Introduction To Antibiotics Flashcards
(15 cards)
Q: What is a key structural difference between prokaryotes and eukaryotes?
Q: What component is unique to Gram-negative bacteria?
Q: What enzyme cross-links peptidoglycan strands?
Q: Which ribosomal subunit is targeted by tetracyclines?
Q: Which antibiotic targets DNA gyrase (topoisomerase II)?
Q: Which class of antibiotics inhibits folate metabolism?
A: Prokaryotes lack a nucleus and membrane-bound organelles; eukaryotes have both.
A: Outer membrane with LPS (lipopolysaccharide).
A: Transpeptidase (inhibited by beta-lactams).
A: 30S subunit of the prokaryotic ribosome.
A: Fluoroquinolones.
A: Sulfonamides (antimetabolites).
Q: Which antibiotics inhibit RNA polymerase?
Q: Which antibiotics inhibit DNA polymerase?
Q: Which antibiotics inhibit Cell Wall?
Q: Which antibiotics inhibit Ribosomes?
Q: Which antibiotics inhibit Folate pathway?
A: Rifampin and rifabutin.
A: Quinolones
A: Beta Lactams
A: Aminoglycosides and Microlides
A: Sulfonamides
Q: Which antibiotic type is preferred in immunocompromised patients?
Q: What is the key difference between MIC and MBC?
Q: What type of antibiotic is used empirically when the pathogen is unknown?
Q: What is antibiotic synergy?
Q: What is a major resistance mechanism in Gram-negative bacteria?
A: Bactericidal.
Bactericidal: Kills bacteria (e.g., beta-lactams).
Bacteriostatic: Inhibits growth (e.g., macrolides, tetracyclines).
A: MIC inhibits growth; MBC kills 99.9% of the bacteria. (Broth dilution tests)
A: Broad-spectrum antibiotic.
A: Enhanced antimicrobial effect when two drugs are combined.
A: Efflux pumps and porin changes that reduce drug entry.
Q: What are two intrinsic mechanisms of resistance?
Q: What is an R factor?
Q: How do bacteria resist penicillin?
Q: What change causes vancomycin resistance?
Q: How do bacteria resist erythromycin?
A: Intracellular location and lack of cell wall.
A: A plasmid carrying antibiotic resistance genes.
A: Beta-lactamase production or altered PBPs.
A: D-Ala-D-Ala to D-Ala-D-Lactate in peptidoglycan.
A: Methylation of 23S rRNA.
Q: Which antibiotic class inhibits peptidoglycan cross-linking?
Q: Which drug inhibits transpeptidase in peptidoglycan synthesis?
Q: What is the mechanism of action of beta-lactam antibiotics?
Q: What structure is essential for penicillin activity?
Q: Which organisms are resistant to natural penicillins?
A: Beta-lactams.
A: Beta-lactams.
A: Inhibit PBPs, blocking cell wall cross-linking and causing bacterial lysis.
A: The β-lactam ring.
A: Staphylococcus aureus and S. epidermidis.
Q: What is the mechanism of MRSA resistance to penicillinase-resistant penicillins?
Q: Which penicillins have better Gram-negative coverage than natural penicillins?
Q: Which penicillin is used for Pseudomonas infections?
Q: What are ESBLs?
Q: Name three β-lactamase inhibitors.
A: Altered penicillin-binding proteins (PBPs).
A: Aminopenicillins (ampicillin, amoxicillin)
A: Piperacillin (extended-spectrum).
A: Enzymes that break down multiple β-lactam antibiotics.
A: Clavulanic acid, Sulbactam, Tazobactam.
Q: What is Zosyn?
Q: Which penicillin combination has the broadest spectrum?
Q: Why are cephalosporins preferred over penicillins in some infections?
Q: Which cephalosporin generation covers MRSA?
Q: What is the general trend in cephalosporin spectrum from 1st to 5th gen?
A: Piperacillin + Tazobactam (broad-spectrum IV antibiotic).
A: Extended-spectrum penicillin + β-lactamase inhibitor (e.g., Zosyn)
A: They are more resistant to β-lactamases and have broader spectrum.
A: 5th generation (ceftaroline). Zoline, Rozime, triazone, Epeme, Trioline
A: Decreasing Gram-positive, increasing Gram-negative coverage.
Q: What are first-gen cephalosporins used for?
Q: What differentiates cephamycins from cephalosporins?
