Katrina is a 19-year-old college student who traveled to New
Delhi, India, with a group of students as part of a medical mission
trip. Her contribution was to teach English at an orphanage.
One day as she made her way from the hostel to the orphanage in
the slum, her backpack was caught by a fast-moving train and she
was thrown onto the track where the train ran over the lower part
of her leg. She was transported to a hospital where what remained
of her leg was amputated below the knee.
Her family was notified and flew to India, and they arranged for
Katrina to be transported to a hospital in the United States.
A Kirby-Bauer disk diffusion assay was performed on the wound
bacteria to identify antibiotics that could be used against the
infection.
•Interpret the results of the antimicrobial
susceptibility test, shown below.
Susceptibility Test Results
Zone diameter
Ciprofloxacin
14 mm
Erythromycin
8 mm
Meropenem
10 mm
Cephalosporin 1
8 mm
Cephalosporin 2
13 mm
Vancomycin
15 mm
Table of Standard Values for
Kirby-Bauer Assay
Resistant
Intermediate
Susceptible
Quinolone
<15
16–20
>21
Macrolide
<13
14–22
>23
Imipenem
<13
14–15
>16
Cephalosporin 1
<14
15–22
>23
Cephalosporin 2
<13
14–20
>21