchromogenicum, respectively. These series were characterized in this study.
The test for susceptibility to kanamycin is useful for differentiating between the genera Rhodococcus and Nocardia. All rhodococci except R. equi, R. erythropolis, and R. aurantiacus are susceptible ...to kanamycin, whereas all nocardiae except N. otitidis-caviarum are resistant to kanamycin. Tests for susceptibility to rifampicin, streptomycin, and minocycline also are useful for differentiating among the species of each genus.
Mycobacterium avium complex strains often contain considerably more numbers of viable bacterial units per mg wet weight than other mycobacteria, especially other slowly growing ones. This finding ...suggests that the life span of M. avium complex strains is often longer than the life span of other mycobacteria. The other mycobacteria, especially slowly growing ones seem to die more rapidly after their multiplication.
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