Control of the intestinal flora by means of antibacterial drugs in surgery of the colon.

Abstract

Qualitative and quantitative assessment of bacterial flora in the colon was made pre-operatively and at operation, Selection of antibiotics was made by sensitivity tests and dosage was based on the amount in [mu]g=(minumum inhibitory concentration) X (log10 of viable count) X (fluid volume of intestine in ml). Details of these factors are noted; the fluid volume exchange in the bowel is arbitrarily taken as 7 1/day. This calculation applied only to unabsorbable antibacterials. Combinations were most frequently used; in the majority of patients, 2 g framycetin + 1 g ampicillin (Penbritin) or 2 g neomycin + 100,000 units bacitracin were effective. A high degree of suppression of bacteria results from relatively small doses of antibiotics, by this method. Incidence of postoperative infection was low, and the transient but frequent appearance of yeasts, staphylococci and other abnormal flora was of no clinical importance.