How bacteria cause disease

Question 1

What leads to different pathotypes in E.coli

Answer 1

Acquisition of pathogenicity islands

Question 2

UHEC

Answer 2

Enterohemorrhagic E.coli

Question 3

EPEC

Answer 3

Enteropathic E.coli

Question 4

UPEC

Answer 4

Uropathogenic E.coli

Question 5

What is an endogenous infection

Answer 5

Commensal microbiota getting in the wrong place

Question 6

What is an exogenous infection

Answer 6

Infection from pathogens from the environment

Question 7

Examples of endogenous infection (PHOM)

Answer 7

Pneumococcal pneumonia
Honeymoon cystitis
Oral strep and endocarditis
Meningococcal meningitis

Question 8

Routes of exogenous encounter and examples

Answer 8

Respiratory (TB)
Faecal-Oral (Shigellosis)
Venereal spread (syphilis)
Inanimate and animate vectors

Question 9

What is ingress

Answer 9

Enter through already open channels

Question 10

What is penetration

Answer 10

Entry through artificial openings

Question 11

Is Vibrio cholera ingress or penetration

Answer 11

Pure ingress

Question 12

Is shigella dusenteriae ingress or penentration?

Answer 12

Invade cells lining GI tract

Question 13

Is S. Typhi, ingress or penetration

Answer 13

invade cells and further into blood supply

Question 14

Exogenous infection: Zoonoses

Answer 14

Tsetse fly and African sleeping sickness (Trypanasoma bruceii)
Cattle and anthrax (B. anthracis)
Fleas and plague (Y. pestis)

Question 15

What does iatrogenic mean

Answer 15

Illness or injury occuring unintentionally during medical treatment or diagnosis

Question 16

Iatrogenic examples

Answer 16

Blood transfusions - syphilis and brucellosis
Contaminated medical devices with CoNS

Question 17

Describe the Type 3 secretion system of Salmonella

Answer 17

Acts like mini hypodermic needle.
1. Encounter M cells in GI tract and adheses.
2. Inject effectors which cause ruffling, bacteria is engulfed and taken up in vacoule.
3. Another type 3 system allows escape from vacoule

Question 18

Spread/avade techniques: S. aureus

Answer 18

Inhibits opsonisation, inhibits chemotaxis and kills phagocutes

Question 19

What part of Streptococcus pneumoniae inhibts phagocytosis?

Answer 19

Capsule

Question 20

What bacterium inhibits lysosomal fusion

Answer 20

M. tuberculosis

Question 21

Features Streptococcus pyogenes:

Answer 21

• Capsule – hyaluronic acid, similar to host connective tissue.
• Leukocidins- Streptolysin O/S and NADase
• Degradation of host tissue/other barriers: Hyaluronidase (connective tissue), streptokinase (clots), streptodornase (DNA) and proteases.

Question 22

Inoxication illnesses (foodborne) are caused by products of what bacteria

Answer 22

S.aureus
B. cereus
C. botulinum

Question 23

What are AB toxins?

Answer 23

Dimers with active component A and binding component B

Question 24

Three methods of action of AB toxin

Answer 24

Inhibition of protein synthesis- C diptheriae
Hyperactivation- V. chlorea
Effects on nerve-muscle transmission- C.tetani

Question 25

Two types of immunopathogenesis

Answer 25

Superantigen - binds TCR to MHC molecule, prevents response LPS- Overide of reaction, leads to toxic shock

Question 26

What type of twin is more likely to have both kids have TB

Answer 26

Monozygotic

Question 27

The two tissue types associated with the two types of leprosy

Answer 27

HLA DR3: Tuberculoid leprosy HLA DQ1: Lepromatous leprosy

Question 28

Causative agent of psittcosis and what factor increases risk

Answer 28

Chlamydophilia psitacci infects birds, stress causes birds to shed bacteria.

Question 29

What bacteria are neonates and young infants at risk to

Answer 29

Bordetella pertussis

Question 30

What disease can be reactivated at old age

Answer 30

TB

Question 31

What was MDR TB resistant to

Answer 31

First line agents like rifampicin and isoniazid

Question 32

What is XDR TB resistant to?

Answer 32

Quinolones and second line injectables

Question 33

What can bacterial pneumonia be caused by?

Answer 33

S. aureus H. infleunzae K. pneuomaniae P. areuginosa S. pneumoniae

Question 34

Synergy examples

Answer 34

Flu + bacterial pnue. HIV + TB COVID19 + bacterial pnue.