Cell Wall Synthesis and Antibiotics
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Questions and Answers

What is the primary role of Fosfomycin in antibiotic therapy?

  • Inhibit monomer production (correct)
  • Promote cross-linking of cell wall
  • Prevent bacteria wall from getting longer
  • Inhibit polymer synthesis

    • Which of the following describes a common characteristic shared by all Beta Lactam antibiotics?

  • Bacteriostatic effects
  • Absorption in the gastrointestinal tract
  • Long half lives
  • Bactericidal mechanism of action (correct)

    • Which type of penicillin is specifically designed to be resistant to penicillinase?

  • Broad-spectrum Penicillin
  • Aminopenicillin
  • Antistaphylococcal Penicillin (correct)
  • Natural Penicillin

    • What is a key difference between Penicillin G and Penicillin V in terms of administration routes?

    <p>Penicillin G is administered intravenously only</p> Signup and view all the answers

    Which of the following statements about beta lactamase is true?

    <p>It destroys beta lactam antibiotics</p> Signup and view all the answers

    Which of the following statements is accurate about beta lactam antibiotics?

    <p>They share similar pharmacodynamics but differ in absorption and PBP targeting.</p> Signup and view all the answers

    Which antibiotic specifically inhibits the monomer necessary for cell wall synthesis?

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

    What characteristic is NOT common among beta lactam antibiotics?

    <p>All have the same absorption properties.</p> Signup and view all the answers

    Which of the following is true regarding antistaphylococcal penicillins?

    <p>They include drugs such as nafcillin and oxacillin.</p> Signup and view all the answers

    What is the primary action of Beta Lactam antibiotics in relation to the bacterial cell wall?

    <p>They prevent the cross-linking of the cell wall.</p> Signup and view all the answers

    Which class of antibiotics is primarily focused on targeting the structural integrity of the bacterial cell wall?

    <p>Beta Lacams</p> Signup and view all the answers

    Which of the following is NOT a property of aminopenicillins like ampicillin and amoxicillin?

    <p>They are effective against beta lactamase producing bacteria.</p> Signup and view all the answers

    What is a common mode of transmission for Pseudomonas aeruginosa?

    <p>Contaminated water and surfaces</p> Signup and view all the answers

    Which of the following is a characteristic feature of Pseudomonas aeruginosa?

    <p>Production of greenish-blue pigment</p> Signup and view all the answers

    Infections caused by Pseudomonas aeruginosa are most commonly associated with which of the following groups?

    <p>Immunocompromised patients and those with chronic illnesses</p> Signup and view all the answers

    Which type of antibiotic is typically less effective against Pseudomonas aeruginosa?

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

    What is a significant concern regarding the treatment of Pseudomonas aeruginosa infections?

    <p>High mutation rate leading to resistance</p> Signup and view all the answers

    Which characteristic is true for Neisseria gonorrhoeae?

    <p>It contains pili for adhesion.</p> Signup and view all the answers

    What is a notable effect of meningococcal lipopolysaccharides in Neisseria meningitidis?

    <p>They are responsible for toxic effects in disease.</p> Signup and view all the answers

    In which environments is Neisseria meningitidis most likely to occur in epidemic waves?

    <p>Military camps.</p> Signup and view all the answers

    Which treatment is currently recommended for infections caused by Neisseria gonorrhoeae?

    <p>Cefixime and ceftriaxone.</p> Signup and view all the answers

    What is a potential consequence of untreated gonococcal ophthalmia neonatorum?

    <p>Vision impairment.</p> Signup and view all the answers

    Which of the following statements about methylmalonyl-CoA mutase is true?

    <p>It converts methylmalonyl-CoA to succinyl-CoA.</p> Signup and view all the answers

    What is the effect of high glucose levels on fatty acid oxidation?

    <p>It increases the synthesis of malonyl-CoA, inhibiting beta-oxidation.</p> Signup and view all the answers

    Which of the following are considered ketone bodies?

    <p>Acetoacetate and β-hydroxybutyrate</p> Signup and view all the answers

    What is ketoacidosis a result of?

