76 Questions
What is the main function of the bacterial cell wall?
To protect from changes in osmotic pressure
Where does the final assembly of the bacterial cell wall take place?
Outside of the inner membrane
Which syndrome is a serious adverse effect mentioned in the text?
Stevens-Johnson syndrome
What makes the enzymes involved in late steps of cell wall synthesis more vulnerable to inhibition?
Their proximity to the cell surface
What is the purpose of the antigenic determinants on the outside of gram-positive bacterial cells?
Allow for attachment to specific target cells
Which of the following is NOT a function of the bacterial cell wall?
Facilitate DNA replication
What characteristic makes Stevens-Johnson syndrome a rare adverse effect?
Its comparative rarity
Why does the final assembly of the bacterial cell wall take place outside of the inner membrane?
To facilitate extrusion and growth
What is the main reason sulfonamides are disqualified for use in late-term pregnancy?
They cause neonatal jaundice
Which process partly deactivates sulfonamides in the liver?
Acetylation at N-4
What is a common form of plasmid-mediated resistance development among gram-negative microorganisms?
Decreased sensitivity of dihydropteroate synthase
Which sulfonamide is used in combination with erythromycin due to its broad antimicrobial spectrum?
Sulfisoxazole
What is the adverse effect most commonly associated with sulfonamides?
Allergic reactions
Which organisms may be susceptible to sulfisoxazole according to the text?
Haemophilus and Proteus
What limits the clinical use of sulfisoxazole, despite its broad antimicrobial spectrum?
Development of bacterial resistance
What is a less common problem associated with sulfonamides mentioned in the text?
Hemolytic anemia
What is the primary role of penicillin binding proteins in bacteria?
Construction of the cell wall
How do β-lactam antibiotics kill bacteria?
Preventing the biosynthesis of a functional cell wall
Why is selective interference by β-lactam antibiotics problematic for bacteria?
It prevents normal growth and repair processes
What distinguishes the outer lipid membrane of gram-negative bacteria from the inner membrane?
Containment of lipopolysaccharides
What role do porins play in gram-negative bacteria?
Regulating the passage of molecules through the membrane
What is the function of the center of the transmembranal pore in porins?
Allowing passage of small molecules
How do complex lipopolysaccharides in the outer lipid membrane influence gram-negative bacteria?
Cause septic shock
Why are penicillin binding proteins essential for bacterial cells?
To facilitate controlled cell growth and repair processes
What is a key consideration controlling porin passage for drugs?
Shape of drugs
What is the key concept associated with antibiotics?
Selective toxicity
Why do antibiotics have greater difficulty penetrating into gram-negative bacterial cells?
Presence of thicker peptidoglycan layer
Where are the β-lactam targets found in bacterial cells?
Cytoplasmic membrane
Who discovered bacteria in 1676?
van Leeuwenhoek
What led to the appreciation of antibiosis in microorganisms?
Interaction of anthrax bacilli with common bacteria
What role do inner membrane proteins play in bacterial cells?
Energy production
In what year did Louis Pasteur report the interaction between 'common bacteria' and anthrax bacilli?
1877
What is the contemporary name for the ring system of a β-lactam?
Azetidinone
Which subclass of β-lactam antibiotics is characterized by a substituted five-membered thiazolidine ring fused to the β-lactam ring?
Penicillins
Who observed a clear zone of inhibition surrounding a Penicillium mold colony?
Alexander Fleming
What shape does the molecule of a β-lactam antibiotic roughly possess due to the fusion and chirality of the β-lactam ring?
"V" shape
What discovery is attributed to France and Germany in 1936?
Discovery of sulfonamides
Which scientist is known for isolating microorganisms from infected patients and reproducing disease symptoms in healthy individuals?
Robert Koch
What is a common function of proteins that actively pump out antibiotics from bacterial cells?
Maintain electrostatic balance
What is the term used to describe substances that inhibit or kill microorganisms but are unrelated to natural products?
Antibiotics
Which group of bacteria does benzylpenicillin primarily target?
