Beta-Lactams Antibiotics Penicillin Flashcards
Antimicrobial drug that can eradicate an infection in the absence of host defense mechanisms; kills bacteria
Bactericidal
Antimicrobial drug that inhibits antimicrobial growth but requires host defense mechanisms to eradicate the infection; does not kill bacteria
Bacteriostatic
Bacterial enzymes that hydrolyze the beta- lactam ring of certain penicillins and cephalosporins
Beta-lactamase
Lowest concentration of antimicrobial drugs capable of inhibiting growth of an organism in a defined growth medium
Minimal Inhibitory Conc. (MIC)
Bacterial cytoplasmic membrane proteins that act as the initial receptors for penicillins and other beta-lactam antibiotics
Penicillin- Binding Proteins (PBP)
Chains of polysaccharides and polypeptides that are cross-linked to form the bacterial cell wall.
Peptidoglycan
Peptidoglycan consists of
N-acetylglucosamine and N-acetylmuramic acid
Bacterial enzymes involved in the cross- linking of linear peptidoglycan chains, which is the final step in cell wall synthesis
Transpeptidase
Penicillins are susceptible to inactivation by
amidases and lactamases
Derivatives of 6-aminopenicillanic acid. Contains a thiazolidine ring structure
Penicillins
Penicillin that are acid stable
Dicloxacillin, ampicillin, amoxicillin
Penicillin that is not acid stable
a. Ampicillin
b. Nafcillin
c. Both
d. Neither
b. Nafcillin
Penicillins that are intramuscular, have long half-lives and cross the BBB.
Procaine and Benzathine Penicilline G
Penicillins that are partly excreted in bile
Ampicillin and Nafcillin
Penicillins that are excreted in both kidney and biliary
Oxacillin, dicloxacillin, cloxacillin
Mechanism of Action of Penicillin
- Binding of the drug to PBPs
- Inhibition of Transpeptidase Enzymes
- Activation of autolytic enzymes
Resistance mechanism of Penicillin
a. Inactivation of antibiotic
b. Modification of target PBPs
c. Both
d. Neither
c. Both
Resistance mechanism of Penicillin
a. Alteration of the PBPs
b. Production of efflux pump
c. Both
d. Neither
c. Both
Methicillin active against
a. pneumococci
b. staphylococci
c. enterococci
d. all of the above
b. staphylococci
Penicillin G resistance in
a. pneumococci
b. staphylococci
c. enterococci
d. a and c
d. a and c (pneumococci and enterococci)
Beta-lactam inhibitors may be used w/ penicillin to prevent their inactivation
clavulanic acid, sulbactam, tazobactam
Narrow Substance Specificity B-Lactamases are produced by
a. Staphylococcus aureus
b. Haemophilus influenzae
c. Escherichia coli
d. All of the above
d. All of the above
What drugs are Penicillins (Narrow-Spectrum Penicillinase-Susceptible Agents)
Penicillin G, Penicillin V, Benzathine and Procaine Penicillin
Penicillins (Narrow-Spectrum Penicillinase-Susceptible Agents) greatest activity against
a. gram (-) rods
b. non-B-lactamase producing anaerobes
c. both
d. neither
b. non-B-lactamase producing anaerobes