BLUE - Spectrum/Coverage

Question 1

Will, a 14 year-old boy develops a bad case of otitis media a few days after swimming in Hideaway Lake, MS. Will’s previous medical history is unremarkable except for having had a minor skin rash two years ago after being treated with amoxicillin for a sore throat. Which of the following shares a common mechanism, but would be very unlikely to produce a similar allergic reaction (e.g. ~1-2% or lower chance)?

A. ampicillin
B. cefuroxime
C. azithromycin
D. doxycycline

Answer 1

B. cefuroxime - 2nd generation cephalosporin that are structurally different enough than penicillin to have <10% cross-reactivity.

Question 2

ESBL stands for what and are only found in gram-____ bacteria.

Answer 2

ESBL = extended spectrum beta lactase

Gram-negative bacteria only

Question 3

A 29-year-old man develops a flu-like illness 10 days after a trip to upstate New York. On physical examination, he has lymphadenopathy and a circular, nonpruritic, erythematous, macular rash on his left arm. One red spot is particularly big and has a clear area in the center. What is the pathogen and preferred tx?

A. Ricksettia spp. - Doxycycline
B. Mycoplasma pneumonia - Azithromycin
C. Borrelia burgdorferi - Doxycycline
D. Treponema pallidum -Ceftriaxone

Answer 3

C. Borrelia burgdorferi - Doxyxline

Question 4

What is the treatment for all Chlamydiae infections?

Answer 4

Azithryomycin (favored Abx due to one-time treatment); Doxycycline

Question 5

Ceftriaxone has good CSF penetration and is commonly used in meningitides, but has poor coverage for ______.

Answer 5

Pseudomonas

3rd generation cephalosporin:

• Ceftriaxone and Cefotaxime has poor coverage for Pseudomonas
• Ceftazidime covers Pseudomonas

Question 6

An 8-year-old boy is brought to his pediatrician by his parents because of a fever and a sore throat. On examination, he has tonsillar exudates and swollen, tender anterior cervical nodes. His parents report no history of cough. Gram stain of the tonsillar exudate reveals gram-positive cocci. What is the most likely pathogen and what is the preferred antibiotic?

Answer 6

Pathogen - Streptococcus pyogenes

Abx - Penicillin

This patient has a classic presentation (fever, sore throat, anterior cervical lymphadenopathy, lack of cough) of streptococcal pharyngitis, or strep throat. Strep throat is caused by Streptococcus pyogenes, or group A streptococcus. Diagnosis is confirmed with a rapid strep test or with throat swab culture. The treatment of choice is penicillin.

Question 7

An 8-year-old girl presents to the emergency department complaining of frequent urination, constant thirst, and new, strange “staining” of her teeth. She recently had a cold, and her pe- diatrician prescribed an antibiotic that she said may hurt her kidneys. She did not bring the bottle with her. Which of the following medi- cations was this patient most likely prescribed?

A. Demeclocycline
B. Neomycin
C. Norfloxacin
D. Penicillin G
E. Vancomycin

Answer 7

A. Demeclocycline

Demeclocycline is a tetracycline that is associated with nephrotoxic- ity, hepatotoxicity, and tooth discoloration

Question 8

A 21-year-old college student presents to his student health center with complaints of mal- aise, headaches, fever up to 38.3° C (101° F), chills, and a nonproductive cough for the past week. His temperature is 38.1° C (100.6° F), heart rate is 90/min, respiratory rate is 20/min, and blood pressure is 118/75 mm Hg. On phys- ical examination the patient appears fatigued. Auscultation of the lungs reveals bilateral dif- fuse wheezes and rales. X-ray of the chest re- veals bilateral infiltrates. The doctor prescribed ceftriaxone, but the patient failed to show any improvement over the subsequent week. Which antibiotic should the physicians pre- scribe instead?

A. Ampicillin
B. Azithromycin
C. Fourth-generation cephalosporin
D. Penicillin

Answer 8

B - Azithromycin

The patient’s presentation is most consistent with an atypical pneumonia likely caused by Mycoplasma pneumoniae. Macrolide antibiotics such as azithromycin are effective in treating this disease. Mycoplasma has no cell wall, so it is not sensitive to the penicillins or cephalosporins, which act by inhibiting cell wall synthesis.

Question 9

____ and Cefoxitin are 2nd generation cephalosporin that are used to treat Bacteriodes fragilis.

Answer 9

Cefotetan

Question 10

The first line treatment for Neisseria meningitides is ______.

Answer 10

Ceftriaxone and/or Penicillin G (only in susceptible isolate)

Question 11

Cefazolin is a _____ (abx class) that is used prior to surgery to prevent Staphylococcus aureus infections

Answer 11

1st generation Cephalosporin