Hi,
I am trying to isolate EMS-associated Vibrio parahaemolyticus using TCBS for whole genome sequencing. However, I notice some green colonies have different shades of green and different textures especially after 48 hours. Anyone who experienced this please advise? Are they all Vibrio parahaemolyticus given their vast genetic diversity? What would be a better way to isolate?
Dear Chrystine Yan,
You can use Vibrio CHROMAgar as a selective media for Vibrio parahaemolyticus, Vibrio Vulnificus, Vibrio Cholera. You will see mauve color colony after 18 hours incubation.
Regards
Dr. Mizan
Vibrio vulnificus also gives green colonies on TCBS agar plae. I agree with Dr Miza, you can use Vibrio CHROMAgar which gives violet colonies for V. parahaemolyticus.
Thank you, Dr Mizan.
Just another thought: What about the species specific markers like ldh or toxR gene? If I run colony PCR amplifying those genes, is it better in terms of specificity, cost and time effectiveness compared to CHROMagar Vibrio?
It depends on your purpose. If you just want to identify VP, you can check through toxR marker and other molecular techniques. CHROMagar will give you visual confirmation as well as count.
There ate two greeb colonies on TCBS agar. Aside from Vibrio parahaemolyticus, Vibrio vulnificus also produces green colonies because they do not ferment sucrose.
SOURCE: Mahon Diagnostic Microbiology
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