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M Tsukamura

Publications and source records attributed to M Tsukamura.

At least 37 records · Page 2Linked to original sources
PubMed1990

The growth of mycobacteria in liquid medium is influenced by the dimension of glass wall in contact with the medium.

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.

Colony Count, Microbial↗
PubMed1990

Growth physiology of mycobacteria in modified Dubos liquid medium.

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.

Colony Count, Microbial↗
PubMed1990

Cefotaxime-resistant Nocardia asteroides strains are isolates of the controversial species Nocardia farcinica.

A recent study of Nocardia asteroides revealed that 95% of clinical strains had one of five antibiotic resistance patterns. We found the pattern of resistance to cefotaxime and cefamandole in 19% of 200 clinical N. asteroides isolates. Isolates with this drug resistance pattern were from numerous geographic sources and were associated with significant clinical disease (56% of patients had disseminated infections). Phenotypic studies revealed that these isolates were relatively homogeneous and matched previous descriptions and reference strains of the controversial species N. farcinica. Growth at 45 degrees C, acid production from rhamnose, ability to utilize acetamide as a nitrogen and carbon source, and resistance to tobramycin and cefamandole were features of N. farcinica that could be tested in the clinical laboratory and allowed their distinction from N. asteroides. The serious nature of disease due to N. farcinica and its resistance to the newer cephalosporins suggest a clinical need for laboratory identification of this species. (Current tests used in clinical laboratories do not distinguish N. farcinica from N. asteroides.) This is the first recognition that N. farcinica has a specific drug resistance pattern and confirms the previously described concept that drug resistance patterns of N. asteroides may be associated with specific taxonomic groups.

Cefotaxime↗
PubMed1990

[Cross-resistance relationship between streptomycin and kanamycin resistances in Mycobacterium smegmatis (strain Jucho)--comparison of the development patterns of resistances to streptomycin and kanamycin among Mycobacterium tuberculosis, Mycobacterium avium complex, and Mycobacterium smegmatis].

The resistance development pattern of Mycobacterium smegmatis strain 17023 (Jucho) to streptomycin and kanamycin was studied. The medium used was Ogawa egg medium, and the level of resistance was determined for each clone derived from single colony by the 'actual count' method. Hence, the resistance level was estimated as the highest concentration of drugs, in which small inocula consisting of 20 to 100 colony-forming units could grow after seven days incubation. Only one type of resistance mutants resistant to more than 1,000 micrograms/ml streptomycin was isolated and these mutants were also resistant to 8 micrograms/ml kanamycin. On the other hand, only one type of kanamycin-resistant mutants resistant to 8 micrograms/ml kanamycin was isolated and these mutants were also resistant to more than 1,000 micrograms/ml streptomycin. Accordingly, there was a complete cross-resistance relationship between streptomycin and kanamycin resistances. Therefore, there existed only one phenotype, which is simultaneously resistant to streptomycin and kanamycin. The mutants occurred at a rate of about 2 x 10(-8) per viable bacterial population of the parent strain. Streptomycin-dependent mutants occurred at a rate of about 2 x 10(-9). The number of resistant phenotypes to streptomycin and kanamycin was only one in M. smegmatis, while it was five in M. tuberculosis and 2 or 3 in M. avium complex (Tsukamura, M. and Mizuno, S.: J. Gen. Microbiol. 88: 269-274, 1975; Tsukamura, M.: Kekkaku 62: 445-458, 1987). The simplicity of the resistance system of M. smegmatis suggests that this organism is evolutionally primitive in the world of mycobacteria.

Drug Resistance, Microbial↗
PubMed1990

[Chemotherapeutic regimens for nontuberculous mycobacterial infection based on in-vitro susceptibility test results].

Treatment of nontuberculous mycobacterial infection should be carried out by the chemotherapeutic regimens most suitable for each species. We performed in-vitro susceptibility tests for various species and determined the probability in which the mycobacteria of each species are inhibited by blood concentrations attainable by the dosages usually used. From such determinations, the following regimens have been recommended: 1) M. avium-M. intracellulare complex, Rifampicin + Enviomycin + Ethambutol; 2) M. kansasii, Ofloxacin + Enviomycin + Rifampicin; 3) M. szulgai, Enviomycin - Ethambutol + Isoniazid; 4) M. fortuitum, Ofloxacin. The effectiveness of the treatment of the infection caused by M. avium complex is less than 15% even using the above regimen, while it is high in the treatment of infections caused by M. kansasii and M. szulgai. There are no effective regimens for the treatment of infection caused by M. chelonae or M. simiae. The above recommendations are useful in practice, because, at present, reliable susceptibility testing of nontuberculous mycobacteria is not yet done commonly.

