Beta-Lactam Antibiotics and other Cell Wall Synthesis Inhibitors Flashcards
1
Q
Penicillins: Limitid spectrum drugs
A
- Penicillin G
- Penicillin V
2
Q
Penicillins: Beta-lactamase-resistant drugs
A
- Methicillin
- Nafcillin
- Oxacillin
3
Q
Penicillins: Wider spectrum drugs
A
- Ampicillin
- Amoxicillin
- Piperacillin
- Ticarcillin
4
Q
Penicillins: Mechanism of Action
A
- Inhibit bacterial cell wall synthesis
- Beta-lactam antibiotic
- Bactericidal drugs
1) Bind to penicillin-binding proteins (PBPs) located on the bacterial cytoplasmic membrane
2) Inhibit transpeptidase enzymes (form part of the cell wall)
3) Activate autolytic enzymes –> cause lesions in the bacterial cell wall
5
Q
Penicillin G
A
- Prototype of narrow-spectrum penicillins
- Beta-lactamase sensitive
- Therapy against: Common streptococci, meningococci, gram-positive bacilli, and spirochetes
- Drug of choice for syphilis!
6
Q
Penicillin V
A
- Narrow-spectrum penicillin
- Beta-lactamase sensitive
- Used in oropharyngeal infections
7
Q
Methicillin, Nafcillin, Oxacillin
A
- Very-narrow spectrum penicillins
- Beta-lactamase resistant
- Mainly used in staphylococcal infections
8
Q
Ampicillin, Amoxicillin
A
- Wide-spectrum penicillins
- Beta-lactamase sensitive
- Used against similar pathogens as Penicillin G: Streptococci, meningococci, gram-positive bacilli, spirochetes
- Also used against: Enterococci, Listeria monocytogenes, E. coli, Proteus mirabilis, H. influenzae, and Moraxella catarrhalis.
- Synergistic with aminoglycosides when used against enterococci and listeria
- Ampicillin; drug of choice against L. monocytogenes
9
Q
Piperacillin, Ticarcillin
A
- Wide-spectrum penicillins
- Beta-lactamase sensitive
- Used against several gram-negative rods: Pseudomonas, Enterobacter, and in some cases Klebsiella species
- Synergistic action when used with aminoglycosides
10
Q
Jarisch-Herxheimer reaction
A
- Side effect when treatment of Syphilis with Penicillin
- Immune-reaction to bacterial components when cell wall are destroyed
11
Q
Cephalosporins: First generation
A
- Cefazolin
- Cephradine
12
Q
Cephalosporins: Second generation
A
- Cefamandole
- Cefaclor
- Cefotetan
- Cefoxitin
13
Q
Cephalosporins: Third generation
A
- Cefoperazone
- Cefotaxime
- Ceftazidime
- Ceftriaxone
14
Q
Cephalosporins: Fourth generation
A
- Cefepime
15
Q
Cephalosporins: Mechanism of Action
A
- Inhibit bacterial cell wall synthesis
- Bactericidal drugs
- Bind to penicillin binding proteins (PBPs) on bacterial cell membranes
16
Q
Cefazolin, Cephalexin
A
- First-generation cephalosporins
- Used against gram-positive cocci (Staphylococci and common Streptococci), and drug of choice in E. coli, and K. pneumonia
- Also used in surgical prophylaxis
17
Q
Cefotetan, Cefoxitin
A
- Second-generation cephalosporins
- Activity against gram-negative organisms
- Drug of choice in E.coli, Proteus and Klebsiella
- Used against Bacteroides fragilis
18
Q
Cefamandole, Cefaclor
A
- Second-generation cephalosporins
- Activity against gram-negative organisms
- Used against H. influenza and M. catarrhalis
19
Q
Ceftazidime, Cefoperazone, Cefotaxime
A
- Third-generation cephalosporins
- Activity against gram-negative organisms resistant to other beta-lactam drugs
- Ability to penetrate the blood-brain barrier (except Cefoperazone)
- Usually reserved for treatment of serious infections (e.g. bacterial meningitis)
20
Q
Ceftriaxone
A
- Third-generation cephalosporins
- Increased activity against gram-negative organisms resistant to other beta-lactam drugs
- Crosses blood-brain barrier
- Drug of choice in gonorrhea (also Cefixime (oral))
21
Q
Cefepime
A
- Fourth-generation cephalosporin
- More resistant to beta-lactamases produced by gram-negative organisms - Enterobacter, Haemophilus, Neisseria, and some penicillin-resistant pneumococci
- Activity against gram-positive and negative organisms
22
Q
Aztreonam
A
- Monobactam
- Inhibitor of bacterial cell-wall synthesis - bind to PBP3
- Synergistic with Aminoglycosides
- Resistant to beta-lactamases produced by certain gram-negative rods; Klebsiella, Pseudomonas, and Serratia
23
Q
Imipenem, Meropenem, Ertapenem
A
- Carbapenems
- Inhibitor of bacterial cell-wall synthesis
- Wide activity against gram-positive cocci, gram-negative rods, and anaerobes.
- Especially useful for infections caused by organisms resistant to other antibiotics
- Drugs of choice for infections cause by Enterobacter
- Imipenem is administered with cilastatin (inhibitor of renal dehydropeptidase I) which increases its plasma half-life
24
Q
Beta-lactamase inhibitors
A
- Clavulanic acid
- Sulbactam
- Tazobactam
- Most active against plasmid-encoded beta-lactamases such as those produced by gonococci, streptococci, E. coli, H. influenza
25
Q
Vancomycin
A
- Bactericidal
- Inhibitor of bacterial cell-wall synthesis
- Bind to D-Ala-D-Ala terminal of the nascent peptidoglycan pentapeptide side chain and inhibits transglycosylation - prevents elongation of peptidoglycan chain
- Resistant bacteria have replaced the terminal D-Ala by D-lactate
- Used for serious infections cause by drug-resistant gram-positive organisms; MRSA, penicillin-resistant pneumococci, and C. difficile
- Rapid IV infusion may cause diffuse flushing (“red man syndrome”)
26
Q
Fosfomycin
A
- Inhibitor of bacterial cell-wall synthesis
- Antimetabolite inhibitor of cytosolic enolpyruvate transferase –> prevents the formation of N-acetylmuramic acid (precursor for peptidoglycan chain formation)
- Resistance occurs via decreased intracellular accumulation of the drug
27
Q
Bacitracin
A
- Inhibitor of bacterial cell-wall synthesis - interferes with a late stage in the synthesis
- Active against gram-positive organisms
- Limited to topical use
