Care of the Family questios and
answers
β-lactam antibiotic MOA - answerAll antibiotics in class share the same mechanism
of action: disruption of the bacterial cell wall.
Inhibition of cell wall synthesis
Empiric Therapy - answerstart treatment without cultures or prior to receiving the
results of a culture
immediate empiric antibiotics - answerCritically ill patients receive (Fill in the Answer)
after the first set of cultures obtained; do not wait for results.
Bactericidal antibiotics - answerDirectly 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 - answerinhibit bacterial proliferation while the host's immune
system does the killing. Agents include clindamycin, macrolides, sulfonamides, and
tetracyclines
β-lactam Antibiotics - answerPenicillins, Cephalosporins, Carbapenems,
Monobactams
Penicillins MOA - answerWeaken bacterial cell wall by two actions:
(1) inhibition of transpeptidases
(2) disinhibition (activation) of autolysins.
PBPs (Penicillin Binding Proteins) - answerTranspeptidases, Autolysins, and other
bacterial enzymes are collectively named as because antibiotic class must bind to
them to produce antibacterial effects.
gram-positive bacteria - answertwo layers: the cytoplasmic membrane and a
relatively thick cell wall; penicillins are generally very active against these organisms.
gram-negative bacteria - answerthree 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 - answer(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 - answerPenicillin G,
Penicillin V
narrow-spectrum penicillinase sensitive susceptible pathogens - answerStreptococci,
Neisseria, anaerobes
very narrow antimicrobial spectrum and are used only against penicillinase-
producing strains of staphylococci (S. aureus and S. epidermidis). - answernarrow-
spectrum penicillins: penicillinase resistant penicillins
narrow-spectrum penicillins: penicillinase resistant penicillins - answerNafcillin,
Oxacillin, Dicloxacillin
narrow-spectrum- penicillinase resistant susceptible pathogens - answerS. Aureus,
S. Epidermidis
Drugs of choice for most staphylococcal infections - answerpenicillinase-resistant
penicillins (Nafcillin, Oxacillin, Dicloxacillin)
Broad spectrum Penicillin: Aminopenicillins - answerAmpicillin, Amoxicillin
Broad spectrum Aminopenicillin susceptible pathogens - answerHaemophilus
influenzae, Escherichia coli, Proteus mirabilis, enterococci, Neisseria gonorrhoeae
Extended spectrum penicillins (antipseudomonal penicillin) - answerPiperacillin
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 - answerBroad spectrum Penicillin: Aminopenicillins
First line for acute otitis media and sinusitis - answerAmoxicillin
Extended spectrum penicillins suceptible pathogens - answerHaemophilus
influenzae, Escherichia coli, Proteus mirabilis, enterococci, Neisseria gonorrhoeae,
pseudomonas, enterobactor, klebsiella
Principle pathogenic target of Piperacillin - answerPseudomonas aeruginosa
beta-lactamase inhibitors to broaden penicillin spectrum - answerclavulanate,
sulbactam, tazobactam
Penicillin/Beta-Lactamase Combinations - answerAmpicillin/sulbactam (Unasyn)
, Amoxicillin/clavulanate (Augmentin)
Piperacillin/tazobactam (Zosyn)
MRSA Drug of Choice - answerVancomycin
Most Important AE of Penicillins - answerHypersensitivity Reaction
Drug of choice when history of anaphylaxis or some other severe allergic reaction to
penicillins - answerAvoid cephalosporin;
Vancomycin, erythromycin, and clindamycin are effective and safe alternatives for
patients with penicillin allergy.
Common drug used to treat bacterial infections in children. - answerPenicillins
First line treatment for infection following animal or human bites -
answerAmoxicillin/clavulanate (Augmentin)
Medication common for streptococcal pharyngitis - answerPenicillin
Penicillin Risk in Pregnancy - answerevidence suggests there is no second or third
trimester fetal risk
Penicillin Risk in Infants - answerUsed safely in infants with bacterial infections,
including syphilis, meningitis, and group A streptococcus.
Amoxicillin - answerSafe use during breastfeeding
Penicillin Use in Older Adults - answerDoses should be adjusted in older adults with
renal dysfunction.
Cephalosporins - answerβ-lactam antibiotics similar in structure and actions to the
penicillins.
Are bactericidal, often resistant to β-lactamases, and active against a broad
spectrum of pathogens.
Useful alternative with mild penicillin allergy
Cephalosporins MOA - answerBactericidal drug similar to penicillins that bind to
penicillin-binding proteins (PBPs):
(1) disrupt cell wall synthesis
(2) activate autolysins (enzymes that cleave bonds in the cell wall). The resultant
damage to the cell wall causes death by lysis. Most effective against cells
undergoing active growth and division.
Ceftriaxone (Rocephin) - answerCephalosporin eliminated largely by the liver.
Dosage reduction is not necessary in patients with renal impairment.
Cephalosporin Administration - answerpoor absorption from the gastrointestinal (GI)
tract, many drugs in this class must be administered parenterally (by the
intramuscular [IM] or intravenous [IV] route).