Pathogens and the Host Flashcards Preview

Principles of Disease > Pathogens and the Host > Flashcards

Flashcards in Pathogens and the Host Deck (116)
Loading flashcards...
1

What is clinical infection characterised by?

Inflammation

Pain

Pyrexia (raised body temperature)

Tachycardia (increased heartrate)

Rigors (sudden feeling of cold with shivers)

Increased white cell count

Increased C reactive protein (CRP)

2

What is pyrexia?

Raised body temperature

3

What is tachycardia?

Increased heartrate

4

What are rigors?

Sudden feeling of cold with shivers

5

What is a pathogen?

An organism that can cause disease

6

What is a commensal?

An organism which is part of normal flora

7

What are examples of commensals?

E coli in the gut

Staph aureus in the nose

8

What is a skin commensal?

Coagulase-negative staphyloccii 

9

When can coagulase-negative staphyloccii be pathogenic?

In the presence of foreign bodies (such as prosthetic heart valves)

10

What is Koch's postulates?

The criteria used to identify the agent of a particular disease

11

What are the principles of Koch's postulates?

 Organism must be found in all cases of the disease

Able to be cultured outside the body for several generations

Should reproduce the disease on inoculation (vaccination)

12

What do non-sterile sites contain that sterile sites do not?

Commensals

13

What do we need knowledge of to determine if something is a pathogen?

Normal flora for the site

Organisms pathogenicity

Clinical context

14

What is pathogenicity?

Ability of an organism to cause disease

15

What is flora?

Collective bacteria and other microorganisms in an ecosystem

16

What does an organism need to be to cause an infection?

Infectivity (ability to become established)

Virulence (ability to cause harmful effects once established)

17

What is infectivity?

Ability to become established

18

What is virulence?

Ability to cause harmful effects once established

19

What are things that help infectivity?

Attachment (such as P-fimbriae on E coli)

Acid resistance (such as urease on helicobacter pylori)

20

What is an example of attachment helping infectivity?

P-fimbriae on E coli

21

What is an example of acid resistance helping infectivity?

Urease on helicobacter pylori

22

What is urease?

An enzyme that catalysis urea to ammonia and carbon dioxide

23

What is virulence supported by?

Invasiveness

Toxin production

Evasion of immune system

24

What is virulence specific to?

Strains, not species

25

What is an example of invasiveness?

Streptococcus pyogenes causing:

Necrotising fascilitis (flesh eating disease)

Cellulitis

Connective tissue breakdown

Fibrinolysis

 

26

What is haemolysis?

The rupture or destruction of red blood cells

27

What are the 3 types of haemolysis?

Alpha haemolytic (partial haemolysis, turns blood agar green)

Beta haemolytic (complete haemolysis, turns blood agar clear)

Non haemolytic

28

What is alpha haemolytic?

Partial haemolysis

29

What colour does alpha haemolytic turn blood agar?

Green

30

What is beta haemolytic?

Complete haemolysis