Sulfa Drugs and βlactam Antibiotics: CHMI3427EL Winter 2024 Dr. S. Montaut
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Questions and Answers

What is the main function of the bacterial cell wall?

  • To prevent the attachment of host enzymes
  • To provide nutrients for the bacterial cell
  • To aid in DNA replication
  • To protect from changes in osmotic pressure (correct)
  • Where does the final assembly of the bacterial cell wall take place?

  • At the inner membrane
  • Outside of the inner membrane (correct)
  • At the cell nucleus
  • Within the cell cytoplasm
  • Which syndrome is a serious adverse effect mentioned in the text?

  • Stevens-Johnson syndrome (correct)
  • Erythema multiforme
  • Mouth mucous membrane ulceration
  • Urethra ulceration
  • What makes the enzymes involved in late steps of cell wall synthesis more vulnerable to inhibition?

    <p>Their proximity to the cell surface</p> Signup and view all the answers

    What is the purpose of the antigenic determinants on the outside of gram-positive bacterial cells?

    <p>Allow for attachment to specific target cells</p> Signup and view all the answers

    Which of the following is NOT a function of the bacterial cell wall?

    <p>Facilitate DNA replication</p> Signup and view all the answers

    What characteristic makes Stevens-Johnson syndrome a rare adverse effect?

    <p>Its comparative rarity</p> Signup and view all the answers

    Why does the final assembly of the bacterial cell wall take place outside of the inner membrane?

    <p>To facilitate extrusion and growth</p> Signup and view all the answers

    What is the main reason sulfonamides are disqualified for use in late-term pregnancy?

    <p>They cause neonatal jaundice</p> Signup and view all the answers

    Which process partly deactivates sulfonamides in the liver?

    <p>Acetylation at N-4</p> Signup and view all the answers

    What is a common form of plasmid-mediated resistance development among gram-negative microorganisms?

    <p>Decreased sensitivity of dihydropteroate synthase</p> Signup and view all the answers

    Which sulfonamide is used in combination with erythromycin due to its broad antimicrobial spectrum?

    <p>Sulfisoxazole</p> Signup and view all the answers

    What is the adverse effect most commonly associated with sulfonamides?

    <p>Allergic reactions</p> Signup and view all the answers

    Which organisms may be susceptible to sulfisoxazole according to the text?

    <p>Haemophilus and Proteus</p> Signup and view all the answers

    What limits the clinical use of sulfisoxazole, despite its broad antimicrobial spectrum?

    <p>Development of bacterial resistance</p> Signup and view all the answers

    What is a less common problem associated with sulfonamides mentioned in the text?

    <p>Hemolytic anemia</p> Signup and view all the answers

    What is the primary role of penicillin binding proteins in bacteria?

    <p>Construction of the cell wall</p> Signup and view all the answers

    How do β-lactam antibiotics kill bacteria?

    <p>Preventing the biosynthesis of a functional cell wall</p> Signup and view all the answers

    Why is selective interference by β-lactam antibiotics problematic for bacteria?

    <p>It prevents normal growth and repair processes</p> Signup and view all the answers

    What distinguishes the outer lipid membrane of gram-negative bacteria from the inner membrane?

    <p>Containment of lipopolysaccharides</p> Signup and view all the answers

    What role do porins play in gram-negative bacteria?

    <p>Regulating the passage of molecules through the membrane</p> Signup and view all the answers

    What is the function of the center of the transmembranal pore in porins?

    <p>Allowing passage of small molecules</p> Signup and view all the answers

    How do complex lipopolysaccharides in the outer lipid membrane influence gram-negative bacteria?

    <p>Cause septic shock</p> Signup and view all the answers

    Why are penicillin binding proteins essential for bacterial cells?

    <p>To facilitate controlled cell growth and repair processes</p> Signup and view all the answers

    What is a key consideration controlling porin passage for drugs?

    <p>Shape of drugs</p> Signup and view all the answers

    What is the key concept associated with antibiotics?

    <p>Selective toxicity</p> Signup and view all the answers

    Why do antibiotics have greater difficulty penetrating into gram-negative bacterial cells?

    <p>Presence of thicker peptidoglycan layer</p> Signup and view all the answers

    Where are the β-lactam targets found in bacterial cells?

    <p>Cytoplasmic membrane</p> Signup and view all the answers

    Who discovered bacteria in 1676?

    <p>van Leeuwenhoek</p> Signup and view all the answers

    What led to the appreciation of antibiosis in microorganisms?

    <p>Interaction of anthrax bacilli with common bacteria</p> Signup and view all the answers

    What role do inner membrane proteins play in bacterial cells?

    <p>Energy production</p> Signup and view all the answers

    In what year did Louis Pasteur report the interaction between 'common bacteria' and anthrax bacilli?

    <p>1877</p> Signup and view all the answers

    What is the contemporary name for the ring system of a β-lactam?

    <p>Azetidinone</p> Signup and view all the answers

    Which subclass of β-lactam antibiotics is characterized by a substituted five-membered thiazolidine ring fused to the β-lactam ring?

    <p>Penicillins</p> Signup and view all the answers

    Who observed a clear zone of inhibition surrounding a Penicillium mold colony?

    <p>Alexander Fleming</p> Signup and view all the answers

    What shape does the molecule of a β-lactam antibiotic roughly possess due to the fusion and chirality of the β-lactam ring?

    <p>&quot;V&quot; shape</p> Signup and view all the answers

    What discovery is attributed to France and Germany in 1936?

    <p>Discovery of sulfonamides</p> Signup and view all the answers

    Which scientist is known for isolating microorganisms from infected patients and reproducing disease symptoms in healthy individuals?

