Medical Microbiology

Question 1

Roughly how many people in the 20th century have been killed by infectious diseases?

Answer 1

1680 million

Question 2

What were the major infections causing concern last century?

Answer 2

Measles
HIV/ AIDS
Hepatitis 
Influenza pandemics
Respiratory viruses
Smallpox

Question 3

What are the current major infections causing concern?

Answer 3

HIV/ AIDS
Influenza
Hepatitis
Emerging threats like Ebola

Question 4

What bacteria is whooping cough caused by?

Answer 4

Bordetella pertussis

Question 5

Why is whooping cough becoming more prevalent in developed nations?

Answer 5

It is becoming more prevalent in developed nations now where people are refusing vaccines

Question 6

What is epidemiology?

Answer 6

The study of nature, distribution, causation, transfer, prevention and control of disease

Question 7

What does the abbreviation YLL mean?

Answer 7

Years of life lost due to premature mortality

Question 8

What is a zoonotic disease?

Answer 8

A disease normally found in animals and insects that goes on to infect humans as well

Question 9

What are some current concerns relating to bacterial infection?

Answer 9

Antibiotic resistance
Reduced vaccination rates
Poverty and its associated issues such as lack of access to sanitary water

Question 10

Define opportunistic pathogen.

Answer 10

Capable of causing damage and infection in a compromised host

Question 11

Define obligate pathogen.

Answer 11

Causes damage and infection as part of its growth and replication

Question 12

Define facultative pathogen.

Answer 12

Causes disease as one of its life cycles or when in a different host

Question 13

Define commensal pathogen.

Answer 13

Induces either no damage or clinically unapparent damage to the host but may elicit an immune response

Question 14

What is a pathogen?

Answer 14

A microbe capable of causing host damage and disease

Question 15

What is a host?

Answer 15

Organism that is colonised or subject to an infection

Question 16

What can bacterial virulence factors do to help the bacteria?

Answer 16

Aids host colonisation
Allows immune evasion 
Host cell invasion or escape
Host destruction
Nutrient scavenging 
Poisoning

Question 17

What are some examples of bacterial virulence factors and what they do/ are?

Answer 17

Pili (adhesion)
Capsule antigens (immune mimicry)
Invasins (intracellular entry)
Glycolipids (endotoxin)
Botulinum (exotoxin)
Siderophores (nutrient acquisition)
Lipases/ proteases (destructive enzymes)

Question 18

What is a virulence factor?

Answer 18

Drives a mechanism or process of infection

Question 19

How do toxin mediated diseases relate to virulence factors?

Answer 19

Toxin mediated diseases may have a central virulence factor

Question 20

What does it mean if virulence factors are encoded into the genome?

Answer 20

The virulence factors will be non transferable and encoded stably into the genome.

Question 21

What are the 2 types of growth rates and an example of each?

Answer 21

Fast growth: M. smegmatis

Slow growth: M. tuberculosis

Question 22

How fast does M. tuberculosis grow? What does this mean in regards to tuberculosis?

Answer 22

2 to 8 weeks

Growths are used to confirm tuberculosis after diagnosis

Question 23

How is diagnosis of tuberculosis done?

Answer 23

Via symptoms because the growth is so slow the patient would be too ill by the time growths could be done to diagnose

Question 24

How much of the world is infected with M. tuberculosis according to WHO?

Answer 24

1/3

Question 25

How many active cases of tuberculosis were there in 2014 according to WHO?

Answer 25

9.6 million

Question 26

How many deaths have there been from tuberculosis?

Answer 26

1.5 million

Question 27

How many lives have been saved from TB diagnosis?

Answer 27

37 million

Question 28

How many people currently have a multi drug resistant strain of TB?

Answer 28

480,000

Question 29

What type of pathogens are all tuberculosis?

Answer 29

Obligate primary pathogens

Question 30

What is the normal site of infection for tuberculosis?

Answer 30

The lungs but it can spread to other sites

Question 31

What happens during the tuberculosis infection process?

