Microbiology - Systematic Bacteriology

Question 1

In microscopy how can you identify organisms?

Answer 1

Shape, size, grouping
Structures e.g. flagella/spores
Staining e.g. Gram, Ziehl Neelson

Question 2

What are the 3 most common shapes of bacteria?

Answer 2

Cocci (spheres), Bacilli (rods) and spiral-shaped.

Question 3

How do cocci bacteria divide?

Answer 3

They divide in one plane or 3, meaning they arrange themselves in chains or clumps.

Question 4

What is an example of a cocci bacteria which divides in one plane?

Answer 4

Diplococcus.

Question 5

What is an example of a cocci bacteria which divides in 3 planes?

Answer 5

Staphylococcus.

Question 6

How do bacilli bacteria join together?

Answer 6

They arrange themselves in chains too and usually have a gram +ve cell wall.

Question 7

What other shape can bacilli bacteria have?

Answer 7

Slightly curved rod and often Gm -ve wall.

Question 8

What are the 2 types of spiral shaped bacterium?

Answer 8

Rigid e.g. spirillum and flexible e.g. spirochaete.

Question 9

What is a spore?

Answer 9

A dormant form of the microogranism.

Question 10

How is a spore formed?

Answer 10

Binary fission and then sporulation creating a prespore. Through cell lysis a spore is made which is a small compact package and dehydrated to make it resistant.

Question 11

If it is a Gram +ve, what colour will it be?

Answer 11

Purple.

Question 12

If it is a Gram -ve what colour will it be?

Answer 12

Pink.

Question 13

What is the Gram stain?

Answer 13

Simple method that distinguishes classes of bacteria according to cell wall structure.

Question 14

What is a limitation of Gm Stain?

Answer 14

Not all organisms strain well with Gram stain e.g. TB

Question 15

What is an obligate aerobe?

Answer 15

They require oxygen.

Question 16

What is an obligate anaerobe?

Answer 16

Killed by oxygen.

Question 17

What is a facultative anaerobe?

Answer 17

They tolerate oxygen.

Question 18

Why is there selective media?

Answer 18

As the presence of specific substances permits the growth of one organism over another.

Question 19

What does CBA stand for?

Answer 19

Cooked blood agar.

Question 20

Why is there differential media?

Answer 20

It incorporates chemicals which produce visible change colonies that facilitate identification.

Question 21

What is heamolysis?

Answer 21

The destruction or rupture of RBC.

Question 22

In alpha heamolysis what happens?

Answer 22

Greening of the colonies.

Question 23

In beta heamolysis what happens?

Answer 23

Destruction of the RBC.

Question 24

In gamma heamolysis what happens?

Answer 24

No heamolysis

Question 25

What does biochemical characterisation allow?

Answer 25

Metabolic profiling of utilisation of C sources and amino acids.

Question 26

What does serological tests allow?

Answer 26

Confirm the presences of specific organisms by a specific molecule.

Question 27

What is agglutination?

Answer 27

the process that occurs if an antigen is mixed with its corresponding antibody.

Question 28

What does Real Time PCR allow?

Answer 28

May indicate the presence of an organism or even specific virulence factor.

Question 29

What does MLST stand for?

Answer 29

Multi Locus Sequence Typing.

Question 30

What does MLST enable?

Answer 30

More knowledge about the evolution of bacteria.

Question 31

What does MALDI-TOF stand for?

Answer 31

Matrix Assisted Laser Desorption Ionisation Time-Of-Flight.

Question 32

What does MALDI-TOF do?

Answer 32

Fragments from proteins to the charged screen with positive and negative ends.
Strength and number of times gives a reading of pattern of composition and quantity.

Question 33

How does MALDI-TOF work?

Answer 33

Generates a series of ions from a sample, separates the ions according to mass and charge, it then detects the spectrum of proteins released from the sample and results in a characteristic signature.