Bacteriologic Studies in Acute Rheumatic Fever with Reference to Soluble Toxin Production.

Abstract

An extensive comparative study was made of the production of soluble toxins by hemolytic and non-hemolytic streptococci, isolated from a large series of normal and diseased individuals. The author encountered a strongly toxigenic strain of a non-hemolytic, non-methemoglobin-forming, inulin-fermenting, bile-insoluble, gram-positive streptococcus, isolated on March 24, 1926, from blood-cultures of a 5-year-old girl, ill with acute rheumatic fever, endocarditis, myocarditis, pericarditis, and pleurisy. Post mortem, the identical organism was isolated from the vegetations on the mitral valves, as well as from the heart's blood. In subsequent studies, a similar non-methemoglobin-forming streptococcus was regularly isolated from the tonsillar crypts, abscesses, and irregularly from blood-cultures, heart-vegetations, feces and urine, of persons with rheumatic fever and the allied forms of this protean disease. Culturally, serologically, and toxigenically, this new type of non-methemoglobin-forming streptococci was found to constitute a closely related group of micro-organisms, distinguishable from the Streptococcus viridans and Streptococcus hemolyticus groups. (Table I.) For toxin production, the tryptic medium employed was the original Douglas' 1 tryptic medium digest, modified by Hartley, 2 Watson and Wallace, 3 and the cultures were incubated at 37°

C. over periods varying from 4 to 10 days, when the cultures were filtered through Berkefeld V candles. Ninety-eight strains of hemolytic streptococci and 247 strains of the green streptococci yielded only 4.7 per cent of toxin producing strains. Among 68 strains of the non-methernoglobin-forming streptococcus isolated from rheumatic fever, 49 strains, or 72 per cent were found to produce a demonstrable soluble toxic filtrate, slightly weaker in toxicity than that obtainable from Streptococcus erysipelatis. 4 When normal persons without history of rheumatic fever were tested intradermally with a skin test dose of 0.1 cc. of 1 to 100 dilution of the soluble toxic filtrate produced by the non-methernoglobin-forming streptococcus, isolated from rheumatic fever, 18 per cent of adults and 11 per cent of children gave positive skin reactions, similar to the Dick test, and measuring more than 1 cm. in diameter within 24 hours after the injection.