29 Questions
What is the primary mechanism of action of Penicillin in inhibiting bacterial cell wall synthesis?
Inhibition of transpeptidation
What is the effect of Penicillin on autolytic enzymes in bacteria?
It activates their activity
What is the name of the protein that Penicillin binds to in the bacterial cell membrane?
Penicillin-binding proteins
Which of the following antibiotics is considered the last line of defense against MRSA?
Vancomycin
What is the common concern associated with the use of Beta-lactam antibiotics?
Allergies
Which of the following antibiotics is only used topically?
Bacitracin
What is the primary mechanism of bacterial resistance to macrolides?
Modification of the ribosomal binding site
What is the mode of action of Fluoroquinolones?
Inhibition of DNA gyrase and topoisomerase IV
Which type of bacteria are macrolides commonly used to treat?
Both Gram-positive and some Gram-negative bacteria
What is a concern with the use of Fluoroquinolones?
Increasing resistance noted
What is the effect of macrolides on bacterial cells at higher concentrations?
Bactericidal activity
What is the target of Rifampin in bacterial cells?
RNA polymerase
What is the primary function of enzymes such as DNA gyrase and topoisomerase IV in bacterial DNA?
To separate DNA strands during replication and transcription
What is the result of fluoroquinolones inhibiting DNA gyrase and topoisomerase IV?
The blockage of DNA replication and transcription
What type of activity do fluoroquinolones exhibit against bacteria?
Bactericidal activity
What is the primary mechanism of resistance to tetracyclines in bacteria?
Modification of the ribosomal binding site
How do macrolides inhibit bacterial protein synthesis?
By blocking the translocation step of protein synthesis
What is the primary effect of macrolides on bacterial cells?
Inhibition of bacterial growth and reproduction
What is the ultimate result of the inhibition of DNA replication and transcription by fluoroquinolones?
The accumulation of DNA damage and the death of the bacterial cell
What is a characteristic of the spectrum of activity of fluoroquinolones?
Broad spectrum of activity
What is the ultimate consequence of macrolide binding to the ribosome?
Inhibition of peptide bond formation
What is the primary mechanism of action of rifampin in inhibiting bacterial growth?
Inhibiting bacterial RNA synthesis
Which of the following is a characteristic of rifampin?
Broad spectrum of activity
What is the primary site of action for macrolides?
50S ribosomal subunit
What is the scope of activity for tetracyclines?
Broad spectrum of activity
What is the primary target of sulfonamides in bacterial cells?
Folic acid synthesis
What is the result of sulfonamides inhibiting folic acid synthesis in bacteria?
Inhibited bacterial survival
What is a common mechanism of bacterial resistance to rifampin?
Efflux of the antibiotic from the bacterial cell
What is the purpose of using rifampin in combination with other antibiotics?
To prevent the development of resistance
Study Notes
Major Targets for Antibacterial Action
- Cell wall synthesis
- Nucleic acid synthesis
- Metabolic processes
Antibiotics that Target Cell Wall Synthesis
- Penicillin (Penicillins, Ampicillin, Carbenicillin, Amoxicillin, Methicillin)
- Mode of action: inhibit transpeptidation and activate autolytic enzymes
- Target organisms: Gram-positive organisms
- Special concerns: allergies, beta-lactamase
Antibiotics that Target Nucleic Acid Synthesis
-
Fluoroquinolones (Ciprofloxacin, Ofloxacin, Lomefloxacin)
-
Mode of action: inhibit DNA gyrase and topoisomerase IV, blocking DNA replication and transcription
-
Target organisms: Gram-positive and Gram-negative bacteria, including mycobacteria
-
Special concerns: increasing resistance, quick resistance development
-
Macrolides (Rifampin)
-
Mode of action: inhibit protein synthesis by binding to the 50S ribosomal subunit
-
Target organisms: Gram-positive and Gram-negative bacteria, including mycobacteria
-
Special concerns: bactericidal activity, modification of the ribosomal binding site, efflux pumps
Antibiotics that Inhibit Metabolic Processes
- Sulfonamides (Gantrisin, SXT, Bactrim)
- Mode of action: inhibit folic acid synthesis by imitating PABA
- Target organisms: Gram-negative and some Gram-positive bacteria
- Special concerns: allergic reactions, sun sensitivity, synergistic use with trimethoprim
Test your knowledge on the mechanisms of action of antibacterial, antifungal, and antiviral drugs, including their targets and common drug names. Learn about the importance of cell wall synthesis and how antibiotics interact with Gram-positive and Gram-negative organisms.
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