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Fecal coliform bacteria are characterized as facultatively anaerobic, rod-shaped, Gram-negative, and non-sporulating.
Answer: True
Explanation: These are indeed the defining microbiological characteristics of fecal coliform bacteria as described in the source material.
Fecal coliforms require oxygen to grow and are known to form spores.
Answer: False
Explanation: Fecal coliforms are facultatively anaerobic, meaning they can grow in the presence or absence of oxygen. Furthermore, they are non-sporulating, meaning they do not form spores.
A key characteristic of fecal coliforms is their ability to grow in the presence of bile salts and produce acid and gas from lactose at 44°C.
Answer: True
Explanation: The ability to grow in the presence of bile salts and to ferment lactose, producing acid and gas at 44°C, are indeed defining biochemical characteristics used for the identification of fecal coliforms.
Common genera included within fecal coliform bacteria are Escherichia, Enterobacter, Klebsiella, and Citrobacter.
Answer: True
Explanation: These genera are indeed recognized as being commonly included within the broader classification of fecal coliform bacteria.
Most bacteria, including fecal coliforms, prefer dark, warm, and moist environments with available nutrients for optimal growth.
Answer: True
Explanation: These conditions—darkness, warmth, moisture, and nutrient availability—are indeed conducive to the optimal growth and proliferation of most bacteria, including fecal coliforms.
A facultatively anaerobic bacterium can only grow in the presence of oxygen.
Answer: False
Explanation: Facultatively anaerobic bacteria possess the metabolic flexibility to grow in both the presence and absence of oxygen.
Being Gram-negative refers to a bacterium's inability to retain the crystal violet stain during Gram staining.
Answer: True
Explanation: This statement accurately describes the outcome of the Gram staining procedure for Gram-negative bacteria, which do not retain the primary stain.
Non-sporulating bacteria are generally more resilient to harsh environmental conditions than sporulating bacteria.
Answer: False
Explanation: Sporulating bacteria form endospores, which are highly resistant structures that allow them to survive extreme environmental conditions, making them generally more resilient than non-sporulating bacteria.
An oxidase-negative result indicates that the bacterium produces the enzyme cytochrome c oxidase.
Answer: False
Explanation: An oxidase-negative result signifies that the bacterium does *not* produce the enzyme cytochrome c oxidase.
The ability to ferment lactose and produce acid and gas is a key characteristic used in identifying fecal coliforms.
Answer: True
Explanation: Lactose fermentation, resulting in acid and gas production, is a critical biochemical test employed in the identification and differentiation of fecal coliform bacteria.
The ability of fecal coliforms to grow in the presence of bile salts is significant because bile salts are found in the animal intestines.
Answer: True
Explanation: This characteristic is significant as bile salts are naturally present in the digestive tracts of animals, making this growth capability a key indicator of fecal origin.
Coliform bacteria are commonly found in soil, vegetation, and the feces of warm-blooded animals.
Answer: True
Explanation: Coliform bacteria are ubiquitous in the environment, commonly inhabiting soil, plant matter, and the intestinal tracts of warm-blooded animals.
Which of the following is NOT a defining microbiological characteristic of a fecal coliform bacterium?
Answer: Oxidase positive
Explanation: Fecal coliforms are typically oxidase-negative. Oxidase positive results are characteristic of other bacterial groups.
According to the source, which of the following genera is typically included within the broader category of fecal coliform bacteria?
Answer: Klebsiella
Explanation: Klebsiella is one of the genera commonly identified within the fecal coliform group, alongside Escherichia, Enterobacter, and Citrobacter.
What environmental conditions do most bacteria, including fecal coliforms, prefer for optimal growth?
Answer: Warm, moist, and dark with nutrients
Explanation: Fecal coliforms, like many bacteria, thrive under conditions that are warm, moist, dark, and provide adequate nutrient availability.
What does it mean for a bacterium to be facultatively anaerobic?
Answer: It can grow in the presence or absence of oxygen.
Explanation: Facultatively anaerobic bacteria possess the metabolic capability to thrive under both aerobic (oxygen-present) and anaerobic (oxygen-absent) conditions.
The term 'fecal coliform' is considered the most scientifically accurate and preferred term by current standards.
Answer: False
Explanation: The term 'thermotolerant coliform' is increasingly preferred due to its more precise description of the bacteria's ability to tolerate elevated temperatures, a key identifying characteristic.
Thermotolerant coliform is preferred because it accurately describes the bacteria's ability to grow at high temperatures.