    <p>Accumulation of ketone bodies</p> Signup and view all the answers

    What role does hydroxocobalamin play according to FDA approval in 12/2006?

    <p>Antidote for cyanide poisoning.</p> Signup and view all the answers

    What is the primary function of ketone bodies during periods of fasting or low carbohydrate intake?

    <p>To provide an alternative energy source for tissues</p> Signup and view all the answers

    Which enzyme is primarily responsible for activating fatty acids prior to their transport into the mitochondria?

    <p>Acyl-CoA synthetase</p> Signup and view all the answers

    Which of the following hormones plays a significant role in the mobilization of fatty acids from adipose tissue?

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

    What is the main difference in energy yield between the oxidation of saturated and unsaturated fatty acids?

    <p>Saturated fatty acids yield more energy due to having fewer double bonds</p> Signup and view all the answers

    What are the key intermediates involved in the metabolism of glycerol?

    <p>Glyceraldehyde-3-phosphate and acetyl-CoA</p> Signup and view all the answers

    What is the main reason that polyunsaturated fatty acid oxidation produces less energy than saturated fatty acid oxidation?

    <p>Polyunsaturated fatty acids need reducing power, which depletes NADPH.</p> Signup and view all the answers

    Which enzyme is needed to convert the cis bond between C-4 and C-5 of an intermediate during mono/polyunsaturated fatty acid oxidation?

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

    What product is formed at the end of the β-oxidation of odd-number fatty acids?

    <p>Propionyl-CoA</p> Signup and view all the answers

    What role does coenzyme B12 play in the oxidation of odd-number fatty acids?

    <p>It catalyzes a key isomerization step.</p> Signup and view all the answers

    What is produced when odd-number fatty acids are fully oxidized?

    <p>Succinyl-CoA</p> Signup and view all the answers

    Why is the oxidation of monounsaturated fatty acids more complex than saturated fatty acids?

    <p>They require additional enzymes like isomerase in certain conditions.</p> Signup and view all the answers

    What happens to the carbon fragments produced from odd-number fatty acids during β-oxidation?

    <p>They are converted into C4 succinyl-CoA.</p> Signup and view all the answers

    In unsaturated fatty acid oxidation, what is the function of isomerase?

    <p>To rearrange double bonds in fatty acid intermediates.</p> Signup and view all the answers

    What leads to the overproduction of ketone bodies in the liver?

    <p>Prolonged starvation and untreated diabetes mellitus</p> Signup and view all the answers

    What happens to oxaloacetate levels during starvation?

    <p>They drop as they are used for gluconeogenesis</p> Signup and view all the answers

    How do peripheral tissues respond to increased ketone body production in untreated diabetes?

    <p>They are unable to use ketone bodies efficiently</p> Signup and view all the answers

    What happens to acetyl-CoA during prolonged starvation?

    <p>It is predominantly converted into ketone bodies</p> Signup and view all the answers

    What is the role of insulin in glucose metabolism?

    <p>Facilitates the entry of glucose into all body cells</p> Signup and view all the answers

    Which of the following describes diabetic ketoacidosis?

    <p>Lack of insulin leads to ketone body overproduction</p> Signup and view all the answers

    What determines whether acetyl-CoA enters the TCA cycle or is converted to ketone bodies?

    <p>The levels of oxaloacetate</p> Signup and view all the answers

    What is the physiological consequence of glucagon stimulation during low insulin levels?

    <p>Heightened breakdown of glycogen</p> Signup and view all the answers

    What is the primary source of energy provided by fats in the liver and heart?

    <p>80% of total energy consumed</p> Signup and view all the answers

    Which component is NOT found in the structure of chylomicrons?

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

    What triggers the mobilization of triacylglycerols stored in adipose tissue?

    <p>Binding of epinephrine</p> Signup and view all the answers

    What must occur to fatty acids before they can undergo oxidation?

    <p>They must be transported inside mitochondria.</p> Signup and view all the answers

    How is the process of conjugating fatty acids with CoA made highly exothermic?

