In our hospital micro lab, we don't use EMB, but MacConkey's instead,
so I can't help you with that part. But I * have* seen Citrobacter look
very similar to Ecoli , both on MAC, and on some commercial ID systems. I
have also seen some pretty mucoid Ecoli's. Try repeating the biochemical
tests- preferably with a different ID system. Watch how your system
interprets some of the biochemicals - some color changes can be subtle.
Double-check your Indole, Citrate, ONPG, and decarboxylase reactions.
Don't be afraid to question your ID system - it's not God, and the bugs
don't always "know" how they're supposed to react - no one ever told them
there was going to be a test.;) Just this week, our system told me I had
99.9% Pseudomonas cepacia, but I *knew* it was really Xanthomonas
maltophilia - my nose knew better than than the machine, and I eventually
proved it! Micro is more or less like a good detective novel. Enjoy!
How about some input from those with more letters after their names than
I?
Kathy
