Enterococcal sepsis and lung microvascular injury in sheep

R. A. Barke, D. L. Dunn, A. Dalmasso, M. O. Allen and E. W. Humphrey
Department of Surgery, Pathology, and Laboratory Medicine, University of Minnesota, Minneapolis.

In a common bile duct contamination model, we studied the effect of Streptococcus faecalis compared with Escherichia coli in sheep with chronic lymph fistulas to investigate the role of enterococcus in acute lung injury and acute sepsis. Early pulmonary hypertension in the E coli group was not expressed in the S faecalis group, probably due to a failure of S faecalis to illicit a thromboxane A2 response. In the late period, E coli was associated with significantly greater lung microvascular damage compared with S faecalis. The lack of difference between groups with respect to complement activation suggests the action of chemotactic factors, in addition to complement, mediating granulocyte aggregation, and neutropenia. In this model, S faecalis demonstrated limited pathogenicity as expressed in lung microvascular injury compared with E coli.