    <p>By the release of pyrophosphate</p> Signup and view all the answers

    What is the net ATP yield from complete oxidation of palmitic acid to acetyl CoA?

    <p>129 ATP</p> Signup and view all the answers

    Which statement about beta-oxidation is true?

    <p>It requires a trans substrate for oxidation.</p> Signup and view all the answers

    Which energy product is generated in Stage 2 of beta-oxidation?

    <p>FADH2</p> Signup and view all the answers

    What percentage of total energy do fats provide compared to sugars upon complete oxidation?

    <p>Fats provide significantly more energy than sugars.</p> Signup and view all the answers

    Which of the following enzymes is primarily stimulated by PKA to hydrolyze triglycerides?

    <p>Hormone-sensitive lipase</p> Signup and view all the answers

    What is the main function of carnitine in fatty acid metabolism?

    <p>To shuttle fatty acids into mitochondria</p> Signup and view all the answers

    Which step in fatty acid catabolism requires ATP consumption?

    <p>Activation of fatty acids</p> Signup and view all the answers

    What is the primary function of the fatty acid oxidation process?

    <p>Produce ATP through breakdown of fatty acids</p> Signup and view all the answers

    How many rounds of beta-oxidation occur for a fatty acid with 16 carbons?

    <p>7 rounds</p> Signup and view all the answers

    What is the main use of Aztreonam in clinical settings?

    <p>For Gram-negative infections in patients allergic to other beta-lactams</p> Signup and view all the answers

    Which statement accurately describes the spectrum of activity of Ertapenem?

    <p>Includes anaerobes and certain anaerobic Gram-positive cocci</p> Signup and view all the answers

    Which of the following statements about Carbapenems is true?

    <p>Most have a useful spectrum against MSSA, streptococci, and certain GNRs.</p> Signup and view all the answers

    What potential adverse effect is more commonly associated with Imipenem than other Carbapenems?

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

    Which of the following statements is correct regarding Susceptibility to Carbapenems?

    <p>Resistance may occur against enterococci and Acinetobacter species.</p> Signup and view all the answers

    What type of hypersensitivity reaction is mediated by IgE and characterized by immediate effects?

    <p>Type I</p> Signup and view all the answers

    What is the main use of Penicillin/Beta-Lactamase Inhibitor Combinations?

    <p>Managing nosocomial infections</p> Signup and view all the answers

    Which class of antibiotics includes Meropenem and Imipenem, often used to combat resistant bacterial infections?

    <p>Beta-lactams</p> Signup and view all the answers

    Which type of hypersensitivity is characterized by T-cell involvement and delayed reactions, such as maculopapular rashes?

    <p>Type IV</p> Signup and view all the answers

    Which type of penicillin is specifically designed to target Gram-negative rods?

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

    Which of the following infections is most commonly associated with E. coli?

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

    Which of the following antibiotics is known to be effective against anaerobic bacteria and is classified as a beta-lactam?

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

    What is a common characteristic of Penicillin/Beta-Lactamase Inhibitor Combinations?

    <p>They offer broad-spectrum activity.</p> Signup and view all the answers

    Which of the following is NOT a mediator involved in hypersensitivity reactions?

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

    Which class of penicillin is specifically better against Staphylococcus?

    <p>Anti-staph Penicillins</p> Signup and view all the answers

    What condition is a risk factor for infection with nosocomial organisms?

    <p>Recent hospitalization</p> Signup and view all the answers

    Which of the following characteristics is NOT associated with penicillins?

    <p>Resistance to beta-lactamase</p> Signup and view all the answers

    Which route is primarily used for administration of Antipseudomonal PCNs?

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

    What are the primary uses of carbapenems?

    <p>For resistant infections and mixed aerobic/anaerobic infections</p> Signup and view all the answers

    Which combination of agents includes a beta-lactamase inhibitor?

    <p>Meropenem-vaborbactam</p> Signup and view all the answers

    What is a characteristic of vaborbactam in relation to meropenem and imipenem?

    <p>It possesses comparable activity against resistant infections</p> Signup and view all the answers

    Which statement correctly describes the spectrum of activity for carbapenems?

