FIGURE 4.

Lytic activity of endolysin P28 over a range of ethylenediaminetetraacetic acid (EDTA). The viable cell numbers (CFUs) of S. maltophilia P28 (A) and P. aeruginosa ATCC 15692 (B) after the addition of 500 μg endolysin P28 were examined. The cells were treated with different concentrations of EDTA (0, 1, 5 mM) for 30 min before the endolysin P28 was added. After incubation for 1 h at 30°C, the CFUs of the mixture was determined and the antibacterial activity was calculated as described in the section “Materials and Methods”. Error bars are the means ± standard deviation of three independent assays.