Answer: True
Explanation: The term 'thermotolerant coliform' is favored as it precisely denotes the bacteria's capacity to thrive at elevated temperatures, a key diagnostic criterion.
E. coli is considered a less precise indicator of fecal contamination than general fecal coliforms.
Answer: False
Explanation: Escherichia coli (E. coli) is generally considered a more specific and precise indicator of fecal contamination from warm-blooded animals compared to the broader category of fecal coliforms.
Which term is increasingly preferred over 'fecal coliform' due to its more precise description of the bacteria's temperature tolerance?
Answer: Thermotolerant coliform
Explanation: The term 'thermotolerant coliform' is favored because it accurately reflects the bacteria's ability to grow at elevated temperatures, a key diagnostic characteristic.
Why is the term thermotolerant coliform considered more accurate than fecal coliform?
Answer: Because it specifically describes the bacteria's ability to grow at elevated temperatures, a key identifier.
Explanation: The term 'thermotolerant coliform' is more precise as it highlights the bacteria's capacity to grow at high temperatures, a defining characteristic, whereas 'fecal coliform' is based on association with feces which may not always be exclusive.
Fecal coliform tests are advantageous due to their low cost, reliability, and rapid results.
Answer: True
Explanation: The source material confirms that fecal coliform tests offer practical advantages, including cost-effectiveness, reliability, and speed, making them suitable for routine monitoring.
The fecal coliform assay is recommended for assessing fecal matter presence even when non-fecal sources are common.
Answer: False
Explanation: The fecal coliform assay is most reliably used when non-fecal sources of coliforms are unlikely, as these alternative sources can lead to misleading results.
Membrane filtration is considered a secondary method for analyzing fecal coliforms.
Answer: False
Explanation: Membrane filtration is widely regarded as the preferred and primary method for analyzing fecal coliforms in water samples due to its efficiency and accuracy.
In membrane filtration, microorganisms are trapped on a filter and then placed on a growth medium.
Answer: True
Explanation: This accurately describes the fundamental process of membrane filtration, where microorganisms are captured by the filter and subsequently cultured on a suitable growth medium.
The M-FC agar and incubation at 44.5°C are used to suppress non-fecal bacteria and allow fecal coliforms to grow.
Answer: True
Explanation: This specific combination of M-FC agar and a high incubation temperature (44.5°C) is designed to selectively inhibit the growth of non-fecal bacteria while promoting that of fecal coliforms.
Fecal coliform colonies appear blue on M-FC agar due to a reaction between acid fermentation products and aniline dye.
Answer: True
Explanation: The characteristic blue coloration of fecal coliform colonies on M-FC agar is a result of the interaction between the acids produced from lactose fermentation and the aniline dye present in the medium.
Newer enzyme-based detection methods rely on the bacteria's ability to produce specific enzymes that change the color of a substrate.
Answer: True
Explanation: Modern enzyme-based assays indeed utilize the enzymatic activity of bacteria to produce a detectable color change when specific substrates are acted upon.
Selective media in fecal coliform analysis are used to encourage the growth of all bacteria present in the sample.
Answer: False
Explanation: Selective media are designed to promote the growth of target organisms (fecal coliforms) while inhibiting the growth of non-target organisms, thereby increasing specificity.
A target colony count of 20-60 colonies per filter ensures accurate quantification in membrane filtration testing.
Answer: True
Explanation: This colony density range is established to ensure statistically reliable and accurate quantification in membrane filtration analyses.
Enzyme substrate assays detect coliforms by identifying specific enzymes that cause a visible color change.
Answer: True
Explanation: Enzyme substrate assays leverage the enzymatic activity of bacteria to produce a colorimetric response, indicating the presence of specific target organisms.
Beta-galactosidase is an enzyme specifically produced by E. coli, while beta-glucuronidase is a general marker for coliforms.
Answer: False
Explanation: The enzymatic roles are reversed: beta-galactosidase is a general marker for coliforms, while beta-glucuronidase is specifically produced by E. coli.
The rapid results from fecal coliform tests allow for quicker identification and response to potential contamination.
Answer: True
Explanation: The expediency of fecal coliform testing enables prompt detection of contamination, facilitating timely interventions to protect public health.
What temperature is specified for the incubation period used to identify fecal coliforms based on their ability to ferment lactose?
Answer: 44 ± 0.5°C
Explanation: The standard incubation temperature for identifying fecal coliforms based on lactose fermentation is 44 ± 0.5°C.
What are the practical advantages of using fecal coliform tests for routine water quality monitoring?