    <p>They kill a broad range of bacteria, including highly resistant pathogens</p> Signup and view all the answers

    What can be concluded about the use of carbapenem antibiotics?

    <p>Their use is increasing due to rising resistance to other agents</p> Signup and view all the answers

    Which of the following cephalosporins is known to cause biliary sludging in neonates?

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

    What is the primary spectrum of activity for Ceftaroline?

    <p>MSSA and MRSA</p> Signup and view all the answers

    Which combination is a first-line treatment option against Pseudomonas aeruginosa?

    <p>Ceftolozane and tazobactam</p> Signup and view all the answers

    What is the route of elimination for Cefepime?

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

    Which of the following is NOT a primary use for 3rd generation cephalosporins?

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

    What unique feature does Cefiderocol possess compared to other cephalosporins?

    <p>It combines with a siderophore for iron transport</p> Signup and view all the answers

    What type of beta-lactamase inhibitors work with Ceftazidime?

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

    Cefepime is primarily effective against which group of organisms?

    <p>Gram-negative rods, including Pseudomonas</p> Signup and view all the answers

    What is the primary characteristic of 1st generation cephalosporins?

    <p>They are effective against MSSA and streptococci.</p> Signup and view all the answers

    Which of the following statements is true regarding 2nd generation cephalosporins?

    <p>Cefotetan and cefoxitin have anaerobic activity.</p> Signup and view all the answers

    What is a noted comparative property of 3rd generation cephalosporins?

    <p>Better Gram-negative coverage than 2nd generation.</p> Signup and view all the answers

    What indicates the presence of anaerobic bacteria in a wound?

    <p>A foul smell and oozing pus.</p> Signup and view all the answers

    Which common use of 1st generation cephalosporins is accurate?

    <p>Prophylaxis in surgical procedures.</p> Signup and view all the answers

    In treating foot ulcers, which cephalosporin would likely be the least effective?

    <p>Ceftazidime.</p> Signup and view all the answers

    What is a significant limitation of 3rd generation cephalosporins compared to earlier generations?

    <p>Decreased antistaphylococcal activity.</p> Signup and view all the answers

    What class of bacteria is typically covered by 2nd generation cephalosporins?

    <p>Primarily Gram-negatives with some anaerobic activity.</p> Signup and view all the answers

    Which cephalosporin is most commonly used for treating urinary tract infections?

    <p>Cephalexin.</p> Signup and view all the answers

    Why are beta-lactams, including cephalosporins, less susceptible to beta-lactamase?

    <p>They possess a six-membered ring structure.</p> Signup and view all the answers

    Study Notes

    Cell Wall Synthesis

    • Cell wall synthesis occurs in four stages: monomer production, polymer formation, linkage, and cross-linking.
    • Monomers are the building blocks of polymers.
    • Polymers are long chains of monomers.
    • Linkage is the process of attaching monomers together.
    • Cross-linking is the process of connecting different polymer chains together.

    Specific Drug Role in Antibiotics

    • Fosfomycin inhibits the production of monomers needed for bacterial cell wall synthesis.
    • Vancomycin and teicoplanin prevent the cell wall from elongating by interfering with the formation of the peptide cross-links.
    • Beta Lactam antibiotics prevent the cross-linking of peptidoglycans in the bacterial cell wall. This weakens the cell wall and can lead to cell lysis.

    Beta Lactam Similarities

    • Beta Lactams have a similar mechanism of action, good tissue penetration, and pharmacokinetic properties.
    • Beta lactams are mainly eliminated by the kidneys.
    • Beta lactams have short half-lives, meaning they are cleared from the body relatively quickly.
    • Beta lactams have bactericidal activity, meaning they kill bacterial cells.
    • Common adverse effects of beta lactams include nausea, hypersensitivity, and diarrhoea.

    Beta Lactam Differences

    • Beta Lactams differ in their absorption, hydrophilicity, and types of penicillin-binding proteins (PBP) targeted.
    • Beta lactams have differing stabilities against degradation.

