What is the appropriate action after a culture from a patient on broad-spectrum antibiotics shows Pseudomonas growth?

Narrowing the spectrum by discontinuing vancomycin is the appropriate action after identification of Pseudomonas growth in a culture from a patient on broad-spectrum antibiotics. Pseudomonas aeruginosa is a specific bacterial pathogen that can often be treated effectively with targeted antibiotics such as piperacillin/tazobactam, ceftazidime, or a fluoroquinolone, depending on susceptibility patterns.

When broad-spectrum antibiotics are initially used, they are designed to cover a wide variety of potential pathogens; however, once the causative organism is identified through cultures, the treatment can be more effectively targeted, which can help reduce toxicity and the risk of developing antibiotic resistance. In this case, if Pseudomonas has been identified, continuing broad-spectrum coverage with vancomycin, which primarily targets Gram-positive organisms including MRSA, becomes unnecessary and may lead to additional unwanted side effects.

The action of narrowing the antibiotic regimen not only optimizes the therapy against the identified pathogen but also minimizes potential adverse effects and preserves the efficacy of the remaining antibiotics.