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Questions and Answers
Which type of microorganism is considered most resistant to microbial control?
Which type of microorganism is considered most resistant to microbial control?
What does the term 'aseptic technique' refer to in microbial control?
What does the term 'aseptic technique' refer to in microbial control?
Which of the following treatments is considered a physical method of microbial control?
Which of the following treatments is considered a physical method of microbial control?
What is the primary purpose of pasteurization?
What is the primary purpose of pasteurization?
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Which of the following methods uses direct flame for microbial control?
Which of the following methods uses direct flame for microbial control?
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What does the Decimal Reduction Time (D-value) measure?
What does the Decimal Reduction Time (D-value) measure?
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Which of the following environments would most likely support bacterial growth?
Which of the following environments would most likely support bacterial growth?
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What color change indicates the effectiveness of an autoclave during operation?
What color change indicates the effectiveness of an autoclave during operation?
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Which of the following organisms has moderate resistance to microbial control?
Which of the following organisms has moderate resistance to microbial control?
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Which method is used to preserve biological samples for long-term storage?
Which method is used to preserve biological samples for long-term storage?
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Which of the following chemicals is classified as a halogen and used for its oxidizing properties?
Which of the following chemicals is classified as a halogen and used for its oxidizing properties?
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What mechanism of action do detergent disinfectants utilize?
What mechanism of action do detergent disinfectants utilize?
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Which of the following best describes the chemotherapeutic index?
Which of the following best describes the chemotherapeutic index?
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In which situation would narrow spectrum antibiotics be preferred over broad spectrum antibiotics?
In which situation would narrow spectrum antibiotics be preferred over broad spectrum antibiotics?
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Which of the following methods is most effective in evaluating the potency of a disinfectant?
Which of the following methods is most effective in evaluating the potency of a disinfectant?
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What is the significance of the minimum inhibitory concentration (MIC) in antimicrobial therapy?
What is the significance of the minimum inhibitory concentration (MIC) in antimicrobial therapy?
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What is the primary role of the enzyme inactivating an antibiotic in the context of resistance?
What is the primary role of the enzyme inactivating an antibiotic in the context of resistance?
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Which of the following is NOT a method for evaluating the effectiveness of disinfectants or antiseptics?
Which of the following is NOT a method for evaluating the effectiveness of disinfectants or antiseptics?
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Which of the following statements regarding synthetic drugs and antibiotics is true?
Which of the following statements regarding synthetic drugs and antibiotics is true?
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Which antimicrobial agent can be derived from the fermentation process of Penicillium mold?
Which antimicrobial agent can be derived from the fermentation process of Penicillium mold?
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What is the primary role of the proglottids in Cestoda?
What is the primary role of the proglottids in Cestoda?
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Which organism is primarily responsible for causing Chagas disease?
Which organism is primarily responsible for causing Chagas disease?
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What symptom is commonly associated with African Sleeping Sickness?
What symptom is commonly associated with African Sleeping Sickness?
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Which method of transmission is associated with Necatoriasis?
Which method of transmission is associated with Necatoriasis?
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What is the mechanism of action of Nitroimidazoles used in anti-protozoal treatment?
What is the mechanism of action of Nitroimidazoles used in anti-protozoal treatment?
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Which of the following symptoms is associated with Toxoplasmosis, especially in immunocompromised individuals?
Which of the following symptoms is associated with Toxoplasmosis, especially in immunocompromised individuals?
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What is the primary vector for the transmission of African Sleeping Sickness?
What is the primary vector for the transmission of African Sleeping Sickness?
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Which medication is commonly used to treat filarial infections like elephantiasis?
Which medication is commonly used to treat filarial infections like elephantiasis?
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What life stage of the Trematode develops after hatch from eggs?
What life stage of the Trematode develops after hatch from eggs?
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Which antiprotozoal drug is recognized for its effectiveness against multidrug-resistant malaria?
Which antiprotozoal drug is recognized for its effectiveness against multidrug-resistant malaria?
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Which method of microbial control uses a temperature of 121°C for a specific duration to achieve sterilization?
Which method of microbial control uses a temperature of 121°C for a specific duration to achieve sterilization?
