Isolation of tubercle bacilli from sputum and determination of their type

Abstract

WHILE engaging in the study of other aspects of tuberculosis, I had opportunities of determining the type of tubercle bacilli isolated from unselected specimens of sputum which had been sent by physicians in ordinary course to the Reporting Department of the Laboratory for examination, and in which tubercle bacilli were detected by the usual microscopic methods. The sputum from thirty-six cases was studied, and in twenty-nine instances cultures were isolated and tested as to their virulence; in the remaining seven cases a complete investigation was not possible, as in two instances the cultures isolated were subsequently found to be dead ; in one instance both guinea-pigs inoculated for the isolation of tubercle bacilli died prematurely; and in the other four instances, where the antiformin method was employed, no growth was obtained. METHOD OF OBTAINING PRIMARY CULTURES. Two methods have been adopted in obtaining primary cultures, '' indirect)' and " direct." Indirect method.-By this method cultures were obtained from fifteen out of eighteen caaes. The sputum was inoculated intraperitonenlly into two OF more guinea-pigs in each case, and cultures were obtained from those which did not die prematurely. If very thick in consistence, the sputum was diluted with normal physiological saline solution before being injected. Direct method.-Cultures were isolated froni fourteen out of eighteen samples of sputum. The sputum, when brought to the Liboratory, was put into a sterile bottle, and, depending on its thickness, such amount of saline solution was added that the resulting h i v e d June I@, 1916.

Knowing Cases

“…General practitioners commonly sent sputum samples from suspected cases of tuberculosis to the Laboratory for routine diagnostic testing. These samples provided material from which researchers were able to conduct further investigations into the incidence of bovine tubercle infection in sections of the population not covered in the previous work (Wang, 1916a(Wang, ,b,c, 1917. 17 The second was based on a large number of moles and melanomas sent in to the Laboratory over a number of years for histological examination and assessment of their likely malignancy.…”