Transfection of lysostaphin-treated cells of Staphylococcus aureus.

After treatment with 1 unit of lysostaphin per ml for 3 min, two strains of Staphylococcus aureus, 233 and PS 44A HJD, were transfected with phenol-extracted deoxyribonucleic acid (DNA) from the staphylococcal bacteriophages, 53 and 44A HJD, respectively. The number of transfected cells was low in both systems, approximately two in 10(7) enzyme-treated cells. There was a saturation effect at high concentrations of DNA; optimal results were obtained at concentrations between 10 to 25 mug/ml. Growth curves and fluctuation tests indicated that cells of strain 44A HJD infected with phage, then converted to protoplasts by a 10-min treatment with lysostaphin, produce only one phage particle and lose their ability to lyse spontaneously in hypertonic media.