45 Questions
Which type of antibiotics kills the organisms?
Bactericidal
Which type of antibiotics temporarily inhibits the growth of an organism?
Bacteriostatic
Which type of antibiotics have specific activity?
Narrow spectrum
Which type of antibiotics have non specific activity?
Broad-spectrum
What is the minimum inhibitory concentration (MIC) for an antibiotic?
The concentration at which the drug is most effective
What can happen if antibiotics with a broad spectrum of activity are used frequently?
Reduced effectiveness of the antibiotics
Why is it generally preferred to treat with a narrow spectrum drug when possible?
Narrow spectrum drugs are more effective
Which type of antibiotic directly interacts with the cell wall by preventing synthesis of the NAG/NAM polymers?
Glycopeptide
Which antibiotic targets the cell wall by inhibiting the transpeptidase, leading to osmotic burst and structural instability?
Beta-lactam antibiotic
Which antibiotic group is known for its resistance due to a beta-lactamase enzyme that breaks the lactam ring?
Penicillins
Which generation of cephalosporins is considered less effective against Gram-positive bacteria compared to the 1st generation?
2nd generation
Which antibiotic group is a cyclic peptide that interferes with dephosphorylation of isoprenyl carriers for cell wall synthesis?
Bacitracin
Which antibiotic binds to a highly conserved motif of lipid II and lipid III, precursors of peptidoglycan and cell wall teichoic acid, respectively?
Teixobactin
Which antibiotic is on the World Health Organization's List of Essential Medicines and is commonly used as an aftercare antibiotic on tattoos and circumcision?
Glycopeptide
Which type of β-lactamases can hydrolyze third-generation cephalosporins but are inhibited by clavulanic acid?
ESBLs
What is a concern in human medicine regarding the evolution of ESBLs?
Build up of reservoirs for ESBLs
Which group of antibiotics binds to the 30S subunit and affects a number of steps in protein synthesis, leading to non-functional proteins?
Aminoglycosides
Which group of antibiotics can be absorbed orally but varies in group, and can cause gastrointestinal imbalances?
Tetracyclines
Which group of antibiotics binds to the 50S subunit and prevents linking of amino acids to growing peptides?
Chloramphenicol
Which group of antibiotics blocks 50S activity and is active against Gram-positive bacteria and anaerobic bacteria?
Macrolides
Which group of antibiotics work on DNA by being a competitive inhibitor of the enzyme dihydropteroate synthase, leading to lack of DNA synthesis?
Sulphonamides and Trimethoprim
Which pathway can be impacted by Rifampicin, potentially affecting the elimination of other medications?
P450 degradative pathway
Why are cationic microbial peptides only tend to be used topically?
They can interact with mammalian cells
What is the impact of infection site on drug activity?
It can alter drug activity
Which type of drug requires anaerobic growth for its effectiveness?
Aminoglycosides
What is the impact of increasing the serum concentration above the MIC for time-dependent antibiotics?
It does not increase killing
What type of drug activity requires high concentrations of drug binding site to be effective?
Concentration-dependent activity
What is the risk of maintaining a high antibiotic concentration for a longer duration?
Increased risk of antibiotic resistance
What is the mechanism of action of Rifampicin?
Inhibits DNA dependant RNA polymerase activity
Why do cationic microbial peptides preferentially interact with bacterial membranes?
Charge dynamics of bacterial membranes differ from that of the host
What is the target of action for antibiotics that target the cell wall?
Cell wall
What is the mechanism of action for beta-lactam antibiotics?
Inhibit the transpeptidase, preventing peptide cross links in the cell wall
What is the resistance mechanism for penicillin?
Beta-lactamase enzyme that breaks the lactam ring
What is the difference between bactericidal and bacteriostatic antibiotics?
Bactericidal antibiotics kill the organisms, while bacteriostatic antibiotics temporarily inhibit the growth of an organism.
What is the significance of the minimum inhibitory concentration (MIC) for antibiotics?
The MIC is the minimum concentration of an antibiotic needed to inhibit the growth of bacteria. It helps determine the effectiveness of the drug during therapy.
Why is it generally preferred to treat with a narrow spectrum antibiotic when possible?
Treating with a narrow spectrum antibiotic targets a specific group of bacteria, reducing the impact on other bacteria and hosts, and minimizing the development of resistance.
What is the mechanism of action of β-lactamases?
β-lactamases hydrolyze/inactivate third-generation cephalosporins.
What is the concern regarding the evolution of ESBLs in human medicine?
ESBLs are a concern because they can reduce the effectiveness of third-generation cephalosporins, an important class of antibiotics.
Which group of antibiotics binds to the 50S subunit and prevents linking of amino acids to growing peptides?
Chloramphenicol binds to the 50S subunit and prevents the linking of amino acids, leading to inhibition of protein synthesis.
Explain the impact of Rifampicin on the p450 degradative pathway in the liver and its potential effect on the elimination of other medications.
Rifampicin can trigger the p450 degradative pathway in the liver, which can affect the elimination of other medications that rely on this pathway for metabolism and clearance.
What is the mechanism of action of cationic microbial peptides and why are they typically only used topically?
Cationic microbial peptides interact with bacterial membranes due to the charge dynamics. They are typically used topically because at high concentrations they can also interact with mammalian cells, causing potential damage.
How can the infection site alter the activity of antibiotics?
The infection site can alter antibiotic activity by creating an environment that is either aerobic or anaerobic, impacting the effectiveness of certain antibiotics. For example, nitroimidazoles require anaerobic metabolism to activate the drug, while aminoglycosides require anaerobic growth to enter bacteria.
Explain the concept of time-dependent activity in antibiotics.
Time-dependent activity refers to the requirement of maintaining the serum concentration of an antibiotic above the minimum inhibitory concentration (MIC) for a certain period of time to effectively kill the bacteria. Increasing the serum concentration above the MIC does not further enhance killing.
What are the characteristics of concentration-dependent activity in antibiotics?
Concentration-dependent activity means that killing of bacteria increases with increasing antibiotic concentration. High concentrations of the drug at the binding site are required for effectiveness. However, it is not always beneficial to maintain high concentrations between doses.
What is the relationship between the duration of antibiotic presence and the risk of antibiotic resistance?
The longer an antibiotic is present at higher concentrations, the greater the risk of selecting for antibiotic resistance.
Test your knowledge on ESBLs and their impact on human and veterinary medicine. Learn about their ability to hydrolyze third-generation cephalosporins and the importance of reducing their use in veterinary settings. Discover the role of clavulanic acid in inhibiting ESBLs and explore the evolution of these enzymes. Explore the use of 5th generation cephalosporins for critical treatment. Take the quiz now and enhance your understanding of ESBLs.
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