Chapter 22 (Infectious Diseases I: Background & Antibiotics)
JC comes to the emergency department with a large wound that is oozing pus on her lower right leg. She has diabetes and did not want to see a doctor earlier because she does not have medical insurance. It is presumed that the infection is due to community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA). Which of the following are oral medications that can be used to treat CA-MRSA? (Select ALL that apply.)
Clindamycin
Sulfamethoxazole/trimethoprim
Linezolid
Which of the following classes of antibiotics exhibit concentration-dependent killing?
Quinolones
Which of the following drugs are active against Pseudomonas aeruginosa? (Select ALL that apply.)
Ciprofloxacin
Doripenem
Cefepime
Amikacin
Pipercillin/tazobactam
Which of the following statements is correct regarding nafcillin?
Nafcillin is a vesicant
RM is a 63-year-old female who comes to the pharmacy with a new prescription for linezolid 600 mg PO Q12H x 7 days for a complicated skin infection that occurred after an abdominal hysterectomy. She takes calcium carbonate, metoprolol succinate, lisinopril, venlafaxine, hydrocodone/acetaminophen as needed for post-operative pain and ibuprofen as needed for back pain. The patient is at risk of a drug-drug interaction between the new medication and which of her current medications?
Venlafaxine
BJ is on tobramycin IV every 8 hours for treating a gram-negative infection and his levels are reported as a peak of 8.3 mcg/mL and a trough of 2.5 mcg/mL. Which of the following recommendations should the pharmacist make to the medical team?
Extend the dosing interval of tobramycin
MP presents to the urgent care center with a large cellulitis wound on his left lower extremity. The patient has a history of MRSA infection 2 months prior and the practitioner wants to prescribe something orally that covers MRSA. Which of the following medications fit this description?
Zyvox
History of Present Illness: BG is a 71-year-old male
who presents to the hospital with a 6-day history of non-bloody
diarrhea that he believes may be a side effect of donepezil. He has
had no sick contacts or changes to his usual diet. He denies fever,
sweating, chills, chest pain, shortness of breath, nausea or vomiting.
Allergies: NKDA
Past Medical History
Parkinson disease (diagnosed 6 weeks ago)Atrial fibrillationMitral valve repair (bioprosthetic valve)Cerebrovascular accidentModerate-severe Alzheimer's diseaseAnkylosing spondylitisCholecystectomyArthroscopy of the right knee
Bleeding risk
Risk for arrhythmia
CNS side effects
Which antibiotic is available as a chewable tablet?
Amoxicillin
Nafcillin is considered a drug of choice for which of the following?
MSSA
MB is a 51-year-old female who has been prescribed Biaxin for pneumonia. She had a heart attack two years ago. During the hospitalization she was found to have an arrhythmia (atrial fibrillation) and was placed on warfarin. Her other medications include simvastatin, citalopram, atenolol and fish oil. The use of Biaxin in this patient increases her risk of: (Select ALL that apply.)
QT prolongation
Hepatotoxicity
Myopathy
Which antibiotics cover atypical pathogens? (Select ALL that apply.)
Vibramycin
Zithromax
Cipro
A patient with multidrug-resistant (MDR) Pseudomonas aeruginosa isolated from the urine culture is admitted to the hospital. The physician would like to avoid using a medication that can worsen kidney function as the patient's SCr has increased from 0.7 to 1.4 over the past week. Which of the following drugs would you recommend?
Ceftolozane/tazobactam
Which of the following statements is correct regarding ceftriaxone?
It has better gram-negative activity than cefotetan
LJ is receiving ampicillin/sulbactam for the treatment of a Proteus mirabilis bacteremia. The physician wants to know how ampicillin/sulbactam works. Which of the following best characterizes the pharmacodynamic properties of ampicillin/sulbactam?
Ampicillin/sulbactam exhibits time-dependent bacterial killing
Choose the correct statements concerning vancomycin pharmacodynamics/pharmacokinetics and therapeutic drug monitoring. (Select ALL that apply.)
Targeting an AUC/MIC ratio of 400-600 is recommended for serious MRSA infections
Alternative agents should be considered if the vancomycin MIC ≥ 2 mcg/mL
Vancomycin troughs should be drawn at steady state (generally before the fourth dose)
BF is a 52 y/o male patient who has been hospitalized in the ICU of a major trauma center for 26 days. He has had multiple abdominal surgeries secondary to traumatic injuries sustained in a farming accident. He subsequently developed a bloodstream infection.