Drug Resistance, Microbial↗
PubMed1990

[Determination of the susceptibilities to antituberculosis agents in Mycobacterium avium-Mycobacterium intracellulare complex].

The determination of the susceptibilities to antituberculosis agents in Mycobacterium avium-Mycobacterium intracellulare complex (MAI complex) is influenced by the size of inoculation used in the determination. Such influences differ greatly according to the drugs. By increasing the number of colony-forming units (CFU) of the inoculation to 10(6)-fold, minimal inhibitory concentrations (MICs) of rifampicin and cycloserine have increased only 2-to 3-fold. However, MICs of ethionamide, streptomycin, enviomycin and ethambutol have increased 4-to 9-fold. In contrast, MICs of isoniazid and sulfadimethoxine have increased 30-to 35-fold. Since the determination of MICs of isoniazid and sulfadimethoxine are so greatly influenced by the size of inoculation, the determinations of MICs of these two drugs should be carried out by use of the "actual count" method (6, 7, 9) or the proportion method (8). In the actual count method, the MIC is determined by inoculating 20-100 CFU. The determination of isoniazid susceptibility of M. tuberculosis (H37Rv) was influenced only slightly by the size of inoculation, but that of M. bovis (BCG) was influenced greatly as occurred in the determination of MAI complex strains.

Antitubercular Agents↗
PubMed1990

[Bactericidal activities of rifampicin, ethambutol, enviomycin and streptomycin on Mycobacterium avium-Mycobacterium intracellulare complex strains].

Bacteriostatic and bactericidal activities of rifampicin, ethambutol, enviomycin and streptomycin on Mycobacterium avium-Mycobacterium intracellulare complex (MAI complex) strains were determined. The susceptibility testings were made in Ogawa egg medium, and minimal inhibitory concentrations (MICs) were determined as the lowest concentration of drugs, in which the growth of 20 to 100 colony-forming units was completely inhibited. The MICs correspond to the MICs that can inhibit the growth of 95 to 99% of bacterial population. Bactericidal activity was determined in a modified Dubos liquid medium (1.3 g of Dubos TB Broth Base were dissolved in 180 ml of distilled water and this solution was supplemented by 20 ml of bovine serum). A one ml-sample of bacterial suspensions (10 mg wet weight per ml) was added to 9 ml of the Dubos liquid medium, and the medium was incubated at 37 degrees C for 0, 1, 3 and 7 days under shaking condition (56 strokes per minute; 8 cm amplitude). The bactericidal activity was measured as the number of colony-forming units contained in a 0.02 ml-sample of the medium. The bactericidal activities of rifampicin and ethambutol were weak or absent even in strains 13008 and 13016, which were very susceptible to all four drugs. However, the bactericidal activities of streptomycin and enviomycin could be observed in these strains.(ABSTRACT TRUNCATED AT 250 WORDS)

Antitubercular Agents↗
PubMed1990

[Bactericidal activity of ofloxacin against Mycobacterium kansasii].

Bactericidal activity of ofloxacin against Mycobacterium kansasii was observed in in-vitro experiment. Tested bacteria were suspended to a concentration of one mg wet weight per ml in 10 ml of Dubos liquid medium containing no drug or containing 1 or 3 micrograms/ml ofloxacin and incubated at 37 degrees C. The number of colony-forming units contained in a 0.02 ml-sample of the Dubos liquid medium was counted after incubation for 0, 1, 3 and 7 days. The number of colonies was counted in Ogawa egg medium, to which was inoculated a 0.02 ml-sample of dilutions of the medium by a spiral loop that can deliver a 0.02 ml-sample by one inoculation. The bactericidal activity of ofloxacin against M. kansasii appeared after incubation of 3 days or later. This characteristic was different from the bactericidal activity against Mycobacterium tuberculosis, which appeared after incubation of 24 hours.

Colony Count, Microbial↗
PubMed1990

[Bactericidal activity of antituberculosis drugs against Mycobacterium avium complex].