Answer: Inexpensive, reliable, and rapid results
Explanation: Fecal coliform tests are valued for their cost-effectiveness, reliability, and the speed at which results can be obtained, facilitating efficient water quality management.
Under what condition is the fecal coliform assay most ideally used for assessing fecal matter presence?
Answer: When non-fecal sources are unlikely
Explanation: The fecal coliform assay provides the most reliable indication of fecal contamination when the likelihood of coliforms originating from non-fecal environmental sources is minimal.
What method is identified as the preferred choice for analyzing fecal coliforms in water samples?
Answer: Membrane filtration
Explanation: Membrane filtration is recognized as the primary and preferred technique for the analysis of fecal coliforms in water samples.
On M-FC agar, fecal coliform colonies typically appear blue due to the reaction between lactose fermentation products and:
Answer: Aniline dye
Explanation: The blue color observed in fecal coliform colonies on M-FC agar results from the interaction between acid products of lactose fermentation and the aniline dye incorporated into the medium.
Newer methods for detecting coliforms often utilize specific enzyme substrates that produce a visible change when acted upon by bacterial enzymes. What is this visible change typically?
Answer: A color change
Explanation: Enzyme substrate assays commonly rely on the production of a visible color change, mediated by specific bacterial enzymes acting on the substrate.
What is the role of the M-FC agar and the specific incubation temperature of 44.5°C in fecal coliform testing?
Answer: To suppress the growth of non-fecal bacteria while allowing fecal coliforms to grow
Explanation: The combination of M-FC agar and incubation at 44.5°C is specifically designed to inhibit non-fecal bacteria, thereby facilitating the selective growth and detection of fecal coliforms.
What recent advancement in detection technology allows for the electrochemical identification of fecal indicator bacteria?
Answer: Using redox-active enzymatic detection compounds
Explanation: The use of redox-active enzymatic detection compounds represents a recent advancement enabling the electrochemical identification of fecal indicator bacteria.
Fecal coliforms can only enter waterways through direct discharge of human or animal feces.
Answer: False
Explanation: Fecal coliforms can enter waterways through various pathways, including direct discharge, agricultural and urban runoff, and combined sewer overflows, not exclusively direct fecal discharge.
Plant material and pulp mill effluent are potential non-fecal sources of coliforms in water.
Answer: True
Explanation: The source material explicitly mentions plant material and pulp mill effluent as potential non-fecal sources contributing to coliform presence in water.
Malfunctioning septic systems cannot contribute to fecal coliform contamination of water sources.
Answer: False
Explanation: Malfunctioning septic systems are a significant pathway through which fecal coliforms can contaminate groundwater and surface water sources.
Combined sewer systems in older cities can lead to fecal coliform contamination during heavy rainfall due to overflows.
Answer: True
Explanation: During heavy rainfall, combined sewer systems can become overloaded and overflow, releasing untreated sewage containing fecal coliforms into waterways, thus causing contamination.
Allowing livestock to graze near water bodies is an agricultural practice that does not contribute to fecal coliform contamination.
Answer: False
Explanation: Agricultural practices such as livestock grazing near water bodies are recognized contributors to fecal coliform contamination.
Agricultural runoff is a minor pathway for fecal coliform contamination compared to direct discharge.
Answer: False
Explanation: Agricultural runoff is considered a significant pathway for fecal coliform contamination, alongside direct discharge and other sources like urban runoff and sewer overflows.
Coliforms can only be present in water if there is direct fecal contamination.
Answer: False
Explanation: Coliforms can be present in water from both direct fecal sources and non-fecal environmental sources, such as soil and vegetation.
Combined sewer overflows (CSOs) primarily release treated wastewater containing low levels of fecal coliforms.
Answer: False
Explanation: Combined sewer overflows typically release *untreated* sewage, which can contain high levels of fecal coliforms and other pathogens, directly into waterways.
Besides direct fecal discharge, which of the following is mentioned as a potential source of fecal coliforms in water?
Answer: Effluent from pulp or paper mills
Explanation: Effluent from pulp or paper mills is cited as a potential non-fecal source that can contribute to fecal coliform contamination in water bodies.
How can malfunctioning septic systems contribute to fecal coliform contamination in water sources?
Answer: By allowing coliforms in effluent to seep into groundwater and surface water
Explanation: When septic systems fail, fecal coliforms present in the effluent can leach into surrounding groundwater and surface water, leading to contamination.
What occurs during heavy rainfall in older cities with combined sewer systems that leads to water contamination?
Answer: Systems become overloaded and overflow, releasing untreated sewage
Explanation: Heavy rainfall can overwhelm combined sewer systems, causing them to overflow and discharge untreated sewage, including fecal coliforms, into receiving waters.
