Bacteriology

Question 1

The classification of bacteria according to shape include

Answer 1

Cocci- circular
Bacilli- rod
Spirochetes- spiral
Pleomorphic- variable shape

Question 2

Describe the cell wall of the bacteria

Answer 2

It is the outermost part of the bacteria
It consists of peptidoglycan
It gives the cell it’s shape.
Some cells have other things external to it like
Pili
Flagella
Capsule

Question 3

Classify bacteria named on flagella

Answer 3

Monotrygous
Lophotrigous multiple on a single pole
Amphitrigous 2 flagella on opposite
poles
Peritrigous multiple flagella all around

Question 4

Staining is carried out by ………… solvent

Answer 4

Crystal Violet or iodine solution

Question 5

Counter staining is carried out using

Answer 5

Neutral red
Safranin

Question 6

Staphlococci that are animal associated include

Answer 6

S. hyicus
S. intermediate
S. schleiferi
S. delphini

Question 7

Human related staphylococci include

Answer 7

S. aureus
saprophyticus
epidermidis
haemolyticus

Question 8

Human related staphylococci include

Answer 8

S. aureus
saprophyticus
epidermidis
haemolyticus

Question 9

All staphylococci that are human related are catalase positive T/F

Answer 9

True

Question 10

Catalase results in conversion of ………. to …………

Answer 10

H202 to H20

Question 11

Coagulation results in conversion of …………. to …………

Answer 11

Fibrinogen to fibrin

Question 12

The s.aureus virulence factors include:

Answer 12

1. Production of enzymes
2. Production of toxins
3. Structural elements

Question 13

What are the structural virulence elements of s.aureus and their roles

Answer 13

Bound coagulase/clumping factors
Extracellular polysaccharide
Protein A

Question 14

The virulence enzes produced by s.aureus and their roles include

Answer 14

●Coagulase - triggers clotting
●Staphylokinase - dissolves fibrin thread allowing bacteria to free itself from the clot
●Hyaluronidase - breaks down hyaluronidic acid allowing spread of bacteria
●lipases breaks down lipids allowing bacteria on skin and cutaneous oil glands
● Beta lactamase breaks down beta lactam antibiotics e.g penicillin allowing bacteria to survive in the presence of the antibodies

Question 15

The virulence enzes produced by s.aureus and their roles include

Answer 15

●Coagulase - triggers clotting
●Staphylokinase - dissolves fibrin thread allowing bacteria to free itself from the clot
●Hyaluronidase - breaks down hyaluronidic acid allowing spread of bacteria
●lipases breaks down lipids allowing bacteria on skin and cutaneous oil glands
● Beta lactamase breaks down beta lactam antibiotics e.g penicillin allowing bacteria to survive in the presence of the antibodies

Question 16

Classify staphylococcal diseases

Answer 16

Invasive vs non invasive
Deep vs system
Superficial vs deep

Question 17

The alternating polymeric chains in the bacteria cell wall consist of ………

Answer 17

Monosaccharide subunits
N actetylglucosamins NAG
N acteylm muraminic acid NAM

Question 18

What is the major antigen determinant of the gram positive bacteria ?

Answer 18

Teichnoic acid

Question 19

The bacteria pleomorphic and has no rigid cell wall is………

Answer 19

Hemophilus influenza

Question 20

A bacteria is …… to …….. in size

Answer 20

1-5 um

Question 21

A bacteria is …… to …….. in size

Answer 21

1-5 um

Question 22

The relationship in size between the bacteria virus and eukaryotic cell is

Answer 22

100× larger than a virus
10 × smaller than an eukaryotic cell

Question 23

The three morphological distinctions of bacteria is

Answer 23

Size
Shape
Staining properties

Question 24

The implication of gram staining is

Answer 24

Therapeutic uses
Gram -ve and Gram +ve susceptibility to antibiotics

Question 25

The bacteria envelope refers to.......

