THE EFFECTS OF BACTERIAL OVERGROWTH AND HEMORRHAGIC-SHOCK ON MUCOSAL IMMUNITY

Impairment in systemic and mucosal immune function is noted after hemo rrhagic shock (HS). Overgrowth of gut microflora is common after shock insults and may act as a reservoir for intensive care unit-acquired i nfections and subsequent remote organ failure. Secretory immunoglobuli n A (IgA), the principle immunoglobulin in intestinal secretions, is t he first line of defense of mucosal surfaces. Although HS and gut bact erial overgrowth are often temporarily related, their combined effect on IgA is unknown and served as the basis for this study. After sham o r HS, self-filling blind loops (SFBL) were created to affect bacterial overgrowth. Intestinal secretions were obtained 7 days later from SFB L and jejunal segments for quantitative culture. Gut washings were als o obtained and secretory IgA levels determined by enzyme-linked immuno sorbent assay. Bacterial overgrowth in the SFBL was associated with si gnificant increases in IgA levels in the sham group only. IgA levels w ere depressed in both jejunal and SFBL segments in the PIS group. Impa ired humoral mucosal defense may be important mechanistically in the d evelopment of nosocomial infections and organ failure after I-IS, part icularly with concurrent gut bacterial overgrowth.