Macrolide Antibiotics and Erythromycin Quiz

78 Questions

What is selective toxicity in the context of antibacterial drugs?

The ability of an antibacterial drug to target only pathogenic bacteria while sparing the host's cells

What is the mechanism of action of penicillins?

Disruption of bacterial cell wall synthesis

Which category of antibacterial drugs includes β-lactam antibiotics?

Inhibitors of Bacterial Cell Wall Synthesis

What is the primary target of inhibitors of folate metabolism in bacteria?

Folic acid synthesis pathway

Which type of antibacterial drugs have a high degree of selective toxicity against bacteria due to the absence of cell walls in mammalian cells?

Inhibitors of Bacterial Cell Wall Synthesis

What is the general target of inhibitors of nucleic acid metabolism in bacteria?

DNA gyrase activity

Which antibiotic binds to the σ subunit of RNA polymerase, leading to the inhibition of protein synthesis?

Fidaxomicin

Which antibiotic exhibits the most unusual property of uptake into several tissues (lung, tonsil, and cervix), maintaining high concentrations for prolonged periods?

Azithromycin

Which antibiotic is much better absorbed after oral administration than erythromycin?

Clarithromycin

Which antibiotic has improved pharmacokinetic properties but only modest changes in the antibacterial spectrum compared to erythromycin?

Azithromycin

Which antibiotic is chemically unlike but pharmacologically similar to erythromycin, with excellent activity against anaerobic bacteria?

Lincomycin

Which antibiotic preferentially binds to the 30S subunit of the microbial ribosome, interfering with binding of amino acyl-tRNA and inhibiting chain elongation and termination?

Doxycycline

Which antibiotic is effective against multiresistant gram-negative bacilli and anaerobes with β-lactamase resistance?

Cefepime

Which antibiotic should not be given intramuscularly due to the risk of tissue necrosis?

Vancomycin

Which antibiotic has the broadest spectrum of all β-lactam antibiotics and is resistant to most β-lactamases?

Imipenem

Which antibiotic can cause nephrotoxicity, risk of fetal harm, and interactions with drugs that prolong the QT interval?

Telavancin

Which antibiotic is specifically bacteriostatic against mainly gram-positive pathogens?

Erythromycin

Which antibiotic prevents bacterial ribosomes from moving along mRNA to read it?

Erythromycin

Which of the following antibiotics is excreted mostly in the bile and feces?

Tigecycline

What is the specific mechanism of action of tetracyclines?

Binding to the 30S subunit of the microbial ribosome, inhibiting protein synthesis

Which antibiotic has resistance to inactivation by many bacterial enzymes and a longer half-life?

Amikacin

What serious side effect is associated with tetracyclines?

Liver damage

Which class of antibiotics is not effective against anaerobic bacteria?

Aminoglycosides

What specific condition can chloramphenicol cause in neonates due to deficient glucuronidation?

"Gray baby syndrome"

Which enzyme is critical for chromosomal segregation in some bacterial strains?

DNA gyrase

What is the main function of DNA gyrase in bacteria?

Introducing negative supercoils

Which type of topoisomerase is needed to intertwine progeny DNA in bacterial chromosomes?

Type II topoisomerase

What is the mechanism of action of fluoroquinolones (Quinolones) as gyrase inhibitors?

Stabilize the DNA-enzyme complex and prevent the separation of DNA strands

Why are fluoroquinolones (Quinolones) selectively toxic to bacteria?

They have a structural difference from eukaryotic topoisomerases

What is the spectrum of activity of fluoroquinolones against bacteria?

Broad spectrum, targeting both gram-positive and gram-negative bacteria

Which type of infections are fluoroquinolones commonly used to treat?

Complicated infections of the genitourinary tract, abdominal, respiratory, skin, and soft tissue infections

What side effect is associated with the use of fluoroquinolones in animal studies involving young animals?

Irreversible damage to developing cartilage

What is the main route of excretion for fluoroquinolones like ciprofloxacin?

Renal excretion through glomerular filtration and active secretion

What effect does dietary calcium have on the absorption of ciprofloxacin?

Dietary calcium reduces the absorption of ciprofloxacin

What is the disadvantage of Penicillin G?

Instability in gastric acid

Which antibiotic is effective against Pseudomonas aeruginosa and other gram-negative bacteria?

Piperacillin

What is the most common adverse effect of penicillins?

Hypersensitivity

Which generation of cephalosporins have improved pharmacokinetics and some penetration into the CSF?

2nd generation cephalosporins

What are β-lactamase inhibitors used for in relation to penicillins?

Combat bacteria that produce β-lactamase

Which antibiotic is chemically unlike but pharmacologically similar to erythromycin, with excellent activity against anaerobic bacteria?

Clindamycin

What serious side effect is associated with tetracyclines?

Photosensitivity

What enzyme is critical for chromosomal segregation in some bacterial strains?

DNA ligase

Which antibiotic preferentially binds to the 30S subunit of the microbial ribosome, interfering with binding of amino acyl-tRNA and inhibiting chain elongation and termination?

