Neisseria and Moraxella

Most neisseria/moraxella are normal flora of

upper respiratory or genital tract

Neisseria and moraxella usually appear as

coffee/kidney bean shapes diplococci

You may see neisseria or moraxella in this particular setting in samples under the microscope

intracellular

Neisseria group has these common biochemical markers

oxidase positive and non-motile

Special implications of plate growth for GNDC

Chocolate is best, may or may not grow on BAP, and will NOT grow on MAC

MTM agar (Modified Thayer-Martin)

Agar with antibiotics to control for most gram negative/positive bacteria, yeast/mold, and proteus

What is MTM used for?

isolation of neisseria

Difference between MTM and MLM

MLM contains anisomycin for yeast and molds instead of nystatin

NYC medium

clear/cornstarch base with horse plasma, 3% hemoglobin, and yeast with antibiotics

yeast/mold antibiotic used in NYC medium

amphotericin B

Neisseria nitrate result

negative

Moraxella nitrate result

positive

Moraxella DNase result

positive

sugars tested in carbohydrate utilization test

glucose, maltose, sucrose, lactose

Superoxol test

catalase test performed using 30% H2O2

Positive superoxol on MTM agar is strongly suggestive of

N. gonorrhoeae

CAT screen tests for

enzyem butyrate esterase

Positive organism for CAT test

MOraxella

Negative organism for CAT screen

Neisseria spp

Virulence factors of Neisseria

capsule, pili, LOS/endotoxin, IgA protease

N. gonorrhoaeae is temp sensitive. What temp should transport occur at?

room temp

Dacron or rayon swabs are required for neisseria because

alginate or cotton swabs can be inhibitory

If transport time is short, neisseria can be transported in media that contains

charcoal (amies)

Colony morphology N. gonorrhoeae

Small, gray, translucent, raised colonies

What will you see in discharge with neisseria?

many PMNs with extracellular and intracellular gram-negative diplococci

Why is it difficult with direct microscopic examination to identify gonorrhoea in a female specimen?

commensal flora resemble GNDC

Carbohydrate N. gonorrhoeae is positive for

Dextrose

Enzyme production N. gonorrhoeae is positive for

PRO

Natural reservoir of neisseria gonorrhoeae

humans

neisseria gonorrhoeae takes this many days to incubate

2-7 days

unreated v can lead to

blood-borne dissemination

Second most common STD

gonorrhoea

T/F N. gonorrhoeae is a reportable disease

true

DGI

gonococcal arthritis

drug for n. gonorrhoeae

broad spectrum cephalosporins

birth complication with N. gonorrhoaea

eye infection of the baby

N. meningitidis virulence factors

pili, polysaccharide capsule

Predominant serogroups of N. meningitidis in the US

b, c, y and W135

Most common serotype of N. meningitidis

B

Most clinically signfiicant isolates of N. meningitidis are recovered from

blood or CSF

N. meningitidis is fastidious and prefers chocolate, 2-8% CO2, but it WILL grow on

blood agar

N. meningitidis colony morphology

blue/gray on SBA, small/tan, mucoid/convex on chocolate

safety consideration with N. meningitidis

must be worked with in biosafety cabinet

N. meningitidis gram stain

GNDC seen intracellularly

N. meningitidis carbohydrate utilization

dextrose and maltose

N. meningitidis enzyme production

variable for PRO, positive for GLUT

N. meningitidis most affected populations

infants, schoola ge children, young adults

Meningitis results if the organism

crosses the blood-brain barrier

Symptoms of meningitis

severe headache, stiff neck, nausea, vomiting, delirium

drug used for N. meningitidis

penicillin

The single dose vaccine available for N. meningitidis protects against which serotypes

A, C, Y and W-135

How to rule out pathogenic Neisseria

pathogenic strains do not grow on BA or CHOC at room temp and do not grow on nutrient agar at 35C

Carbohydrate utilization of N. lactamica

Dextrose, maltose, and lactose all positive

Enzyme results for N. lactamica

only positive for BGAL

N. lactamica is normal flora of

nasopharynx

respiratory specimen with GNDC colonies showing yellow color can be reported as

normal flora

Moraxella catarrhalis gram stain

intracellular GNDC in resp specimen

Moraxella catarrhalis colony morphology

"Hockey puck" remains intact when pushed across media with loop

Key moraxella catarrhalis biochemicals

oxidase positive, negative carb utilization, DNase positive, nitrate positive, CAT positive, IB positive

Moraxella is

normal flora of the upper respiratory tract