Intro to bacteriology

Question 1

what is the theory of spontaneous generation? 3

Answer 1

simple organisms could come from dust mud etc

• living organisms from non living matter
• later discovered appearance of maggots resulted from presence of fly eggs

Question 2

how were microorganisms discovered?

Answer 2

boiling microorganisms killed them off but they still arose after few days
- discovered by Pasteur and used fermentation to investigate

Question 3

what is germ theory?

Answer 3

microorganisms are cause of disease, lead to development of antisepsis adn sterilisation

Question 4

what are Koche’s 4 postulates?

Answer 4

• bacterium must be present in every case of disease
• bacterium must be isolated from diseased host and grown in pure culture
• disease must be reproduced when a pure culture of bacterium is inoculated into a healthy susceptible host
• bacterium must be recoverable from experimentally infected host

Question 5

what are limitations of postulates?

Answer 5

normally harmless bacterium part of normal flora can become harmful

Question 6

what is a pathogen

Answer 6

an organism that can invade body and cause disease

Question 7

what is pathogenicity

Answer 7

ability to cause disease

Question 8

what is virulence

Answer 8

degree of pathogenicity (highly virulent organism can casue disease in low numbers)

Question 9

what are 4 things organisms must do to cause disease?

Answer 9

• maintain a resevoir before and after infection
• leave the resevoir and gain access to new host
• colonise host
• harm host

Question 10

what 3 factors does disease depend on?

Answer 10

microorganism
number of bacteria entering the body
quality of persons specific and non-specific body defences (immune system)

Question 11

what is the chain of infection?

Answer 11

causative agent to transmission to host

Question 12

what is epidemiology?

Answer 12

study of determinants , occurance and distribution of disease

Question 13

what are 7 non-specific defences?

Answer 13

skin'
normal flora
flushing effect
gastrointestinal tract
secretions
phagocytosis
complementary proteins

Question 14

what are non-specific defences?

Answer 14

not directed at a particular organism

Question 15

describe skin and normal flora defences?

Answer 15

skin-tough impermeable barrier unless breached by injury and disease
normal flora- presence of harmless bacteria in body can make difficult to invade

Question 16

describe flushing effect and gastrointestinal tract defenses?

Answer 16

flushing- tears, urine, mucus etc

GI tract- low ph stomach acid helps inactivate ingested viruses and some bacteria

Question 17

describe phagocytosis?

Answer 17

defense mechanism where bacteria and viruses are ingested by scavenger cells
include macrophages

Question 18

what are macrophages?

Answer 18

large, granular cells

initiate inflammatory responses and when activated are antibacterial

Question 19

what are complementary proteins?

Answer 19

a complex of blood proteins produces in a cascade which become activated upon infection to enhance phagocytosis

Question 20

what are opsonins?

Answer 20

antibodies adn complementary proteins - they enhance phagocytosis

Question 21

what are specific defenses?

Answer 21

mediated response by host immune system and directed at a particular organisms

Question 22

2 examples of specific defenses?

Answer 22

humoral or cell mediated