The relation of streptococci to scarlet fever and its complications / [R.A. O'Brien, C.C. Okell].

  • O'Brien, Richard Alfred, 1878-1970.
Date:
[1926?]
Catalogue details

Licence: In copyright

Credit: The relation of streptococci to scarlet fever and its complications / [R.A. O'Brien, C.C. Okell]. Source: Wellcome Collection.

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    coccus haemolyticus to scarlet fever and its complications? There seems little doubt that haemolytic streptococci are closely related to scarlet fever, and we are justified, for the purpose of discussion, in postulating a “ Streptococcus scarlatinae ” (or possibly a group of streptococci) which causes infectious scarlet fever. But as soon as we seek to define this S. scarlatinae our difficulties begin. If we isolate from the throat of a patient suffering from scarlet fever a streptococcus which we think may be the characteristic organism, we must determine that it is haemolytic, and that on the ordinary media it grows like the haemolytic streptococci obtained from any other pathological con¬ ditions ; it has, unfortunately, no characteristic of growth sufficiently distinctive to help us materially in identifica¬ tion. Its fermentation reactions must agree with those of Streptococcus pyogenes; lactose, salicin, and saccharose must be fermented, but not raffinose or inulin; mannite is fermented by some strains and not by others, yet in both cases we must accept these strains as true Strepto¬ coccus scarlatinae. (In passing we may note that this character appears to be not very deeply implanted, for a strain of the mannite-fermenting variety, which Dr. Dick kindly sent us, has in our laboratory, in the course of some months, apparently lost its power to ferment mannite.) The organism, when grown in ordinary peptone or tryptic- digest broth, must produce in the filtrate a toxin ” having the same property as that described by G. F. and G. H. Dick. It must, in a reasonably high dilution, give a positive “ Dick ” reaction in almost all cases of scarlet fever tested during the first two or three days of the disease; it must, when injected into positive Dick reactois in a quantity containing about 1,000 times the minimal skin reacting dose, produce in the majority of instances “ miniature lion-infectious scarlet fever ” or the “ scarla¬ tinoid syndrome ”—that is, sore throat, fever, vomiting, and characteristic rash; it must be neutralized by the specific antiserum, so that when a mixture of toxin and antitoxin is injected intradermally into a positive reactor to the Dick test, no reaction is produced. Before our scien¬ tific scepticism is satisfied we may ask more—that is, that oui living culture will, when applied to the throat of a positive Dick reactor, produce unmistakable scarlet fever. It is probable that only three strains in existence have had their authenticity tested thus far—the mannite-fermenting and also the non-fermenting strains of the Dicks, and one strain in Park’s laboratory, which was accidentally sucked into the mouth of a worker and apparently caused typical scarlet fever. We may inhumanly still press our demands and say that we are not yet satisfied, for natural scarlet fever is infec¬ tious, and we have yet to prove that the disease we have produced will infect susceptible contacts as the natural disease does. This test has not been carried out, nor is it probable that our common humanity will ever allow it. It is only the interesting history of swine fever that makes
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