Bacteria classification

Question 1

What are the general characteristics used to classify bacteria

Answer 1

• traditional: size, shape, arrangement, gram reaction, need for O2
• ability to metabolize sugar
• metabolic end products

Question 2

What are bacteria supplemented by

Answer 2

Comparison of 100 to 300 characteristics
Nucleic acid sequence of ribosomal RNA
Antigenic composition
Based on O2 requirement

Question 3

What are aerobes

Answer 3

grow in ambient air and small amounts of CO2

Question 4

What obligate aerobes

Answer 4

have absolute requirement for O2, cannot ferment

Question 5

What are anaerobes

Answer 5

usually can not grow in the presence of oxygen. the methods that exclude: closed vessels, reducing agents, anaerobic jar and glove box

Question 6

What are obligate anaerobe

Answer 6

are killed by normal atmospheric concentration of oxygen

Question 7

What are facilitative anaerobe

Answer 7

oxygen is present, respire aerobically otherwise capable of shifting to fermentation or anaerobic respiration

Question 8

What are microaerophilic

Answer 8

need oxygen but not high concentration

Question 9

What are aerotolerant

Answer 9

does not require oxygen and are not poisoned by it

Question 10

What types of test administered for bacteria

Answer 10

sugar and catalase

Question 11

What sugars are used for identifying bacteria

Answer 11

sucrose, glucose, mannitol and lactose

Question 12

what bacteria uses the sugar test

Answer 12

E.coli and Staphloccocus

Question 13

What is catalase test

Answer 13

a test where enzymes of a bacteria decompose H2O2

Question 14

What is citrate utilization test

Answer 14

some bacteria utilize citrate as the sole source of carbon and alkalinize the medium.

Question 15

What is the medium of the citrate test

Answer 15

Simmon’s citrate medium that has bromothymol blue

Question 16

What is H2S production test

Answer 16

is produced by the breakdown of sulphur containing amino acids and thisulphate

Question 17

What happens to the medium of the H2S production

Answer 17

Medium rich in iron show a black color due to the formation of ferrous sulphide

Question 18

What bacterias are tested with H2S

Answer 18

ex. salmonella and proteus

Question 19

What bacteria are tested with citrate

Answer 19

Klebsiella and E.coli

Question 20

What is the Indole test

Answer 20

some organisms convert tryptophan to free indole

Question 21

What is the reaction that happens in indole test

Answer 21

tryptophan is hydrolysed by tryptophanase

Question 22

What bacteria is tested in the indole test

Answer 22

E. coli

Question 23

What is the urease test

Answer 23

Urea by the enzyme urease. it uses the christensen urease medium that is made of 2% urea and phenol

Question 24

What is the indicator of the urease test

Answer 24

red indicator. ammonia release raises pH intense pink-red color

Question 25

What bacteria are tested in the urease test

Answer 25

ex. Klebsiella and E.coli

Question 26

What is the deaminase test

Answer 26

deamination produces phenylpyruvic acid which is defected in a colormetric test. after growth add ferric cholride reagent like for green color. 


Question 27

What is the Voges Prskauer test

Answer 27

chemical test for acetone

Question 28

What bacteria are tested with the Voges Proskauer

Answer 28

it separate Klebsiella and enterobacter from Escherichia

Question 29

What is nitrate reduction test

Answer 29

nitrate as alternate electron acceptor reduced to NO2. broth with nitrate and agter incubation detects nitrate with anpthylamine, sulfanilic acid

Question 30

What is the gelatin liquefaction test

Answer 30

many protease hydrolyze gelatin and destroy the gel

Question 31

What is coagulase test

Answer 31

enzyme cause clotting of blood plasma. mix dense liquid suspension of bacteria with plasma, incubate and look for sign of lot in few minutes

Question 32

What bacteria are tested in coagulase test

Answer 32

ex. S. aureus and S. epidermidis