Tetracycline

What effect does dietary calcium have on the absorption of ciprofloxacin?

Decreases absorption

Which type of topoisomerase is needed to intertwine progeny DNA in bacterial chromosomes?

Topoisomerase IV

What is the mechanism of action of β-lactam antibiotics such as penicillins?

Inhibition of bacterial cell wall synthesis by targeting transpeptidase

What is the primary target of inhibitors of nucleic acid metabolism in bacteria?

Bacterial RNA polymerase

Which category of antibacterial drugs includes erythromycin and exhibits excellent activity against anaerobic bacteria?

Inhibitors of protein synthesis

What is the mechanism of action of chloramphenicol, an antibiotic that can cause a specific condition in neonates due to deficient glucuronidation?

Inhibition of bacterial protein synthesis by binding to the 30S ribosomal subunit

What is the specific mechanism of action of tetracyclines, a class of antibiotics that has resistance to inactivation by many bacterial enzymes?

Binding to the 30S ribosomal subunit

Which type of topoisomerase is needed to intertwine progeny DNA in bacterial chromosomes?

Type II topoisomerase

Which antibiotic is much better absorbed after oral administration than erythromycin?

Azithromycin

What is the main clinical use of Fidaxomicin?

Infections caused by C. difficile

Which antibiotic binds to the σ subunit of RNA polymerase, leading to the inhibition of protein synthesis?

Fidaxomicin

What is the specific mechanism of action of tetracyclines?

Binding to the 30S subunit of the microbial ribosome, interfering with binding of amino acyl-tRNA

What is the most unusual property of azithromycin?

Uptake into several tissues, maintaining high concentrations for prolonged periods

What is the best absorption obtained with for erythromycin?

Estolate salt

Which antibiotic is a glycopeptide that inhibits bacterial cell wall synthesis by binding to terminal D-alanine-D-alanine in peptidoglycan precursors?

Vancomycin

Which antibiotic is a monobactam with a spectrum against gram-negative bacteria and can cause phlebitis and skin rashes?

Aztreonam

Which antibiotic is a lipoglycopeptide that inhibits peptidoglycan polymerization and may cause nephrotoxicity, risk of fetal harm, and interactions with drugs that prolong the QT interval?

Telavancin

Which antibiotic prevents bacterial ribosomes from moving along mRNA to read it and is bacteriostatic against mainly gram-positive pathogens?

Erythromycin

Which antibiotic has the broadest spectrum of all β-lactam antibiotics, binding all penicillin binding proteins and being resistant to most β-lactamases?

Imipenem

Which antibiotic is a 4th generation cephalosporin with extended spectrum, effective against gram-positive organisms including MRSA, gram-negative organisms including P. aeruginosa, multiresistant gram-negative bacilli, and significant activity against anaerobes with β-lactamase resistance?

Cefepime

What specific condition can chloramphenicol cause in neonates due to deficient glucuronidation?

Gray baby syndrome

What is the primary mechanism of resistance to tetracyclines?

Overexpression of efflux pumps

Which antibiotic is bacteriostatic, has a broad spectrum of activity, and is resistant to inactivation by many bacterial enzymes?

Chloramphenicol

What is the main route of excretion for tetracyclines like doxycycline and minocycline?

Bile

Which antibiotic has a longer half-life, good tissue distribution, and is excreted mostly in the bile and feces?

Doxycycline

What is the primary function of DNA gyrase in bacteria?

Introducing negative supercoils

What is the specific condition that fluoroquinolones like ciprofloxacin should not be prescribed to due to irreversible damage to developing cartilage in young animals?

Patients who are young

What is the main route of excretion for fluoroquinolones like ciprofloxacin?

Urine

What is the mechanism of action of fluoroquinolones (Quinolones) as gyrase inhibitors?

Stabilize the DNA-enzyme complex in a form where both DNA strands are broken

Which adverse effect is associated with the use of penicillins in neonates due to deficient glucuronidation?

Gray baby syndrome

Which enzyme is critical for chromosomal segregation in some bacterial strains?

Topoisomerase IV

What specific effect does dietary calcium have on the absorption of ciprofloxacin?

Reduces absorption

What is the spectrum of activity of fluoroquinolones against bacteria?

Wide variety of gram-negative bacteria

What type of infections are fluoroquinolones commonly used to treat?

Complicated infections of the genitourinary tract

What is the most common adverse effect of penicillins?

