Cirrhosis impairs serum bacteriostasis for Escherichia coli

To study the effects of cirrhosis on serum inhibition of Escherichia coli, cirrhosis with ascites was induced in male Sprague-Dawley rats by intragastric administration of carbon tetrachloride. Heat-inactivated (56 degrees C for 30 minutes) serum from cirrhotic rats (CRS) or that from control rats (NRS) was inoculated with 1 x 10(5) colony-forming units per milliliter (CFU/ml) of E. coli, and growth was measured after 24 hours. The mean growth of E. coli in CRS was significantly higher than growth in NRS: 3.5 +/- 5.4 x 10(8) CFU/ml versus 1.2 +/- 2.0 x 10(6) CFU/ml, respectively (p < 0.01). Fifty-four percent of CRS samples (22/41) completely lacked bacteriostatic activity. These CRS samples were categorized as growth-supporting (G+CRS) because their growth exceeded the mean + 2 SD of NRS (5.2 x 10(6) CFU/ml). Serum bacteriostasis could be restored to G+CRS by adding purified rat apotransferrin (1 mg/ml), suggesting the presence of excess iron in G+CRS. However, serum iron concentration (SI) and total iron binding capacity (TIBC) were virtually the same in G+CRS (SI = 120 +/- 22 micrograms/dl; TIBC = 351 +/- 45 micrograms/dl) as in growth-inhibitory CRS (SI = 131 +/- 16 micrograms/dl; TIBC = 347 +/- 46 micrograms/dl) but were significantly less than NRS (SI = 208 +/- 29 micrograms/dl; TIBC = 533 +/- 57 micrograms/dl), p < 0.01. The percent transferrin saturation was similar in all groups: 34% +/- 6%; 38% +/- 5% and 39% +/- 9%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)