Neisseria and Moraxella

Neisseria and Moraxella sugar tests:
The Neisseria and Moraxella species that can be distinguished using sugar fermentation tests are all G- diplococci, oxidase +, catalase +, and grow on chocolate agar. Diplo means double and cocci means round or sphere shape, so these bacteria remain in pairs after reproducing. The following sugar fermentation results help distinguish species:

N. gonorrhoeae = glucose
N. meningitides = glucose, maltose
N. lactamica = glucose, maltose, lactose
N. sicca = glucose, maltose, sucrose
Moraxella catarhalis = no sugar fermentation

Shorthand table:

g	G
m	G	M
l	G	M	L
s	G	M	S

Study tip:
Use the mnemonic Max the cat hates sugar to remember Moraxella catarhalis does not ferment sugar.

Other notes about Neisseria/Moraxella:
N. gonorrhoeae should be plated immediately or transported with activated charcoal to absorb inhibitory substances. Modified Thayer Martin (MTM), 35C. MTM is chocolate with added antibiotics.

N gonorrhoeae – superoxol test, gram stain from male patient with neutrophils = presumptive positive, increased CO₂

N. lactamica – betagalactosidase

Neisseria spp – kidney bean shape