CMB1003/L08 Infectious Disease

Question 1

How do pathogenic microbes cause disease?

Answer 1

Gaining a foothold in a particular niche

Question 1

Which part of the respiratory tract is typically devoid of microbes?

Answer 1

Lower respiratory tract

Question 2

Give 2 mechanisms by which Mycobacterium tuberculosis becomes drug resistant.

Answer 2

Cell wall structure and efflux

Question 3

How is Mycobacterium tuberculosis transmitted?

Answer 3

Respiratory expulsion

Question 4

How does Legionella pneumophila survive inside immune cells?

Answer 4

Generates a protective vacuole

Question 5

Why is Legionella pneumophila described as an amino acid auxotroph?

Answer 5

Promotes proteasomal degradation to gain nutrients

Question 6

Give 3 causes and infectious characteristics of gastroenteritis.

Answer 6

Bacterial - ingestion, faecal-oral, contamination
Viral - vomiting bugs
Parasitic - water-bourne

Question 7

What is the difference between InPEC and ExPEC E. coli?

Answer 7

Intestinal vs extraintestinal

Question 8

What is the most common serotype of E. coli?

Answer 8

O157:H7
Associated with beef and leafy greens

Question 9

What are the effects of the Shiga Toxin encoded by E. coli?

Answer 9

Causes HUS

Question 10

What is the result of phage-encoded CTX produced by Vibrio cholerae?

Answer 10

Massive fluid loss

Question 11

Give 2 examples of pathogens that can cause UTIs.

Answer 11

E. coli
P. mirabilis
P. aeruginosa
K. pneumoniae
C. freundii
A. baumanii

Question 12

Define ‘opportunistic pathogen’.

Answer 12

An organism that causes disease in the absence of normal host resistance

Question 13

Define inflammation.

Answer 13

A nonspecific reaction driven by neutrophil accumulation

Question 14

Define bacteraemia.

Answer 14

Presence of bacteria in the bloodstream

Question 15

Define sepsis.

Answer 15

Extreme, system-wide inflammatory response to blood poisoning

Question 16

Define systemic shock.

Answer 16

Systemic drop in blood pressure leading to mass organ failure

Question 17

What kind of E. coli lives harmlessly in the gut?

Answer 17

UPEC

Question 18

How does enrichment media differ from general media? (2)

Answer 18

Supplement media with sheep’s blood
For fastidious bacteria

Question 19

Describe selective media.

Answer 19

Represses growth of unwanted pathogens

Question 20

Describe differential media.

Answer 20

General purpose with chromogenic substrate additives
Tests for presence/absence of enzymes for diagnosis

Question 21

Describe selective/differential media. (3)

Answer 21

Contains bile salts and crystal violet that inhibits Gram +ve bacteria
pH indicators allow fermentation of sugars to be monitored
Contains lactose