Does Neisseria gonorrhoeae test positive or negative in the Simmons Citrate Test?

Question

Does Neisseria gonorrhoeae test positive or negative in the Simmons Citrate Test?

Answer 1

The Simmons Citrate Test uses a bacterial growth media that has citrate as the only source of carbon and therefore bacteria can only grow if they express citrate-permease or citrase and use this to transport citrate into the cell. The bacteria growth media contains a pH indicator, polyethylene blue, which changes color when the pH is at 7..5 or above. If the bacteria can grow with citrate as the only source of carbon, then the pH will increase and the agar will turn blue.

The Neisseria species of bacteria are catalase positive, except for neisseria elongata, and therefore would test positive in the Simmons Citrate Test.