FIGURE 7.

Antigen detection in E. faecium blood isolates. A, geographic, and B, MLST distribution of E. faecium clinical strains (n = 101). C, bacterial surface antigen expression in this set of strains analyzed separately by flow cytometry with matched pre- and postimmune antisera to Pf2-CRM₁₉₇, Pf3(LTA), and Pf4-CRM₁₉₇. Percentages of strains binding antibodies to individual antigens (above three times immune to preimmune serum activity threshold) are indicated. D, variability of independent preparations of Tx16 used as internal control for each batch of strains analyzed. Corresponding geometric mean titers and 95% confidence intervals (error bars) are shown in red.