Answer 25

All the layers enclosing the bacteria

Question 26

The linear polymer of alternating monosaccharide in the peptidoglycan cell wall are linked by ............

Answer 26

Peptide at the NAM

Question 27

The presence of D amino acids render the bacteria cell wall resistance to .......

Answer 27

Host peptidase

Question 28

The presence of D amino acids render the bacteria cell wall resistance to .......

Answer 28

Host peptidase

Question 29

The primary role of bacteria cell wall is ......

Answer 29

To prevent the cell from exploding in hypertonic solutions due to its higher internal osmotic pressure

Question 30

Penicillin works by destroying bacteria cell wall and also activates ............ enzymes

Answer 30

Endogenous lyrics enzyme to contribute to the distruption

Question 31

Penicillin works by destroying bacteria cell wall and also activates ............ enzymes

Answer 31

Endogenous lyrics enzyme to contribute to the distruption

Question 32

Channels are........... Carriers are .............

Answer 32

Porins Permeases

Question 33

The teichoic acid is a polymer of substituted units linked by .........

Answer 33

Phosphodiester bond

Question 34

In a teichoic acid variant a ribitol Is substituted for

Answer 34

Glycerol

Question 35

All gram positive bacteria have teichoic acid ........... linked to glycolipid

Answer 35

Covalently

Question 36

What is the major cell surface antigen of gram positive bacteria

Answer 36

Teichoic acid

Question 37

The O polysaccharide The A lipid of a gram -ve are ........... and ........... respectively

Answer 37

Antigenic region Toxic region endotoxins

Question 38

The external capsule is usually a polysaccharide except in ......... which it is a polysaccharide-D-glutamic

Answer 38

Bacillus anthracis

Question 39

The capsule of the bacteria contributes to its virulence or pathogenicity

Answer 39

By allowing for adhesion Protection from antibodies and phagocytes

Question 40

A sticky capsule is ...........

Answer 40

A glycocalyx

Question 41

The flagella is composed of protein

Answer 41

Flagellin

Question 42

The flagella is attached to the cell wall or cell membrane by ..........

Answer 42

A basal body

Question 43

The flagella are highly antigenic

Answer 43

Thy do not form compact colonies on agar surface, instead swan over the surface of the agar

Question 44

What are enterobacteriacea

Answer 44

They are non spore forming, gram-ve facultative anaerobes rods or bacilli that are present in bowel or gut of vertebrates and man thus they are intestinal flora

Question 45

The enteriobacteriacea are divided into

Answer 45

Lactose fermenter Non lactose fermenters

Question 46

Examples of lactose fermenter are

Answer 46

Escherichia colli Klebsiella spp Enterobacter Citrobacter Serratia

Question 47

The non lactose fermenter are

Answer 47

Salmonella spp Shigella spp Yersinia spp

Question 48

List the properties of enterobacteriacea

Answer 48

Oxidase -ve Catalase +ve Non spore forming Gram -ve Facultative anarobes Part of the intestinal floral

Question 49

What is sterilisation?

Answer 49

This is a chemical or physical process that results to removal of all microbial life including spores

Question 50

What is sterilisation?

Answer 50

This is a chemical or physical process that results to removal of all microbial life including spores

Question 51

Differentiate between disinfectant and antiseptic

Answer 51

Inanimate vs non living

Question 52

What is pasteurisation

Answer 52

This is the process of reducing viable organisms to the point where they are unlikely to cause disease

Question 53

How is an autoclave monitored?

Answer 53

Physical : Thermocouple to measure accurately the temperature Chemical : A chemical that changes colour at the right temperature and at right exposure Autoclave tape Browne's tube Biological : A spore forming organism is added and then cultured later to see if it has been killed

Question 54

All streptococcus are capsulated except

Answer 54

Viridians streptococci groups

Question 55

All streptococcus are non spore forming except

Answer 55

Peptostreptococcus.