Question

If a P. aeruginosa culture obtained from a patient with an infected wound showed a zone size of 12 mm when tested against Ciprofloxacin, why would that drug not be given to that patient?

Answer 1

A culture of P. aeruginosa with a 12 mm zone of inhibition against Ciprofloxacin likely indicates resistance, as standardized charts used with the Kirby-Bauer disk diffusion test would categorize this zone size as too small to be considered susceptible to the antibiotic.

Step-by-step explanation:

If a P. aeruginosa culture obtained from a patient with an infected wound showed a zone size of 12 mm when tested against Ciprofloxacin, that drug would likely not be given to the patient because the size of the zone indicates resistance to the antibiotic. This determination is based on standardized susceptibility charts which correlate zone sizes to susceptibility categories. The Kirby-Bauer disk diffusion test indicates whether a bacterium is susceptible, intermediate, or resistant to a certain antibiotic based on the size of the zone of inhibition around antibiotics' discs placed on a bacterial culture that has been spread on an agar plate. In this case, a 12 mm zone size for Ciprofloxacin would be considered too small to indicate susceptibility.

It's important to note that the Kirby-Bauer test is only one aspect of antibiotic susceptibility testing, and clinical decisions are often based on a combination of such tests, the site of infection, the patient's health condition, and other factors.