280 PRACTICE QUESTIONS, VERIFIED SOLUTIONS, AND DETAILED
ANSWER RATIONALES GUARANTEED PASS GRADED A+.
β-lactam antibiotic MOA - - ANS - -All antibiotics in class share the same mechanism
of action: disruption of the bacterial cell wall.
Inhibition of cell wall synthesis
Empiric Therapy - - ANS - -start treatment without cultures or prior to receiving the
results of a culture
immediate empiric antibiotics - - ANS - -Critically ill patients receive (Fill in the
Answer) after the first set of cultures obtained; do not wait for results.
Bactericidal antibiotics - - ANS - -Directly kill bacteria: Agents include
aminoglycosides, beta-lactams, fluoroquinolones, metronidazole, most
antimycobacterial agents, streptogramins, and vancomycin.
preferred for immunocompromised patients such as those with diabetes, HIV, or
cancer and for those who have overwhelming infections
Bacteriostatic agents - - ANS - -inhibit bacterial proliferation while the host's
immune system does the killing. Agents include clindamycin, macrolides,
sulfonamides, and tetracyclines
,β-lactam Antibiotics - - ANS - -Penicillins, Cephalosporins, Carbapenems,
Monobactams
Penicillins MOA - - ANS - -Weaken bacterial cell wall by two actions:
(1) inhibition of transpeptidases
(2) disinhibition (activation) of autolysins.
PBPs (Penicillin Binding Proteins) - - ANS - -Transpeptidases, Autolysins, and other
bacterial enzymes are collectively named as because antibiotic class must bind to
them to produce antibacterial effects.
gram-positive bacteria - - ANS - -two layers: the cytoplasmic membrane and a
relatively thick cell wall; penicillins are generally very active against these
organisms.
gram-negative bacteria - - ANS - -three layers: the cytoplasmic membrane, a
relatively thin cell wall, and an additional outer membrane; only certain penicillins
(e.g., ampicillin) are able to cross and reach penicillin binding proteins (PBPs)
Four Major Groups of Penicillins - - ANS - -(1) narrow-spectrum penicillins that are
penicillinase sensitive
(2) narrow-spectrum penicillins that are penicillinase resistant (antistaphylococcal
penicillins)
(3) broad-spectrum penicillins (aminopenicillins)
,(4) extended-spectrum penicillins (antipseudomonal penicillins).
narrow-spectrum penicillins: Penicillinase sensitive penicillins - - ANS - -Penicillin G,
Penicillin V
narrow-spectrum penicillinase sensitive susceptible pathogens - - ANS - -
Streptococci, Neisseria, anaerobes
very narrow antimicrobial spectrum and are used only against penicillinase-
producing strains of staphylococci (S. aureus and S. epidermidis). - - ANS - -narrow-
spectrum penicillins: penicillinase resistant penicillins
narrow-spectrum penicillins: penicillinase resistant penicillins - - ANS - -Nafcillin,
Oxacillin, Dicloxacillin
narrow-spectrum- penicillinase resistant susceptible pathogens - - ANS - -S. Aureus,
S. Epidermidis
Drugs of choice for most staphylococcal infections - - ANS - -penicillinase-resistant
penicillins (Nafcillin, Oxacillin, Dicloxacillin)
Broad spectrum Penicillin: Aminopenicillins - - ANS - -Ampicillin, Amoxicillin
Broad spectrum Aminopenicillin susceptible pathogens - - ANS - -Haemophilus
influenzae, Escherichia coli, Proteus mirabilis, enterococci, Neisseria gonorrhoeae
, Extended spectrum penicillins (antipseudomonal penicillin) - - ANS - -Piperacillin
Has the same antimicrobial spectrum as penicillin G, plus increased activity against
certain gram-negative bacilli, including Haemophilus influenzae, Escherichia coli, and
Salmonella and Shigella - - ANS - -Broad spectrum Penicillin: Aminopenicillins
First line for acute otitis media and sinusitis - - ANS - -Amoxicillin
Extended spectrum penicillins suceptible pathogens - - ANS - -Haemophilus
influenzae, Escherichia coli, Proteus mirabilis, enterococci, Neisseria gonorrhoeae,
pseudomonas, enterobactor, klebsiella
Principle pathogenic target of Piperacillin - - ANS - -Pseudomonas aeruginosa
beta-lactamase inhibitors to broaden penicillin spectrum - - ANS - -clavulanate,
sulbactam, tazobactam
Penicillin/Beta-Lactamase Combinations - - ANS - -Ampicillin/sulbactam (Unasyn)
Amoxicillin/clavulanate (Augmentin)
Piperacillin/tazobactam (Zosyn)
MRSA Drug of Choice - - ANS - -Vancomycin
Most Important AE of Penicillins - - ANS - -Hypersensitivity Reaction