The bactericidal activity of antituberculosis drugs against two strains of M. avium complex 13008 (serotype 20) and 13016 (serotype 4), was observed using modified Dubos liquid medium (1.3 g of Dubos Broth Base (Difco) in 180 mil of distilled water plus 20 ml of bovine serum). The strains were most susceptible to antituberculosis drugs among M. avium complex strains (Table). The test strains were cultivated in Ogawa egg medium at 37 degrees C for 10 days, and growing colonies were homogenized by shaking with glass beads for 10 minutes and suspended in the modified Dubos liquid medium to a concentration of 2 mg wet weight per ml. The media containing drug and containing no drug were incubated at 37 degrees C for 24 hours under shaking (8 cm-moving range and 56 strokes per minute). After incubation, the medium was diluted by a 0.1% Tween 80 aqueous solution to 10(-7), and each 0.02 ml-sample of 10(-4) to 10(-7) suspensions was inoculated onto Ogawa egg medium. The Ogawa egg medium slants were incubated at 37 degrees C for 28 days, and the number of colonies was counted. The bactericidal activity was determined as a ratio of the number of colony-forming units in 10 ml-aliquot of drug-containing Dubos liquid medium against the number of colony-forming units in the control Dubos liquid medium. The results are shown in Figures 1 and 2. Under the condition tested, rifampicin, isoniazid, ethambutol, ethionamide and cycloserine did not exhibit any bactericidal activity, and only streptomycin and enviomycin exhibited bactericidal activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Antitubercular Agents↗
PubMed1990

[In-vitro susceptibility of Mycobacterium avium complex to isoniazid and ethionamide].

In this study, it was investigated whether or not Mycobacterium avium complex strains were inhibited by such low concentrations of isoniazid and ethionamide as possible in blood. The inhibitory concentrations were determined by the "Actual Count" method (Tsukamura, M.: Japan J. Tuberc. 12: 46-54, 1964), in which the inhibitory concentration was measured as a concentration that can inhibit the growth of 'countable' colony-forming units. The ratio of strains which were inhibited by such low concentrations as 0.2 microgram/ml isoniazid or 5 micrograms/ml ethionamide was 14%. The result suggests that there are some strains in which isoniazid or ethionamide are clinically effective, though their prevalence was low (14%).

Ethionamide↗
PubMed1990

[In-vitro combined effect of antituberculosis drugs on Mycobacterium avium complex].

In-vitro combined activity of antituberculosis drugs on Mycobacterium avium complex strain 13034 (serotype 18) was observed. A twofold dilution series of each drug was combined with 17 additional drugs and the control without drug. Each medium was inoculated by a 0.02 ml-sample of four different bacterial suspensions, original suspension (10 mg wet weight per ml) and its 10(-5), 10(-6) and 10(-7) suspensions, and incubated at 37 degrees C for 28 days. The inoculation was made by a spiral loop that can deliver a 0.02 ml-sample by one inoculation. Since a total of media reached 6480 (1620 combinations x 4 different suspensions), only one strain was investigated in this study. Inoculation size used for determining minimal inhibitory concentrations was adjusted to 20 to 80 colony-forming units per medium. This was obtained by inoculating 10(-6) suspensions. The diameter of colonies was measured on media that were inoculated with 10(-7) suspensions. Since 96% confidence limits of determining minimal inhibitory concentrations are between 1/4 to fourfold, decrease or increase of the minimal inhibitory concentration equal to or above this level was regarded as significant. Such significant change of the minimal inhibitory concentrations occurred in combinations of drugs is shown in Table 2. As shown in tables, no antagonism was observed. The combinations, in which significant decrease was seen, contained ethambutol, sulfadimethoxine and ethionamide. It was shown that these concentrations of the drugs cause marked delay of growth. In control medium, the diameter of colonies was 5-6 mm, whereas in media containing one of these drugs, it was 1 mm.(ABSTRACT TRUNCATED AT 250 WORDS)

Antitubercular Agents↗
PubMed1989

Carotenoid pigments of genus Rhodococcus.

A study of carotenoid pigments of the genus Rhodococcus was carried out. According to carotenes contained, Rhodococcus species were divided into three groups: the first group of Rhodococcus luteus, R. coprophilus, R. lentifragmentus, and R. maris, which formed beta-carotene; the second group of R. equi, R. rubropertinctus, R. aichiensis, R. sputi, R. chubuensis, R. obuensis, R. bronchialis, R. roseus, R. rhodochrous, R. rhodnii, and R. terrae, which formed gamma-carotene-like substance; and the third group of R. aurantiacus, which formed neither carotene. Other carotenoid pigments were different according to the species.

Carotenoids↗
PubMed1989

Different correlations of drug susceptibilities to colonial morphology in Mycobacterium avium complex strains.

In Mycobacterium avium and Mycobacterium intracellulare complex strains isolated from patients who were not treated previously by any antituberculosis drugs or from fowls, the colonial morphology, smooth, domed, opaque (SmD) or smooth, flat, transparent (SmT) colonial forms, significantly correlated with susceptibilities to rifampicin, minocycline, streptomycin, kanamycin, enviomycin, ethambutol, and sulfadimethoxine, whereas it did not correlate with susceptibilities to isoniazid, cycloserine, and ethionamide. Strains with the SmT colonial morphology were more resistant to the former seven drugs than strains with the SmD colonial morphology. Since the susceptibilities to antituberculosis drugs with large molecules correlated with the colonial morphology, it has been suggested that a permeability barrier that allows passage of small molecules but prevents passage of large molecules exists in the strains with the SmT colonial morphology.

