Temperature-Dependent Photochromogenic Strains of Mycobacterium szulgai

• Published in: MICROBIOLOGY and IMMUNOLOGY 1978/04/20, Vol.22(4), pp.231-232
• Main Authors: Tsukamura, Michio, Shimoide, Hisao
• Format: Article
• Language: English
• Subjects: Humans; Light; Male; Middle Aged; Mycobacterium - metabolism; Mycobacterium Infections - microbiology; Mycobacterium Infections, Nontuberculous - microbiology; Nontuberculous Mycobacteria - metabolism; Pigments, Biological - biosynthesis; Species Specificity; Sputum - microbiology; Temperature
• ISSN: 0385-5600; 1348-0421
• DOI: 10.1111/j.1348-0421.1978.tb00367.x

Mycobacterium szulgai (1) is a new species recently described. It belongs to slowly growing scotochromogens (Runyon's Group II (2)). Recently we isolated three strains of mycobacteria from sputum specimens of a patient, a 50 year-old male carpenter. The strains were isolated on the 23rd, 24th and 25th of June 1976 and formed 86, 44 and 4 colonies, respectively, on isolation media. At that time, the chest X-ray film of the patient showed a large cavity with pericavitary infiltration in his left upper lobe. After six-month-administration of a streptomycin-isoniazidrifampicin regimen, the cavity became thin-walled and the organism disappeared from sputum. In view of the above course of the disease, the organism was considered to have caused the disease in the patient. The strains were examined according to the methods previously described (4) and identified as M. szulgai (Table 1). The strains used in the study were isolated from single colonies. The most interesting characteristic of the strains was their temperature-dependent photochromogenicity. The strains were nonchromogenic when incubated on Ogawa egg medium at 28 C in the dark for 14 days, whereas the colonies became scotochromogenic (orange-pigmented) when incubated at 37 C in the dark. The colonies that grew at 28 C in the dark became pigmented after exposure to daylight for one day. Temperature-dependent photochromogenicity of M. szulgai in several strains was reported by Schaefer et al (3). The findings in the present study show that such strains occur and lung disease due to this organism is also present in this country.