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Bacteriology Lecture (Midterm- Finals) > FINALS: Microbiology of Water (Lab) > Flashcards

FINALS: Microbiology of Water (Lab) Flashcards

1
Q

This serves as excellent nutritional sources for the growth and multiplication of microorganisms

A

Vast amounts of organic matter in polluted waters

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2
Q

These diseases or intestinal infections are acquired from (polluted) water

A
  1. bacillary dysentery
  2. typhoid fever
  3. cholera
  4. paratyphoid fever.
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3
Q

About 3.4 million deaths annually are caused by dangerous waterborne enteric bacterial pathogens such as

A
  • Shigella dysenteriae
  • Campylobacter jejuni
  • Salmonella typhi
  • Vibrio cholerae

SSCV

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4
Q

In addition to bacterial infections, unsafe water supplies are responsible for numerous parasitological infections, including helminth diseases such as

A

schistosomiasis and especially guinea worm (Dracunculus medinensis)

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5
Q

(Few) Parasitic protozoa responsible for major diarrheal disease in humans

A
  • Balantidium coli
  • Entamoeba histolytica
  • Giardia intestinalis
    (formerly called G. lamblia)

BEG

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5
Q

In addition to bacterial infections, unsafe water supplies also causes intestinal, hepatic, and pulmonary flukes, including:

A
  • Fasciolopsis buski
  • Clonorchis sinensis
  • Paragonimus westermani
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6
Q

The bacterium that indicates fecal pollution

A

Escherichia coli

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7
Q

This bacterium is always present in the human intestine, its presence in water alerts public health officials to the possible presence of other human or animal intestinal pathogens

A

E. coli

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8
Q

TRUE OR FALSE: In the tropics and subtropics E. coli is not considered a reliable indicator of fecal pollution because the soil in these regions naturally contains high levels of E. coli

A

TRUE.

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9
Q

E. coli is present
in the water anytime there is ________?

A

surface runoff

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10
Q

Both ________ and ________ methods are used to determine the sanitary condition of water

A

qualitative; quantitative

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11
Q

The three basic (Qualitative) tests to detect coliform bacteria in water are:

A
  1. Presumptive test
  2. Confirmed test
  3. Completed test
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12
Q

TRUE OR FALSE: Presumptive, confirmed, and completed tests are not performed sequentially on each sample under analysis

A

FALSE. They are performed sequentially
on each sample under analysis

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13
Q

IDENTIFY: These are indicators of fecal contamination, are gram-negative, non– spore-forming bacilli that ferment lactose with the production of acid and gas

A

Coliform bacteria

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14
Q

Coliform bacteria is detectable following a __________ incubation period at _____.

A

24-hour; 37°C

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15
Q

This is only for detection of coliform bacteria. Measure aliquots of the water to be tested are added to a lactose fermentation broth containing an inverted gas vial.

A

presumptive test

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16
Q

Why is lactose fermentation broth used for detecting coliform bacteria?

A

Because COLIFORM bacteria are capable of using lactose as a carbon source (the other enteric organisms are not)

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17
Q

In this experiment, you will use lactose fermentation broth containing an inverted Durham tube for gas collection.

A

Presumptive test

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18
Q

Tubes of the lactose medium are inoculated with?

A

10-ml, 1-ml, and 0.1-ml aliquots of the water sample

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19
Q

In the presumptive test, aliquots of water are tested in a lactose fermentation broth, it is composed of ________, and each of this contains at least _______.

A

3 groups; 5 tubes

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20
Q

What do we observe in the presumptive test?

A

Gas formation

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21
Q

What are the positive and negative results in the presumptive test?

A

Positive: Gas in fermentation tube
Negative: No gas in fermentation tube

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22
Q

This/These are singe-strength lactose broth

A

Groups with 1.0 mL and 0.1 mL aliquots of water sample

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23
Q

This/These are double-strength lactose broth

A

Group with 10 mL aliquot of water sample

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24
Q

Incubation time for the Lactose fermentation broth with aliquots of water

A

48 hours at 37°C

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25
Q

This test confirm the presence of enteric microorganisms

A

Confirmed test

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26
Q

TRUE OR FALSE: In the presumptive test, the greater the number of tubes per group, the greater the sensitivity of the test.

A

TRUE

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27
Q

This is presumptive evidence of the presence of coliform bacteria in the sample

A

Development of
gas in any of the tubes

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28
Q

This is estimated by determining the number of tubes in each group that show gas following the incubation period

A

most probable number (MPN)

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29
Q

This test requires that selective and differential media (e.g., eosin methylene blue (EMB) or Endo agar) be streaked from a positive lactose broth tube obtained from the presumptive test

A

Confirmed test

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30
Q

This medium contains the dye methylene blue, which inhibits the growth of gram-positive organisms. In the presence of an acid environment, it forms a complex that precipitates out onto the coliform colonies, producing dark centers and a green metallic sheen

A

Eosin–methylene blue

31
Q

This reaction on EMB is characteristic for
Escherichia coli, the major indicator of fecal pollution

A

dark centers and a green metallic sheen

32
Q

A nutrient medium containing the dye fuchsin, which is present in the decolorized state

A

Endo agar

33
Q

In Endo agar, the presence of _____ is produced by
the coliform bacteria, ____ forms a dark pink complex that turns the E. coli colonies and the surrounding medium pink

A

acid; fuchsin

34
Q

TRUE OR FALSE: Positive presumptive test may be due to noncoliform origin

A

TRUE

35
Q

Incubation time in Confirmed test:

A

24 hr at 37°C

35
Q

Positive confirmed test:

A

Typical coliform
colonies, water
nonpotable

36
Q

Negative confirmed test:

A

No coliform colonies, water potable

37
Q

The final analysis of the water sample. It is used to examine the coliform colonies that appeared on the EMB or Endo agar plates used in the confirmed test.

