Lecture 1- Basic Concepts Of Microbial Pathogenicity And Virulence

Question 1

What are opportunistic infection?

Answer 1

Intentions caused by organisms that wouldn’t usually cause disease in a healthy person.

Question 2

Which 3 groups of people are susceptible to opportunistic infections?

Answer 2

Young babies

Immunocompromised patients

Older people

Question 3

What are zoonotic infections?

Answer 3

Infections from animals.

Question 4

What is a horizontal gene transfer?

Answer 4

When an organism acquires genome from other organisms

Question 5

Which two factors cause rapid change in the genetic make up of microbes?

Answer 5

Horizontal gene transfer

Hyper-mutation

Question 6

What are new new diseases?

Answer 6

Diseases caused by PREVIOUSLY UNIDENTIFIED microbes.

Question 7

Which classification of diseases recently entered human population?

Answer 7

New new diseases

Question 8

Name on characteristic of new new diseases with relation to human lifestyle.

Answer 8

New-new diseases take advantage of changes in human lifestyle.

Question 9

Name two examples of new-new diseases?

Answer 9

Lyme disease

Legionnaires disease

Question 10

What are new-old diseases?

Answer 10

Diseases that have been known for a long time but now their microbiological cause has been determined.

Question 11

Name 2 examples of new-old diseases.

Answer 11

Campylobacter - food Bourne disease.

Helicobacter Pylori - causes stomach ulcers.

Question 12

What are old-new diseases?

Answer 12

Diseases with known causes that were once thought to be under control but are re-emerging.

Question 13

What characteristic is allowing old-new diseases to re-emerge?

Answer 13

The long known pathogens of old-new diseases acquire new traits.

Question 14

Give 4 examples of old-new diseases.

Answer 14

MRSA

Tuberculosis

E.Coli

Influenza A

Question 15

What are old-old diseases?

Answer 15

These are diseases with known causes but recently recognised again because of their importance.

Question 16

Give one example of old-old diseases.

Answer 16

Chlamydia trachomatis

Question 17

What is colonization?

Answer 17

The ability of a microbe to remain in one place and multiply there.

This is usually a precursor to an infection

Question 18

How does colonization play a role in infection?

Answer 18

It is usually the precursor to an infection.

Question 19

What is an infection?

Answer 19

The successful colonisation and multiplication of a microbe capable of causing disease.

Question 20

What is disease?

Answer 20

The dynamic process involving a sufficient change in the normal function of an organism’s cells or tissues to cause symptoms.

Question 21

What is pathogenicity?

Answer 21

A microbe’s ability to cause disease (relative term)

Question 22

What is virulence?

Answer 22

The degree of pathology caused by a microbe (quantitative term)

Question 23

What is pathogenesis?

Answer 23

The mechanisms a microbe uses to cause a disease.

Question 24

What are virulence factors?

Answer 24

These are features that contribute to a microbe’s ability to colonise and cause disease

Question 25

Which two categories describe microbes able to cause disease?

Answer 25

True or opportunistic.

Question 26

What are TRUE microbes?

Answer 26

These are microbes that READILY produce disease in healthy hosts.

Question 27

What are OPPORTUNISTIC microbes?

Answer 27

These are microbes that cause disease in a COMPROMISED HOST or when a PARTICULAR MICROBE enters an UNUSUAL SITE in a host.

Question 28

Give examples of 3 TRUE MICROBES.

Answer 28

Vibrio CHOLERA, Yersinia PESTIS, SALMONELLA sp.

Question 29

Give 2 examples of OPPORTUNISTIC MICROBES.

Answer 29

Staphylococcus AUREUS, Streptococcus PNEUMONIAE.

Question 30

What are Koch's postulates?

Answer 30

The commandments of infectious disease.

Question 31

Recite the 4 Koch's postulates

Answer 31

1) Microbe must BE ASSOCIATED with SYMPTOMS or the disease and BE PRESENT at the site of infection. 2) Microbe must be ISOLATED from disease lesions and GROWN AS PURE CULTURE. 3) CULTURED MICROBE must REPRODUCE the disease when INNOCULATED into a susceptible healthy host. 4) The microbe must be RE-ISOLATED in pure culture from the SUSCEPTIBLE HEALTHY HOST in 3.

Question 32

What is the proposed 5th Koch's postulate?

Answer 32

Knowledge or microbe should enable effective therapeutic and preventative measures.