Blood Culture and Susceptibility Report: E. coli
Amikacin - R Ciprofloxacin - R Gentamicin - R Tobramycin - I
Levofloxacin - R Piperacillin/tazobactam - R Cefepime - R Imipenem - S
SMX/TMP - R
Extended-spectrum beta-lactamase +
Which of the following strategies is best to manage BF’s infection?
Meropenem 1 g IV Q8H
FH is a 51-year-old male with a chronic indwelling urinary catheter secondary to a spinal cord injury. He was admitted to the hospital 2 days ago with fever and altered mental status and his allergies include: Zosyn (wheezing), sulfamethoxazole (Stevens-Johnson), morphine (itching).
His urine specimen has grown Pseudomonas aeruginosa with the following susceptibilities:
Piperacillin/tazobactam - S
Ceftazidime - S
Cefepime -
S
Gentamicin - I
Aztreonam - S
Ciprofloxacin -
R
Imipenem - S
Tobramycin - S
Which of the following would be an appropriate treatment for
this patient?
Aztreonam
RF is a 58-year-old male who is in the medical intensive care unit with a severe Pseudomonas aeruginosalung infection. He is on ciprofloxacin and cefepime and his infection does not seem to be clearing. Which of the following medications could be used to cover the same pathogen in place of the current therapy
Meropenem
Cefotetan is a 2nd generation cephalosporin that is useful in colorectal surgery prophylaxis because of which of the following?
Anaerobic activity
The clinical pharmacist is preparing for rounds. He calls the laboratory to see if the culture results are available for an ICU patient. The laboratory states that the Gram stain contains dark purple diplococci. Which of these organisms is consistent with this Gram stain?
S. pneumoniae
Chief Complaint: Trauma
History of Present Illness: MV is a
43-year-old male brought to the ED on 12/4 after a skiing accident
with closed head trauma, facial lacerations and pulmonary contusion
with underlying rib fracture on the right side of chest. Patient has
been intubated in the ICU since admission for airway support. Due to
extensive injuries and difficulty weaning off the ventilator, MV
remains intubated on hospital day 7. Past medical history includes a
fractured tibia as a child and social history includes social alcohol
use and occasional marijuana use.
Allergies: sulfa (full body rash)
What dose of gentamicin should be initiated in MV as part of the empiric antibiotic regimen?
560 mg
MV is obese, so his adjusted body weight (~80 kg) should be used for aminoglycoside dosing. The dose used most commonly for extended interval dosing is 7 mg/kg (but may range from 4-7 mg/kg).
On 12/12, MV is clinically stable and the physician would like to
streamline the antibiotic therapy based on the culture and
susceptibility report below. Which antibiotic would you recommend?
Endotracheal aspirate culture: S. aureus
Clindamycin (MIC > 16) – R
Erythromycin (MIC > 4)– R
Oxacillin (MIC > 2) – R
Linezolid (MIC = 2) – S
Tetracycline (MIC ≤ 0.5) – S Sulfamethoxazole/Trimethoprim (MIC ≤ 0.5/9.5) – S
Vancomycin (MIC = 2) – S
Linezolid
When the vancomycin MIC is ≥ 2, alternative antibiotics should be considered. Daptomycin and dalbavancin are not indicated for pneumonia and sulfamethoxazole/trimethoprim should not be used in a patient with a sulfa allergy.
Which of the following beta-lactam antibiotics can be given by mouth? (Select ALL that apply.)
Augmentin
Cefdinir
Keflex
A patient with an extensive history of alcohol abuse comes into the hospital with classic signs and symptoms of an infection. Which of the following antibiotics presents a safety issue in light of his social history?
Cefotetan
Chief Complaint: confusion
History of Present Illness: this is a 65-year-old
male who presents to the emergency department with altered mental
status. According to the patient's daughter, he has been confused
since yesterday and is now dragging his right side. The patient does
not recognize his daughter and he is unable to answer questions
related to recent events. He denies chest pain or shortness of breath.
The daughter also noticed some blood in the patient's urine this morning.
Past Medical History:HypertensionPeripheral vascular
diseaseCOPDTobacco use (1 PPD)DyslipidemiaDiabetes Chronic kidney
disease, stage 2
Allergies: NKDA
Which of the following best represents the mechanism of resistance of the microorganism causing the infection?
