Mycobacteria other than tuberculosis producing disease in a tertiary referral hospital

Over the period of 1987 to 1989, three hundred and two isolates of ten species of mycobacteria other than tuberculosis (MOTT) produced disease in 282 patients. M. avium intracellulare was the most common (53% patients), followed by M. gordonae and M. fortuitum-chelonae (20%). The most common clinical presentation was of a protracted respiratory infection in 82%. At least one significant associated illness or predisposing factor was present in 83% patients. A significant immunosuppressive state was present in 1117 (45%) patients which included solid tumors, reticuloendothelial malignancies and organ transplant recipients. However, unequivocal florid disease including pneumonia, pericarditis and pericecal mass occurred in several immunocompetent patients. Of 202 patients with brochopulmonary infection, 59 (29%) were found to be concomintantly infected with microorganisms other than MOTT, and in these patients a significant association with acute chest radiographical changes was found, and posed difficulty for deciding the role of MOTT in these patients. In many patients, the illness associated with MOTT was mild, although approximately one-half of patients received an antimicrobial which had some antimycobacterial activity. The clinical spectrum of disease produced by MOTT may be quite broad and a low grade pathogenic role in many patients cannot be excluded.