Inhibition phenomenon of staphylococci by bacteriophages

In the study of the relationship between bacteriophage and strains of staphylococci showing inhibition, slight differences were observed in the ability to adsorb phage between staphylococci of full phage sensitivity and those showing inhibition by phage. Only a few plaques were produced by inhibitory phages adsorbed on strains showing inhibition, whereas almost all of the phages adsorbed on corresponding phage-propagating strains produced plaques. Some strains showing inhibition were converted to full sensitivity to certain phages by heat shock or trypaflavine treatment. Treated strains adsorbed inhibitory phages to almost the same degree as nontreated strains, but most of the phages adsorbed on treated strains produced plaques. Killing was not always observed in cells adsorbing inhibitory phages. These results suggest that inhibition is not due to low adsorption rates, but rather to plaque formation by a small number of the sensitive fraction of the population and overgrowth by nonlysed cells.

Relationship of staphylococcal toxins and enzymes with serological and phage types

A study has been made of 523 strains of staphylococci on the basis of biological properties, phage typing, and serology. The value of serology in the identification of pathogenic staphylococci has been assessed.

Staphylococcus aureus H autolytic activity: general properties

Staphylococcus aureus strain H has an autolytic activity which can be found in the cell wall but is most easily obtained from high-speed supernatant fractions of broken-cell preparations. As measured either turbidimetrically or radioactively, this activity is much greater on murein extracted from penicillin-treated cells than on murein extracted from normal cells.