A 60 year old female was admitted to the hospital for an abdominal aortic aneurysm repair. The patient did welll intraoperatively and was recovering nicely for the first five days post-operation. On the sixth day, she had five bouts of diarrhea and blood was noted on the most recent bout. Her hospital medications included clindamycin.

What is the most likely diagnosis?

What is the next step in management?

What is the most likely causative agent?

What is the most likely pathogen causing this condition?

What is the mechanism of action leading to this condition?

What is the drug of choice use to treat this condition?

What is the alternative drug used to treat this condition?

What si the mechanism of action for both of these antimicrobials?