No growth on selective agar, but growth on selective/differential

[rschaler]

Hello,

 

I was wondering if there was an explanation for a sample showing growth on selective/differential MSA agar but not showing any growth at all on TSA (non-selective)

 

Thanks!

[Asthfx]

Uhm, my guess is you have an obligate halophile, maybe you can tell where you are taking your samples from?

Also, found this article that may help. Biology of Moderately Halophilic Aerobic Bacteria

Quote

Pseudomonas beijerinckii, grew from 3 to 18% salt but not at 0.5%, showing its obligate halophilic character.