Vibrio cholerae can be confirmed by performing motility, it shows a typical darting motility and serological tests . There are various non pathogenic vibrio species too

You could do a 16s rRNA PCR and sequence it. That will give you the exact information you are looking for.

can you give images of a gm stain, that might help.

The information given is not even enough to speculate the type of bug you might be dealing with.

When Vibrio cholerae grows in TCBS agar, it gives you typical yellow colonies, that is the first step to spacifically search for it. Those colonies should be yellow and the touch will be mucoid, giving like a stream of mucus but not too humid.

With the colonies you already have in your plate right now, the most quick thing to do is to take an isolated colony and grow it in a blod agar base slant tube. From there you can peroform the oxydase test. If positive, chances are you have gotten Vibrio. Although for cholerae you still are supposed to perform bioqchemical tests and agglutination with specific O1 anti-serum. Hope my comment was petinent.

Another thing to do is to take one-two colonies and put them in the tip of a cotton wooden stick, then place it at the bottom of a tube containing 5-6 ml of peptoned water broth pH 9.0. Vibrio cholerae will grow in the surface, looking for oxygen, since it has the nicest flagellum, it will swim to the surface and make like a film. This is the way people enrich the cultures suspected to contain Vibrio cholerae. Nevertheless, you are certein of epidemic Vivrio using the set boichemical tests and the anti-O1 Serum,