Which agricultural practice is identified as a contributor to fecal coliform contamination of water bodies?
Answer: Allowing livestock to graze near water bodies
Explanation: Allowing livestock to graze in proximity to water bodies is a recognized agricultural practice that can lead to fecal coliform contamination.
Which of the following is NOT listed as a potential source of fecal coliforms in water?
Answer: Naturally occurring deep-sea vents
Explanation: Naturally occurring deep-sea vents are not identified in the provided text as sources of fecal coliform contamination in water systems.
The primary purpose of a fecal coliform assay is to directly identify the presence of all known waterborne pathogens.
Answer: False
Explanation: The fecal coliform assay serves as an indicator of potential fecal contamination and the possible presence of pathogens, rather than directly identifying all known waterborne pathogens.
The presence of fecal coliforms in water guarantees that the water is unsafe for consumption.
Answer: False
Explanation: While the presence of fecal coliforms indicates a potential risk and suggests that harmful pathogens may also be present, it does not definitively guarantee that the water is unsafe for consumption without further assessment.
Increased fecal coliform levels in water can signal potential failures in water treatment or distribution systems.
Answer: True
Explanation: Elevated fecal coliform counts are indeed recognized as potential indicators of compromised water treatment processes or breaches in the distribution system's integrity.
High concentrations of fecal coliforms in water are associated with a reduced risk of waterborne gastroenteritis.
Answer: False
Explanation: Conversely, high concentrations of fecal coliforms are associated with an increased risk of waterborne gastroenteritis due to the potential presence of associated pathogens.
The presence of fecal coliforms indicates a low risk of harmful pathogens being present in the water.
Answer: False
Explanation: The presence of fecal coliforms signifies a higher risk that harmful pathogens may also be present in the water, necessitating caution and further investigation.
Water contaminated with fecal coliforms can potentially harbor pathogens causing diseases like typhoid fever and hepatitis A.
Answer: True
Explanation: Indeed, water contaminated with fecal coliforms may also contain pathogens responsible for serious waterborne diseases such as typhoid fever and hepatitis A.
The decomposition of organic matter containing fecal coliforms can increase dissolved oxygen levels in waterways.
Answer: False
Explanation: The aerobic decomposition of organic matter, particularly fecal matter, consumes dissolved oxygen in waterways, potentially leading to hypoxic conditions detrimental to aquatic life.
An indicator microorganism is used to directly measure the concentration of a specific virus in water.
Answer: False
Explanation: Indicator microorganisms, such as fecal coliforms, are used to infer the potential presence of pathogens (including viruses, bacteria, and protozoa), not to directly measure the concentration of a specific virus.
Waterborne gastroenteritis is characterized by symptoms like vomiting and diarrhea and is linked to high fecal coliform levels.
Answer: True
Explanation: Waterborne gastroenteritis, marked by symptoms such as vomiting and diarrhea, is indeed associated with elevated levels of fecal coliforms, indicating a potential risk from associated pathogens.
Fecal coliform testing helps identify potential contamination with harmful bacteria, viruses, or protozoa.
Answer: True
Explanation: The presence of fecal coliforms serves as an indicator, suggesting the potential contamination of water with a range of harmful microorganisms, including bacteria, viruses, and protozoa.
Reduced dissolved oxygen levels in waterways due to decomposition can harm aquatic ecosystems.
Answer: True
Explanation: The depletion of dissolved oxygen caused by the decomposition of organic matter can indeed lead to severe harm or mortality for aquatic life, disrupting the ecosystem.
Elevated fecal coliform levels indicate potential issues with water treatment or distribution systems.
Answer: True
Explanation: An increase in fecal coliform counts serves as a critical warning sign for potential deficiencies in water treatment efficacy or integrity of the distribution network.
What is the primary intended purpose of conducting a fecal coliform assay in water quality monitoring?
Answer: To serve as an indicator of potential fecal contamination
Explanation: The fecal coliform assay is primarily utilized as an indicator organism to signal the potential presence of fecal contamination and associated pathogens.
Which statement accurately reflects the significance of fecal coliform presence in water, according to the provided text?
Answer: It indicates a potential risk, but not necessarily direct harm.
Explanation: The presence of fecal coliforms suggests a potential risk of pathogen presence but does not definitively confirm direct harm or guarantee the water is unsafe without further context.
Increased levels of fecal coliforms in water quality monitoring serve as a warning for potential issues related to:
Answer: Breaches in the water distribution system
Explanation: Elevated fecal coliform counts can signal potential failures in water treatment or breaches in the distribution system, indicating compromised water safety.