    Aminopenicillin

    • Ampicillin and amoxicillin are examples of aminopenicillins.
    • They are susceptible to breakdown by bacterial beta lactamases.
    • They are typically used to treat upper respiratory infections, urinary tract infections and ulcer disease.

    Beta Lactamase

    • Beta lactamases are enzymes produced by bacteria to break down beta-lactam antibiotics.
    • This inactivation of the antibiotic can lead to resistance.

    Natural Penicillin Routes

    • Penicillin G is administered intravenously (IV) only.
    • Penicillin V is administered orally (PO) only.
    • Penicillin G Benzathine is administered intramuscularly (IM) only.

    Antistaphylococcal Penicillin

    • Antistaphylococcal penicillins are not well absorbed orally.
    • They are widely available.
    • Some bacteria are resistant to penicillin, necessitating the use of nafcillin, oxacillin, and dicloxacillin.

    Cell Wall Synthesis

    • Cell wall synthesis involves four major steps:
    • Monomer production
    • Polymer formation
    • Linkage
    • Cross-linkage

    Antibiotic Mechanisms

    • Fosfomycin inhibits the production of monomers required for bacterial cell wall synthesis.
    • Vancomycin and teicoplanin prevent the elongation of the bacterial cell wall.
    • Beta-lactams disrupt the cross-linking process in bacterial cell wall synthesis.

    Beta-lactam Antibiotics

    • Beta-lactam antibiotics share a similar mechanism of action, exhibit good tissue penetration, and are primarily eliminated through the kidneys.
    • They demonstrate short half-lives and are bactericidal.
    • Common adverse effects include nausea, hypersensitivity, and diarrhea.
    • Beta-lactam antibiotics differ in their absorption, hydrophilicity, target penicillin-binding proteins (PBPs), and stability against degradation.

    Aminopenicillin

    • Ampicillin and amoxicillin are examples of aminopenicillin.
    • Aminopenicillins are susceptible to beta-lactamases.
    • Main uses include upper respiratory infections (URIs) and ulcer disease.

    Beta-Lactamase

    • Beta-lactamases are enzymes that target beta-lactam antibiotics, rendering them ineffective.

    Natural Penicillin Routes

    • Penicillin G is administered intravenously (IV) only.
    • Penicillin V is given orally (PO) only.
    • Penicillin G benzathine is administered intramuscularly (IM) only.

    Antistaphylococcal Penicillin

    • Antistaphylococcal penicillins are poorly absorbed.
    • They are widely available despite their resistance to penicillin.
    • Nafcillin, oxacillin, and dicloxacillin are commonly used for treating staphylococcal infections.

    Fosfomycin's Role in Antibiotic Therapy

    • Fosfomycin inhibits an early step in the production of peptidoglycan, a crucial molecule in bacterial wall construction.

    Common Characteristic of Beta-Lactam Antibiotics

    • Beta-lactam antibiotics all contain a beta-lactam ring within their molecular structure. This ring is vital for their antibacterial action.

    Penicillinase-Resistant Penicillin

    • Methicillin is a penicillin specifically designed to be resistant to penicillinase, an enzyme produced by some bacteria to break down penicillin.

    Administration Route Difference Between Penicillin G and V

    • Penicillin G is administered intravenously, while Penicillin V is taken orally.

    Facts about Beta Lactamase

    • Beta-lactamase is an enzyme produced by certain bacteria to break down beta-lactam antibiotics, rendering them ineffective.

    Accuracy Regarding Beta-Lactam Antibiotics

    • Beta-lactam antibiotics work by interfering with bacterial cell wall synthesis, particularly by inhibiting the transpeptidases required for this process.

    Antibiotic that Inhibits Cell Wall Synthesis Monomer

    • Bacitracin specifically inhibits the monomer necessary for cell wall synthesis.

    Characteristic NOT Common Among Beta-Lactam Antibiotics

    • Resistance to inactivation by bacterial enzymes is NOT a characteristic common among all beta-lactam antibiotics.

