Fig. 5.

PSM production in HA-MRSA, CA-MRSA, and ST8 MSSA strain collections. Strains collected at hospitals in the San Francisco area were analyzed by RP-HPLC/electrospray ionization-MS for PSM production. Carriage isolates are from nonhospitalized homeless youth and urban poor in the same area. PSMα3 and δ-toxin levels are shown. Horizontal bars depict the mean. Statistical analysis is by unpaired t tests or one-way ANOVA for comparison of USA300, USA500, and MSSA carriage or infection isolates, respectively, which showed no statistically significant differences. N.S., not significant. ∗∗P < 0.01, ∗∗∗P < 0.001.