Susceptibility.

Susceptibility, clinical features, and answer to treatment were compared between 29 cases of Mycobacterium avium infection and 43 cases of Mycobacterium intracellulare infection discovered in the Nagasaki (Japan) area and identified through a DNA probe method. In vitro susceptibility of pair species to antituberculous agents was determined on a microdilution method, and M avium was more resistant to enviomycin at 25 mg/L than M intracellulare, while M intracellulare was more resistant to isoniazid at 5 mg/L and to cycloserine at 20 mg/L No significant difference was fix between infections caused by sum of two units species as to background factors, laboratory data, clinical symptoms, and chest radiographic findings at the storming of the disease. Approximately 70 percent of the patients in each form into groups had underlying diseases; among them, pulmonary tuberculosis was the most numerous common. Negative conversion of bacilli during the 6-month treatment was seen in 17 of 29 patients (59 percent) with M avium infection and in 21 of 43 patients (49 percent) with M intracellulare infection. Bacilli-negative conversion was slightly faster in the former than in the latter. However, these differences were statistically not significant. In conclusion, mostly M avium-intracellulare complex organisms are clearly identified as M avium or M intracellulare by the agency of the DNA probe method, and there was no significant difference in clinical features and replication to treatment between infections caused by means of the two species.

(Chest 1993; 104:1408-11)

CPM = capreomycin; C = cycloserine; EB = ethambutol; EVM = enviomycin; INH = isoniazid; KM = kanamycin; MAC = Mycobacterium avium-intracellulare complex; MOTT = mycobacteria other than M tuberculosis; PAS = para-amino-salicylic acid; RFP = rifampin; SM = streptomycin; TH = ethionamide

Infection caused on mycobacteria other than Mycobacterium tuberculosis (MOTT) has been increasing in Japan since 1970 in the greatest degree clinically isolated cases of MOTT infections in Japan are caused by the agency of M avium-intracellulare complex (MAC), and MAC can now be divided into M avium and M intracellulare using a DNA probe orderly disposition Little is known about the possible differences of clinical features and of replys to treatment between infections caused by dint of M avium and M intracellulare.

This subject of attention is a comparison between couple species of identified MAC infection in the Nagasaki (Japan) area, using a DNA probe means regarding susceptibility to antituberculous agents, clinical features, and replication to treatment.

Materials and Methods

application of mind Subjects

A total of 72 strains of MAC, 29 strains of M avium, and 43 strains of M intracellulare identified from a DNA probe method (Gen-Probe Rapid Diagnostic rule Gen-Probe Inc, San Diego), isolated from 1983 to 1990 was make submissiveed to the study In this research 29 cases of M avium infection were defined as collection 1 and 43 cases of M intracellulare infection were defined as cluster 2.

In Vitro mix with drugs Susceptibility Test

The in vitro susceptibility of mycobacteria to various antituberculous agents was determined using a microdilution rule (Kyokuto Pharmaceutical Co, Tokyo). exampleed agents were isoniazid (INH), ethambutol (EB) rifampin (RFP) para-amino-salicylic acid (PAS), streptomycin (SM) kanamycin (KM) capreomycin (CPM) enviomycin (EVM) ethionamide (TH) and cycloserine (CS)

Ogawa incite medium, 0.2 ml of 1 percent containing different concentrations of agents was poured into each well of a microdilution plate, and after coagulation and disinfection, 002 ml of bacilli suspension was prepared at suspending a 1 to 3 mg colony in 1 ml sterile distilled water inoculated in each well, with incubation for 37 [degrees] C for 3 to 4 weeks. Criteria for interpreting flows of susceptibility tests are the following: susceptible - no increase on agent-containing medium; partially resistant - color of agent-containing medium changed to golden or thin-coat growth of colony upon agent-containing medium; and resistant - thick-coat sprouting of colony on agent-containing medium. These criteria of clinical resistance are adopted in the "standard orderly disposition treatment for tuberculosis" in Japan.[1]

Clinical Study

Background factors similar as age, sex, symptoms and laboratory data, chest radiographic findings at detection, and answer to treatment were compared. Patients without underlying pulmonary diseases were defined as having primary protoplast and patients with underlying pulmonary diseases were defined as having secondary type

Statistical Analysis

Differences between brace species in susceptibility to antituberculous physics and response to treatment were trialed by Fisher's exact test, and differences between couple groups in clinical features were compared on Student's t test.

Results

In Vitro Susceptibility to Antituberculous Agents

In vitro susceptibility of standarded strains to various antituberculous remedys is shown in Table 1 greatest in number strains of two species were resistant to all antituberculous agents, and a susceptibility pattern was similar in the two species except M avium was more resistant to EVM and M intracellulare was more resistant to INH and CS

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