Environmental bacteria grown on TCBS agar plates (TCBS strains) were investigated for the presence ofVibrio cholerae in aquatic environments. TCBS strain counts were 0.01 - 0.001 times the total viable counts in pairs of the same samples. The TCBS strains were of two types which required N(a)Cl (salt strain) and did not require N(a)Cl (non-salt strain) to grow in peptone water. Non-salt strains made up 85.3 - 92.1% of TCBS strains isolated from river water. TCBS strains isolated from an estuary contained 40.9% of non-salt strains and 57.4% of salt strains. Salt strains made up 69.2 - 86.8% of TCBS strains isolated from seawater. The percentages ofVibrio species in TCBS strains were 11.9 - 47.9%. V.alginolyticus andV. parahaemolyticus were isolated from seawater.V. vulnificus was only isolated from estuary water.V. cholerae non-Ol was isolated from both river water and estuary water which had low salinity.V. fluvialis was isolated from all three aquatic environments. This investigation suggests thatVibrio species were present in each sample station and thatV. cholerae existed in river water.
Keywords: TCBS; Vibrio cholerae; ecology; river; sea.