Q: Which 3rd-gen cephalosporin crosses the blood-brain barrier and treats meningitis?
Q: Which penicillin resists penicillinase?
Q: Name 2 ways bacteria resist antibiotics.
A: Minor skin infections and UTIs.
A: Cephamycins have moderate anaerobic activity.
A: Ceftriaxone or cefotaxime.
A: Nafcillin. Oxacillin
A: Enzyme inactivation and efflux pumps.
Q: What is CRE?
Q: Which beta-lactam is safe in penicillin allergy?
Q: How does daptomycin kill bacteria?
Q: Which ribosomal subunit do macrolides target?
Q: What is the mechanism of action of penicillins?
A: Carbapenem-Resistant Enterobacteriaceae.
A: Aztreonam.
A: Inserts into membrane and causes lysis.
A: 50S.
A: Inhibit transpeptidase enzymes, blocking bacterial cell wall synthesis.
Q: Which organisms are resistant to natural penicillins?
Q: What is added to aminopenicillins to broaden their spectrum?
Q: What is Piperacillin-Tazobactam (Zosyn) used for?
Q: What is the role of clavulanic acid?
Q: Which cephalosporin generation covers MRSA?
A: Staphylococcus aureus and Staphylococcus epidermidis (produce penicillinase).
A: β-lactamase inhibitors (e.g., clavulanic acid).
A: Broad-spectrum coverage including Pseudomonas.
A: Inhibits β-lactamase enzymes to protect penicillins.
A: 5th generation (Ceftaroline).
Q: Why are carbapenems considered last-line antibiotics?
Q: Which β-lactam is safe for penicillin-allergic patients?
Q: How does vancomycin resistance develop in Enterococci?
Q: Why is daptomycin ineffective in pneumonia?
Q: Which antibiotics inhibit the 30S ribosomal subunit?
A: Broad spectrum and reserved for multidrug-resistant infections.
A: Aztreonam.
A: Change from D-Ala-D-Ala to D-Ala-D-Lac.
A: It is inactivated by lung surfactant.
A: Aminoglycosides and Tetracyclines.
Q: What is the most common resistance mechanism to aminoglycosides?
Q: What is the mechanism of tetracycline resistance?
Q: What is the macrolide mechanism of action?
Q1: What do all cephalosporins have in common?
Q2: Which generation of cephalosporins covers MRSA?
A: Enzyme modification preventing ribosome binding.
A: Plasmid-encoded efflux pump.
A: Bind 23S rRNA of 50S ribosome → inhibit translocation and elongation.
A1: Beta-lactam structure; inhibit cell wall synthesis by binding PBPs.
A2: 5th generation (ceftaroline).
Q3: Which cephalosporin has Pseudomonas coverage?
Q4: What’s the most broad-spectrum beta-lactam class?
Q5: What is the MOA of vancomycin?
Q6: What is the main side effect of clindamycin?
Q7: What is the MOA of aminoglycosides?
A3: Cefepime (4th gen) and ceftazidime (3rd gen).
A4: Carbapenems.
A5: Binds D-Ala-D-Ala to block peptidoglycan cross-linking.
A6: C. difficile-associated diarrhea.
A7: Irreversibly bind 30S, block initiation, cause mRNA misreading.
Q8: Which protein synthesis inhibitors bind the 50S subunit?
Q9: What causes resistance to macrolides?
Q10: What’s the MOA of fluoroquinolones?
Q11: Which RNA polymerase inhibitor is used in TB?
Q: What is the MOA of isoniazid?
A8: Macrolides, clindamycin, streptogramins, oxazolidinones.
A9: Methylation of 23S rRNA or efflux pump
A10: Inhibit DNA gyrase (topoisomerase II).
A11: Rifampin.
A: Inhibits synthesis of mycolic acid in mycobacterial cell wall
Q: Which two enzymes are inhibited by TMP/SMX?
Q: What non-bacterial pathogens are covered by TMP/SMX?
Q: What is the primary mechanism of action of metronidazole?
Q: Which antibiotics target bacterial RNA synthesis?
Q: What resistance mechanism allows MRSA to evade beta-lactams?
A: Dihydropteroate synthase and dihydrofolate reductase.
A: Toxoplasma gondii and Pneumocystis jirovecii.
A: Free radical formation leading to DNA strand breaks in anaerobic bacteria.
A: Rifampin and rifabutin.
A: Altered penicillin-binding proteins (PBPs).
