L-20 Cephalosporins Quiz

<p>Methicillin-resistant Staphylococcus aureus (MRSA) (D)</p> Signup and view all the answers

<p>Blocks tubular secretion, thus increasing plasma concentration (D)</p> Signup and view all the answers

<p>Enterococcal infections (A)</p> Signup and view all the answers

<p>Gram-negative bacilli (C)</p> Signup and view all the answers

<p>Excreted in the urine via renal tubular secretion (A)</p> Signup and view all the answers

<p>Prophylaxis in perioperative infections and as penicillin G substitutes that are resistant to staphylococcal penicillinase. (C)</p> Signup and view all the answers

<p>Enterococci and <em>Pseudomonas aeruginosa</em>. (A)</p> Signup and view all the answers

<p>They have broader gram-negative coverage and some can cross the blood-brain barrier. (D)</p> Signup and view all the answers

<p>Cefaclor (D)</p> Signup and view all the answers

<p>The specific activity of the drug may vary between different strains of bacteria. (B)</p> Signup and view all the answers

<p><em>Proteus</em>, <em>E.coli</em>, and <em>Klebsiella pneumoniae</em>. (C)</p> Signup and view all the answers

<p>Cefazolin (C)</p> Signup and view all the answers

<p>Enterobacter's resistance is due to chromosome-mediated beta-lactamase. (B)</p> Signup and view all the answers

<p>Cefoperazone (D)</p> Signup and view all the answers

<p>Inhibition of enolpyruvate transferase, thus preventing formation of N-acetylmuramic acid. (A)</p> Signup and view all the answers

<p>A single 2-g dose of azithromycin orally. (D)</p> Signup and view all the answers

<p>Colitis caused by Clostridium difficile (A)</p> Signup and view all the answers

<p>It is a broad-spectrum oral beta-lactam antibiotic. (B)</p> Signup and view all the answers

<p>Ceftizoxime (C)</p> Signup and view all the answers

<p>Inhibition of cell wall synthesis. (B)</p> Signup and view all the answers

<p>Oral (C)</p> Signup and view all the answers

<p>Cefixime 400 mg orally plus azithromycin 1g orally single dose or doxycycline 100 mg orally twice daily for 7 days. (B)</p> Signup and view all the answers

<p>They are effective due to their CNS penetration. (D)</p> Signup and view all the answers

<p>Inactivate beta-lactamases, protecting penicillins from degradation. (D)</p> Signup and view all the answers

<p>Clostridium difficile (D)</p> Signup and view all the answers

<p>Cefoperazone and Ceftazidime (C)</p> Signup and view all the answers

<p>Increased risk of ototoxicity and nephrotoxicity. (C)</p> Signup and view all the answers

<p>They are hydrolyzed by Enterobacter chromosomal beta lactamases. (A)</p> Signup and view all the answers

<p>Inhibition of cell wall phospholipids and peptidoglycan polymerization by binding to D-alanyl-D-alanine. (A)</p> Signup and view all the answers

<p>It exhibits limited distribution in bodily tissues. (D)</p> Signup and view all the answers

<p>Daptomycin relies solely on membrane disruption, whereas telavancin combines membrane disruption with vancomycin-like action. (B)</p> Signup and view all the answers

<p>It is inactivated in pulmonary tissues. (C)</p> Signup and view all the answers

<p>It shares a similar structure with daptomycin. (D)</p> Signup and view all the answers

<p>Both daptomycin and telavancin are effective. (A)</p> Signup and view all the answers

<p>It is poorly absorbed, resulting in local antibacterial activity with minimal systemic effects. (A)</p> Signup and view all the answers

<p>Disrupting bacterial cell membrane integrity by interacting with phospholipids. (C)</p> Signup and view all the answers

<p>They have a high risk of nephrotoxicity and neurotoxicity, and poor tissue distribution. (A)</p> Signup and view all the answers

<p>The incorporation of D-alanine into peptidoglycans. (B)</p> Signup and view all the answers

<p>Polymyxins are used for topical applications and in the treatment of corneal ulcers caused by Pseudomonas. (D)</p> Signup and view all the answers

<p>It can lead to proteinuria, hematuria, and nitrogen retention if systemically administered. (D)</p> Signup and view all the answers

<p>By blocking the conversion of L-alanine to D-alanine and incorporation into peptidoglycans. (B)</p> Signup and view all the answers

<p>Bacitracin, Polymyxins, and Neomycin (A)</p> Signup and view all the answers

First-generation cephalosporins are effective against a range of gram-positive bacteria, including Staphylococcus aureus, and some gram-negative bacteria like Proteus, E. coli, and Klebsiella pneumoniae.

First-generation cephalosporins are generally not effective against enterococci or Pseudomonas aeruginosa.

Cefazolin is a first-generation cephalosporin that is often used for surgical prophylaxis due to its effectiveness against common surgical site infections.

Second-generation cephalosporins have a broader spectrum of activity compared to first-generation cephalosporins, being effective against more gram-negative bacteria, including Haemophilus influenzae, Enterobacter aerogenes, and Neisseria.

Second-generation cephalosporins are generally not effective against enterococci or Pseudomonas aeruginosa.

Third-generation cephalosporins have an even broader spectrum of activity than second-generation cephalosporins, with enhanced gram-negative coverage and some ability to cross the blood-brain barrier.

