sem 1 - definitions revision lectures 1-7

Question 1

standard infection control

Answer 1

the same cross infection control procedure must be used for all patients

Question 2

enrichement media

Answer 2

addition of blood/serum/extract will support growth of fastidious organisms

Question 3

selective media

Answer 3

presence of a specific substance permits the growth of one substance over the other

Question 4

differential media

Answer 4

facilitates identification

Question 5

virulence test

Answer 5

can be critical in pathogenesis eg adhesin and toxin

Question 6

define Kochs postulates

Answer 6

• micro-organism which is present in only disease

- must be isolated and grown in pure culture

Question 7

mutualistic

Answer 7

relationship which host and organism gain mutual value

Question 8

parasitic

Answer 8

live on ir in living creatures creating damage to the host

Question 9

pathogen

Answer 9

microbe capable of causing host damage

Question 10

virulence

Answer 10

the capacity of the microbe to cause damage to the host

Question 11

virulence factor

Answer 11

component of the pathogen that damages the host

Question 12

list the virulence factors

Answer 12

adhesin invasion impedin agressin and modulin

Question 13

obligate pathogens

Answer 13

must cause disease for transmission

Question 14

opportunistic pathogens

Answer 14

do not have to cause disease for transmisssion

Question 15

accidental pathogens

Answer 15

disease that hinders or prevents transmission

Question 16

epidemiology

Answer 16

the study of occurrence spread and control of disease

Question 17

prevalence

Answer 17

proportion of population affected

Question 18

exogenous

Answer 18

infective material derived from outside patients body

Question 19

endogenous

Answer 19

bacteria fungi transferred from sterile to non-sterile state

Question 20

commensal to pathogen

Answer 20

• damage to epithelium
• presence of foreign body
• transfer of bacteria to incorrect site
• immune suppression
• infection by exogenous pathogen
• disruption of microflora by antibiotics

Question 21

Five Is

Answer 21

• Inhalation
• inocolation
• ingestion
• mother to Infant
• intercourse

Question 22

HAI infections

Answer 22

6.4% of patients acquire infection during hospital stay

Question 23

factors which influence disease transmission

Answer 23

Agent
environment
host

Question 24

Membrane attack complex (MAC)

Answer 24

C3b activates producing C5a and C5b which are cells that bind to kill bacteria and mark cells for phagocytosis

Question 25

virulence factors from staphylococcu aureus

Answer 25

adhesin - fibrinogen binding protein

kills leukocytes - leukocidin (PVL)

shock, rash desquamtion - TSST-1

Question 26

superantigen

Answer 26

massive release of cytokines and innapropriate immune response
activates 1 in 5 T cells

Question 27

Panton Valentine Leukocidin

Answer 27

PVL + alpha toxin linked with CA-MRSA responsible for necrotizing pneumonia and severe skin infections

Question 28

examples of evasion of host defences

Answer 28

superantigens

protein A - binds to FC portion of IgG antibody

Question 29

Coagulase

Answer 29

forrms staphylthrombin promotes the conversion of fibrinogen to fibrin and therefore clotting

Question 30

strep throat

Answer 30

Group A streptococci (GAS)

beta heamolytic S.pyogenes

Question 31

scarlet fever

Answer 31

severe form of strep throat associated with rash

Question 32

Acute streptococcal gingivitis

Answer 32

• infective gingivae red/ swollen/ oedematous often follow sore throat

Question 33

rheumatic fever

Answer 33

1-4 weeks after sore throat/scarlet fever

- delayed reaction due to inadequate recovery from GAS

Question 34

identification

Answer 34

haemolysis is used to classify streptococci

Question 35

Lancefield group A

Answer 35

• serotyping of cell wall carbohydrate

- GAS bacitracin sensitive

Question 36

antibiotic treatment of strep throat and GAS disease

Answer 36

penicillin V course

amoxicillin