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Questions and Answers
What characterizes anti-staphylococcal penicillins?
What characterizes anti-staphylococcal penicillins?
Which of the following drugs is classified as an aminopenicillin?
Which of the following drugs is classified as an aminopenicillin?
Which statement is true regarding methicillin-resistant Staphylococcus aureus (MRSA)?
Which statement is true regarding methicillin-resistant Staphylococcus aureus (MRSA)?
What is the primary use of anti-pseudomonal penicillins?
What is the primary use of anti-pseudomonal penicillins?
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What type of infections does aminopenicillin target effectively?
What type of infections does aminopenicillin target effectively?
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Which agent is a penicillinase inhibitor used in combination with penicillins?
Which agent is a penicillinase inhibitor used in combination with penicillins?
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What is the primary mode of resistance in MRSA?
What is the primary mode of resistance in MRSA?
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Which of these is considered a broad-spectrum penicillin?
Which of these is considered a broad-spectrum penicillin?
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Which carbapenem is compounded with cilastatin to prevent metabolism?
Which carbapenem is compounded with cilastatin to prevent metabolism?
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Which of the following correctly describes aztreonam?
Which of the following correctly describes aztreonam?
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What is one of the adverse effects associated with high levels of imipenem?
What is one of the adverse effects associated with high levels of imipenem?
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Which statement is true regarding the activity of vancomycin?
Which statement is true regarding the activity of vancomycin?
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What is a common route of administration for aztreonam?
What is a common route of administration for aztreonam?
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Which is a characteristic of carbapenems?
Which is a characteristic of carbapenems?
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What common side effect can occur with the use of vancomycin?
What common side effect can occur with the use of vancomycin?
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Why is cilastatin used with imipenem?
Why is cilastatin used with imipenem?
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What is the primary action of bactericidal drugs?
What is the primary action of bactericidal drugs?
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Which type of antibacterial agent is known for causing structurally deficient cell walls?
Which type of antibacterial agent is known for causing structurally deficient cell walls?
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Which of the following antibiotics is classified as a beta-lactam?
Which of the following antibiotics is classified as a beta-lactam?
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What is the mechanism of action for penicillin-binding proteins?
What is the mechanism of action for penicillin-binding proteins?
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Which of the following penicillins is administered orally?
Which of the following penicillins is administered orally?
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Which bacteria are more sensitive to penicillins?
Which bacteria are more sensitive to penicillins?
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What can confer resistance to penicillins in bacteria?
What can confer resistance to penicillins in bacteria?
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What is the primary role of bacteriostatic drugs?
What is the primary role of bacteriostatic drugs?
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Which classification of antibiotics includes cephalosporins?
Which classification of antibiotics includes cephalosporins?
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What effect do bacteriostatic drugs have when combined with bactericidal drugs in immunosuppressed patients?
What effect do bacteriostatic drugs have when combined with bactericidal drugs in immunosuppressed patients?
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Which of the following is a characteristic of aminopenicillins?
Which of the following is a characteristic of aminopenicillins?
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Which group of antibacterial agents has an antagonistic effect when combined?
Which group of antibacterial agents has an antagonistic effect when combined?
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Which of the following is NOT a class of antibacterial drugs?
Which of the following is NOT a class of antibacterial drugs?
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Which bacterial infections are bactericidal antibiotics preferred for?
Which bacterial infections are bactericidal antibiotics preferred for?
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Which fluoroquinolone has increased activity against gram-positive bacteria?
Which fluoroquinolone has increased activity against gram-positive bacteria?
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What is the effect of dietary supplements containing iron or zinc on fluoroquinolone antibiotics?
What is the effect of dietary supplements containing iron or zinc on fluoroquinolone antibiotics?
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Which of the following bacteria is NOT typically treated with Cotrimoxazole?
Which of the following bacteria is NOT typically treated with Cotrimoxazole?
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What type of bacteria does Moxifloxacin primarily target?
What type of bacteria does Moxifloxacin primarily target?
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Which protozoan is treated with Metronidazole?
Which protozoan is treated with Metronidazole?
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Which statement about Trimethoprim and Sulfamethoxazole is true?
Which statement about Trimethoprim and Sulfamethoxazole is true?
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Which of the following is an effect of Metronidazole?
Which of the following is an effect of Metronidazole?
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What is the primary use of Ciprofloxacin?
What is the primary use of Ciprofloxacin?
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What adverse effects are commonly associated with the infusion of certain antibiotics?
What adverse effects are commonly associated with the infusion of certain antibiotics?
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Which mechanism is primarily responsible for aminoglycosides' bactericidal action?
Which mechanism is primarily responsible for aminoglycosides' bactericidal action?
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Which site on the ribosome do tetracyclines primarily target?
Which site on the ribosome do tetracyclines primarily target?
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What is a significant risk factor for developing nephrotoxicity and ototoxicity from aminoglycosides?