Enzyme inactivation
**case above**
An appropriate recommendation for continued antibiotic treatment would include discontinuation of ceftriaxone and initiation of:
Doripenem
Which antibiotics are expected to have activity against MRSA (Select ALL that apply.)
Doxycycline
Teflaro
Cubicin
JP has a blood culture report showing Gram-positive cocci resembling Streptococci, Klebsiella pneumoniae and anaerobes. Which of the following medications would provide adequate coverage for these organisms?
Ertapenem
A patient gave the pharmacist a prescription for Z-Pak. Which of the following is the generic name and an appropriate dosing regimen for Z-Pak?
Azithromycin 250 x 2 on day 1, then 250 mg x 1 on days 2-5
Which antibiotic is paired correctly with its mechanism of action?
Cefazolin- prevents peptidoglycan synthesis in bacterial cell walls
Which two antibiotics should be separated from multivitamin supplements?
Minocycline and levofloxacin
Chief Complaint: “I’m out of my inhaler and I can’t breathe".
History of Present Illness: KS is a 30-year-old
female who comes to the ER today for worsening shortness of breath and
cough. She is out of her albuterol inhaler. She occasionally lives on
the street, but has been staying in the local homeless shelter for 3
nights. She reports fatigue, but denies night sweats and hemoptysis.
Her cough is nonproductive. A mild right lower extremity cellulitis
extending from right ankle to right calf is noted. The patient states
that she scraped her leg on a fence and it has not healed. She has not
been treated with antibiotics.
Allergies: NKDA
Past Medical History: HIV x 5 years, PCP pneumonia 5
years ago when she was diagnosed with HIV, asthma and dyslipidemia
Based on chest X-ray, KS will be treated empirically for PCP. An order is received for Bactrim 20 mg/kg/day IV divided Q6H. What is the correct dose?
Bactrim 240 mg IV Q6H
105 pounds = 47.7 kg. 47.7 kg x 20 mg/kg = 954 mg Bactrim per day divided Q6H. Approximately 238.5 mg IV Q6H, so the dose is rounded to 240 mg IV Q6H.
**case above**
The physician asks the pharmacist on rounds to assist with transitioning the patient to oral Bactrim 20 mg/kg/day in preparation for hospital discharge. What is the correct dose?
Bactrim DS 2 tabs TID
105 pounds = 47.7 kg. 47.7 kg x 20 mg/kg = 954 mg Bactrim/day. Bactrim is dosed from the TMP component and DS tabs have 160 mg TMP per tab. KS would need 6 tabs per day (954 mg Bactrim / 160 mg TMP per tab) to treat her infection. To avoid errors, mg/kg doses should reference the TMP component. When using higher SMX/TMP doses like this, monitor the patient carefully for side effects.
KS is diagnosed with PCP and stabilized. She is ready for discharge. Her provider is concerned that the cellulitis has not healed as well as he had hoped. He asks the pharmacist about a single dose medication for bacterial skin and skin structure infections that he heard about. He thinks this patient would be a good candidate for this drug. Which drug is he referring to?
Oritavancin
Which of the following antimicrobials has a risk for additive QT prolongation when combined with amiodarone?
Zithromax
What is the generic name of Zosyn?
Piperacillin and tazobactam
LD is a 74-year-old African American female who is being admitted to
a nursing home. Her family can no longer care for her at home due to
increasing episodes of urinary incontinence.
Allergies: NKDA
Past Medical History: dementia, hypertension,
osteoporosis, type 2 diabetes, incontinence Recent
Labs:eGFR: 40 mL/min/1.73 m2A1C: 7.5%LD develops a
urinary tract infection.
The pharmacist is consulted to review her profile and make a recommendation. Which of the following antibiotics is contraindicated in LD?
Nitrofurantoin
Hospitalized patients with MRSA skin and soft tissue infections are often treated with IV therapy and transitioned to an oral agent to allow ease of use and discharge from the hospital. Which antibiotic requires a D-test to be performed prior to use for MRSA skin and soft tissue infections?
Clindamycin
TM is a 42-year-old male who has been started on Biaxin for treatment of pneumonia. Which of the following medications does not pose a drug interaction with the antibiotic treatment?
Sucralfate