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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
**Incubation time** for the **Lactose fermentation broth** with aliquots of water
***48 hours at 37°C***
25
This test **confirm** the presence of **enteric microorganisms**
Confirmed test
26
TRUE OR FALSE: In the presumptive test, the **greater the number of tubes** per group, the **greater the sensitivity of the test**.
TRUE
27
This is **presumptive evidence** of the presence of coliform bacteria in the sample
**Development of gas** in any of the tubes
28
This is **estimated** **by determining the number** of tubes in each group that show gas following the incubation period
**most probable number (MPN)**
29
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
Confirmed test
30
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**
Eosin–methylene blue
31
This **reaction** on EMB is characteristic for **Escherichia coli**, the major indicator of fecal pollution
**dark centers and a green metallic sheen**
32
A **nutrient medium** containing the **dye fuchsin**, which is present in the decolorized state
Endo agar
33
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
acid; fuchsin
34
TRUE OR FALSE: Positive presumptive test **may be due to noncoliform origin**
TRUE
35
**Incubation time** in Confirmed test:
24 hr at 37°C
35
**Positive confirmed test:**
**Typical coliform colonies, *water nonpotable***
36
**Negative confirmed test:**
**No coliform colonies, water potable**
37
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.
**Completed test**
38
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
**lactose broth; nutrient agar slant**
39
**Several testing methods** are available for testing for safe water including:
- Most probable numbers (MPN) - ATP testing - Membrane filtration - Use of pour plates **NagkaMAMU**
40
In the complete test, **if gas is produced**, the next step is?
**Prepare gram stain** from the slant
41
It is a **quantitative analysis** and is used for counts of **total coliforms, fecal coliforms, and E. coli**
Most probable number (MPN)
42
This **has the ability** to inoculate greater amounts of sample, **has higher sensitivity** than plate count method, and is **versatile**
**Most probable number (MPN)**
43
Incubated at 35°C for 24 hours and is **checked for growth/ gas production**
**Lauryl Sulphate Tryptose (LST)**
44
**Selective** **medium** for total coliforms and is checked for growth/ gas production
**Brilliant Green Broth (BGB)**
45
This broth **inhibits noncoliforms** and contains **lactose** and **2% bile**
**Brilliant Green Broth (BGB)**
46
**Presumptive evidence** of coliform contamination in **LST**:
**Bubble** in the Durham tube
47
**Bubbles** in Durham tube **indicates**?
Gas production
48
This is verified by **turbidity or cloudiness**
**Growth**
49
**Confirmation** of coliform contamination in BGB:
**bubble** in the Durham tube
50
In the quantitative analysis of water, bacteria-tight membrane filters is capable of **retaining** microorganisms **larger than** _______ are frequently used for analysis of water.
**0.45 micrometer (µm)**
51
**Advantages** of bacteria-tight membrane filters
(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
In the membrane filter method, trapped microorganisms are **transferred** in _______ containing ________
***Petri dish; absorbent pad***
53
In the membrane filter method, this **determines the potability of water**
Total count of coliform bacteria
54
In membrane filter method, you aseptically place an absorbent pad in a ______ petri dish.
**50-mm**
55
It is customary to ____ **heavily polluted samples**, thereby reducing the number of cells collecting on the membrane
dilute
56
What **agar** is used in the **membrane-filter method**?
Endo agar
56
Formula for **total colony count:**
colony count x dilution factor /ml of sample used x 100
56
**Steps** or **procedure** in the quantitative analysis of water
Special porous membrane -> Trap microorganisms -> Endo agar -> Coliform growth (red or metalic colonies)
57
*Presumptively identifies* **Enterobacteriaceae** and **verotoxin** producing E. coli
**4- Methylumbelliferyl- B-d- Glucuronide (MUG) Test**
58
**Reagent** used for MUG test
***4- Methylumbelliferyl-B-d-glucuronide***
59
**Substrate** in the MUG test
***B-d-glucopyranosid-uronic***
60
**Enzyme** in the MUG test
***B-d-glucuronidase***
61
B-d-glucopyranosid-uronic is **split/derivatives to:**
**Aglycons** & **D-glucuronic acid**
62
**End product** in the MUG test
**4-methylumbelliferyl moiety**
63
MUG test **positive result**
**Electric Blue fluorescence** observed in **366-nm UV**
64
**Differentiates** microorganisms based on ***metabolic reaction in litmus milk***
Litmus Milk Medium
65
Litmus Milk **indicator**
Litmus dye
66
Appearance of Indicator (Litmus Dye): **Pink, mauve**
pH Change to- Acid Record- Acid (A)
67
Appearance of Indicator (Litmus Dye): **Purple**
pH Change to- No change Record- No change
68
Appearance of Indicator (Litmus Dye): **White**
pH Change to- Independent of pH change; result of reduction of indicator Record- Decolorized
69
Appearance of Indicator (Litmus Dye): **Blue**
pH Change to- Alkaline Record- Alkaline (K)
70
In Litmus milk, **Coagulation or clot** occurs when pH is: Indicate record as well
Acid or alkaline Record: clot
71
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
Alkaline Record: Peptonization
72
In Litmus milk, dissolution of clot with grayish, watery fluid and a shrunken, ***insoluble pink clot*** occurs when pH is: Indicate record as well
Acid Record: Digestion

Bacteriology Lecture (Midterm- Finals) (9 decks)

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