Untitled Flashcard Set
Chapter 13: Controlling Microbes in the Environment
1. Define:
a. Antiseptic – Chemical used on living tissue to reduce or eliminate microorganisms.
b. Aseptic – Environment or procedure free of contamination by pathogens.
c. Degerming – almost all microbes are reduced but not completely removed: examples are hand-washing with soap and wiping skin with ethanol.
d. Disinfection – inactivates most microbes on the surface by using antimicrobial chemicals or heat.
e. Pasteurization – Gentle heating process to kill pathogens and spoilage organisms in food and drinks. 2 methods (HTST -Hight temp short time) & (UHT- Ultra high temp)
f. Sanitation – Lowering microbial counts to safe public health levels (e.g., cleaning utensils, bathrooms, hospital rooms).
g. Sterilization – Complete destruction or removal of all microorganisms, including endospores.
2. A fungicidal agent kills fungi; a fungistatic agent only inhibits fungal growth.
3. Two ways antimicrobials work:
• Damage to cell walls or membranes.
• Interference with protein or nucleic acid synthesis. (stop microbe from reproducing/survive)
4. The ideal antimicrobial should be:
• fast acting, stable, easy to prepare, inexpensive, and easy to use.
5. Factors affecting antimicrobial efficacy:
• Environment (temperature, pH).
• microbial susceptibility (some are more resistant than others)
6. how does heat kill microbes?
Heat kills microbes by denaturing proteins and destroying cell membranes.
7. How does desiccation differ from lyophilization?
Desiccation; removes water with heat.
Lyophilization; removes water by freezing and vacuum drying — preserves shape and allows rapid rehydration.
8. How does osmotic pressure stop microbial growth? What type of microbe survives well with high osmotic pressure?
Osmotic pressure draws water out of cells, dehydrating and killing microbes.
Halophiles survive well under high osmotic pressure.
9. How does radiation kill microbes?
Radiation kills microbes by damaging DNA and causing mutations or breaks in nucleic acids.
Chapter 14: Controlling Microbes in the Body
Matching:
1 Antibiotics from Streptomyces – Waksman
2 Discovered penicillin – Fleming
3 Discovered sulfanilamide – Domagk
4 Used arsenic compounds as “magic bullets” – Ehrlich
2. Compare natural, semisynthetic, and synthetic antibiotics.
• Natural antibiotics: (actinomycetes) produced by microorganisms in nature (ex fungus).
• Semisynthetic: is a chemically modified derivative of a natural antibiotic..
• Synthetic: completely manufactured by chemical synthesis not found in nature (man made).
3. Explain selective toxicity. Why are there more antibiotics effective in killing bacteria than eukaryotic pathogens and viruses?
Selective toxicity: Drug harms the microbe without damaging the host.
There are more antibiotics for bacteria because bacteria are prokaryotic and structurally different from human cells; eukaryotes and viruses are more similar to host cells, so fewer selective targets.
4. Six mechanisms of antibiotic action:
1 Inhibit cell wall biosynthesis.
2 Inhibit biosynthesis of proteins.
3 Disrupt membranes.
4 antimetabolites.
5 Inhibit nucleic acid synthesis.
6 Mycobacterial adenosine triphosphate (ATP) synthase inhibitor
5. The ideal antibiotic should be:
• Selectively toxic, stable, easy to administer, effective in low doses, and not lead to resistance.
6. Compare narrow-spectrum to broad-spectrum antibiotics. Is there a disadvantage to using a broad-spectrum antibiotic?
• Narrow-spectrum: targets specific set of bacteria (only target gram-positive bacteria or target only gram-negative bacteria).
• Broad-spectrum targets a wide variety of bacteria (both gram-positive and gram-negative), and is used as to cover a wide range of pathogens while waiting on the laboratory identification of the infecting pathogen.
7. What are the positive/negative attributes of:
a. Topical: applied on skin; low side effects but limited use.
b. Oral: convenient but takes longer to reach its peak
c. Intramuscular: takes longer for concentration to reach its peak
d. Intravenous: concentration peaks very fast and gradually decreases. For most drugs, the plasma levels are much higher if drug is administered intravenously.
8. List 3 examples of how the use of antibiotics cause a patient harmful side effects.
• Toxicity to organs.
• Allergic reactions.
• Disruption of normal microbiota.
9. How can microbes become resistant to antibiotics? List 5 mechanisms of resistance.
1 Enzyme destroys or deactivates drug.
2 Prevent drug entry.
3 Alter drug target.
4 Pump drug out of cell.
5 Bypass metabolic pathway.
10. How can we slow down the development of antibiotic resistance?
• Finishing prescriptions.
• Using drugs only when needed.
• Combining therapies.
• Preventing infections through hygiene and vaccination.
Chapters 15–16: Epidemiology
1. What is symbiosis? Compare mutualism, commensalism, and parasitism.
a) Symbiosis: Relationship between organisms.
b) Mutualism: both benefit.
c) Commensalism: one benefits, other unaffected.
d) Parasitism: one benefits, other harmed.
2. What are normal microbiota? Where do they live?
Normal microbiota: Microorganisms that live on/in the body without causing disease.
3. List 3 ways normal microbiota become opportunistic pathogens.
• Moved to new location.
• Immune system is suppressed.
• Normal microbiota disrupted by antibiotics.
4. what are Reservoirs of infection?
Sites where pathogens are maintained and can infect new hosts.
5. What are zoonoses? List one example of each including animal reservoir:
Zoonoses (animal diseases transmissible to humans):
a. Helminthic – tapeworms in animals.
b. Protozoan – malaria from mosquitoes.
c. Fungal – ringworm from cats.
d. Bacterial – anthrax from cattle.
e. Viral – rabies from dogs.