What elevated health risk is specifically associated with high concentrations of fecal coliforms in water?
Answer: Elevated risk of waterborne gastroenteritis
Explanation: High concentrations of fecal coliforms are linked to an increased risk of waterborne gastroenteritis, an illness characterized by gastrointestinal distress.
While fecal coliforms may not always be directly harmful in large quantities, their presence signifies:
Answer: A higher risk that harmful pathogens may also be present
Explanation: The presence of fecal coliforms serves as an indicator of a heightened risk that pathogenic microorganisms may also be present in the water.
Which of the following waterborne diseases can potentially coincide with fecal coliform contamination?
Answer: Hepatitis A
Explanation: Hepatitis A is one of the waterborne diseases that can be associated with water contaminated by fecal matter, indicated by the presence of fecal coliforms.
What is the environmental consequence of the aerobic decomposition of organic matter containing fecal coliforms in waterways?
Answer: Consumption of dissolved oxygen, harming aquatic life
Explanation: Aerobic decomposition consumes dissolved oxygen, which can lead to hypoxic conditions detrimental to aquatic ecosystems.
What is the primary risk indicated by the presence of fecal coliforms in water?
Answer: The water may contain harmful pathogens.
Explanation: The presence of fecal coliforms serves as an indicator that harmful pathogens, which often coexist with fecal contamination, may be present in the water.
Municipalities are typically responsible for monitoring and treating fecal coliforms in public water supplies.
Answer: True
Explanation: Public water systems are generally managed and monitored by municipalities, which bear the responsibility for ensuring water quality standards, including fecal coliform levels, are met.
The 1989 Total Coliform Rule (TCR) by the U.S. EPA reduced the number of routine coliform tests required for public water systems.
Answer: False
Explanation: The 1989 Total Coliform Rule actually increased the number of routine tests required for many public water systems, particularly smaller ones, and mandated repeat testing.
The U.S. EPA last revised the Total Coliform Rule in 2013, with minor corrections in 2014.
Answer: True
Explanation: The Total Coliform Rule was indeed revised by the U.S. EPA in 2013, with subsequent minor corrections issued in 2014.
The primary goal of the 2013 EPA revisions to the Total Coliform Rule was to simplify testing procedures.
Answer: False
Explanation: The revisions in 2013 and 2014 aimed to update and enhance the regulations for monitoring coliform bacteria, typically focusing on improving public health protection rather than solely simplifying procedures.
Who is typically responsible for monitoring and treating fecal coliforms in public water supplies?
Answer: Municipalities managing the water supplies
Explanation: The responsibility for monitoring and treating fecal coliforms in public water systems typically falls under the purview of the municipalities that operate these systems.
The U.S. EPA's Total Coliform Rule (TCR), established in 1989, primarily aimed to:
Answer: Mandate automatic repeat testing after positive results
Explanation: A key component of the 1989 TCR was the requirement for automatic repeat testing following any positive total coliform detection, a measure designed to ensure thorough investigation of potential contamination.
Using chlorine to disinfect wastewater can kill beneficial bacteria essential for the aquatic environment.
Answer: True
Explanation: While chlorine is effective against pathogens, it can also eliminate beneficial bacteria crucial for the ecological balance of aquatic environments.
Boiling, chlorination, and UV treatment are common methods used to inhibit fecal coliform growth.
Answer: True
Explanation: These methods—boiling, chlorination, and UV treatment—are standard practices employed to inhibit or eliminate fecal coliforms in water.
Wearing gloves is not considered a critical safety precaution when handling samples for fecal coliform testing.
Answer: False
Explanation: Wearing gloves is a critical safety precaution to protect laboratory personnel from potential exposure to microorganisms in the samples.
What is a potential negative consequence of using chlorine to reduce fecal coliforms in wastewater?
Answer: It can kill beneficial bacteria essential for the aquatic environment.
Explanation: Chlorination, while effective for disinfection, can also harm beneficial microorganisms vital to the health of aquatic ecosystems.
Which of the following is a common method used to inhibit the growth of fecal coliforms in water?
Answer: Boiling the water
Explanation: Boiling water is a widely recognized and effective method for inhibiting the growth and survival of fecal coliforms.
What essential safety precaution must be taken when handling samples for fecal coliform testing?
Answer: Always wear gloves
Explanation: Wearing gloves is a fundamental safety measure to prevent direct contact with potentially hazardous microorganisms present in samples during fecal coliform testing.