Microbiology- Systematic Bacteriology

Question 1

4 main classifications of microorganisms

Answer 1

1 appearance/ structure
2 growth requirements
3 enzyme/ metabolic tests
4 molecular test

Question 2

streptococcus structure

Answer 2

chain of 4-20 cocci

think stripe

Question 3

staphylococcus structure

Answer 3

found in clumps

Question 4

Example of organisms which do NOT stain well with gram stain

Answer 4

mycobacterium TB
- lipid rich/ waxy cell wall

Treponema pallidium
- causes syphyllis

Question 5

aerobic

Answer 5

grow in oxygen

Question 6

obligate aerobes

Answer 6

require oxygen

Question 7

obligate anaerobes

Answer 7

killed by oxygen

Question 8

facultative anaerobes

Answer 8

tolerate oxygen

Question 9

capnophilic

Answer 9

prefer CO2 high environment

Question 10

Selective media

Answer 10

presence of specific substances permits the growth of one organism over the other

Question 11

Differential media

Answer 11

incorporation of chemicals produce visible changes in colonies that facilitate identification

Question 12

Identification of streptococcus

Answer 12

haemolysis

Question 13

colour of alpha haemolysis colonies

Answer 13

green

Question 14

colour of beta haemolysis colonies

Answer 14

gold halo

Question 15

colour of gamma haemolysis colonies

Answer 15

no haemolysis

Question 16

What does metabolic profiling utilise?

Answer 16

carbon sources and amino acids

Question 17

MALDI-TOF

Answer 17

matrix assisted laser desorption ionisation time of flight

not good for strep or staph

Question 18

Virulence

Answer 18

capacity of a microbe to cause damage to the host

Question 19

commensal

Answer 19

organism which s part of the normal flora

Question 20

opportunistic pathogen

Answer 20

an organism that causes infection when opportunity/

change in natural immunity arises

Question 21

Example of fungal infections

Answer 21

Candida
yeast
aspergilus
moulds

Question 22

Examples of gram negative prokaryotic pathogens

Answer 22

neisseria

escherichia

Question 23

Examples of gram positive prokaryotic pathogens

Answer 23

streptococcus
staphylococcus
enterococcus

clostridium

Question 24

coliform

Answer 24

species of gram negative bacilli that look like E. Coli on gram film and blood agar

Question 25

in which environment do coliforms best grow in?

Answer 25

aerobically

Question 26

First line antibiotic used for treatment of infections caused by coliforms

Answer 26

gentamicin

Question 27

cause of alpha haemolysis

Answer 27

enzymes denature Hb inside RBC-> green partial haemolysis

Question 28

cause of beta haemolysis

Answer 28

enzymes lyse RBC-> completely clears the surrounding the colony complete haemolysis most pathogenic streptococci are beta haemolytic

Question 29

most significant pathogenic streptococci

Answer 29

Group A Streptococcus

Question 30

cause of pneumonia

Answer 30

inhalation of streptococcus pneumonia, causing fibrous exudate to clog alveoli and bronchioles

Question 31

streptococcus pneumoniae

Answer 31

Gm +ve alpha haemolytic cocci commonest cause of pneumonia

Question 32

most important group of non haemolytic streptococci

Answer 32

enterococci Most common cause of UTI but part of normal bowel flora

Question 33

clostridiodes

Answer 33

Gm +ve anaerobic bacilli produce exotoxins which cause severe tissue damage

Question 34

Why do patients with coliform (gram negative) sepsis become quickly unwell?

Answer 34

GM -ve cell wall releases endotoxin when bacteria dies