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Antimicrobial Resistance and Infectious Disease Flashcards
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1
Question
What are the primary mechanisms by which microbes develop resistance to antimicrobial drugs?
Page 3
Answer
The primary mechanisms include efflux pumps that expel the drug, decreased permeability that prevents drug entry, modification of drug targets, and enzymatic degradation of the drug.
2
Question
How does the efflux pump mechanism contribute to drug resistance?
Page 3
Answer
Efflux pumps actively transport antimicrobial drugs out of the microbial cell faster than they can enter, reducing intracellular drug concentration below effective levels.
3
Question
Describe the role of decreased permeability in antimicrobial resistance.
Page 3
Answer
Decreased permeability involves alterations to the cell membrane or wall that block the entry of antimicrobial drugs into the microbial cell.
4
Question
What is modification of the drug target in the context of resistance?
Page 3
Answer
Modification of the drug target occurs when microbes alter the structure or function of the drug's intended molecular target, preventing the drug from binding or acting effectively.
5
Question
How do enzymes contribute to drug inactivation as a resistance mechanism?
Page 3
Answer
Enzymes, such as beta-lactamases, break down or modify the antimicrobial drug, rendering it inactive before it can affect the microbe.
6
Question
What is the difference between intrinsic and acquired drug resistance?
Page 4
Answer
Intrinsic resistance is a natural, pre-existing property of the microbe, while acquired resistance develops through genetic changes like mutation or horizontal gene transfer.
7
Question
Name the types of enzymatic modification that lead to drug resistance.
Page 4
Answer
The types include hydrolysis (e.g., beta-lactamases for penicillins), group transfer (e.g., acetylation), and modification of the drug target.
8
Question
How does plasmid-mediated resistance occur?
Page 5
Answer
Plasmids, which are extrachromosomal DNA elements, carry resistance genes that can be transferred between microbes via conjugation, spreading resistance rapidly.
9
Question
What role do integrons play in antibiotic resistance?
Page 5
Answer
Integrons are genetic elements that capture and express multiple resistance genes, facilitating the assembly and dissemination of resistance cassettes among bacteria.
10
Question
Describe the impact of inappropriate antibiotic use on resistance development.
Page 6
Answer
Inappropriate use, such as overuse or misuse in humans and agriculture, selects for resistant strains, reducing the effectiveness of current antibiotics and leading to more infections.
11
Question
What are the goals of appropriate antibiotic use?
Page 6
Answer
The goals include optimizing individual patient outcomes, reducing resistance emergence, and minimizing adverse effects and costs.
12
Question
How many deaths per year are estimated due to antimicrobial resistance globally?
Page 7
Answer
Antimicrobial resistance is estimated to cause over 700,000 deaths per year worldwide.
13
Question
What is the projected annual death toll from antimicrobial resistance by 2050?
Page 7
Answer
By 2050, antimicrobial resistance is projected to cause 10 million deaths annually if not addressed.
14
Question
What are common host-drug interactions that can lead to adverse effects?
Page 8
Answer
Common interactions include allergic reactions, direct toxicity to organs, and disruption of normal microbiota leading to secondary infections.
15
Question
What percentage of people taking antimicrobials experience adverse effects?
Page 8
Answer
Approximately 5-25% of people taking antimicrobials experience adverse effects.
16
Question
How do you determine the correct antimicrobial for an infection?
Page 9
Answer
Select based on the pathogen's identity, susceptibility testing, site of infection, patient factors, and drug properties like spectrum and pharmacokinetics.
17
Question
What is the difference between antiseptics and disinfectants?
Page 10
Answer
Antiseptics are chemical agents applied to living tissue to reduce microbes, while disinfectants are used on inanimate objects to kill pathogens.
18
Question
Define sterilization in microbiology.
Page 11
Answer
Sterilization is the complete removal or destruction of all viable microorganisms, including spores, from an object or surface.
19
Question
What does the microbial death curve represent?
Page 11
Answer
The microbial death curve is a logarithmic plot showing the reduction in viable microbes over time under a lethal agent, indicating the rate of killing.
20
Question
What are the modes of action for antimicrobial drugs targeting protein synthesis?
Page 12
Answer
They inhibit translation by binding to ribosomes, preventing peptide bond formation or translocation, such as aminoglycosides and tetracyclines.
21
Question
How does moist heat kill microorganisms?
Page 13
Answer
Moist heat denatures proteins and enzymes by coagulation, disrupting cellular function more effectively than dry heat.
22
Question
What is the thermal death time?
Page 13
Answer
Thermal death time is the shortest time needed to kill all microbes in a sample at a specified temperature.
23
Question
Describe pasteurization and its purpose.
Page 13
Answer
Pasteurization is a mild heat treatment (e.g., 63°C for 30 min) to reduce spoilage organisms and pathogens in food without fully sterilizing it.
24
Question
How does dry heat control microbial growth?
Page 14
Answer
Dry heat oxidizes cellular components and denatures proteins through dehydration and high temperatures, used for glassware and powders.
25
Question
What is ionizing radiation's mechanism against microbes?
Page 14
Answer
Ionizing radiation penetrates cells, creating reactive ions that damage DNA and other molecules, preventing replication and causing death.
26
Question
How does filtration achieve microbial control?
Page 15
Answer
Filtration physically removes microbes by passing fluids through filters with pores smaller than microbial cells, used for heat-sensitive materials.
27
Question
What is desiccation's effect on microorganisms?
Page 15
Answer
Desiccation removes water essential for metabolism, inhibiting growth and causing death in vegetative cells, though spores resist.
28
Question
How do halogens like chlorine act as antimicrobial agents?
Page 16
Answer
Halogens denature proteins by oxidizing functional groups and disrupting membranes, commonly used in water treatment.
29
Question
What is the action of alcohols as disinfectants?
Page 16
Answer
Alcohols denature proteins and dissolve lipids in cell membranes, effective against vegetative cells but not spores; used at 70% concentration.
30
Question
Describe the mechanism of phenolic compounds in microbial control.
Page 17
Answer
Phenolics disrupt cell membranes and denature proteins, allowing leakage and inactivation; used in antiseptics and disinfectants.