A patient on clindamycin develops profuse watery diarrhea and tests positive for C. difficile toxin. Which of the following management steps is the most appropriate immediate action?

Discontinue the suspected offending antibiotic if clinically feasible, initiate targeted therapy for C. difficile (e.g., oral vancomycin or fidaxomicin per guidelines), and implement contact precautions with environmental cleaning using a sporicidal agent.

Advise immediate probiotics as the only intervention because they will reliably restore the microbiome within hours and solve C. difficile-associated diarrhea without need for testing or specific therapy.

Immediately administer broad-spectrum intravenous antibiotics to eliminate any possible mixed bacterial causes of diarrhea and delay C. difficile testing until after empiric escalation is shown ineffective.

Continue clindamycin to ensure the primary infection is controlled, start systemic antifungals to prevent concurrent Candida overgrowth, and avoid contact precautions to reduce patient isolation stress.