Experimental Studies on Postoperative Enterocolitis with Methicilline-resistant Staphylococcus aureus

Kunihiko Kawai

Third Department of Surgery, Toho University School of Medicine

Viable cells of methicillin-resistant Staphylococcus aureus (MRSA) were inoculated into the intestinal tract of rats to clarify the mechanism of MRSA-induced enterocolitis and the process of progression to generalized infection. MRSA-induced enterocolitis frequently occurs after gastrectomy, and alteration of intestinal bacterial flora by treatment with an antibiotic is thought to create a condition of high susceptibility to this disease. Therefore were compared MRSA-inoculated rats by dividing them into antibiotic-treated and non-treated groups and gastrectomized and non-gastrectomized groups. Before gastrectomy, MRSA in a kanamycin-metronidazole-treated group, and was detected at 10² CFU/g up to post-inoculation day 4 and at 10⁵ CFU/g from day 5 in the non-treated group, disclosing the presence of significantly more MRSA in the former group. After gastrectomy, there was no growth of the inoculated MRSA in the latamoxef-non-treated group. When fecal MRSA counts of the gastrectomized and non-gastrectomized groups treated with an antibiotic before and after inoculation of MRSA were compared, the gastrectomized group was found to have a significantly higher MRSA count. As for the route of transmission of MRSA to the organs, it was suggested that MRSA in the intestinal tract penetrates through the intestinal wall into the portal vein, reaches the liver, and then spreads over the entire body, resulting in systemic infection, because MRSA was detected in the liver first.

Key words
MRSA, postoperative enterocolitis, change of intestinal flora, spread of MRSA enterocolitis

Reprint requests
Kunihiko Kawai Third Department of Surgery, Ohashi Hospital
1-17-6 Ohashi, Meguroku, Tokyo, 153 JAPAN

Accepted
December 8, 1993

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