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What is the term that describes the permanent loss of reproductive capability in microorganisms?
What is the term that describes the permanent loss of reproductive capability in microorganisms?
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During which process are gamma rays primarily employed for sterilizing medical items?
During which process are gamma rays primarily employed for sterilizing medical items?
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Which of the following organisms is classified under 'moderate resistance' to microbial control?
Which of the following organisms is classified under 'moderate resistance' to microbial control?
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Which method of physical control utilizes a temperature of 170°C for two hours?
Which method of physical control utilizes a temperature of 170°C for two hours?
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What is the primary function of HEPA filters in microbial control?
What is the primary function of HEPA filters in microbial control?
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What does the term 'fomite' refer to in the context of microbial control?
What does the term 'fomite' refer to in the context of microbial control?
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What is the minimum time required to eliminate an entire microbial population in a specific environment called?
What is the minimum time required to eliminate an entire microbial population in a specific environment called?
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Which term describes the reduction of microbial populations to safe levels on surfaces?
Which term describes the reduction of microbial populations to safe levels on surfaces?
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Which of the following microbial control methods involves scrubbing with mild chemicals to reduce microbes on living tissue?
Which of the following microbial control methods involves scrubbing with mild chemicals to reduce microbes on living tissue?
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What is a primary characteristic that distinguishes narrow spectrum antibiotics from broad spectrum antibiotics?
What is a primary characteristic that distinguishes narrow spectrum antibiotics from broad spectrum antibiotics?
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Which of the following statements about HEPA filters is accurate?
Which of the following statements about HEPA filters is accurate?
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What does the phenol coefficient indicate?
What does the phenol coefficient indicate?
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What is the primary function of contractile vacuoles in protozoa?
What is the primary function of contractile vacuoles in protozoa?
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Which mechanism is commonly employed by antibiotics that target cell walls?
Which mechanism is commonly employed by antibiotics that target cell walls?
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In the context of antibiotic resistance, what is meant by 'target modification'?
In the context of antibiotic resistance, what is meant by 'target modification'?
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Which life cycle stage of protozoa is characterized as being the dormant phase?
Which life cycle stage of protozoa is characterized as being the dormant phase?
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Which of the following methods is used to determine the minimum inhibitory concentration (MIC) of an antibiotic?
Which of the following methods is used to determine the minimum inhibitory concentration (MIC) of an antibiotic?
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What describes the primary role of aldehydes as antimicrobial agents?
What describes the primary role of aldehydes as antimicrobial agents?
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What critical aspect should a good disinfectant possess?
What critical aspect should a good disinfectant possess?
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Study Notes
Unit 3: Control of Microorganisms - Study Notes
Section 1: Chapter 13 – Control of Microbial Growth
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Microbial Resistance to Control:
- Most resistant: Prions; Bacterial endospores
- Moderate resistance: Bacteria (e.g., Mycobacteria); Zygospores; Naked viruses
- Least resistant: Fungal spores; Hyphae (fungal filaments); Yeasts
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Key Terms:
- Fomite: An object that transmits disease.
- Sterilization: Complete removal of all living microbes.
- Sanitization: Reduction of microbes to safe levels.
- Disinfection: Killing pathogens on nonliving surfaces.
- Asepsis: Killing pathogens on living tissue.
- Aseptic technique: Preventing contamination of sterile surfaces.
- Degerming: Reducing microbes on living tissue using mild chemicals and scrubbing.
- -cide: Kills organisms.
- -static: Inhibits growth.
- Microbial death: Permanent loss of reproductive capability.
- Microbial death curve: Graph illustrating the progress of microbial control.
- Decimal Reduction Time (D-value): Time to kill 90% of a microbial population.
- Thermal death time: Minimum time to kill all microbes at a specific temperature.
- Incineration: Destruction by direct flame.
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Physical Methods of Microbial Control:
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Heat: Oxidizes cellular components.
- Boiling: 100°C for lab preparation and personal use.
- Dry heat oven: 170°C for 2 hours to sterilize equipment.
- Incineration: Burns microorganisms with direct flame.
- Autoclave: 121°C for 15 minutes, sterilizes media and equipment.
