Gram stain of urine shows numerous gram negative rods

An 8 year old girl is brought to physician because of a severe sore throat. Treatment with pencillin is begun. Twelve hours later, she is brought to the emergency department becuase of a diffuse maculopapular rash, shortness of breath, and wheezing. Her condition is successfully treated, and she is discharged. Three months later,she develops fever, chills severe Flank pain, nausea, vomiting and costovertebral angle tenderness. Gram stain of urine shows numerous gram negative rods. Which of the followimg antibiotics could most likely be safely given to this patient.

A. Cephalexin
B. Ciprofloxacin
C. Doxycycline
D. Sulfamethoxazole/Trimethoprim
E. Trcarcillin

Answer: The correct Answer is D

Explaination:
The child currently has a Urinary tract infection as evident from sign and symptoms.
Antibiotics used for treatment of urinary tract infection in children include amoxicillin, amoxicillin/clavulanate, cefexime, ceftriaxone, cephalexin, nitrofurantoim and sulfamethoxazole/trimethoprim.
However the child was treated with a pencillin for her sore throat and she developed an anaphylactic reaction. Therefore this time she can not be given pencillin for her UTI. There is cross-allergencity between all the pencillins. And patient who have sensitivity pencillin may also be sensitive to cephalosporins. Based on this information the best option is Option D (Sulfamethoxazole/Trimethoprim.