Anti-Bacterial Agents↗
PubMed1989

Identification and partial characterization of Mycobacterium avium and Mycobacterium intracellulare by using DNA probes.

We attempted to identify the Mycobacterium avium complex (MAC) isolated in Japan by using DNA probes specific for M. avium or Mycobacterium intracellulare (Gen-Probe Rapid Diagnostic System for MAC; Gen-Probe, Inc., San Diego, Calif.). The source and drug susceptibility distributions were examined. This assay system proved to be rapid, sensitive, specific, and reliable for identification of MAC and of the species as either M. avium or M. intracellulare. The DNA probe test showed that of the generally accepted MAC serovars, serovars 1 to 6, 8 to 11, and 21 belonged to M. avium and 7 and 12 to 20 belonged to M. intracellulare. Moreover, with the DNA probe test we found that the distribution patterns of M. avium and M. intracellulare isolates in Japan differed depending on the district in which MAC was isolated. The ratio of M. avium was much higher in eastern Japan. In Tokai and Shimane districts, the ratio of M. avium and M. intracellulare isolates significant in human disease was related to that of isolates from soil and house dust (natural sources). In M. avium, human disease-associated isolates were more resistant to rifampin, streptomycin, and kanamycin than were isolates from natural sources. However, this source dependence was not evident for M. intracellulare. In human disease-associated MAC, M. avium isolates were more resistant to most agents, except for quinolones, than were M. intracellulare isolates.

Animals↗
PubMed1989

Correlations among naturally occurring resistances to antituberculosis drugs in Mycobacterium avium complex strains.

In Mycobacterium avium complex strains, which were not exposed previously to any antituberculosis drugs, resistances to rifampin, minocycline, and kitasamycin, and resistances to streptomycin and kanamycin appeared frequently in the same strains. These data indicate that patterns of drug resistance in these organisms are not random but occur through linked mechanisms.

Animals↗
PubMed1989

Superiority of enviomycin or streptomycin over ethambutol in initial treatment of lung disease caused by Mycobacterium avium complex.

The rate of sputum conversion (continuously negative cultures for six months or more) was compared among four regimens given to 83 patients with moderately advanced, cavitary lung disease caused by Mycobacterium avium complex untreated previously. The regimens of rifampin + isoniazid + enviomycin and rifampin + isoniazid + streptomycin appeared to be superior to the regimen of rifampin + isoniazid + ethambutol. No statistically significant difference was observed between the regimens rifampin + isoniazid + enviomycin and rifampin + isoniazid + streptomycin.

Clinical Protocols↗
PubMed1989

[Evaluation of cycloserine in the treatment of infections caused by nontuberculous mycobacteria viewed from in vitro experiments].

Evaluation of cycloserine as a drug in the treatment of infections caused by nontuberculous mycobacteria was made from in-vitro studies, in which Mycobacterium tuberculosis strains were used as the standard of the evaluation. The susceptibility testing to cycloserine was made using Ogawa egg medium. Bacterial suspensions, 10 mg wet weight/ml, prepared from 10 day-old cultures (M. tuberculosis, 14 day-old cultures) growing on Ogawa egg medium were used as the source of inoculation. A 0.02 ml-sample of the suspensions was inoculated onto Ogawa egg medium containing cycloserine or containing no drug, and the media inoculated were incubated at 37 degrees C. The minimal inhibitory concentration (MIC) was determined after incubation for 14 days (M. tuberculosis, for 21 days). The MIC was determined as the lowest concentration of the drug, on which the growth of test strains was completely inhibited. However, residual growth was sometimes observed. This was regarded as growth inhibition, because control medium containing no drug showed always abundant, membraneous growth. The results are shown in Fig.. The growth of M. tuberculosis strains was inhibited by the concentrations of 6.25 to 25 micrograms/ml. However, considering our previous observations on the relationship between the cycloserine resistance and the drug efficacy (reference 1), we regarded the MIC 12.5 micrograms/ml as critical concentration for presumable clinical efficacy. The ratios of strains of various mycobacterial species showing the MICs lower than the critical concentration are shown in Table. As seen in this table, clinical efficacy of cycloserine was expected in the treatment of infections caused by Mycobacterium kansasii, M. malmoense, M. simiae, M. scrofulaceum and M. marinum.(ABSTRACT TRUNCATED AT 250 WORDS)

Cycloserine↗