Podcast
Questions and Answers
An antimicrobial medication is a chemical used to treat an infectious disease.
An antimicrobial medication is a chemical used to treat an infectious disease.
True (A)
Antimicrobial medications are best defined as ______.
Antimicrobial medications are best defined as ______.
chemicals that inhibit the growth of or kill microorganisms
What was the first antibiotic discovered in 1928 by Alexander Fleming?
What was the first antibiotic discovered in 1928 by Alexander Fleming?
penicillin
Most antibiotics come from species of bacteria and fungi that normally live _______.
Most antibiotics come from species of bacteria and fungi that normally live _______.
Medically useful antimicrobial drugs exhibit _________, meaning they cause greater harm to microbes than to the human host.
Medically useful antimicrobial drugs exhibit _________, meaning they cause greater harm to microbes than to the human host.
What are chemicals used in the therapy of infectious diseases called?
What are chemicals used in the therapy of infectious diseases called?
Why is a urinary tract infection a good example for treatment with bacteriostatic antimicrobials?
Why is a urinary tract infection a good example for treatment with bacteriostatic antimicrobials?
Chemotherapeutic agents that are used to treat microbial infections can be more specifically called?
Chemotherapeutic agents that are used to treat microbial infections can be more specifically called?
In 1928, Alexander Fleming identified the mold producing the first discovered antibiotic as a species of?
In 1928, Alexander Fleming identified the mold producing the first discovered antibiotic as a species of?
Which of the following species are the four major producers of antibiotics? (Select all that apply)
Which of the following species are the four major producers of antibiotics? (Select all that apply)
A broad-spectrum antimicrobial is most likely effective against?
A broad-spectrum antimicrobial is most likely effective against?
Effective antimicrobial drugs need to demonstrate selective toxicity. What does this mean?
Effective antimicrobial drugs need to demonstrate selective toxicity. What does this mean?
When antimicrobials are used in combination and their interaction is neither antagonistic nor synergistic, the combination is said to be?
When antimicrobials are used in combination and their interaction is neither antagonistic nor synergistic, the combination is said to be?
When treating a case where the patient's defenses are unlikely to clear an infection, which would be the more appropriate choice of an antimicrobial drug?
When treating a case where the patient's defenses are unlikely to clear an infection, which would be the more appropriate choice of an antimicrobial drug?
What is a special consideration when giving antimicrobials to patients who have kidney or liver dysfunction?
What is a special consideration when giving antimicrobials to patients who have kidney or liver dysfunction?
Antimicrobials that are effective against a wide range of bacteria are known as?
Antimicrobials that are effective against a wide range of bacteria are known as?
When certain bacteria are said to have intrinsic (innate) resistance, this means they have ______.
When certain bacteria are said to have intrinsic (innate) resistance, this means they have ______.
When treating an infection with a combination of antimicrobials, why might a bacteriostatic drug be antagonistic when used with a bactericidal drug?
When treating an infection with a combination of antimicrobials, why might a bacteriostatic drug be antagonistic when used with a bactericidal drug?
What does each class of antibacterial medication target?
What does each class of antibacterial medication target?
Certain bacteria are inherently resistant to the effects of some antimicrobials. Inherent resistance is called ______.
Certain bacteria are inherently resistant to the effects of some antimicrobials. Inherent resistance is called ______.
Among the most useful antibacterial medications that interfere with metabolic pathways are the ______ biosynthesis inhibitors: sulfonamides and trimethoprim.
Among the most useful antibacterial medications that interfere with metabolic pathways are the ______ biosynthesis inhibitors: sulfonamides and trimethoprim.
Match each antibacterial medication with its appropriate mechanism of action.
Match each antibacterial medication with its appropriate mechanism of action.
How do certain antibacterial medications that interfere with cell membrane integrity lead to bacterial cell death?
How do certain antibacterial medications that interfere with cell membrane integrity lead to bacterial cell death?
What best explains why the first-line drugs are generally given in combination to patients who have active tuberculosis?
What best explains why the first-line drugs are generally given in combination to patients who have active tuberculosis?
After testing to determine the susceptibility of an organism to various drugs, what are important considerations when choosing a drug to use?
After testing to determine the susceptibility of an organism to various drugs, what are important considerations when choosing a drug to use?
Which of the following antimicrobials inhibit nucleic acid synthesis?
Which of the following antimicrobials inhibit nucleic acid synthesis?
The Kirby-Bauer disc diffusion test is routinely used to determine ______.
The Kirby-Bauer disc diffusion test is routinely used to determine ______.
