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Questions and Answers
What is the main reason bacteria need to constantly produce new biomolecules?
What is the process by which mRNA is synthesized from DNA genes?
What is the target of antibiotics that inhibit bacterial transcription and translation?
What is the name of the antibiotic that is used to 'adorn' traditional treatment wardrobes?
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What is the purpose of setting villages and isolated buildings on fire in the quote from Julius Caesar?
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What are the rifamycins used to do?
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What is the function of mRNA templates in bacteria?
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What is the term for the generation of proteins from mRNA templates?
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What is the oldest aminoglycoside?
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Which aminoglycoside is commonly used?
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Which bacteria is tobramycin not effective against?
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What is a characteristic of gentamicin?
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Which aminoglycoside has better overall activity against aerobic gram-negative bacteria?
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Which aminoglycoside is effective against some strains of enterococci?
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What is true about gentamicin-resistant strains?
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Which aminoglycoside is not used for infections caused by enterococci?
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What type of bacterial infections is telithromycin approved for?
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Which of the following strains of bacteria is telithromycin active against?
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Why are some strains of staphylococci resistant to telithromycin?
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Which of the following bacteria is NOT susceptible to telithromycin?
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What is the reason for telithromycin's effectiveness against more strains of staphylococci than macrolides?
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What type of bacteria is telithromycin NOT active against?
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What is NOT mentioned about telithromycin's activity?
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What is the class of bacteria that includes Legionella pneumophila?
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What is the usual modification made to the peptidoglycan precursor by enterococci?
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What is the anticipated consequence of the transferability of the gene clusters that encode glycopeptide resistance in enterococci?
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What was the origin of the soil sample that led to the discovery of vancomycin?
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What is the meaning of the word 'vancomycin'?
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What is the name of the journal that published the article about vancomycin use reviewed by Griffith RS?
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What is the result of the modification of the peptidoglycan precursor by enterococci?
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What is the name of the fatal condition in neonates caused by chloramphenicol?
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What type of bacteria is Haemophilus influenzae?
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What is the term for the range of microorganisms that an antibiotic is effective against?
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What type of bacteria is Bacteroides fragilis?
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What is the name of the antibiotic shown in Figure 6-7?
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Which of the following is NOT typically affected by chloramphenicol?
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What is a common neurologic abnormality associated with chloramphenicol?
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What type of bacteria is Chlamydia trachomatis?
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Study Notes
Peptidoglycan Precursor Modification
- Some bacteria modify the structure of peptidoglycan precursor, changing the d-alanyl-d-alanine dipeptide, often to d-alanyl-d-lactate.
- This modification prevents glycopeptides from recognizing and binding to the altered precursors.
Glycopeptide Resistance
- The gene clusters that encode this modification activity are transferable and have been found in S. aureus.
- It is anticipated that glycopeptide resistance will increase in frequency in staphylococci.
Vancomycin History
- Vancomycin was discovered from a soil sample sent by a missionary from Borneo to an organic chemist at Eli Lilly and Company.
- The soil sample harbored a bacterium that produced a compound with potent activity against gram-positive bacteria.
- The compound was purified and named vancomycin, derived from the word "vanquish".
Bacterial Protein Production
- Bacteria constantly produce new biomolecules to replace old ones and build new bacteria.
- This process involves transcription (synthesis of mRNA from DNA genes) and translation (generation of proteins from mRNA templates).
- Antibiotics can target these processes to inhibit bacterial growth and multiplication.
Rifamycins
- Rifamycins are "accessory" antibiotics that enhance the effect of traditional treatments.
- They consist of rifampin (rifampicin), rifabutin, rifapentine, and rifaximin.
Aminoglycosides
- Streptomycin is the oldest aminoglycoside and is rarely used today, but remains effective against some enterococci strains.
- Gentamicin is the most commonly used aminoglycoside, active against both aerobic gram-negative and gram-positive bacteria.
- Tobramycin has a similar spectrum of activity to gentamicin, but lacks activity against enterococci.
- Amikacin is effective against strains of aerobic gram-negative bacteria that are resistant to gentamicin and tobramycin.
Telithromycin
- Telithromycin is approved for use in patients with bacterial respiratory infections.
- It is active against most strains of S. pneumoniae, including penicillin-resistant and macrolide-resistant strains.
- It is also active against more strains of staphylococci and other streptococci than macrolides, but some strains are resistant.
Chloramphenicol
- Chloramphenicol has a broad spectrum of activity that includes many aerobic gram-positive, gram-negative, anaerobic, and atypical bacteria.
- Its use is limited by its toxicity profile, which can cause gray baby syndrome and neurologic abnormalities.
- It is effective against many bacteria, including Streptococcus pyogenes, Haemophilus influenzae, and anaerobic bacteria.
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Description
This quiz covers how bacteria modify peptidoglycan precursors to resist glycopeptides, including the alteration of d-alanyl–d-alanine dipeptide to d-alanyl–d-lactate. It also touches on the transferability of the gene clusters encoding this activity.