Answer 31

Tubercules form in the lung Pathogens are engulfed by alveolar macrophages The T-cells then activate more macrophages The infection is attacked but this may fail to clear all bacteria Forms calcified compact clusters Disease may become systemic causing meningitis and issues in the kidneys, spine and bones.

Question 32

What are the general symptoms of tuberculosis?

Answer 32

Persistent cough (sputum/ bloody) Night sweats Weight loss Abnormal lung x-ray

Question 33

What is the impact of M. tuberculosis having a lipid rich cell wall?

Answer 33

Makes it difficult to treat, acid fast and inflammatory to the immune system

Question 34

What is the general treatment for tuberculosis?

Answer 34

Directly observed, short course treatment 6 months, 3 times weekly Take multiple antibiotics to avoid the emergence of resistance over the treatment period

Question 35

Why are patients observed in the treatment of M. tuberculosis?

Answer 35

Improve compliance as the drugs have multiple irritating side effects

Question 36

How well does the BCG vaccination work?

Answer 36

Over 80% effective in Europe but offers little to no protection in Sub-saharan Africa and India, possibly due to exposure to environmental mycobacteria

Question 37

Why have genomics revolutionised understanding of tuberculosis?

Answer 37

As it grows so slowly, it evolved slowly

Question 38

What is cystic fibrosis?

Answer 38

Most common autosomal recessive genetic disorder coming from a mutation in a single gene

Question 39

What does cystic fibrosis cause?

Answer 39

Causes altered chloride ion transport meaning secretory epithelial tissues are affected Causes abnormal lung function and microbial infection

Question 40

What happens to people with cystic fibrosis throughout their life?

Answer 40

Will get recurrent and chronic bacterial infections, which are a major cause of morbidity and death May also suffer fungal and other viral infections

Question 41

What is ESKAPE?

Answer 41

The resistance pathogens that are escaping control by antibiotics

Question 42

Define diarrhoea.

Answer 42

Passage of unusually loose or watery stools, usually at least 3 times in a 24 hour period

Question 43

What are the 4 clinical types of diarrhoea?

Answer 43

Acute watery diarrhoea Acute bloody diarrhoea Persistent diarrhoea Diarrhoea with severe malnutrition

Question 44

How many cases of diarrhoea diseases are there in children each year?

Answer 44

1.7 billion

Question 45

How often do most adults get diarrhoea?

Answer 45

One episode every 2 years

Question 46

What is the leading cause of malnutrition in children under 5?

Answer 46

Diarrhoea

Question 47

What are some common causes of diarrhoea?

Answer 47

``` Rotavirus Shigella Salmonella enterica Campylobacter jejuni Yersinia E. coli ```

Question 48

What is the reservoir of an infectious agent?

Answer 48

The reservoir of an infectious agent is the habitat in which agent normally lives, grows and multiplies. Reservoirs include humans, animals and the environment. The reservoir may or may not be the source from which an agent is transferred to the host.

Question 49

What are the key sources of contamination?

Answer 49

Water Food Humans

Question 50

How can enteric diseases be prevented?

Answer 50

Access to safe drinking water Use of improved sanitation Exclusive breastfeeding for the first 6 months of life Good personal and food hygiene Vaccination (rotavirus and cholera) Health education e.g. washing hands properly

Question 51

How does washing hands with soap help?

Answer 51

Reduces the number of people getting sick with diarrhoea and general illnesses like colds

Question 52

How can diarrhoea be controlled?

Answer 52

Rehydration Zinc supplements to reduce length of time of episode Nutrient rich foods to avoid subsequent malnutrition Antibiotics Loperamide - slows movement of the gut to reduce frequency of diarrhoea

Question 53

What is a latent infection?

Answer 53

An infection that is hidden, inactive or dormant

Question 54

What does systemic mean?

Answer 54

Relating to a system, as opposed to just one part

Question 55

What is cell mediated immunity?

Answer 55

An immune response that doesn't involve antibodies