Most antibacterial medications interfere with metabolic pathways.
Most antibacterial medications interfere with metabolic pathways.
The lowest concentration of a specific antimicrobial drug needed to prevent the growth of a given bacterial strain in vitro is known as the ______.
The lowest concentration of a specific antimicrobial drug needed to prevent the growth of a given bacterial strain in vitro is known as the ______.
Antibacterials like daptomycin and polymyxin B essentially make holes in the bacterial membrane. Why is this deadly to bacteria?
Antibacterials like daptomycin and polymyxin B essentially make holes in the bacterial membrane. Why is this deadly to bacteria?
Compared to conventional methods, commercial modifications of antimicrobial susceptibility testing offer what advantages?
Compared to conventional methods, commercial modifications of antimicrobial susceptibility testing offer what advantages?
A group of medications called the _________ drugs are preferred for use against species of Mycobacterium.
A group of medications called the _________ drugs are preferred for use against species of Mycobacterium.
Susceptibility of a pathogen to a specific antimicrobial drug is almost always predictable.
Susceptibility of a pathogen to a specific antimicrobial drug is almost always predictable.
Explain how drug resistance develops in bacteria and ultimately limits the usefulness of all known antimicrobials.
Explain how drug resistance develops in bacteria and ultimately limits the usefulness of all known antimicrobials.
The minimum inhibitory concentration (MIC) is the ______.
The minimum inhibitory concentration (MIC) is the ______.
Compared to conventional methods of antimicrobial susceptibility testing, commercial modifications are less labor-intensive.
Compared to conventional methods of antimicrobial susceptibility testing, commercial modifications are less labor-intensive.
Match the antifungal medications listed with the correct cellular target.
Match the antifungal medications listed with the correct cellular target.
What is targeted by antiviral medications such as acyclovir, ribavirin, and AZT?
What is targeted by antiviral medications such as acyclovir, ribavirin, and AZT?
Which of the following mechanisms do antiviral medications work? (Select all that apply)
Which of the following mechanisms do antiviral medications work? (Select all that apply)
Why do β-lactam antibiotics vary in their spectrum of activity? (Select two reasons)
Why do β-lactam antibiotics vary in their spectrum of activity? (Select two reasons)
What type of penicillin is produced by Penicillium chrysogenum?
What type of penicillin is produced by Penicillium chrysogenum?
What type of penicillin was developed in response to resistant Staphylococcus aureus?
What type of penicillin was developed in response to resistant Staphylococcus aureus?
What type of penicillin is active against penicillin-sensitive Gram-positive and many Gram-negative bacteria?
What type of penicillin is active against penicillin-sensitive Gram-positive and many Gram-negative bacteria?
What type of penicillin has greater activity against Pseudomonas aeruginosa?
What type of penicillin has greater activity against Pseudomonas aeruginosa?
What type of penicillin is a combination of agents resistant to enzymatic destruction?
What type of penicillin is a combination of agents resistant to enzymatic destruction?
Why did the police officer die when tested with penicillin?
Why did the police officer die when tested with penicillin?
For diseases caused by which pathogen would a medication inhibiting microtubule formation NOT be used?
For diseases caused by which pathogen would a medication inhibiting microtubule formation NOT be used?
What term describes compounds that cause greater harm to microbes than to the human host?
What term describes compounds that cause greater harm to microbes than to the human host?
What term describes the molecular method by which a compound might kill or inhibit a microbe?
What term describes the molecular method by which a compound might kill or inhibit a microbe?
What term is used to describe the range of different microbes that a compound can kill or inhibit?
What term is used to describe the range of different microbes that a compound can kill or inhibit?
Which class of antimicrobials would have the most selective toxicity?
Which class of antimicrobials would have the most selective toxicity?
Antibiotics targeting which of the following would be effective against viruses?
Antibiotics targeting which of the following would be effective against viruses?
What enzymes are inhibited by β-lactam antibiotics?
What enzymes are inhibited by β-lactam antibiotics?
Why are few medications effective against Mycobacterium tuberculosis? (Select all that apply)
Why are few medications effective against Mycobacterium tuberculosis? (Select all that apply)
Which type of antibiotic would be the most appropriate to prescribe for meningococcal meningitis?
Which type of antibiotic would be the most appropriate to prescribe for meningococcal meningitis?
All of the following statements about the Kirby-Bauer test are true EXCEPT
All of the following statements about the Kirby-Bauer test are true EXCEPT
Antiviral medications that interfere with genome integration will be useful against all animal viruses.