What is a significant risk factor for developing nephrotoxicity and ototoxicity from aminoglycosides?
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Which antibiotic is mentioned as being effective against mycoplasma?
Which antibiotic is mentioned as being effective against mycoplasma?
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What mechanism contributes to resistance against aminoglycosides?
What mechanism contributes to resistance against aminoglycosides?
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Which class of antibiotics binds irreversibly to the 50s subunit of the ribosome?
Which class of antibiotics binds irreversibly to the 50s subunit of the ribosome?
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Doxycycline is noted for having a superior characteristic compared to other tetracyclines.
Doxycycline is noted for having a superior characteristic compared to other tetracyclines.
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Which antibiotic is known to inhibit calcium uptake leading to neuromuscular paralysis?
Which antibiotic is known to inhibit calcium uptake leading to neuromuscular paralysis?
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What effect do macrolides have on gram-positive bacteria?
What effect do macrolides have on gram-positive bacteria?
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Study Notes
Antimicrobial Drugs
- Drugs that kill or inhibit the growth of microorganisms.
- Examples include antibiotics, antivirals, antifungals and antiprotozoals.
Antibacterial Drugs
- Bactericidal drugs kill bacteria
- Bacteriostatic drugs stop the growth of bacteria.
- Treating severely ill or immunosuppressed patients with bacterial infections should be with bactericidal antibiotics.
- Bacteriostatic drugs can reduce the efficacy of bactericidal drugs when combined.
- Antibacterials are classified by their mechanism of action: Cell wall synthesis inhibitors, protein synthesis inhibitors, nucleic acid synthesis inhibitors, and miscellaneous agents.
Cell Wall Synthesis Inhibitors
- These drugs cause a structurally deficient cell wall
- They are bactericidal
- They include beta-lactam drugs and vancomycin.
Beta-Lactam Drugs
- These drugs include penicillins, cephalosporins, carbapenems, and monobactams.
- Inhibit the formation of peptidoglycan by inhibiting the enzyme DD-transpeptidase.
- They are susceptible to resistance mechanisms.
- Resistance may be due to:
- Penicillinases (beta-Lactamases)
- Structural changes of PBPs (Penicillin-binding proteins)
- Changes in porin channels.
Penicillins
- Penicillins are classified into natural, anti-staphylococcal, aminopenicillins and antipseudomonal groups.
- Gram-positive bacteria are more sensitive to penicillins compared to gram-negative organisms.
Natural Penicillins
- Penicillin V (oral)
- Penicillin G (parenteral)
- They are sensitive to penicillinases.
- They have activity against gram-positive bacteria, gram-negative cocci, anaerobes, and spirochetes.
Anti-Staphylococcal Penicillins
- This group includes: Methicillin, Nafcillin, Oxacillin, Cloxacillin.
- They are penicillinase resistant
- They are narrow spectrum
- DOC (Drug of choice) for staphylococci.
- There is a type of staphylococcus resistant to this group called Methicillin-resistant Staphylococcus aureus (MRSA).
Aminopenicillins
- This group includes: Ampicillin, Amoxicillin.
- They are extended spectrum
- They are penicillinase sensitive.
- They target gram-negative bacteria such as Haemophilus influenzae, Escherichia coli, Proteus, Salmonella, Shigella.
Anti-Pseudomonal Penicillins
- This group includes: Piperacillin, Ticarcillin.
- They are extended spectrum.
- They are penicillinase sensitive.
Penicillinase Inhibitors
- Sulbactam
- Tazobactam.
Carbapenems
- This group includes: Imipenem and meropenem.
- They are resistant to beta-lactamases
- They have broad-spectrum activity against gram-positive, gram-negative, and anaerobic organisms.
- They are not active against MRSA.
- They are administered intravenously or intramuscularly.
- Imipenem is often combined with CILASTATIN to protect it from metabolism by renal dehydropeptidase.
- High levels of imipenem may provoke seizures.
Monobactams
- This group includes: Aztreonam.
- They are administered IV or IM
- They are active against most gram-negative bacteria but not against gram-positive organisms.
- There is no cross-allergenicity with other beta-lactam drugs.
- They are relatively non-toxic but can cause phlebitis and skin rash.
Vancomycin
- Inhibits peptidoglycan polymerization by acting on the d-alanyl-d-alanine portion of the cell wall.
- Effective against most gram positives, including MRSA.
- Intravenous form used to treat sepsis.
- Oral form used to treat gastrointestinal infections with Clostridium difficile.
- Has infusion-related adverse effects (phlebitis, flushing).
- Has dose-related ototoxicity and nephrotoxicity.
- Resistance is possible due to modification of the D-Ala-D-Ala binding site of the peptidoglycan building block, where D-Ala is replaced by D-lactate.
Protein Synthesis Inhibitors
- Their target is translation.
