Medium. Tryptic soy agar, heart infusion agar,
brain heart infusion agar, and nutrient agar were purchased
from Difco Laboratories (Detroit, Mich.). Wagatsuma
medium was obtained from Nisui-Seiyaku
(Tokyo). Peptone (Difco)-NaCl agar was an agar-solidified
medium prepared from a liquid medium used
for preparation of the thermostable direct hemolysin
of V. parahaemolyticus (6). It contained 1% peptone,
3% NaCl, 0.5% Na2HPO4, and 0.5% glucose