Antiviral medications that interfere with genome integration will be useful against all animal viruses.
Why should a patient with 'walking pneumonia' NOT be given penicillin?
Why should a patient with 'walking pneumonia' NOT be given penicillin?
How does an antibiotic that inhibits protein synthesis achieve selectivity?
How does an antibiotic that inhibits protein synthesis achieve selectivity?
What antibacterial medications inhibit cell wall synthesis?
What antibacterial medications inhibit cell wall synthesis?
How do beta-lactam antibiotics interfere with peptidoglycan synthesis?
How do beta-lactam antibiotics interfere with peptidoglycan synthesis?
What family of Beta-lactam antibacterial medications has different groups that vary in their spectrum of activity and their susceptibility to beta-lactamase?
What family of Beta-lactam antibacterial medications has different groups that vary in their spectrum of activity and their susceptibility to beta-lactamase?
What family of Beta-lactam antibacterial medications has later generations that are generally more effective against Gram-negative bacteria but less susceptible to destruction by most beta-lactamases?
What family of Beta-lactam antibacterial medications has later generations that are generally more effective against Gram-negative bacteria but less susceptible to destruction by most beta-lactamases?
What family of Beta-lactam antibacterial medications has a broad spectrum of activity and is not destroyed by most beta-lactamases, including extended-spectrum beta-lactamases?
What family of Beta-lactam antibacterial medications has a broad spectrum of activity and is not destroyed by most beta-lactamases, including extended-spectrum beta-lactamases?
What Beta-lactam antibiotic is primarily active against members of the family Enterobacteriaceae?
What Beta-lactam antibiotic is primarily active against members of the family Enterobacteriaceae?
How do Glycopeptide antibiotics interfere with peptidoglycan synthesis?
How do Glycopeptide antibiotics interfere with peptidoglycan synthesis?
How does bacitracin inhibit cell wall synthesis?
How does bacitracin inhibit cell wall synthesis?
What antibacterial medications inhibit protein synthesis?
What antibacterial medications inhibit protein synthesis?
What protein synthesis medication is bactericidal against aerobic and facultative bacteria?
What protein synthesis medication is bactericidal against aerobic and facultative bacteria?
What protein synthesis medication is bacteriostatic against some Gram-positive and Gram-negative bacteria?
What protein synthesis medication is bacteriostatic against some Gram-positive and Gram-negative bacteria?
What protein synthesis medication is bacteriostatic against many Gram-positive bacteria?
What protein synthesis medication is bacteriostatic against many Gram-positive bacteria?
What protein synthesis medication is bacteriostatic and broad-spectrum?
What protein synthesis medication is bacteriostatic and broad-spectrum?
What protein synthesis medication is bacteriostatic against a variety of Gram-positive and Gram-negative bacteria?
What protein synthesis medication is bacteriostatic against a variety of Gram-positive and Gram-negative bacteria?
What protein synthesis medication is bacteriostatic against various Gram-positive bacteria?
What protein synthesis medication is bacteriostatic against various Gram-positive bacteria?
What protein synthesis medication is bacteriostatic against a variety of Gram-positive bacteria?
What protein synthesis medication is bacteriostatic against a variety of Gram-positive bacteria?
What protein synthesis medication is a synergistic combination of two medications?
What protein synthesis medication is a synergistic combination of two medications?
What antibacterial medications inhibit nucleic acid synthesis?
What antibacterial medications inhibit nucleic acid synthesis?
What nucleic acid synthesis medication is bactericidal against a wide variety of Gram-positive and Gram-negative bacteria?
What nucleic acid synthesis medication is bactericidal against a wide variety of Gram-positive and Gram-negative bacteria?
What nucleic acid synthesis medication is bactericidal against Gram-positive and some Gram-negative bacteria?
What nucleic acid synthesis medication is bactericidal against Gram-positive and some Gram-negative bacteria?
What nucleic acid synthesis medication is bactericidal against anaerobes?
What nucleic acid synthesis medication is bactericidal against anaerobes?
What antibacterial medications inhibit folate biosynthesis?
What antibacterial medications inhibit folate biosynthesis?
What folate biosynthesis medication is bacteriostatic against a variety of Gram-positive and Gram-negative bacteria?
What folate biosynthesis medication is bacteriostatic against a variety of Gram-positive and Gram-negative bacteria?
What folate biosynthesis medication is used with a sulfonamide for synergistic effect?
What folate biosynthesis medication is used with a sulfonamide for synergistic effect?
What antibacterial medications inhibit cell membrane integrity?
What antibacterial medications inhibit cell membrane integrity?