A

Completed test

38
Q

In the completed test, colony from the confirmatory test plate is inoculated into a tube of __________ and streaked on a _____________ to perform a Gram stain

A

lactose broth; nutrient agar slant

39
Q

Several testing methods are available for testing for safe water including:

A
  • Most probable numbers (MPN)
  • ATP testing
  • Membrane filtration
  • Use of pour plates

NagkaMAMU

40
Q

In the complete test, if gas is produced, the next step is?

A

Prepare gram stain from the slant

41
Q

It is a quantitative analysis and is used for counts of total coliforms, fecal coliforms, and E. coli

A

Most probable number (MPN)

42
Q

This has the ability to inoculate greater amounts of sample, has higher sensitivity than plate count method, and is versatile

A

Most probable number (MPN)

43
Q

Incubated at 35°C for 24 hours and is checked for growth/ gas production

A

Lauryl Sulphate Tryptose (LST)

44
Q

Selective medium for total coliforms and is checked for growth/ gas production

A

Brilliant Green Broth (BGB)

45
Q

This broth inhibits noncoliforms and contains lactose and 2% bile

A

Brilliant Green Broth (BGB)

46
Q

Presumptive evidence of coliform contamination in LST:

A

Bubble in the Durham tube

47
Q

Bubbles in Durham tube indicates?

A

Gas production

48
Q

This is verified by turbidity or cloudiness

A

Growth

49
Q

Confirmation of coliform contamination in BGB:

A

bubble in the Durham tube

50
Q

In the quantitative analysis of water, bacteria-tight membrane filters is capable of retaining microorganisms larger than _______ are frequently used for analysis of water.

A

0.45 micrometer (µm)

51
Q

Advantages of bacteria-tight membrane filters

A

(1) results are available in a shorter period of time
(2) larger volumes of sample can be processed, and
(3) because of the high accuracy of this method, the results are readily reproducible.

52
Q

In the membrane filter method, trapped microorganisms are transferred in _______ containing ________

A

Petri dish; absorbent pad

53
Q

In the membrane filter method, this determines the potability of water

A

Total count of coliform bacteria

54
Q

In membrane filter method, you aseptically place an absorbent pad in a ______ petri dish.

A

50-mm

55
Q

It is customary to ____ heavily polluted samples, thereby reducing the number of cells collecting on the membrane

A

dilute

56
Q

What agar is used in the membrane-filter method?

A

Endo agar

56
Q

Formula for total colony count:

A

colony count x dilution factor /ml of sample used x 100

56
Q

Steps or procedure in the quantitative analysis of water

A

Special porous membrane ->
Trap microorganisms -> Endo agar ->
Coliform growth (red or metalic colonies)

57
Q

Presumptively identifies Enterobacteriaceae and verotoxin producing E. coli

A

4- Methylumbelliferyl- B-d- Glucuronide (MUG) Test

58
Q

Reagent used for MUG test

A

4- Methylumbelliferyl-B-d-glucuronide

59
Q

Substrate in the MUG test

A

B-d-glucopyranosid-uronic

60
Q

Enzyme in the MUG test

A

B-d-glucuronidase

61
Q

B-d-glucopyranosid-uronic is split/derivatives to:

A

Aglycons & D-glucuronic acid

62
Q

End product in the MUG test

A

4-methylumbelliferyl moiety

63
Q

MUG test positive result

A

Electric Blue fluorescence observed in 366-nm UV

64
Q

Differentiates microorganisms based on metabolic reaction in litmus milk

A

Litmus Milk Medium

65
Q

Litmus Milk indicator

A

Litmus dye

66
Q

Appearance of Indicator (Litmus Dye): Pink, mauve

A

pH Change to- Acid
Record- Acid (A)

67
Q

Appearance of Indicator (Litmus Dye): Purple

A

pH Change to- No change
Record- No change

68
Q

Appearance of Indicator (Litmus Dye): White

A

pH Change to- Independent of pH change; result of reduction of indicator
Record- Decolorized

69
Q

Appearance of Indicator (Litmus Dye): Blue

A

pH Change to- Alkaline
Record- Alkaline (K)

70
Q

In Litmus milk, Coagulation or clot occurs when pH is:

Indicate record as well

A

Acid or alkaline
Record: clot

71
Q

In Litmus milk, dissolution of clot with grayish, watery fluid and a clear, shrunken, insoluble blue clot occurs when pH is:

Indicate record as well

A

Alkaline
Record: Peptonization

72
Q

In Litmus milk, dissolution of clot with grayish, watery fluid and a shrunken, insoluble pink clot occurs when pH is:

Indicate record as well

A

Acid
Record: Digestion

Bacteriology Lecture (Midterm- Finals) (9 decks)

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