Predation assays.

Predation assays were carried out using a lawn culture method (11, 53). Briefly, prey organisms (E. coli ATCC 25922, Klebsiella pneumoniae ATCC 700603, Proteus mirabilis NCTC 10975, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 29213, Staphylococcus epidermidis NCTC 11047, Staphylococcus saprophyticus [wild strain], Enterococcus faecalis ATCC 29212, Bacillus subtilis ATCC 6633, and Candida albicans NCTC 32) were grown in Luria-Bertani (LB) broth for 16 to 18 h and centrifuged at 10,400 × g for 15 min. Cells were then washed with TM buffer (50 mM Tris [pH 7.8], 10 mM MgSO₄) and a lawn made by spreading onto WAT agar (14-cm plates) and air drying. CA052B was grown in CYE broth at 30°C for 7 days in baffled flasks in a shaking incubator to obtain a dense, smooth cell suspension. Cultures were then centrifuged at 10,400 × g for 15 min, the pellet was washed in TM buffer, and 10 μl of resuspended cells was inoculated onto the prey lawn. Plates were incubated for 7 days, and the diameter of the zone of swarming (predation) was recorded on days 3 and 7.