What cell membrane integrity medication is bactericidal against Gram-positive bacteria?
What cell membrane integrity medication is bactericidal against Gram-positive bacteria?
What cell membrane integrity medication is bactericidal against Gram-negative bacteria?
What cell membrane integrity medication is bactericidal against Gram-negative bacteria?
What medications are effective against Mycobacterium tuberculosis?
What medications are effective against Mycobacterium tuberculosis?
How is ethambutol effective against TB?
How is ethambutol effective against TB?
How is isoniazid effective against TB?
How is isoniazid effective against TB?
How is pyrazinamide effective against TB?
How is pyrazinamide effective against TB?
Flashcards
Antimicrobial Medications
Antimicrobial Medications
Chemicals that treat infectious diseases by inhibiting microbial growth or killing microorganisms.
Selective Toxicity
Selective Toxicity
The ability of a medication to harm microbes without significant damage to human cells.
Penicillin
Penicillin
First antibiotic, discovered in 1928 from Penicillium mold.
Broad-spectrum Antimicrobials
Broad-spectrum Antimicrobials
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β-lactam Drugs
β-lactam Drugs
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Rifamycins
Rifamycins
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Polymyxin B
Polymyxin B
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Sulfonamides
Sulfonamides
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Tetracyclines
Tetracyclines
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Bactericidal Drugs
Bactericidal Drugs
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Bacteriostatic Drugs
Bacteriostatic Drugs
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Minimum Inhibitory Concentration (MIC)
Minimum Inhibitory Concentration (MIC)
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Drug Resistance
Drug Resistance
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Intrinsic Resistance
Intrinsic Resistance
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Combination Therapy
Combination Therapy
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Kirby-Bauer Disc Diffusion Test
Kirby-Bauer Disc Diffusion Test
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First-line Drugs (for TB)
First-line Drugs (for TB)
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β-lactam Antibiotics
β-lactam Antibiotics
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Stopping Antibiotics Prematurely
Stopping Antibiotics Prematurely
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Antivirals
Antivirals
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Antifungals
Antifungals
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Natural penicillins
Natural penicillins
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Penicillinase-resistant penicillins
Penicillinase-resistant penicillins
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Aminoglycosides
Aminoglycosides
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Tetracyclines
Tetracyclines
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Macrolides
Macrolides
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Fluoroquinolones
Fluoroquinolones
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Rifamycins
Rifamycins
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Sulfonamides and Trimethoprim
Sulfonamides and Trimethoprim
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Daptomycin and Polymyxins
Daptomycin and Polymyxins
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Study Notes
Antimicrobial Medications Overview
- Antimicrobial medications are chemicals intended to treat infectious diseases by either inhibiting the growth or killing microorganisms.
- Selective toxicity allows these medications to harm microbes while minimizing damage to human cells.
Historical Context
- Penicillin, the first antibiotic, was discovered by Alexander Fleming in 1928 from the mold Penicillium.
- Most antibiotics originate from bacteria and fungi found in soil.
Mechanisms of Action
- Broad-spectrum antimicrobials are effective against both Gram-positive and Gram-negative bacteria.
- Specific classes target different bacterial mechanisms:
- β-lactam drugs inhibit cell wall synthesis.
- Rifamycins interfere with nucleic acid synthesis.
- Polymyxin B targets cell membrane integrity.
- Sulfonamides inhibit metabolic pathways like folate biosynthesis.
- Tetracyclines affect protein synthesis.
Treatment Considerations
- Bactericidal drugs kill bacteria, while bacteriostatic drugs inhibit growth; the latter relies on the host's immune system to clear the infection.
- When treating patients with kidney or liver dysfunction, dosages may need to be adjusted due to slower excretion or metabolism of drugs.
- The minimum inhibitory concentration (MIC) indicates the lowest concentration of a drug needed to prevent bacterial growth.
Resistance and Combination Therapy
- Drug resistance occurs when antimicrobials favor resistant strains, leading to challenges in treatment; intrinsic resistance is an inherent characteristic of some bacteria.
- Combination therapy reduces the risk of developing resistant bacterial mutants and enhances treatment efficacy.
Laboratory Testing
- The Kirby-Bauer disc diffusion test assesses the susceptibility of bacterial strains to various antimicrobial drugs.
- Commercial modifications of antimicrobial susceptibility testing are quicker and less labor-intensive.
Special Drug Categories
- First-line drugs, like isoniazid and ethambutol, target processes unique to Mycobacterium tuberculosis for effective and lower-toxicity treatment.