    <p>Robert Koch</p> Signup and view all the answers

    What is a common function of proteins that actively pump out antibiotics from bacterial cells?

    <p>Maintain electrostatic balance</p> Signup and view all the answers

    What is the term used to describe substances that inhibit or kill microorganisms but are unrelated to natural products?

    <p>Antibiotics</p> Signup and view all the answers

    Which group of bacteria does benzylpenicillin primarily target?

    <p>Gram-positive cocci</p> Signup and view all the answers

    What is a key advantage of phenoxymethylpenicillin compared to benzylpenicillin?

    <p>More acid stability</p> Signup and view all the answers

    Where are β-lactamases secreted in gram-negative bacteria?

    <p>Periplasmic space</p> Signup and view all the answers

    Which reaction is occasionally immediate and profound due to allergy?

    <p>Cardiovascular collapse</p> Signup and view all the answers

    What is the main reason benzylpenicillin remains a useful agent for treatment?

    <p>Lack of toxicity except for allergic patients</p> Signup and view all the answers

    How is penicillin V primarily produced?

    <p>Fermentation in enriched medium</p> Signup and view all the answers

    What distinguishes the secretion of β-lactamases in gram-negative bacteria?

    <p>Secretion into the periplasmic space between membranes</p> Signup and view all the answers

    Which type of bacteria are more susceptible to phenoxymethylpenicillin?

    <p>Gram-positive cocci</p> Signup and view all the answers

    What is the primary reason for coadministering tazobactam with piperacillin?

    <p>Inhibiting β-lactamases</p> Signup and view all the answers

    Which compound was described as the broadest spectrum penicillin currently available in the text?

    <p>Zosyn</p> Signup and view all the answers

    Why was cephalosporin C not considered a useful antibiotic?

    <p>It lacked antibacterial activity</p> Signup and view all the answers

    What distinguishes the chemical structure of 7-aminocephalosporanic acid from cephalosporin C?

    <p>Additional side chains</p> Signup and view all the answers

    Why is resistance due to β-lactamases highlighted as a prominent feature of using piperacillin and tazobactam?

    <p>To enhance antibacterial properties</p> Signup and view all the answers

    What motivated the chemical alteration of cephalosporin C to produce 7-aminocephalosporanic acid?

    <p>Improved potency against gram-negative bacteria</p> Signup and view all the answers

    What is the role of tazobactam in the piperacillin and tazobactam combination?

    <p>Inhibiting β-lactamases</p> Signup and view all the answers

    What is a distinguishing characteristic of cefotetan and cefoxitin?

    <p>Possession of antianaerobic activity</p> Signup and view all the answers

    Which organisms are often sensitive to third-generation cephalosporins as per the text?

    <p>Klebsiella and Pseudomonas aeruginosa</p> Signup and view all the answers

    What is a notable feature of fourth-generation cephalosporins compared to third-generation drugs?

    <p>Higher activity against gram-positive organisms</p> Signup and view all the answers

    What is the most commonly experienced toxicity of cephalosporins besides allergic reactions?

    <p>Temporary nausea, vomiting, and diarrhea</p> Signup and view all the answers

    What is the activating leaving group present at C-3 in cefazolin according to the text?

    <p>Thiadiazole ring</p> Signup and view all the answers

    Which statement regarding the third-generation cephalosporins is accurate based on the text?

    <p>Useful against Morganella sp. and Staphylococcus aureus</p> Signup and view all the answers

    What improvement has been made to newer third-generation cephalosporins to enhance their spectrum against β-lactamase–producing strains?

    <p>Combined with β-lactamase inhibitors</p> Signup and view all the answers

    'The moiety is not subject to the inactivating host hydrolysis reaction.' - This statement directly refers to which part of cefazolin?

    <p>$C-3$</p> Signup and view all the answers

    What characteristic of ertapenem makes it different from imipenem and meropenem?

    <p>It is inactive against Pseudomonas species</p> Signup and view all the answers

    Which enzyme does the 4-β-methyl group in carbapenems confer stability toward?

    <p>Dehydropeptidase-1</p> Signup and view all the answers

    What makes aztreonam primarily effective against gram-negative microorganisms?

    <p>Strong affinity for PBP-3</p> Signup and view all the answers

    What is a key feature of the monobactams that differentiates them from other β-lactam antibiotics?

    <p>Presence of a fused ring</p> Signup and view all the answers

    Which type of infections is aztreonam primarily used to treat?

    <p>Gram-negative bacterial infections</p> Signup and view all the answers

    Why should ertapenem not be substituted for other carbapenems in the treatment of Pseudomonas or Acinetobacter infections?

    <p>It is inactive against these organisms</p> Signup and view all the answers

    What does the α-oriented methyl group at C-2 contribute to in aztreonam?

    <p>Stability toward β-lactamases</p> Signup and view all the answers

    What is the main indication for Ceftaroline Fosamil as mentioned in the text?

    <p>Treatment of pneumonia</p> Signup and view all the answers

    Which group at C-3 of Cefepime assists in the penetration into gram-negative bacteria?

    <p>Quaternary N-methylpyrrolidine group</p> Signup and view all the answers

    What differentiates Carbapenems structurally from penicillins and cephalosporins?

    <p>Absence of a β-lactam ring</p> Signup and view all the answers

    What enhances the spectrum and β-lactamase stability of Cefepime?

    <p>Aminothiazolyl group at C-7</p> Signup and view all the answers

    What is the mechanism of action of Ceftaroline Fosamil against methicillin-resistant Staphylococcus aureus?

    <p>Affinity for PBP-2a</p> Signup and view all the answers

    Which type of bacteria does Cefepime have enhanced antistaphylococcal activity against?

    <p><strong>Streptococcus</strong> sp.</p> Signup and view all the answers

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