Podcast
Questions and Answers
Which organism listed has the highest resistance to microbial control?
Which organism listed has the highest resistance to microbial control?
What is the abbreviation for the time required to kill 90% of a microorganism population?
What is the abbreviation for the time required to kill 90% of a microorganism population?
What process is used primarily for sterilizing medical instruments?
What process is used primarily for sterilizing medical instruments?
Which method involves removing moisture to prevent microbial growth?
Which method involves removing moisture to prevent microbial growth?
Signup and view all the answers
Which of the following is the correct temperature condition for effective pasteurization?
Which of the following is the correct temperature condition for effective pasteurization?
Signup and view all the answers
What is the purpose of using HEPA filters in microbial control?
What is the purpose of using HEPA filters in microbial control?
Signup and view all the answers
Which term describes the complete removal of all living microbes?
Which term describes the complete removal of all living microbes?
Signup and view all the answers
Which of the following accurately describes microbial death?
Which of the following accurately describes microbial death?
Signup and view all the answers
What is the purpose of autoclave tape in sterilization processes?
What is the purpose of autoclave tape in sterilization processes?
Signup and view all the answers
What factor does NOT affect bacterial growth?
What factor does NOT affect bacterial growth?
Signup and view all the answers
What is the main method by which Trypanosoma brucei is transmitted to humans?
What is the main method by which Trypanosoma brucei is transmitted to humans?
Signup and view all the answers
Which stage of the trematode life cycle first infects the secondary host after the miracidium stage?
Which stage of the trematode life cycle first infects the secondary host after the miracidium stage?
Signup and view all the answers
What class of flatworms is characterized by having a mouth and suckers for attachment?
What class of flatworms is characterized by having a mouth and suckers for attachment?
Signup and view all the answers
Which of the following symptoms is associated with Chagas disease caused by Trypanosoma cruzi?
Which of the following symptoms is associated with Chagas disease caused by Trypanosoma cruzi?
Signup and view all the answers
Which antihelminth agent is specifically used for treating infections caused by flukes?
Which antihelminth agent is specifically used for treating infections caused by flukes?
Signup and view all the answers
What is the primary transmission method for Necator americanus, the hookworm?
What is the primary transmission method for Necator americanus, the hookworm?
Signup and view all the answers
Which organism is responsible for causing pinworm disease?
Which organism is responsible for causing pinworm disease?
Signup and view all the answers
Which protozoal drug is known to disrupt protozoal metabolism?
Which protozoal drug is known to disrupt protozoal metabolism?
Signup and view all the answers
Which symptom is specifically associated with schistosomiasis?
Which symptom is specifically associated with schistosomiasis?
Signup and view all the answers
Which larval stage is infectious for the host in the life cycle of nematodes?
Which larval stage is infectious for the host in the life cycle of nematodes?
Signup and view all the answers
What is the primary mechanism of action for halogens as chemical antimicrobial agents?
What is the primary mechanism of action for halogens as chemical antimicrobial agents?
Signup and view all the answers
What characteristic is essential for a good disinfectant or antiseptic?
What characteristic is essential for a good disinfectant or antiseptic?
Signup and view all the answers
Which of the following describes the concept of the phenol coefficient?
Which of the following describes the concept of the phenol coefficient?
Signup and view all the answers
What defines narrow-spectrum antibiotics?
What defines narrow-spectrum antibiotics?
Signup and view all the answers
Which life cycle stage of protozoa is actively feeding and growing?
Which life cycle stage of protozoa is actively feeding and growing?
Signup and view all the answers
Which structural feature is characteristic of ciliates?
Which structural feature is characteristic of ciliates?
Signup and view all the answers
What mechanism describes the prevention of drug uptake in antibiotic resistance?
What mechanism describes the prevention of drug uptake in antibiotic resistance?
Signup and view all the answers
Which method is used to determine the minimum inhibitory concentration (MIC) of an antibiotic?
Which method is used to determine the minimum inhibitory concentration (MIC) of an antibiotic?
Signup and view all the answers
What is a defining feature of apicomplexans?
What is a defining feature of apicomplexans?
Signup and view all the answers
Which of the following is an example of a synthetic antimicrobial?
Which of the following is an example of a synthetic antimicrobial?
Signup and view all the answers
Study Notes
Unit 3: Control of Microorganisms
Section 1: Chapter 13 – Control of Microbial Growth
-
Resistance to Microbial Control: Prions and bacterial endospores are the most resistant, followed by bacteria (like Mycobacteria), zygospores, and naked viruses. Fungal spores, hyphae, and yeasts are least resistant.
-
Key Terms:
-
Fomite: Object transmitting disease.
-
Sterilization: Complete removal of all living microbes.
-
Sanitization: Reduces microbes to safe levels.
-
Disinfection: Kills pathogens on nonliving surfaces.
-
Asepsis: Killing pathogens on living tissue.
-
Aseptic technique: Prevents contamination of sterile surfaces.
-
Degerming: Mild chemicals + scrubbing to reduce microbes on living tissue.
-
-cide: Kills organisms.
-
-static: Inhibits growth.
-
Microbial death: Permanent loss of reproductive capability.
-
Microbial death curve: Graph of microbial control progress.
-
Decimal Reduction Time (D-value): Time to kill 90% of a population.
-
Thermal death time: Minimum time to kill the entire population at a specific temperature.
-
Incineration: Destruction by direct flame.
-
Physical Control Methods:
-
Heat: Oxidizes cellular components (e.g., autoclaving, boiling).
-
Boiling: 100°C for lab prep and personal use.
-
Dry heat oven: 170°C for 2 hours to sterilize lab equipment.
