Water Bacteriology

Question 0

Which is false?
A. Coliforms include E.coli, Citrobacter, Enterobacter and Klebsiella
B. Presence of E.coli = definite fecal contamination
C. Coliforms can ferment lactose in culture at 35-37 deg C
D. Coliforms are secondary indicators of fecal pollution

Answer 0

D

Primary sila

Question 1

Which is false?
A. Fecal streptococci are slightly more resistang to disinfection than coliform organisms
B. Fecal streptococci grow in water with moderate salt concentration
C. Fecal streptococci always multiply in polluted water
D. Fecal streptococci are secondary indicators of fecal pollution

Answer 1

C

rarely dapat

Question 2

False about C.perfringens
A. Sulfite-oxidizing
B. Spore is resistant to disinfection
C. Presence of spores indicates contamination from a distant source

Answer 2

A

Oxidizing dapat

Question 3

Colony count is useful in detecting early signs of contamination. True or false?

Answer 3

True

Question 4

The presence of \_\_ indicates that water quality is not good.
A. B.pertussis
B. P.aeruginosa
C. G.vaginalis
D. C.trachomatis

Answer 4

B

Question 5

What method was used in the lab experiment for initial count of bacteria?

Answer 5

Heterotrophic Plate Count

Question 6

Fermentation tubes were used in the experiment. What specific substance was in each tube?

Answer 6

Lauryl tryptose broth

Question 7

Which Petri dish dilution was not part of the experiment?
A. Undiluted
B. 1:10
C. 1:100
D. 1:1000

Answer 7

D

Question 8

If plates you see fr all dilutions have no colonies, report the count as __

Answer 8

Less than the reciprocal of the lowest dilution used

Question 9

If the number of colonies per plate exceeds 300, what must one do?

Answer 9

Use a colony counter
Count colonies in 13 squares
Multiply sum by 5

Question 10

In the fermentation tubes, which does not count as a positive result?
A. Presence of gas
B. Heavy growth
C. Breaking of glass
D. None of the above

Answer 10

C

Question 11

For the confirmed phase, one loopful of culture has to be transferred to ___

Answer 11

BGLB (Brilliant Green Bile Lactose Broth)