Gram-positive cocci
What is a key advantage of phenoxymethylpenicillin compared to benzylpenicillin?
More acid stability
Where are β-lactamases secreted in gram-negative bacteria?
Periplasmic space
Which reaction is occasionally immediate and profound due to allergy?
Cardiovascular collapse
What is the main reason benzylpenicillin remains a useful agent for treatment?
Lack of toxicity except for allergic patients
How is penicillin V primarily produced?
Fermentation in enriched medium
What distinguishes the secretion of β-lactamases in gram-negative bacteria?
Secretion into the periplasmic space between membranes
Which type of bacteria are more susceptible to phenoxymethylpenicillin?
Gram-positive cocci
What is the primary reason for coadministering tazobactam with piperacillin?
Inhibiting β-lactamases
Which compound was described as the broadest spectrum penicillin currently available in the text?
Zosyn
Why was cephalosporin C not considered a useful antibiotic?
It lacked antibacterial activity
What distinguishes the chemical structure of 7-aminocephalosporanic acid from cephalosporin C?
Additional side chains
Why is resistance due to β-lactamases highlighted as a prominent feature of using piperacillin and tazobactam?
To enhance antibacterial properties
What motivated the chemical alteration of cephalosporin C to produce 7-aminocephalosporanic acid?
Improved potency against gram-negative bacteria
What is the role of tazobactam in the piperacillin and tazobactam combination?
Inhibiting β-lactamases
What is a distinguishing characteristic of cefotetan and cefoxitin?
Possession of antianaerobic activity
Which organisms are often sensitive to third-generation cephalosporins as per the text?
Klebsiella and Pseudomonas aeruginosa
What is a notable feature of fourth-generation cephalosporins compared to third-generation drugs?
Higher activity against gram-positive organisms
What is the most commonly experienced toxicity of cephalosporins besides allergic reactions?
Temporary nausea, vomiting, and diarrhea
What is the activating leaving group present at C-3 in cefazolin according to the text?
Thiadiazole ring
Which statement regarding the third-generation cephalosporins is accurate based on the text?
Useful against Morganella sp. and Staphylococcus aureus
What improvement has been made to newer third-generation cephalosporins to enhance their spectrum against β-lactamase–producing strains?
Combined with β-lactamase inhibitors
'The moiety is not subject to the inactivating host hydrolysis reaction.' - This statement directly refers to which part of cefazolin?
$C-3$
What characteristic of ertapenem makes it different from imipenem and meropenem?
It is inactive against Pseudomonas species
Which enzyme does the 4-β-methyl group in carbapenems confer stability toward?
Dehydropeptidase-1
What makes aztreonam primarily effective against gram-negative microorganisms?
Strong affinity for PBP-3
What is a key feature of the monobactams that differentiates them from other β-lactam antibiotics?
Presence of a fused ring
Which type of infections is aztreonam primarily used to treat?
Gram-negative bacterial infections
Why should ertapenem not be substituted for other carbapenems in the treatment of Pseudomonas or Acinetobacter infections?
It is inactive against these organisms
What does the α-oriented methyl group at C-2 contribute to in aztreonam?
Stability toward β-lactamases
What is the main indication for Ceftaroline Fosamil as mentioned in the text?
Treatment of pneumonia
Which group at C-3 of Cefepime assists in the penetration into gram-negative bacteria?
Quaternary N-methylpyrrolidine group
What differentiates Carbapenems structurally from penicillins and cephalosporins?
Absence of a β-lactam ring
What enhances the spectrum and β-lactamase stability of Cefepime?
Aminothiazolyl group at C-7
What is the mechanism of action of Ceftaroline Fosamil against methicillin-resistant Staphylococcus aureus?
Affinity for PBP-2a
Which type of bacteria does Cefepime have enhanced antistaphylococcal activity against?
Streptococcus sp.
Test your knowledge on antibiotics, focusing on sulfa drugs and βlactam antibiotics. The quiz covers topics such as the history of antibiotics, selective toxicity, and antimicrobial agents.
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