FIG. 1.

Triton X-100 autolysis assay of clinical GISA isolates. GISA isolates IL-F, MI, PC, and NJ are clinical isolates from Illinois, Michigan, Port Chester, N.Y., and New Jersey, respectively (6-9, 21, 23). Cultures were grown to mid-logarithmic growth phase and suspended in buffered 0.05% Triton X-100. At 1-h intervals, an aliquot was collected for absorbance determinations at 600 nm and for determination of viable cell count (CFU/ml). Absorbances are represented as percentages of the absorbance at 600 nm relative to that at time zero for each sample.