Module 1: Neisseria and Moraxella

Question 1

Genera in the family Neisseriaceae

Answer 1

Neisseria
Moraxella
Acinetobacter
Kingella

Question 2

Charcoal transport media

Answer 2

Used to absorb fatty acids from clinical specimen which may interfere with N. gonorrhoeae growth

Question 3

Synthetic material for swabs

Answer 3

Calcium alginate

Can also use cotton swabs soaked in charcoal

Question 4

Oxidase test detects:

Answer 4

Cytochrome oxidase enzyme

Question 5

Active ingredient in the oxidase test reagent

Answer 5

Dimethyl or tetramethyl para-phenylenediamine dihydrochloride

Question 6

Kovac’s oxidase reagent

Answer 6

1% solution of dimethyl or tetramethyl para-phenylenediamine dihydrochloride
Used in most labs

Question 7

A 1% solution of dimethyl or tetramethyl para-phenylenediamine dihydrochloride is called:

Answer 7

Kovac’s oxidase reagent

Question 8

False positives in oxidase test

Answer 8

Nichrome loops

Question 9

False negatives in oxidase test

Answer 9

Old cultures

Inhibitory media

Question 10

Gonorrhea in a direct smear of urethral exudate

Answer 10

Gram negative diplococci in the cytoplasm of neutrophils

Question 11

N gonorrhoeae growth requirements

Answer 11

Obligate aerobes
Capnophilic (3-7% CO2 required)
35C
Moist environment required
BAP not recommended - chocolate agar is best for growth

Question 12

Best non-selective medium for isolation of N. gonorrhoeae

Answer 12

Chocolate agar

Question 13

Preparation of chocolate agar

Answer 13

Uses the same ingredients as blood agar
Heat the medium slowly to 75-85C just after the blood is added; medium is held at this temp for 10-15min until RBCs are lysed (chocolate brown colour)
Medium is then cooled to 50C and supplements are added before plates are poured

Question 14

Supplements added to chocolate agar

Answer 14

2 common supplements: supplement B and Iso-VitaleX

Provide growth factors including vitamins

Question 15

Nystatin

Answer 15

Inhibits growth of yeast

Question 16

Colistin

Answer 16

Inhibits Gram negative rods

Question 17

Main difference between MTM and NYC media

Answer 17

NYC is translucent; MTM is brown

Question 18

Consistency of N. gonorrhoeae colonies

Answer 18

Sticky colonies that may lift off as an entire colony

Question 19

Genus ID of Neisseria

Answer 19

Gram stain and oxidase

Question 20

N. gonorrhoeae acid production

Answer 20

Produces acid from glucose

Question 21

N. meningitidis acid production

Answer 21

Produces acid from glucose and maltose

Question 22

Antibiotic used for treatment of penicillin resistant strains of N. gonorrhoeae

Answer 22

Ceftriaxone

Question 23

Why might N. meningitidis fail to grow in a blood culture?

Answer 23

Sodium polyanethol sulfonate anticoagulant in the blood culture bottle

Question 24

Where can N. meningitidis be found as normal flora?

Answer 24

In the nasopharynx

Question 25

Colonial morphology of M. catarrhalis

Answer 25

1-3mm, gray-white, opaque, nonhemolytic, matt consistency

Question 26

API NH results for N. gonorrhoeae

Answer 26

Glucose +, Maltose -, Sucrose -, Lipase -

Question 27

API NH results for N. meningitidis

Answer 27

Glucose +, Maltose +, Sucrose -, Lipase -

Question 28

API NH results for M. catarrhalis

Answer 28

Glucose -, Maltose -, Sucrose -, Lipase +

Question 29

Species of Neisseria which can cause an STI

Answer 29

Neisseria gonorrhoeae

Question 30

Colour of a positive oxidase test

Answer 30

Pink/purple

Question 31

Where is non-pathogenic Neisseria found as normal flora?

Answer 31

Upper respiratory tract

Question 32

Possible infections caused by Moraxella

Answer 32

Septicemia, endocarditis, otitis media infection