Clinical Cases
Beta-Lactam Answers
Case 1
• What antibiotic would you recommend for
intravenous therapy in a 40yo BM with a
Staphylococcus aureus (MSSA) bacteremia?
Nafcillin or oxacillin
– What if the patient had a penicillin allergy (rash)?
cefazolin
– What if the patient had a penicillin allergy
(anaphylaxis)? vancomycin
– What if the bacteria instead was MRSA? NKDA
vancomycin or linezolid (others possible)
Case 2
• A 22yo WF presents with a cellulitis.
– What would you recommend for an oral antibiotic
to cover MSSA and Streptococcal species? NKDA
dicloxacillin or cephalexin or cefadroxil
Case 3
• A 55yo WM develops an Enterococcus faecalis
endocarditis. What IV antibiotics would you
recommend? NKDA
Penicillin G Potassium (or Sodium) (+ aminoglycoside) or
Ampicillin (+ aminoglycoside)
Case 4
• CC is a 65yo WM develops an intrabdominal
infection s/p surgery for colon cancer. You
would like broad coverage (gram +, gram -,
anaerobes). What would you recommend?
NKDA
Carbapenem or beta-lactam/beta-lactamase
inhibitor combo or cefoxitin or cefotetan
Case 5
• A 70yo WF is admitted to the hospital for CHF.
After being in the hospital for 5 days, you now
suspect a superimposed hospital-acquired
pneumonia. What would you recommend for
gram negative coverage including
Pseudomonas aeruginosa?
Drugs of choice: Cefepime or ceftazidime or
piperacillin/tazobactam or ticarcillin/clavulanate
Others could use: Aztreonam or carbapenem
(except ertapenem)
Case 6
• A 2yo WM presents to the pediatrician with
fever and bilateral ear pain for 5 days. Otitis
media is diagnosed. You would like to treat for
for possible resistant Streptococcus
pnemoniae. What do you recommend? NKDA
Amoxicillin 90mg/kg/day
– What if the patient had a penicillin allergy (rash)?
Cephalopsorin (generally for Steptococcus pneumoniae, a
2nd or 3rd generation would be used over a 1st
generation because of resistance) such as cefdinir,
cefpodoxime, cefprozil, cefuroxime axetil)
Case 7
• A 25yo BF is seen by the PA for a 5 day history of fever and
sore throat. A rapid strept test is positive. What antibiotic
would you recommend? NKDA
Strept throat caused by Group A Streptococcus
Drug of choice: Penicillin VK
Others: amoxicillin or ampicillin
– Should this antibiotic be taken with or without food?
(penicillins except amoxicillin can be bound by food
proteins and inactivated by acid)
Penicillin VK and ampicillin on empty stomach (1h before
or 2 h after eating)
Amoxicillin—with or without food
Case 8
• A 70yo WM with a history of COPD is admitted
to the hospital for a COPD exacerbation.
Sputum cultures reveal beta-lactamase
positive hemophilus influenzae. What would
you recommend? NKDA
– Name the penicillin/beta-lactamase inhibitor combinations.
• Amoxicillin/clavulanic acid (Augmentin®) PO
• Ampicillin/sulbactam (Unasyn®) IV
• Ticarcillin/clavulanic acid (Timentin®) IV
• Piperacillin/tazobactam (Zosyn®) IV
– What other bacteria produce a beta-lactamase? Beta lactamase producing organisms
• Haemophilus influenza, Proteus, Klebsiella, E. Coli, Moraxella catarrhalis, N.
gonnorrhea
• Staphylococcus aureus
• Bacteroides