- They act on the 30S or 50S ribosomes.
- They include Aminoglycosides, Tetracyclines, Macrolides, Chloramphenicol, and Clindamycin.
Aminoglycosides
- This group includes Streptomycin, Tobramycin, Gentamycin, Amikacin.
- They are inhibitors of the initiation complex formation, leading to mRNA misreading and breakup of polysomes.
- They are bactericidal
- They target gram-negative rods, gram-positive cocci, and mycoplasma.
- They have significant nephrotoxicity and ototoxicity, especially with prolonged intake, elderly patients, renal insufficiency, or overdose.
- They can inhibit calcium uptake, which can lead to neuromuscular paralysis.
- Resistance is possible due to ribosome alteration, efflux pumps, and drug-modifying enzymes.
Tetracyclines
- This group includes: Tetracycline, Doxycycline, Minocycline.
- They inhibit protein synthesis by binding to the 30S ribosomal subunit and preventing tRNA from binding to the A-site.
- They are bacteriostatic.
- They have a broad spectrum against both Gram-positive and Gram-negative organisms.
- They are effective against chlamydia, mycoplasmas, and rickettsia.
- They can cause discoloration of teeth in developing children
- Tetracyclines can have photosensitivity.
Macrolides
- This group includes: Erythromycin, Azithromycin, Clarithromycin.
- They bind to the 50S ribosomal subunit and inhibit the translocation step.
- They are primarily bacteriostatic and effective against gram-positive bacteria, particularly Streptococcus pneumoniae, Streptococcus pyogenes and Staphylococcus aureus.
- They can be used to treat infections caused by Mycoplasma pneumoniae, Legionella pneumophila, and Chlamydia trachomatis.
- They can also reduce the number of Helicobacter pylori bacteria in the stomach.
- Azithromycin has a better oral bioavailability.
- They may cause articular cartilage erosion, which is why they are avoided in children.
Chloramphenicol
- It binds to the 50S ribosomal subunit and prevents peptide bond formation.
- It has a broad spectrum of activity against both Gram-positive and Gram-negative bacteria, also against some anaerobes.
- It can cause aplastic anemia (severe bone marrow suppression).
- It has dose-related toxicity.
Clindamycin
- It binds to the 50S ribosomal subunit and inhibits protein synthesis at a step called translocation.
- It is effective against Staphylococcus aureus and other gram-positive bacteria.
- It is also used to treat infections caused by Bacteroides fragilis and other anaerobic bacteria.
Fluoroquinolones
- This group includes: Ciprofloxacin, Levofloxacin, Moxifloxacin.
- They target DNA gyrase and topoisomerase IV, crucial enzymes for bacterial DNA replication.
- They are bactericidal.
- They have a broad spectrum of activity against Gram-negative and some Gram-positive bacteria.
- Ciprofloxacin is a synthetic second-generation fluoroquinolone with the following properties:
- A broad spectrum of activity against aerobic Gram-negative bacteria, including Escherichia coli, Salmonella, Shigella, Pseudomonas aeruginosa, and Neisseria gonorrhoeae.
- Moderate activity against Gram-positive bacteria, including Staphylococcus aureus and Streptococcus pneumoniae.
- Minimal activity against anaerobes.
- Levofloxacin, a third-generation fluoroquinolone, is often used for treating lower respiratory tract infections, acute sinusitis, and urinary tract infections. It has increased activity against Gram-positive bacteria and some anaerobes.
- Moxifloxacin is a fourth-generation fluoroquinolone that has increased activity against anaerobic bacteria.
- Ingestion of fluoroquinolones with dietary supplements containing iron or zinc can reduce their absorption.
Trimethoprim and Sulfamethoxazole
- The combination is known as cotrimoxazole.
- They are bacteriostatic.
- They have a broad spectrum against bacteria, MRSA, Nocardia, Escherichia coli, etc..
- They are effective against fungi like Pneumocystis jiroveci.
- They are also active against protozoa such as Toxoplasma gondi, Giardia lamblia, Entamoeba histolytica, Trichomonas vaginalis, and Gardnerella vaginalis.
Metronidazole
- It forms toxic free radical metabolites that damage bacterial DNA.
- It targets anaerobic bacteria like Bacteroides fragilis, Clostridium difficile.
- It is also active against some protozoa, including Giardia lamblia, Entamoeba histolytica, Trichomonas vaginalis, and Gardnerella vaginalis.
Important Note
- This summary is meant as a guide and does not replace the need for a comprehensive understanding of these drugs. It is always recommended to consult reliable sources for complete information.
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Description
This quiz covers various types of antimicrobial drugs, including antibacterial, antiviral, antifungal, and antiprotozoal agents. It delves into the classifications of antibacterial drugs and their mechanisms of action. Ideal for students and healthcare professionals looking to enhance their understanding of pharmacology.