6. Human carriers: Infected individuals who spread disease without symptoms.
7. Nonliving reservoirs: Soil, water, and food.
8. Define:
a. Contamination – presence of microbes on a surface or object.
b. Infection – invasion and growth of microbes in the body.
c. Portals of entry – routes pathogens enter (mouth, skin, etc.).
d. Virulent – highly infectious or harmful.
e. Avirulent – not harmful.
f. Morbidity – rate of disease occurrence.
g. Signs – observable/measurable evidence of disease.
h. Symptoms – subjective feelings of illness.
i. Syndrome – group of signs/symptoms characteristic of disease.
j. Etiology – study or cause of disease.
9. how do microbes attach to hosts?
Microbes attach to hosts using adhesion factors like fimbriae, pili, or surface proteins.
10. Types of Diseases
1 Heredity – errors in DNA from parents.
2 Congenital – defects present at birth.
3 Degenerative – results from aging.
4 Endocrine – excess or deficient hormones.
5 Immunological – defective immune response.
6 Idiopathic – cause unknown.
7 Infectious – caused by infectious agent.
8 Nutritional – result from lack of nutrients.
9 Neoplastic – abnormal cell growth.
10 Iatrogenic – caused by medical treatment.
11 Nosocomial – acquired in health setting.
11. Three categories of virulence factors:
• Adhesion factors.
• Extracellular enzymes.
• Toxins or antiphagocytic factors.
12. Label the 5 stages graph below and explain each stage
1 Incubation – no symptoms, pathogen multiplying.
2 Prodromal – mild symptoms begin.
3 Illness – most severe signs/symptoms.
4 Decline – symptoms subside, immune response wins.
5 Convalescence – recovery, tissues repaired.
13. Portals of exit:
• Nose, mouth, feces, urine, semen, skin flakes, or blood.
14. Contrast direct contact, indirect contact and droplet transmission. What are fomites?
Transmission:
• Direct contact: person-to-person (touching, kissing).
• Indirect contact: through contaminated objects (fomites).
• Droplet: via mucus droplets (sneezing/coughing).
Fomites: contaminated nonliving objects.
15. Contrast vehicle, waterborne, airborne and bodily fluid transmission.
Vehicle transmission: via air, water, food, or bodily fluids.
• Waterborne: contaminated water.
• Airborne: dust or droplets.
• Bodily fluids: saliva, semen, blood.
16. what are Biological vectors?
Animals (especially arthropods) that transmit pathogens — e.g., mosquitoes (malaria), ticks (Lyme).
17. Types of Infections and Diseases
1 Asymptomatic – disease without symptoms.
2 Latent – disease appears long after exposure.
3 Acute – symptoms and course of disease run quickly.
4 Contagious – easily spread.
5 Noncommunicable – disease from opportunistic infection.
6 Chronic – mild symptoms; slow and long-lasting disease.
7 Systemic – widespread infection.
8 Focal – infection serves as a source of pathogens for other body sites.
9 Communicable – transmitted from one host to another.
10 Primary – initial infection.
11 Secondary – infections that follow the primary infection.
12 Local – infection confined to a small region.
18. Compare incidence and prevalence
Incidence – number of new cases in a period.
Prevalence – total number of existing cases.
19.define
• a. Endemic – Diseases that are constantly present in a population in a particular geographic region.
• b. Epidemic – a larger than normal number of cases in a short time within a geographic region.
• c. Pandemic – An epidemic that occurs worldwide
Chapter 17: Innate Immunity
Characteristics:
• First line of defense.
• Non-specific.
• Immediate.
• No memory.
• Acts against viruses, bacteria, fungi.
Three lines of defense:
1 Physical/Mechanical defenses.
2 Chemical defenses.
3 Cellular defenses.
Physical Defenses:
• Cell junctions: tight junctions, gap junctions, desmosomes.
• Skin: keratinized barrier, dry and acidic.
• Mucous membranes: trap microbes; contain antimicrobial peptides. Secretes mucous
• Cilia: move mucus and debris out of lungs.
Mechanical Defenses:
• Shedding skin cells.
• Mucociliary escalator.
• Urine, tears, feces remove microbes.
• Eyelids and blinking clear debris.
• Microbiota compete with pathogens.
Chemical Defenses:
• Sebum: blocks bacteria, creates acidic skin.
• Saliva and mucus: contain lysozyme and lactoperoxidase.
• Gastric acid: kills most microbes.
• Pancreatic enzymes, bile, and intestinal enzymes: antimicrobial effects.
Complement system (C1–C9):
• Found in blood; activated by microbes.
• Causes opsonization, inflammation, chemotaxis, and cytolysis (MAC formation).
Antimicrobial peptides (AMPs):
• Destroy cell membranes or cell walls.
• Include defensins and bacteriocins.
Cytokines:
• Proteins for cell communication.
• Interleukins – activate leukocytes.
• Chemokines – attract immune cells.
• Interferons – defend against viruses.
Cellular Defenses (Leukocytes):
• Granulocytes: Neutrophils, Basophils, Eosinophils.
• Agranulocytes: Lymphocytes, Monocytes.
Neutrophils: Kill bacteria by phagocytosis and enzyme release.
Eosinophils: Attack parasites and cause allergic reactions.
Natural Killer Cells: Kill virus-infected or cancer cells lacking MHC I.
Phagocytes: Recognize pathogens using PRRs that bind to PAMPs such as peptidoglycan, flagella, or LPS.