Introduction to bacteriology

Question 1

Who disproved the theory of spontaneous generation

Answer 1

Louis Pasteur

Question 2

What was Pasteur’s Flask experiment

Answer 2

boiled meat broth in a flask, then bent the neck of the flask into an s shape - air could enter the flask by micro organisms could not, they got stuck in the neck, so therefore they did not generate from the broth

Question 3

Koch’s postulates

Answer 3

1. bacterium must be present in very case of the disease
2. the bacterium must be isolated from the disease host and grown in pure culture
   3.the specific ideas must be reproduced when a pure culture of bacterium is inoculated into a healthy susceptible host
3. the bacterium must be recovered from the experimentally infected host

Question 4

Limitations to Kochs Postulates

Answer 4

normal bacterium can become a pathogen - when they gain access to deep tissue (surgery), gain extra violence factors, in immunocompromised patients

not all those infected or colonies be pathogenic bacterium will develop into a disease

some bacteria are a cultural in vitro

assumption that other host must have the same genetic makeup as the original host to react

Question 5

What is a pathogen?

Answer 5

an organism that can invade the boast and cause disease

Question 6

What is pathogenicity?

Answer 6

the ability to cause disease in another organism

Question 7

What is virulence?

Answer 7

the degree of pathogenicity

Question 8

Difference between colonised and infected

Answer 8

the host is colonies by bacteria

infection is the entry, establishment and multiplication of pathogens within a host

Question 9

How to cause a disease

Answer 9

1) maintain a reservoir before and after infection
2) leave the reservoir and gain access to the new host
3) colonise the host
4) Harm the host

Question 10

what does an infectious disease depend on?

Answer 10

the microorganism
the number of Bactria that enter the body/wound
the quality of the persons specific and non-specific body defences

Question 11

what is the chain of infection

Answer 11

causative agent - transmission - host

Question 12

examples of causative agent

Answer 12

pathogenicity

infectious dose

reservoir source

Question 13

examples of transmission

Answer 13

contact

common vehicle

airborne vector

Question 14

What is epidemiology?

Answer 14

The study of the determinants, occurrence, distribution and control of health and disease in a defined population

Question 15

The host-parasite relationship can…

Answer 15

…determine the outcome of the infection

Question 16

Non-specific defences

Answer 16

not directed at any particularly organism

Question 17

Specific defences?

Answer 17

mediated by the host immune system and direct at a particular organism

Question 18

what are the two types of specific defences?

Answer 18

Humoral and cell-mediated

Question 19

Humoral defenses

Answer 19

due to specific antibody production

Question 20

cell-mediated

Answer 20

due to T lymphocytes and the cytokines they produce

Question 21

Non-specific defence

Answer 21

skin (barrier), Normal Flora (make is difficult for exogenous pathogens to invade), flushing effect (tears/urine/mucus remove organisms), gastrointestinal tract (low pH of stomach acid inactivates ingested viruses), Vaginal secretions (low pH due to lactobacilli protection from bacterial infection)

Question 22

Phagocytosis - non-specific defence

Answer 22

Neutrophils - multilines nucleus and granules contain antimicrobial compounds - phagocytose and kill bacteria

Macrophages - large, granular cells - intimate inflammatory response and when activates are antibacterial

Question 23

Complement proteins - non-specific defence

Answer 23

Opsonins - enhance phagocytosis - called opsonisation

Question 24

What is complement

Answer 24

a comes of blood proteins produced in a cascade which becomes activated upon infection to enhance phagocytosis and lyse bacteria