Pulmonary disease caused by Mycobacterium avium-intracellulare in HIV-negative patients: five-year follow-up of patients receiving standardised treatment.
OBJECTIVE
Previous reports on small numbers highlighted the need for a prospective study of the clinical features and response to treatment of pulmonary disease caused by Mycobacterium avium-intracellulare (MAC).


METHODS
Patients with two positive cultures were randomised to 2 years of rifampicin and ethambutol or of rifampicin, ethambutol and isoniazid. Clinical, bacteriological and radiological progress was monitored for 5 years.


RESULTS
Seventy-five patients entered the study. They had a mean age of 64 years (range 29-87) and the sexes were balanced. Approximately two-thirds had previous/ co-existing lung disease(s). Sputum was positive on direct smear in 56%, and cavitation was observed in 61%, most having at least one large cavity. Just under half had bilateral disease and one-third extensive disease. Disease was confined to upper zone(s) in 25%. Twenty-seven (36%) died within 5 years, three because of MAC disease. There were 11 treatment failures and 10 relapses, with no correlation between those and in vitro resistance. Forty-five (60%) were alive at 5 years, of whom 23 were confirmed cured.


CONCLUSIONS
Pulmonary disease caused by MAC is associated with high morbidity and mortality. Standard susceptibility tests do not correlate with the response of the disease to chemotherapy. Rifampicin and ethambutol, with or without isoniazid, cured 31%, a result comparable with or better than that found previously with more toxic regimens, but mortality (36%) remains high. More effective regimens are needed, and management of coexisting illnesses and general health needs to be to maximised.
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents; D000995:Antitubercular Agents / Q000627:therapeutic use*; D024901:Drug Resistance, Multiple, Bacterial; D004359:Drug Therapy, Combination / Q000627:therapeutic use*; D004977:Ethambutol / Q000008:administration & dosage; D005260:Female; D018023:HIV Seronegativity; D006801:Humans; D007538:Isoniazid / Q000008:administration & dosage; D008171:Lung Diseases / Q000188:drug therapy* / Q000382:microbiology; D008297:Male; D008875:Middle Aged; D015269:Mycobacterium avium Complex / Q000302:isolation & purification*; D015270:Mycobacterium avium-intracellulare Infection / Q000188:drug therapy* / Q000382:microbiology; D011446:Prospective Studies; D013902:Radiography, Thoracic; D012293:Rifampin / Q000008:administration & dosage; D013183:Sputum / Q000382:microbiology; D016896:Treatment Outcome
D000900:Anti-Bacterial Agents; D000995:Antitubercular Agents; D004977:Ethambutol; D007538:Isoniazid; D012293:Rifampin