Gram -ve cocci- Neisseria meningitidis

Question 1

General Characteristics of Neisseria meningitidis:

Answer 1

1.encapsulated gram -ve diplococci
2. catalase +ve
3. Oxidase +ve
4. Part of normal human flora
5. Less sensitive than neisseria gonorrheae

Question 2

Neisseria meningitidis can be life threatening when:

Answer 2

when the bacteria invade the blood or the cerbospinal fluid

Question 3

Structure of Neisseria meningitidis

Answer 3

1. pili
2. Capsule contains polysaccharide

Question 4

Types of Neisseria meningitidis

Answer 4

*A
*B
*C
*Y
*W135

Question 5

Epidemiology of Neisseria meningitidis

Answer 5

1.Neisseria meningitidis is found in nasopharyngeal flora
2. Transmission occurs by inhalation of respiratory droplets through closed contact with an infected person

Question 6

Clinical representation of Neisseria meningitidis

Answer 6

Meningitis:
* Fever
*Fatigue
*Weakness
*CNS:
1.Loss of consciousnesses
2.convulsion
3.motor disability
Disseminated intravascular coagulation
:
1. because of endotoxin
** Fatal if not treated early**

Question 7

Laboratory diagnosis of Neisseria meningitidis

Answer 7

1. specimens:
   *Pharyngeal swab
2. Skin lesions
3. Cerbospinal fluids

Question 8

Laboratory tests for Neisseria meningitidis

Answer 8

1. Gram stain:
   *Large numbers of encapsulated small gram-ve diplococci and leukocytes can be seen through a microscope
2. culture:
   *Thayer -Martin media
   *Modified Thayer Martin media
   
   • Blood or chocolate agar
     Incubation conditions
   • incubate at temp of 35 to 37 C for 17 hours
     *CO2 enriched ex candle jar (5-7%)

Question 9

Biochemical Tests on Neisseria meningitidis

Answer 9

1. Oxidase +ve
2. Glucose and maltose +ve
3. Nitrate reduction test -ve