    Antistaphylococcal Penicillins

    • Antistaphylococcal penicillins, like methicillin, nafcillin and oxacillin are designed to be effective against Staphylococcus aureus, a bacterium often resistant to other penicillins.

    Primary Action of Beta Lactam Antibiotics

    • Beta-Lactam antibiotics primarily disrupt the formation of peptidoglycans, which are essential for bacterial cell wall integrity.

    Class of Antibiotics Targeting Bacterial Cell Walls

    • The primary class of antibiotics focused on targeting the structural integrity of the bacterial cell wall is the beta-lactams.

    Property NOT Common to Aminopenicillins

    • Aminopenicillins, like ampicillin and amoxicillin, are commonly used against gram-negative bacteria but are not effective against Pseudomonas aeruginosa due to their resistance to these drugs.

    Transmission of Pseudomonas aeruginosa

    • Pseudomonas aeruginosa is often transmitted through contact with contaminated water or surfaces; it can also be found in soil and various environments.

    Characteristic Feature of Pseudomonas aeruginosa

    • Pseudomonas aeruginosa is known for its ability to form biofilms, which protect it from antibiotics and host defenses.

    Infections Associated with Pseudomonas aeruginosa

    • Pseudomonas aeruginosa infections are commonly associated with individuals with compromised immune systems, those with severe burns, and those who have been hospitalized for extended periods.

    Type of Antibiotic Typically Less Effective Against Pseudomonas aeruginosa

    • Aminoglycoside antibiotics are typically less effective against Pseudomonas aeruginosa.

    Significant Concern Regarding Treating Pseudomonas aeruginosa Infections

    • A significant concern with Pseudomonas aeruginosa infections is the development of multi-drug resistance, making treatment challenging.

    HACEK Bacteria

    • Eikenella corrodens: Small, fastidious, gram-negative rod found in the gingival and bowel flora, known for its ammonia odor.
    • Eikenella corrodens Isolates from wounds due to human bites.

    Moraxella Species

    • Coccobacillus associated with bronchitis and pneumonia.

    Neisseria Species

    • N. gonorrhoeae and N. meningitidis are two important species
    • Neisseria meningitidis is a capsulated bacterium, part of the normal upper respiratory flora, and a leading cause of meningitis in adults.
    • Neisseria meningitidis ferments maltose and has 13 serogroups, with vaccines available for protection.
    • Neisseria gonorrhoeae is the causative agent of gonorrhea, a sexually transmitted disease.
    • Neisseria gonorrhoeae lacks a capsule and cannot ferment maltose.

    Neisseria meningitidis

    • Humans are the natural host of Neisseria meningitidis.
    • The nasopharynx is the portal of entry for Neisseria meningitidis.
    • Meningococcal lipopolysaccharides are responsible for the toxic effects of Neisseria meningitidis infection.
    • Neisseria meningitidis infections can progress to coma.

    Neisseria gonorrhoeae

    • Neisseria gonorrhoeae attacks the genitourinary tract, eyes, and rectum.
    • Men typically experience creamy, yellow pus, while women may experience endocervix extending to the vagina.
    • Neisseria gonorrhoeae can lead to septic arthritis.
    • Penicillin is no longer an effective treatment for Neisseria gonorrhoeae infections; treatment now relies on cefixime and ceftriaxone.

    Neisseria meningitidis - Epidemics

    • Neisseria meningitidis outbreaks occur in epidemic waves, particularly in college dorms and military camps.
    • Treatment with penicillin alone does not eliminate the bacteria. Treatment often includes rifampin or ciprofloxacin.

    Gonococcal Ophthalmia Neonatorum

    • Gonococcal ophthalmia neonatorum is acquired during infection of the birth canal.
    • Untreated gonococcal ophthalmia neonatorum can cause blindness.

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    Description

    This quiz covers the four stages of cell wall synthesis and the specific roles of antibiotics like Fosfomycin, Vancomycin, Teicoplanin, and Beta Lactams. Understand how these drugs impact monomer production, polymer formation, and cross-linking in bacterial cell walls. Test your knowledge on the mechanisms of antibiotic action.

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