Nonchromogenic Acid-Fast Bacilli Isolated from Tuberculous Swine

Abstract

There are an increasing number of reports of progressive pulmonary tuberculosis in humans that is caused by a slow-growing, nonchromogenic, acid-fast organism which differs from the typical human variety of Mycobacterium (1-8). This group of organisms, referred to as the type (3), has been placed by Runyon (9) in Group III of the unclassified mycobacteria causing disease in man. The source of this infection has not been established. A search for the reservoir of Battey infections becomes important because of the world-wide incidence of these cases-the southeastern United States (3, 8), the Dutch West Indies (10), Canada (11), Australia (7)-and because pulmonary disease is produced which is clinically indistinguishable from tuberculosis but frequently resistant to the usual antituberculosis chemotherapeutic regimen. A number! of investigators (3, 4, 8, 12-15) have reported the resemblance of these organisms to Mycobacterium avium isolated from tuberculous fowl, and similar avian-like acid-fast organisms have been recovered from tuberculous swine (16). Undoubtedly, swine contribute to the soil reservoir of M. avium and may thus indirectly constitute a source of human Battey infections. Hence, it seemed worth while to explore the relationship among the very similar nonchromogenic acid-fast bacilli isolated from swine and avian and human sources.