Published online by Cambridge University Press: 15 May 2009
(1) Fifty S. aureus and 30 S. albus strains obtained from infective processes in man have been investigated. Such cultural reactions as were completed did not differentiate between strains of S. albus and S. aureus, or serve to group these cocci; we found, however, that 94 per cent, of the S. aureus strains fermented mannite, as opposed to 40 per cent, of the S. albus strains. These results are in accordance with the findings of Cummins and Cumming (1913) and Hine (1922).
(2) A close degree of correlation between pathogenicity for rabbits, pigment formation, and biochemical activity was noticed among the S. aureus strains. Out of 19 pathogenic strains of S. aureus, 9 showed medium pigmentation and 10 were strongly pigmented.
(3) Anti-sera were prepared by inoculating rabbits with living cultures, 24 hours old, of the various strains. The S. aureus rabbits and a few of the S. albus received two preliminary doses of the specific vaccine, but little or no protective action was afforded from the doses of living cocci injected.
(4) Nineteen out of 25 cultures of S. aureus killed rabbits, but only 3 out of 18 cultures of S. albus.
(5) Fifteen strains of S. aureus and 15 of S. albus were used for the preparation of anti-sera, and tested against as many antigens as possible, by the methods described by Dudgeon and Bamforth.
(6) Cultures of S. aureus produced efficient anti-sera more readily than S. albus cultures, but when an active S. albus anti-serum was produced, it appeared to be as effective as the S. aureus anti-sera.
(7) A marked difference in efficiency between S. aureus and S. albus antigens was noted. S. aureus antigens were almost three times more active than S. albus antigens.
(8) Pathogenic strains of S. aureus and S. albus produced more efficient precipitin antigens than non-pathogenic.
(9) From the microscopical examination of the deposit formed in the precipitin reactions, a difference was noted between S. aureus and S. albus antigens.
(10) The study of the precipitin reactions has failed to show any hard and fast dividing line between staphylococci of different colours, or of different cultural reactions. We are inclined to agree with Winslow, Rothberg and Parsons (1920) and with Dudgeon's original view in 1908, that the pyogenic, Gram-positive staphylococci must be regarded as members of one common family.