- Pasteurization: Prevents spoilage in food at various temperatures.
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Cold: Reduces microbial metabolic rate.
- Freezing: Long-term storage at -2°C.
- Refrigeration: Short-term storage at 0-7°C.
- Desiccation (Dehydration): Removes moisture, used in food preservation.
- Lyophilization: Rapid freezing under vacuum, used in preservation.
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Radiation:
- Ionizing: Gamma rays, sterilizes medical items, food, and spices.
- Non-ionizing: UV rays, used to sterilize lab materials and water.
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Filtration: Removes microorganisms from liquids or gases.
- HEPA filters: Trap particles, organisms, and spores from air.
- Membrane filters: Used in vaccine production.
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Heat: Oxidizes cellular components.
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Factors Affecting Microbial Growth: Temperature, pH, moisture, nutrient availability, oxygen, and other environmental factors.
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Monitoring Autoclave Effectiveness: Autoclave tape changes color during a successful cycle.
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Filter Types:
- Membrane filters remove microorganisms from solutions.
- HEPA filters trap airborne particles, organisms, and spores.
Section 2: Chapter 14 – Antimicrobial Drugs
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Key Scientists:
- Paul Ehrlich: Developed the first synthetic antimicrobial (arsphenamine).
- Gerhard Domagk: Discovered prontosil (synthetic antimicrobial dye).
- Alexander Fleming: Discovered penicillin from Penicillium mold.
- Florey and Chain: Demonstrated penicillin's effectiveness against diseases.
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Types of Antimicrobial Drugs:
- Synthetic drugs: Lab-made (e.g., prontosil).
- Antibiotics: Naturally occurring agents that kill/inhibit organisms (e.g., penicillin).
- Semi-synthetic: Chemically modified for enhanced activity.
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Broad/Narrow Spectrum Antibiotics:
- Narrow spectrum: Targets one microbial group (e.g., penicillin).
- Broad spectrum: Affects multiple groups (e.g., tetracycline). This can lead to superinfections and resistance.
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Drug Administration: Dosage and route (oral, topical, parenteral).
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Chemotherapeutic Index: Ratio of toxic dose to therapeutic dose.
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Antibiotic Targets and Classes:
- Cell wall: β-lactams (penicillin), Glycopeptides, Bacitracin.
- Protein synthesis: Polymyxins, Lipopeptides.
- Ribosomes: 30S and 50S subunits (aminoglycosides, tetracyclines).
- Metabolic pathways: Folate synthesis (sulfonamides, trimethoprim).
- DNA synthesis: Fluoroquinolones.
- RNA synthesis: Rifamycins.
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Antibiotic Resistance Mechanisms: Drug modification, uptake prevention, and target modification.
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Minimum Inhibitory Concentration (MIC): Lowest drug concentration inhibiting visible microbial growth.
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Susceptibility Assays:
- Disk diffusion
- Tube dilution
- Microdilution tray
- E-test
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Chemical Antimicrobial Agents:
- Phenolics: Denature proteins, disrupt membranes (e.g., Lysol).
- Metals: Bind to proteins, inhibit enzymes (e.g., mouthwash).
- Halogens: Oxidize macromolecules (e.g., bleach).
- Alcohols: Denature proteins, disrupt membranes (e.g., hand sanitizers).
- Peroxides: Oxidize cellular components (e.g., hydrogen peroxide, benzoyl peroxide).
- Aldehydes: Inactivate viruses, destroy bacterial cells (e.g., formaldehyde).
- Detergents: Surfactants that disrupt membranes.
- Gases: Sterilize materials (e.g., ethylene oxide).
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Effective Disinfectant/Antiseptic Characteristics: Kills/slows microbial growth, non-toxic to humans/animals, inexpensive, substantial shelf life.
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Evaluating Disinfectants/Antiseptics: Phenol coefficient, disk diffusion, use dilution test, in-use test
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Explore the essential concepts of microbial control as discussed in Chapter 13. This quiz covers key terms related to microbial resistance, sterilization, disinfection, and aseptic techniques. Test your knowledge on the methods used to manage microbial populations and their effectiveness.
