Water Bacteriology Flashcards
Vehicle for many diseases that are caused by different microorganisms.
Water
Done to address problems of water potability.
Bacteriologic Examination of Water
Two Causes of Unsafe Drinking Water
- Direct contamination
2. Indirect Contamination
Human or animal feces.
Direct contamination
Improperly functioning sewage treatment systems
Indirect contamination
Top 10 Causes – Outbreaks in Public Water Systems (CDC)
- Giardia
- Legionella
- Norovirus
- Shigella
- Campylobacter
- Copper
- Salmonella
- Hepatitis A
- Cryptosporidium
- E.coli, excess fluoride (tie)
Contaminated water can transmit diseases
True
Diseases caused by contaminated water
- Diarrhea
- Cholera
- Dysentery
- Typhoid
- Polio
Total diarrheal deaths recorded each year according to WHO 2021
485, 000 diarrheal deaths
It is possible to test each water sample for each pathogen.
False. It is impossible to test each water sample for each pathogen
It is not easier to test for the presence of coliforms as indicator organisms.
False. It is much easier to test for the presence of coliforms as indicator organisms.
Which among the choices are true about Coliforms?
a. non-aerobic, non-facultatively, aerobic, gram-positive, endosporic, rod shaped bacteria
b. aerobic, non-facultative, gram-negative, endosporic, rod shaped bacteria
c. aerobic, facultatively aerobic, gram-negative, non-endospore forming, rod shaped bacteria
d. non-aerobic, facultatively aerobic, gram-positive, non-endospore forming, rod shaped bacteria
e. aerobic, facultatively aerobic, gram-positive, non-endospore forming, rod shaped bacteria
Letter C. Coliforms are aerobic or facultatively aerobic, gram-negative, non-endospore forming, rod shaped
Does coliforms ferment lactose?
Yes. Coliforms ferment lactose to form gas.
How many hours do coliforms incubate prior to forming gas?
a. 72 hours of incubation at 27 degree Celsius.
b. 48 hours of incubation at 31 degree Celsius.
c. 48 hours of incubation at 35 degree Celsius.
d. 40 hours of incubation at 35 degree Celsius.
e. 24 hours of incubation at 27 degree Celsius.
Letter C. Coliforms ferment lactose to form gas within 48 hours of incubation at 35 degree Celsius.
Which among the bacteria is the most predominant coliforms to cause disease in human?
a. Escherichia coli
b. Enterobacter
c. Klebsiella
d. Salmonella
Letter A. The most pre-dominant coliforms ever to cause disease in humans is Escherichia coli or E.coli.
When E.coli is present in water, what does it indicate?
a. It is contaminated with dirt.
b. It is contaminated with urine from animals.
c. It is contaminated with fecal matter.
d. It is contaminated with urine from humans.
e. It is contaminated from improper sewage systems.
Letter C. The presence of E.coli in water indicates that it is contaminated with fecal matter.
Aside from E. coli, there are other fecal coliforms that could contaminate drinking water:
a. Klebsiella and Enterobacter species.
b. Klebsiella and Campylobacter species
c. Enterobacter and Campylobacter species
d. Enterobacter and Shigella species
e. Legionella and Gardia species
Letter A. Klebsiella and Enterobacter species
Other forms of coliforms in drinking water are saprophytic. What does saprophytic mean?
a. intestinal in origin.
b. non-intestinal origin.
Letter B. Other forms of coliforms in drinking water are saprophytic, thus, non-intestinal in origin.
A dilution test which estimates the concentration of a target microbe in a water sample.
a. Bacteriologic Examination of Water (BEW)
b. Most Probable Number Test (MPN)
c. Multiple Tube Fermentation Technique (MTFT)
Letter B. Most Probable Number Test is a dilution test which estimates the concentration of a target microbe in a water sample.
TRUE or FALSE
MPN is not based on the application of probability to the number of observed negative growth responses to a single standard dilution.
False. MPN is based on the application of probability to the number of observed positive growth responses to a series of standard dilution.
Which among the choices is true ?
- Most Probable Number Test uses a single tube with selective broth.
- Multiple Tube Fermentation Technique uses a single tube with a non-selective broth.
- Most Probable Number Test uses a series of single tube with a non-selective broth.
- Most Probable Number Test uses a single tube with non-selective broth.
- Multiple Tube Fermentation Technique uses a series of tubes with selective broth.
- Multiple Tube Fermentation Technique uses a single tube with non-selective broth.
a. 2 of the choices.
b. only one of the choices.
c. 3 of the choices.
d. NOTA
d. AOTA
Letter B. Multiple Tube Fermentation Technique uses a series of tubes with selective broth.
The most probable number (MPN) of bacteria is obtained from the:
a. Number of tubes which show positive result.
b. A single tube which show positive result.
c. Number of tubes which show negative result.
d. A single tube which show negative result.
Letter A. Number of tubes which show positive result.
A statistical test that provides an estimate of the coliform contamination in the water sample or an estimate of the mean density of coliform in the sample.
Multiple Tube Fermentation Technique
State whether the assumption (MPN Test) is true or not:
Bacteria are not distributed randomly within a sample.
False. Bacteria are distributed randomly within the sample.
State whether the assumption (MPN Test) is true or not:
Bacteria are separated and are clustered together.
False. Bacteria are separated and not clustered together.
State whether the assumption (MPN Test) is true or not:
Every tube (or plate, wells) whose inoculum contains even one.
True.
State whether the assumption (MPN Test) is true or not:
Every tube (or plate, wells) whose inoculum contains one or more.
False. Every tube (or plate, wells) whose inoculum contains even one.