BACTERIA: SLIDES

Question 1

What are the basic principles of the chain of infection?

Answer 1

Infectious agent
Susceptible host
Portal of exit
Portal of entry 
Mode of transmission
Reservoir

Question 2

What are the symptoms of complicated and uncomplicated influenza?

Answer 2

C- fever, myalgia, headache, malaise, nonproductive cough, sore throat and rhinitis.

U- primary influenza viral pneumonia, exacerbate underlying medical conditions which leads to secondary pneumonia or otitis media and sinusitis.

Question 3

What does virulence mean?

Answer 3

Ability of a microbe to cause disease.

Question 4

Haemagglutinin

Answer 4

14 diff types- Influenza hemagglutinin (HA) or haemagglutinin[p] (British English) is a homotrimeric glycoprotein found on the surface of influenza viruses and is integral to its infectivity.

Hemagglutinin is a Class I Fusion Protein, having multifunctional activity as both an attachment factor and membrane fusion protein. Therefore, HA is responsible for binding Influenza virus to sialic acid on the surface of target cells, such as cells in the upper respiratory tract or erythrocytes,[1] following which event the virus is internalised.

Question 5

Neuroaminidase

Answer 5

9 N types. Neuraminidases are enzymes that cleave sialic acid groups from glycoproteins and are required for influenza virus replication.

Question 6

What is antigenic shift and drift?

Answer 6

Antigenic drift is a kind of genetic variation in viruses, arising by the accumulation of mutations in the virus genes that code for virus-surface proteins that host antibodies recognize. … These receptors can be antibodies in the bloodstream or similar proteins on the surfaces of immune-system cells.

Antigenic Shift. Antigenic shift occurs when a radical and abrupt change in influenza type A virus hemagglutinins occurs. … It occurs when two viruses simultaneously infect the same animal. MAJOR CHANGE.

Question 7

How long is the flu infectious for and what is the incubation period?

Answer 7

Incubation period 2-3 days
Infectious once symptoms appear
Virus shed in upper respiratory tract secretions
Infectious for 3-5 days
Children infectious for longer !

Question 8

How far can big and small particles can travel?

Answer 8

Big- over 10 micrometres, droplet, 2m.

Small- under 10, aerosol, 2m.

Question 9

What does RSV stand for?

Answer 9

Respiratory syncytial virus (RSV) is a very common virus that leads to mild, cold-like symptoms in adults and older healthy children. It can be more serious in young babies, especially those in certain high-risk groups.

Question 10

How long does influenza virus stay on steel and plastic for?

Answer 10

1-2 days

Question 11

How long does influenza virus stay on cloth paper and tissues for?

Answer 11

8-12 hours.

Question 12

How long does the influenza virus stay on your hands for?

Answer 12

5 minutes.

Question 13

Name some examples where a virus can enter the body.

Answer 13

Respiration (aerosols)
Inhalation (all particles)
Direct contact (droplets)
In-direct contact (settled particles – face touching)
Role of conjunctiva uncertain

Question 14

What individuals are offered a free flu vaccine?

Answer 14

Children (2-11yrs) – Live attenuated virus nasal spray vaccine
Adults >65yrs offered vaccine
Adults 18-65yrs at risk of complications offered vaccine

Question 15

What are the colours of the hospital bins?

Answer 15

red- bathrooms, washrooms and floors.
blue- general areas including wards, basins in public areas and offices.
green- food areas.
yellow- isolation

Question 16

What are the 10 standard infection control procedures?

Answer 16

Patient Placement.
Hand Hygiene.
Respiratory hygiene and cough etiquette.
Personal Protective Equipment (PPE)
Management of care equipment.
Control of the environment.
Safe management of linen.
Management of blood and body fluid spillages.

Question 17

What is the dose of an infectious agent mean?

Answer 17

The number of microbes entering
the body (DOSE)

Question 18

Name some examples of exotoxins and endotoxins.

Answer 18

Exotoxins
P. gingivalis (protease)
S. aureus (enterotoxin & leukocidin)

Endotoxins
	Lipopolysaccharide
	 (P. gingivalis & E. coli)

Question 19

What is the infectious dose of TB, syphillis, E.coli and the flu?

Answer 19

TB = 1 bacillus
Syphilis = 57 bacteria (ID50)
E. coli 0157 = <10 cfu
Influenza virus = <10

Question 20

Microbes are ubiquitous in nature
· ANIMALS: some human pathogens come
from animals (zoonoses) e.g. anthrax, bacillis anthrocis, Drums contaminated with anthrax- inhale it and you die.

Answer 20

.

Question 21

What is the incubation period?

Answer 21

The time between the contamination and the development of symptoms.

Question 22

Acute phase- easily recognised eg. influenza and common cold.

Podromal phase- not easily recognised: mumps, measles and rubella.

Healthy carries of microorganism- not easily recognised eg. HIV, hepatitis, herpes etc.

Answer 22

.

Question 23

Endogenous and exogenous?

Answer 23

Endogenous (own flora) or exogenous (acquired from somewhere else).

Question 24

What is the classification of human pathogens based on?

Answer 24

Ability to cause infection
Severity of the disease
Vaccine and treatment
Risk of population spread.

Question 25

What is the R0 number?

Answer 25

The expected number of secondary cases produce by infected individuals in an epidemic.
R0 less than 1= infection will eventually die out
over 1= ability to spread in a population.

Question 26

What affects the R0 number?

Answer 26

Infectiousness, number of susceptible people and duration of infectiousness.

Question 27

What shape is staph aureus?

Answer 27

Gram positive cocci.

Question 28

What bacteria is most commonly associated with apical periodontitis?

Answer 28

Enterococcus faecalis.

Question 29

Follow:- Manufacturer’s instructions- COSHH requirements (Decanting)

Consider:- amount to be used / dilution- contact time
Avoid the use of sprays.

Answer 29

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