Cefaclor, a second-generation cephalosporin, is highly susceptible to beta-lactamase, an enzyme produced by some bacteria that can inactivate the drug.

The choice of cephalosporin depends on the specific type of infection, the patient's sensitivity, and the potential for resistance.

Cephalosporins are a class of antibiotics with a similar structure and mechanism of action to penicillins. They contain a beta-lactam ring and a six-membered sulfur-containing ring, and their effectiveness against bacteria is determined by the presence of specific 'R' groups.

Cephalosporins are classified into four generations, with each generation having increasing resistance to beta-lactamases, which are enzymes produced by bacteria to break down antibiotics.

Cephalosporins are generally not effective against methicillin-resistant Staphylococcus aureus (MRSA), Listeria monocytogenes, Clostridium difficile, and Enterococci.

Cephalosporins are typically administered intravenously or orally, but most do not penetrate the central nervous system (CNS).

The half-lives of cephalosporins vary widely. They are mostly excreted in the urine through renal tubular secretion, and the process can be blocked by probenecid, leading to higher plasma concentrations.

Cephalosporins are effective against many gram-positive cocci, including staphylococci and many strains of gram-positive bacilli. However, they are ineffective against enterococci.

Cephalosporins are drugs of choice for infections caused by S. pyogenes, Klebsiella pneumoniae, and Pneumococcal pneumonia.

Cephalosporins have an expanded spectrum of activity that includes effectiveness against Proteus, Bacteroides fragilis, Serratia, Enterobacter, and some activity against Pseudomonas.

First line drug for N. gonorrhoeae infections. Its use is declining due to resistance.

A third generation cephalosporin that's a good choice for N. gonorrhoeae treatment, especially when resistance is a concern.

Third generation cephalosporins are known for their broad spectrum of activity, including effectiveness against a variety of gram-negative bacteria.

Ceftazidime (Fortaz) and Cefoperazone (Cefobid) are two examples that are particularly effective against P. aeruginosa, a challenging bacteria.

Ceftriaxone and Cefoperazone are eliminated primarily through the biliary system, meaning they are excreted in bile. This makes them good choices for patients with kidney issues as they don't require dosage adjustments based on kidney function.

Their ability to penetrate the central nervous system (CNS) makes them suitable for treating serious infections like meningitis.

Cefditoren is especially good at combating beta-lactamase producing strains of Haemophilus influenzae, a common cause of ear infections.

Highly penicillin-resistant strains of pneumococci may not be effectively treated by third generation cephalosporins alone. Adding rifampin or vancomycin might be necessary.

Cycloserine is an antibiotic that inhibits the growth of mycobacteria, often used to treat tuberculosis. It's taken orally and mainly excreted in its active form in urine.

Daptomycin is a bactericidal antibiotic that disrupts bacterial cell membranes, also interfering with protein and DNA synthesis. It's effective against resistant gram-positive bacteria such as MRSA and VRE, but not used for pneumonia.

Telavancin is a bactericidal antibiotic similar to vancomycin in structure, but with a broader spectrum of activity. It's effective against resistant bacteria like MRSA and is used for complicated skin infections and pneumonia.

Cycloserine can cause side effects on the central nervous system, including headaches, tremors, psychosis, and even convulsions.

Daptomycin is inactivated by pulmonary tissue and is therefore not used for treating pneumonia. It's effective for complicated skin infections and bacteremia.

A type of antibiotic that works by inhibiting the synthesis of cell wall phospholipids and peptidoglycan polymerization. It is particularly effective against methicillin-resistant staphylococcal infections.

A group of antibiotics often used for urinary tract and respiratory tract infections.

Antibiotics such as clavulanic acid, sulbactam, and tazobactam that enhance the effectiveness of penicillins by deactivating bacterial beta-lactamases.

A type of antibiotic that works by binding to D-alanyl-D-alanine cell wall precursors, thereby inhibiting cell wall synthesis. Effective against gram-positive bacteria.

A rare side effect of vancomycin treatment characterized by flushing, redness, and itching, typically affecting the face and neck. This is caused by the release of histamine.

An antibiotic that works by inhibiting the early stages of cell wall synthesis. It is effective against both gram-positive and gram-negative bacteria.

A mixture of polypeptides that inhibits bacterial cell wall synthesis (particularly effective against gram-positive bacteria).

Situations in which vancomycin is clinically indicated. This includes infections by resistant Staphylococcus species, such as sepsis or endocarditis.

Polymyxins are a group of antibiotics active against gram-negative bacteria. They are cationic detergents that disrupt bacterial cell membranes, effectively killing the bacteria. Despite their effectiveness, their nephrotoxicity and neurotoxicity limit their use to topical applications.

Polymyxin B is a specific type of polymyxin used in the USA. It is a cationic peptide that disrupts bacterial cell membranes, killing gram-negative bacteria like Pseudomonas. Its use is primarily restricted to topical applications due to its toxicity.

Colistin, also known as Polymyxin E, is another type of polymyxin that is used outside of the USA. Like other polymyxins, it is effective against gram-negative bacteria and is used primarily in topical applications due to its toxicity.

Cycloserine is a structural analogue of D-alanine, a molecule crucial for building bacterial cell walls. It works by inhibiting the formation of D-alanine, which is necessary for cell wall synthesis. This disruption prevents the bacteria from multiplying and causing infection.