Research: Vibrio-like bacteria from deep-sea copepods closely resemble Vibrio cholerae strains

Speaker 3, Lecturer, described plating crushed deep-sea copepods collected near hydrothermal vents and recovering colonies that produced Vibrio-like results on thiosulfate–citrate–bile salts (TCBS) agar. “We got the bright yellow colonies, and we tested them phonetically and then, through some gene probes confirmed that they were vibrio cholera like,” Speaker 3 said.

The lecturer said that full-genome sequencing (work in collaboration with Los Alamos National Laboratory) comparing the small and large chromosomes showed high similarity between the vent isolates and Vibrio cholerae, and also similarity to other pathogenic vibrios such as Vibrio vulnificus and Vibrio parahaemolyticus. “The Vibrios that we isolated from the deep sea, copepods were practically identical to the Vibrio cholerae,” Speaker 3 said.

Speaker 3 reported sequencing roughly 27 Vibrio cholerae isolates and a couple of Vibrio mimicus isolates and said the team is analyzing the biogeography of fully sequenced strains to explore how isolates from different regions — the speaker named examples including Sudan, South America, Chesapeake Bay and Asia — relate evolutionarily. The talk referenced prior confirmation that V. cholerae carries two chromosomes and noted the team’s role in sequencing both chromosomes for comparative purposes.

Audience members asked about how long divergence might have taken; Speaker 3 suggested future comparative work isolating Vibrio from deep-sea hosts on different sides of geographic barriers to estimate divergence timing.

This account reports the speaker's descriptions of laboratory and sequencing work; Speaker 3 characterized the findings as preliminary and said detailed comparative analyses are ongoing.