Gram Negative Cocci

Question 1

Neisseria characteristics

Answer 1

Non-motile, aerobic, capnophilic

Cold sensitive

non-hemolytic

Question 2

capnophilic

Answer 2

Needs increased CO2

Question 3

Transport medium

Answer 3

Amies with Charcoal, Transgow, JEMBEC (To make sure Neisseria receives increased CO2 continuously)

Question 4

ferments what?

Answer 4

CHO

Question 5

colonies

Answer 5

Develops non-pigmented colonies except; N. flava, N. flavescens, N. subflava

Question 6

all are catalase and oxidase (+) except

Answer 6

N. elongata

Question 7

Screening test

Answer 7

cytochrome oxidase test
- 1% hydrogen peroxide

(+) Result: purple

Question 8

Cytochrome oxidase test reagent

Answer 8

tetramethyl-p-phenylenediamine dihydrochoride (No DMSO)

Question 9

test to speciate

Answer 9

CHO utilization test

Question 10

CHO utilization test

Answer 10

Media: Cystine Trypyticase agar + CHO (glucose, sucrose, etc)

Indicator: phenol red

In an acid pH (+) media will turn YELLOW, (-) is RED

Question 11

Gramm negative species

Answer 11

N. gonorrhoeae
N. meningitidis
M. catarhallis

Question 12

Neisseria gonorrhoeae characteristics

Answer 12

• never a normal flora, always a pathogen
• kidney, coffee bean shaped diplococci intracellular with PMN

-

Question 13

what should be used to collect specimen for

Answer 13

• ryon / dacron fibers

- because it is sensitive to 2 Cs- Calcium aglinate and Cotton swab

Question 14

Neisseria gonorrhoeae virulence factor

Answer 14

pili

Question 15

rapid test for Neisseria gonorrhoeae

Answer 15

Superoxol test - uses 30% hydrogen peroxide

Question 16

What does Neisseria gonorrhoeae ferment

Answer 16

glucose only

Question 17

Neisseria gonorrhoeae causes what

Answer 17

• gonorrhea
• opthalmia neonatorum ( conjunctival gonorrhea in newborns)
• PID that causes sterility and perihepatitis/ Fits Hugh Curits syndrome

Question 18

Media used for Cultivating Neisseria gonorrhoeae

Answer 18

• thayer martin
• modified thayer martin
• martin lewis
• new york
• gc lec

Question 19

Thayer Martin media

Answer 19

• Enhanced Chocolate agar – Heated blood agar
• Selective for Neisseria
• Contains VCN
• Vancomycin - inhibits gram (+)
• Colistin - inhibits gram (-)
• Nyastatin – prevents fungi

Question 20

Modified Thayer Martin Media

Answer 20

VCN-T

• Trimetophrim lactate – prevents swarming organisms like Proteus

Question 21

Martin Lewis Media

Answer 21

• Contains VCAT

* “A” is Anisomycin – prevent fungi

Question 22

New York City Media

Answer 22

Contains VCAT
• “A” is Amphotericin B -prevents fungi
• Can also be used for Mycoplasma hominis and
Ureaplasma urealyticum (urogenital pathogens)

Question 23

GC Lect Medium:

Answer 23

Contains VCAT but A is

Amphotericin B and additional LINCOMYCIN – prevents growth of gram (+)

Question 24

Neisseria meningitidis characteristics

Answer 24

• Bean shaped diplococcic; sensitive to SPS
• Natural habitat is oro and nasopharynx
• Specimen detect carrier state: nasopharyngeal swab

Question 25

Neisseria meningitidis virulence factor

Answer 25

capsule, therefore Neufeld quelling test (+)

Question 26

Neisseria meningitidis what does it ferment

Answer 26

maltose and glucose

Question 27

Neisseria meningitidis causes

Answer 27

o Bacterial meningitis (5- 29 years old) o Meningococcemia (bacterial infection of blood) o Waterhouse–Friderichsen syndrome syndrome (Severe form of Meningococcemia characterized by bleeding of adrenal glands)

Question 28

N.lactamica & N.sicca

Answer 28

• N.lactamica: Glucose, Maltose, Lactose (+) & ONPG (+) o ONPG detects late lactose fermenters; (+) indicator is a yellow color • N.sicca: Glucose, Maltose, Sucrose (+)

Question 29

Moraxella catarrhalis characteristics

Answer 29

• Morphologically and biochemically resembles Neisseria • Encapsulated, with Pili, non-motile • Oxidase (+) because of Indophenol oxidase • Catalase (-) negative • Gamma hemolytic • A normal flora of oro and nasopharynx but may cause otitis media • Does not degrade sugar – Asaccharolytic / Non saccharolytic

Question 30

Rapid test for M. catarhalis

Answer 30

byurate disk test / tributyrin test positive +) result: blue color after 5 mins

Question 31

Moraxella catarrhalis

Answer 31

Develops HOCKEY PUCK COLONIES – these are colonies | remaining intact when pushed across the plate using inoculating loop

Question 32

Best test to differentiate M. catarrhalis from other Moraxella

Answer 32

DNase test