- β-lactam antibiotics exhibit a high therapeutic index due to their targeted action against bacterial cell walls.
Consequences of Misuse
- Stopping antibiotics prematurely can lead to the development of resistance.
- Antivirals target viral nucleic acid synthesis and block various stages of the viral life cycle, including entry and maturation.
Antifungals and Mechanisms
- Different antifungal medications target various cellular components, including:
- Griseofulvin for cell division.
- Echinocandins for cell wall synthesis.
- Polyenes, Azoles, and Allylamines for plasma membrane function.
- Flucytosine for nucleic acid synthesis.
Summary of Antibiotic Classes
- Natural penicillins: Narrow-spectrum, effective against specific Gram-positive bacteria.
- Penicillinase-resistant penicillins: Developed for resistant Staphylococcus aureus strains.
- Broad-spectrum penicillins: Effective against various Gram-positive and Gram-negative bacteria.
- Extended-spectrum penicillins: Enhanced activity against Pseudomonas aeruginosa.
Key Points on Antibiotic Resistance Mechanisms
- Increase in elimination through efflux pumps.
- Decreased uptake of medications via altered porins.
- Altered target sites to prevent binding.
- Production of drug-inactivating enzymes which neutralize the antibiotics.### Penicillin and β-Lactam Antibiotics
- Discovered by Alexander Fleming, penicillin was first tested on a police officer with Staphylococcus aureus but was ineffective due to insufficient purification and the bacterium's intrinsic resistance.
- Since Staphylococcus aureus lacks peptidoglycan, it demonstrates intrinsic resistance to penicillin, revealing limitations of this antibiotic.
- β-lactam antibiotics target penicillin-binding proteins (PBPs), inhibiting bacterial cell wall synthesis.
Selective Toxicity
- Selective toxicity refers to compounds that selectively harm microbes while sparing human cells, a crucial concept in antibiotic development.
- Antimicrobials that act on bacterial cell walls show high selective toxicity because human cells lack this structure.
Antimicrobial Action
- Antimicrobial action describes the mechanisms by which compounds kill or inhibit the growth of microbes.
- The spectrum of activity is the range of different microbes affected by a specific antimicrobial agent.
Antibacterial Spectrum and Treatment
- Penicillins offer a specific action against cell wall synthesis and maintain high selective toxicity.
- Broad-spectrum antibiotics, with high therapeutic indexes, are preferred for treating infections like meningococcal meningitis caused by Neisseria meningitidis.
Kirby-Bauer Test
- The Kirby-Bauer test evaluates bacterial sensitivity to antibiotics, measuring the zone of inhibition around antibiotic discs; smaller zones do not necessarily indicate extreme sensitivity.
Mycobacterium tuberculosis Challenges
- Mycobacterium tuberculosis poses treatment challenges due to slow generation time, cell wall properties, and resistance to multiple medications.
- Drugs like ethambutol, isoniazid, and pyrazinamide are effective against TB through mechanisms that disrupt cell wall synthesis and ribosomal function.
Protein Synthesis Inhibitors
- Various antibiotics inhibit protein synthesis at different ribosomal subunits:
- Aminoglycosides cause misreading of mRNA on the 30S subunit.
- Tetracyclines block tRNA attachment to the 30S subunit.
- Macrolides prevent protein synthesis elongation on the 50S subunit.
Nucleic Acid Synthesis Inhibitors
- Fluoroquinolones inhibit DNA gyrase, while rifamycins block RNA polymerase. Metronidazole works by damaging anaerobically activated DNA.
Folate Biosynthesis Inhibitors
- Sulfonamides and trimethoprim inhibit folate biosynthesis; sulfonamides mimic PABA, while trimethoprim targets downstream enzyme activity.
Membrane Integrity Disruption
- Daptomycin and polymyxins compromise the integrity of bacterial membranes, with daptomycin effective against Gram-positive and polymyxins against Gram-negative bacteria.
Resistance Mechanisms
- β-lactam antibiotics face challenges from β-lactamases, which degrade the antibiotic, while resistant strains may require treatment with specific drug classes to overcome resistance.
Summary of Antibacterial Classes
- Antimicrobials are categorized by their mechanisms: cell wall synthesis inhibitors (β-lactams), protein synthesis inhibitors (aminoglycosides, tetracyclines, macrolides), nucleic acid synthesis inhibitors (fluoroquinolones, rifamycins), and folate synthesis inhibitors (sulfonamides, trimethoprim). Each class has specific targets within microbial cells that contribute to their bactericidal or bacteriostatic effects.
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