-
Incineration: Burns microorganisms.
-
Autoclave: 121°C for 15 minutes, sterilizes media and equipment.
-
Pasteurization: Prevents spoilage in food.
-
Cold: Reduces microbial metabolic rate.
-
Freezing: Long-term storage at -2°C.
-
Refrigeration: Short-term storage at 0-7°C.
-
Desiccation (Dehydration): Removes moisture.
-
Lyophilization: Rapid freezing under vacuum for preservation.
-
Radiation:
-
Ionizing: Gamma rays, sterilizes items, food, and spices.
-
Non-ionizing: UV rays for sterilizing lab materials and water.
-
Filtration: Removes microorganisms from liquids or gases.
-
HEPA filters: Trap particles, organisms, and spores from air.
-
Membrane filters: Used in vaccine production.
-
Factors Affecting Bacterial Growth: Temperature, pH, moisture, nutrient availability, oxygen, and other environmental factors.
-
Monitoring Autoclave Effectiveness: Autoclave tape: strips change color to indicate successful sterilization.
-
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).
-
Aldehydes: Inactivate viruses, destroy bacterial cells (e.g., formaldehyde).
-
Detergents: Surfactants disrupting membranes.
-
Gases: Sterilize materials like paper, plastics (e.g., ethylene oxide).
-
Evaluation of Disinfectants/Antiseptics:
-
Phenol coefficient: Compares disinfecting ability to phenol.
-
Disk diffusion: Chemicals applied to filter paper disks.
-
Use dilution test: Exposures of cultures to chemical agents.
-
In-use test: Use of diluted disinfectant on agar.
Section 2: Chapter 14 – Antimicrobial Drugs
-
Key Scientists:
-
Paul Ehrlich: 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.
-
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.
-
Antibiotic Spectrum:
-
Narrow spectrum: Targets one group (e.g., penicillin).
-
Broad spectrum: Affects multiple groups (e.g., tetracycline).
-
Drug Administration:
-
Dosage: Amount of medication.
-
Route: Method of introduction (oral, topical, parenteral).
-
Chemotherapeutic Index: Ratio of toxic dose to therapeutic dose.
-
Antibiotic Targets and Classes:
-
Cell wall: B-lactams, Glycopeptides, Bacitracin.
-
Protein synthesis: Polymyxins, Lipopeptides.
-
Ribosomes: 30S and 50S subunits (e.g., aminoglycosides, tetracyclines).
-
Metabolic pathways: Folate synthesis (e.g., sulfonamides, trimethoprim).
-
DNA synthesis: Fluoroquinolones.
-
RNA synthesis: Rifamycins.
-
Antibiotic Resistance Mechanisms:
-
Drug modification: Enzyme inactivates the antibiotic.
-
Prevention of uptake: Drug doesn't enter or is pumped out.
-
Target modification: Altered binding site.
-
Minimum Inhibitory Concentration (MIC): Lowest drug concentration inhibiting visible growth.
-
Susceptibility Assays:
-
Disk diffusion: Apply chemicals to paper disks.
-
Tube dilution: Determine MIC by serial dilution.
-
Microdilution tray: Test MIC using microplates.
-
E-test: Determine MIC using a gradient strip.
Unit 4 Section 1: Unicellular Eukaryotic Parasites (Protozoa)
Section 2: Chapter 5.2: Helminths
-
Helminths: Parasitic worms causing diseases. Two main types: Roundworms (Nematodes) and Flatworms (Platyhelminthes).
-
Flatworms (Platyhelminthes): Flat, soft-bodied, often segmented, and lack a digestive system (absorb nutrients through skin).
-
Trematoda (Flukes): Flattened, leaf-shaped, nonsegmented; have mouth and suckers for attachment; transmitted by walking in infected water; cause diseases like schistosomiasis.
-
Cestoda (Tapeworms): Long, segmented bodies; no mouth, absorb nutrients; transmitted by eating undercooked meat; cause tapeworm infections.
-
Cestoda Structures:
-
Proglottids: Segments containing reproductive organs.
-
Scolex: The head with suckers and/or hooks for attachment.
-
Trematode Life Cycle: Miracidia (free-swimming larva) infects snail, develops into cercariae.
-
Nematode Life Cycle: Rhabditiform larva in host digestive system, develops into filariform larva.
-
Helminth Diseases and Treatments:
-
Pinworm: Enterobius vermicularis, transmitted by contaminated surfaces, itchy anus; treated with mebendazole or albendazole.
-
Trichinellosis: Trichinella spiralis, from undercooked pork/wild game, abdominal and muscle pain; treated with mebendazole or albendazole.
-
Ascariasis: Ascaris lumbricoides, from contaminated soil/food, abdominal pain, coughing; treated with mebendazole or albendazole.
-
Necatoriasis (Hookworm): Necator americanus, from skin contact with contaminated soil, itchy rash, anemia; treated with mebendazole or albendazole.
-
Elephantiasis (Lymphatic Filariasis): Wuchereria bancrofti, from mosquito bite, swelling of limbs/genitals; treated with ivermectin or diethylcarbamazine.
-
Schistosomiasis (Blood Fluke): Schistosoma species, from contact with contaminated water, fever, abdominal pain; treated with praziquantel.
-
Antihelminth Agents: Praziquantel (trematodes/cestodes), mebendazole (nematodes), avermectin, ivermectin (nematodes).
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Explore the mechanisms of microbial growth control in this quiz based on Chapter 13 from Unit 3. Learn about the resistance levels of various microorganisms and key terms related to sterilization, disinfection, and aseptic techniques. Test your understanding of important concepts such as D-value and microbial death.
