[An outbreak of tuberculosis involving foreign workers from South America]

A twenty-four year old male Peruvian of Japanese origin, who came to Japan in September 1990 and had been working in a minor factory in a rural area, was admitted to a hospital in March '91 with severe cough. Smear examination of his sputum smear was positive for acid-fast bacilli and his chest X-ray showed multiple cavities (Index case). Subsequent contact examination identified further four patients with pulmonary tuberculosis among his colleagues in the factory, all of whom lived in the same house with the index case. During following three years, further six patients with mycobacteriosis, two Peruvians and four Japanese, were found among the employee of that factory. M. tuberculosis was cultured from the sputa obtained from seven of these eleven patients. Another patient was diagnosed as non-tuberculous mycobacteriosis. Restriction fragment length polymorphism (RFLP) analysis carried out with five strains of M. tuberculosis isolated from these patients revealed the identical RFLP pattern which is uncommon in Japan. Still more, an isolate from another patient was subjected to RFLP analysis by chance, and was found to show the same RFLP pattern. Later epidemiological study revealed that the last patient, a 53 year-old saleswoman of boxlunch, might have some contact with the index case at her booth. Though RFLP analysis was not done for the isolate from the index case, from the identity of RFLP patterns of other isolates, clinical course and epidemiological study, it is considered that six patients were certainly, and two others were probably infected from the index case.(ABSTRACT TRUNCATED AT 250 WORDS)