Water microbiology Part 4

Question 1

Uses hydrolysable substrates for the simultaneous detection of total coliform and E. coli enzymes

Both Total coliform count and Thermotolerant is being detected

Answer 1

Enzyme substrate test

Question 2

Enzyme Cleaves chromogenic substrate that is posses by coliforms bacteria

Answer 2

Beta-D- Galactosidase

Question 3

Enzyme that cleaves the fluorogenic substrate that is posses by E. coli?

Answer 3

B-glucoronidase

Question 4

NOTE: E.coli posses both B-D-galactosidase and B-glucoronidase

Question 5

Enzyme substrate test can be used in?

Answer 5

Multiple tube
Multiple well
Presence-absence format (100 mL)

Question 6

Example of chromogenic substrate (Reagent) that is used for Total coliform count

Answer 6

Ortho-nitrophenyl-B-D-galactopyranoside
Chlorophenol red-B-D-galactopyranoside

Question 7

What is the action happen in Total coliform count for Enzyme substrate test?

Answer 7

Hydrolysis

Question 8

Principle for Total coliform bacteria in Enzyme substrate test?

Answer 8

ONPG + Enzyme (B-D-galactosidase from bacteria)

=

B-D- galactose + O-Nitrophenol

Question 9

What is the result from Total coliform count reaction that colors the reaction?

Answer 9

O-Nitrophenol

Question 10

What is the Fluorogenic substrate for E. coli?

Answer 10

4-methylumbelliferyl-B-D-glucuronide

Question 11

What is the enzyme for E. coli?

Answer 11

B. glucuronidase

Question 12

What is the fluorescence long wavelength for E.coli?

Answer 12

366nm UV

Question 13

Fluorogenic substrate > Fluorogen

Question 14

What is the result from the reaction of MUG causes the fluorescens?

Answer 14

4-Methyl-umbelliferone

Question 15

What are the 2 kits that are FDA approve for enzyme substrate test in the Philippines?

Answer 15

Collilert-18 (Idex)
Redicol

Question 16

Incubation for Enzyme substrate?

Answer 16

35-37C 18 hrs

Question 17

Bacteria that grows but no color change in Enzyme substrate?

Answer 17

Not Coliforms

Question 18

Bacteria that grows and has color change in Enzyme substrate?

Answer 18

Coliform

Question 19

Organisms that fluores?

Answer 19

E. coli

Question 20

contains metallic sheen n endo-type medium containing lactose?

Answer 20

Coliform

Question 21

Lacks sheen?

Answer 21

Non-Coliforms

Question 22

Advantage of Membrane filter technique?

Answer 22

Highly reproducible
Large sample can test
more rapid

Question 23

Disadvantage of membrane filter technique?

Answer 23

High turbidity

Question 24

What is the standard volume for MFT?

Answer 24

100mL

Question 25

What is the Unit for MFT?

Answer 25

CFU/100mL

Question 26

Incubation for MFT?

Answer 26

44 C (24-48 hrs)

Question 27

What is the value for MFT that indicates absence

Answer 27

<1 (Units= CFU/100mL)