Gray baby syndrome

Study Notes

Penicillins are a type of antibiotic that inhibit bacterial cell wall synthesis by inhibiting transpeptidase
Penicillins are bactericidal, especially effective against bacteria during their growth and replication phase
Penicillin G has disadvantages, including instability in gastric acid and susceptibility to penicillinase
Penicillinase-resistant penicillins, such as oxacillin and methicillin, have a narrow spectrum and are effective against gram-positive organisms that produce penicillinase
Extended-spectrum penicillins, such as amoxicillin and ampicillin, have a broader spectrum but remain sensitive to β-lactamase and do not penetrate the CSF unless used for treating meningitis
Piperacillin is an antipseudomonal penicillin that is effective against Pseudomonas aeruginosa and other gram-negative bacteria
β-lactamase inhibitors, such as clavulanic acid, are used to combat bacteria that produce β-lactamase and destroy the activity of penicillins
Penicillins can be neurotoxic in high doses, likely due to their ability to antagonize GABA in the central nervous system
Hypersensitivity to penicillins is the most common adverse effect and is likely due to the modification of human proteins by β-lactams, leading to the creation of an immunogenic hapten
The Cephalosporins are also β-lactam antibiotics, produced by Cephalosporium and Streptomyces species, and classified into four generations based on their activity against gram-negative bacteria and improved pharmacokinetics.
1st generation cephalosporins, such as cefazolin and cephalexin, are susceptible to β-lactamase and do not penetrate the CSF
2nd generation cephalosporins, such as cefuroxime and cefaclor, have improved pharmacokinetics and some penetration into the CSF
3rd generation cephalosporins, such as ceftriaxone and ceftazidime, are resistant to β-lactamases and effective against gram-negative bacteria
4th generation cephalosporins, such as ceftolozane and ceftazidime/avibactam, have a broad spectrum and are effective against gram-negative bacteria that produce extended-spectrum β-lactamases.
Tetracyclines: a group of antibiotics with a broad spectrum of activity against various microorganisms, including gram-positive and gram-negative bacteria.
Tetracyclines have different mechanisms of elimination: most are excreted in urine, but doxycycline and minocycline are excreted in bile.
Tetracyclines are rapidly eliminated from the body but doxycycline and minocycline have long half-lives.
Tetracyclines can cause side effects, including irritation to mucous membranes, alteration of gut flora, and formation of insoluble complexes with cations. Long-term use can result in damage to developing teeth and bones, and liver damage, particularly in pregnant women.
The mechanism of action of tetracyclines involves their binding to the 30S subunit of the microbial ribosome, inhibiting protein synthesis.
Tigecycline is a glycylcycline, a tetracycline relative, which has a similar mechanism of action but is more broad-spectrum and bacteriostatic.
Tigecycline has a large volume of distribution, good tissue distribution, but low plasma concentrations, making it unsuitable for bloodstream infections.
Tigecycline is excreted mostly in the bile and feces, and dose adjustments are necessary in hepatic insufficiency patients.
Resistance to tetracyclines is due to overexpression of efflux pumps.
Serious side effects of tetracyclines include acute pancreatitis, which may lead to death, and clearance of warfarin, which can increase the risk of bleeding in patients taking warfarin.
Aminoglycosides are a group of antibiotics that interfere with protein synthesis by inducing the binding of wrong amino acyl-tRNA complexes, resulting in the synthesis of false proteins.
Aminoglycosides are bactericidal and have a broad spectrum of activity against gram-negative bacteria, but they depend on oxygen-dependent enzymes for transport into bacteria and are not effective against anaerobic bacteria.
Aminoglycosides are not absorbed from the GI tract but can be administered intramuscularly or subcutaneously. They have poor penetration in the CSF and are excreted unchanged through the kidneys.
The mechanism of action of aminoglycosides involves their interaction with the 30S subunit of the bacterial ribosome, inhibiting protein synthesis, and disrupting the bacterial cell membrane function.
Amikacin is a derivative of kanamycin and has a longer half-life and resistance to inactivation by many bacterial enzymes.
Serious side effects of aminoglycosides include renal toxicity and ototoxicity, which can damage the vestibular and auditory functions of the vestibulocochlear nerve.
Chloramphenicol is an antibiotic that inhibits the enzyme peptide synthetase, preventing the formation of a peptide chain.
Chloramphenicol is bacteriostatic and has a broad spectrum of activity against various microorganisms.
Chloramphenicol is well absorbed orally and has good distribution, allowing it to penetrate into CSF, ocular fluids, and joint fluids. It is excreted rapidly in the urine, mostly unchanged.
Chloramphenicol has serious side effects, including irreversible aplastic anemia and reversible bone marrow depression. It can also cause a rare condition called the “gray baby syndrome” in neonates due to deficient glucuronidation.
Chloramphenicol is more effective than tetracyclines against typhoid fever and other Salmonella infections but its use is limited due to bone marrow toxicity.
Protein synthesis inhibitors, including tetracyclines and aminoglycosides, are used to treat various bacterial infections. They act by inhibiting protein synthesis, either by binding to the ribosome or interfering with amino acid transport.
Gyrase inhibitors, such as fluoroquinolones, are another class of antibiotics that inhibit bacterial DNA gyrase, preventing the replication of bacterial DNA. They are used to treat a wide range of bacterial infections.

Test your knowledge about macrolide antibiotics and specifically erythromycin. Learn about their mechanism of action, pharmacokinetic properties, and antibacterial spectrum.

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