Abstract
There are three different types of clinically important bacteria, obligate anaerobes, facultative anaerobes, and obligate aerobes. Intestinal contents maintain anaerobic condition, and the intestinal bacterial flora is dominated by anaerobes. Intestinal bacteria suppressabnormal propagation with a synergic effect among species, produce immunoglobulin A, induce macrophage activity, and so on. Thus they play a part in defense against infection. However, postoperative infections, opportunistic infections, or bacterial translocations can be caused by intestinal bacteria. The intestinal flora, thus has merits and demerits for the human body. On the other hand there are many variant factors influencing intestinal flora. Treatment with histaminergic H2 receptor antagonists, gastric resection, antibiotic, total parenteral nutrition, etc. is important for a surgical patient. It is important to fully consider the weakness if antibiotic therapy, because postoperative prophylactic antibiotic therapy is inevitable in digestive tract surgery.
