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Semester 5 November > Medical Microbiology > Flashcards

Flashcards in Medical Microbiology Deck (59)
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Morphology of N meningitidis

Gram negative diplococci

1

Sero groups of N meningitidis

A, B, C, W135

2

Up to half N meningitidis membrane made up of

Lipo-oligosaccharide (containing endotoxin Lipid A)

3

Predisposing factors for N meningitidis

Asplenia ( anatomical or functional)
Complement deficiency (C8/C9)

4

Most common sporadic serogroup for N meningitidis in WP

Serogroup B

5

What does the lipo-oligosaccharide do in N meningitidis

Activates macrophages - TNF released = shock mediator in septicaemia

Alters permeability of BBB = CNS invasion

6

Who gets chemoprophyaxis in N meningitidis

Direct contacts
Mouth to mouth resus

7

What drugs are used as chemoprophyaxis in N meningitidis

Ceftriaxone
Ciprofloxacin
Rifampicin

8

What is factor X and where is it found

Haemin
Found in whole blood

9

What is factor V and where is it found

NAD
Found inside RBC

10

How is factor V created in petridish

Blood is heated = chocolate blood agar
Or
Organisms added to blood eg. Staphylococci. H influenzae grows on edges of colonies = satellitism

11

What is the typical pathogenesis of untypeable H influenzae

Contiguous spread from nasopharynx
- conjunctivitis
- otitis media
- sinusitis
- acute exacerbations of chronic bronchitis

12

What is pathogenesis of type b H influenzae

Spread beyond resp tract -> bacteraemia -> metastatic infection
- acute meningitis
- acute epiglottitis
- pneumonia
- septic arthritis
- cellulitis

13

Rx of H influenzae

3rd gen cephalosporin

If non invasive = oral co-amoxiclav

14

Lab diagnosis of H influenzae

MC&S
Latex agglutination - PRP Ag

15

Vaccine type given to those under 2 years for h influenza

Conjugate vaccine

16

What stain doesH influenzae have

Gram negative coccobacilli

17

What is the morphology of strep pneumonia

Gram positive lanceolate diplococci
Alpha haemolysis

18

What are the predisposing factors for strep pneumonia

Asplenia
Overcrowding
Viral URTI
Diabetes
Fluid in alveoli eg CCF, aspiration

19

What is the lab diagnosis of s pneumonia

Gram stain tissue
NB culture in pneumonia as bacteraemia is common

20

Rx of s pneumonia

IV penicillin except in meningitis must give third gen cephalosporin

21

Type of vaccine for s pneumonia

Protein conjugate (polyvalent) pneumococcal vaccine

22

Who gets s pneumonia vaccine

Splenectomy
? Those with predisposing factors

23

Do you isolate s pneumonia pts and why

No. Infection is most often endogenous

24

Complication of pneumonia in s pneumonia infection

Pleural effusion
Pericarditis = rare

25

Pathologies caused by s pneumonia

Pneumonia, meningitis, otitis media, sinusitis, endocarditis, arthritis, peritonitis

26

Gram stain of E. coli

Gram negative bacilli

27

Types of surface Ag on E. coli

O - LPS
K - polysaccharide capsule
H - flagella

28

Gram stain of listeria monocytogenes

Small gram positive bacilli

29

What is the appearance on culture of l monocytogenes

Translucent grey/white colonies
B haemolysis on blood agar