Hi I am currently trying to subculture vancomycin resistant enterococci onto Slanetz and Bartley agar (Oxoid) which contains vancomycin (concentration of 16mg/ml). Expected colonies should be red/maroon in colour however the colonies growing are cream in colour. My tutor has told me that expected red colonies have been retrieved from vials in previous use.
Incubation period has been done at 24 hour 37oC and 48 hour 37oC with same results. Gram stained results positive cocci, catalse negative and oxidase negative.
Anyone experienced anything similar?
I have attached a pic - apologies as its not the clearest
Hi, Scott! The red color is the ability to metabolize TTC. Please look at product scheet from Oxoid under PRECAUTIONS: pale colonies should not be ignored!
http://www.oxoid.com/uk/blue/prod_detail/prod_detail.asp?pr=CM0377&org=68&c=uk&lang=en
Try to identify this cocci with another agar (CPS for urine cultur/ turquise colonies or a aesculin medium or bilesalt-Agar).
I did never work with this agar. On a blood agar plate it would be easier to recognise enterococci for me.
Heidelinde Schranz,
Thanks for your reply that's great. I have managed to confirm it on Bile Esculin Agar and currently running a multiplex PCR so hopefully that works :)
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