COULTER, JOHN R. (Institute of Medical and Veterinary Science, Adelaide, Australia); Production, purification, and composition of staphyloccocal a toxin. J. Bacteriol. 92:1655-1662. 1966-Pure staphylococcal a toxin has been prepared in quantities suitable for chemical, biological, and clinical characterization. Purification was achieved by acid-methanol precipitation, chromatography on G100 Sephadex, and electrophoresis in G100 Sephadex. We recovered 25% of the crude toxin in pure form, a yield of 12 mg/liter of crude culture supernatant fluid. The pure material gave a single line on gel diffusion and on immunoelectrophoresis and gave a single symmetrical peak in the ultracentrifuge. The a toxin was highly unstable, with a halflife of 3 days at 0 C (pH 7.8); solutions of it could not be frozen, and we found no method to stabilize it. On standing, a thready precipitate appeared; it was inactive against rabbit red cells, was not lethal to rabbits, but was able to elicit specific anti-a antibody production in the rabbit. There is evidence that a toxin is an associating molecule, with a mean sedimentation coefficient of approximately 3.0 and a molecular weight of approximately 30,000. The lowest molecular weight, found by equilibrium ultracentrifugation, was 21,200 400. The amino acid composition was determined, and the high positive charge was explained by the presence of lysine, arginine, and histidine, and by amination of the aspartic and glutamic acid residues. Histidine and arginine were shown to be N-terminal amino acids, a fact which suggests the presence of two polypeptide chains. No carbohydrate was present. The ultraviolet absorption spectrum showed a maximum at 274.5 m,, a minimum at 251.5 m,u, and a shoulder at 292 m,u. The toxin was without proteolytic or phospholipase activity, and its highly specific action on cell membranes still remains unexplained.

The nasal carriage of 407 mothers before, during and after admission to a maternity hospital and that of their babies during and after hospital stay was investigated together with the nasal carriage by the hospital staff.The nasal carrier rate among mothers admitted to hospital was 38%, 40% of these strains being resistant to penicillin.The nasal carrier rate among the nursing staff was 38 and 72% of these were resistant to penicillin.If a population is swabbed only once approximately 25% of the carriers will be missed. Those showing slight carriage were no more likely to be missed than those showing heavy carriage. The concentration of organisms in the nose is evidently varying continuously.Heavy carriers are no more likely to transmit than light carriers and it is therefore not right to report on the profusion or otherwise of growth if that implies a greater chance of transmission.The biggest increase in resistance among nursing staff strains occurred in the non-typable group which could be explained by resistance to phage developing concurrent with resistance to antibiotics.The difference in phage-distribution between patient and staff strains centred in group II which formed 19% of patient strains but only 7% of hospital strains.The carrier rate was no higher for those with a history of hospital admission within 12 months or without a history of staphylococcal sepsis.Those giving a history of penicillin therapy had the same resistance rate as those without a history of such therapy.

Highly purified staphylococcal alpha toxin has been used to produce monospecific anti-alpha antibody in rabbits. Gamma globulin prepared from the serum of these rabbits was coupled with ferritin by using toluene diisocyanate. Staphylococcal cells which had been disrupted by two passages through an LKB X-press were treated with this conjugate. Electron microscopic examination of this material showed alpha toxin or an antigenically mature precursor located on the cytoplasmic membrane. The possible function of alpha toxin in this situation is discussed.

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