I had a patient on whom I operated 4 days after a laparoscopic removal of an ovarian cyst. She had been on ampicillin, gentamicin, and clindamycin since the laparoscopy for uncertain reasons.
At operation there was a large abscess in the lower abdomen, and a large perforation of the sigmoid colon. Cultures were taken. I did a Hartmann procedure. A week later I reoperated for multiple abscesses, and left her abdomen open. She had multiple trips to the OR but eventually recovered completely. ALL her cultures grew only Candida Albicans. She was treated initially with fluconazole, but eventually was given a full dose of Amphotericin B. I still scratch my head when I recall that case. I guess the triple antibiotics supressed everything but fungus, which turned out to be more pathogenic than the usual flora. Anyway, the cultures turned out to be useful.
If one were to culture the fluid identified at operation after perforation of a duodenal ulcer, and Candida were to be identified, would anyone treat it?
I certainly understand your rationale, and I don't culture shit from community-acquired peritonitis, sometimes it's worthwhile to obey the dogma and not think so much.