Neisseria grown in MacConkey - (Apr/10/2019 )

Hey!

I've been doing some research about canine periodontal disease and the main bacteria responsible for its evolution.
Just spent a week trying to grow Neisseria zoodegmatis (gram-negative) in MacConkey media but seems to be impossible despite all the evidence described in literature.

Any ideas why this happening? Is there any exceptions for gram-negative grown in this media?

Thanks a lot!!

The ATCC and other culture collections have varying methods of growing this species. ATCC recommends using brain-heart infusion agar/broth, while others recommend Columbia blood medium and Medium 72 for trypto casein soy agar. I did see one paper mention McConkey, and another that used blood or chocolate agars (presumably based on tryptic soy agar). It looks like most people grow them in 5% CO₂ as well.

I think most Neisseria species are fastidious, so unless you have the right components in your agar you won't get them to grow. From the recommended agars I would guess that this is the case for N. zoodegmatis too - they probably need some blood and/or specific nutrients.

It should grow on unamended MacConkey agar, esp. as that is in the species description - https://www.microbiologyresearch.org/docserver/fulltext/ijsem/56/8/1801.pdf?expires=1555426058&id=id&accname=guest&checksum=661CEB65DABBF9DCC6257A3280CAD0F3

Suggest you get an isolate from ATCC for growth promotion/qualification of your MacConkey.

If you are confident that you actually have Neisseria zoodegmatis (and what data support you in that id?) and can't get growth on qualified MacConkey, I'd contact the original author VanDamme et al. in Belgium for comment and poss amendment of species description.  http://lmg.ugent.be/users/prof-dr-peter-vandamme