Bacterial colonization and endotoxin activity during experimental acute fowl typhoid in chickens

These parameters were assayed by means of colony forming units test (CFU) a nd the Limulus Amebocyte Lysate test (LAL), respectively. Birds were infect ed per os with 1,5 x 10(9) CFU/ml of wild strain of S. gallinarum isolated from a dead hen. Approximately 1,5 x 10(2); 1,3 x 10(2) and 1,2 x 10(2) CFU of S. gallinarum were recorded from 1 g of liver, 1 g of spleen and 1 ml o f blood from the chickens on day 1 post infection. By day 4 corresponding d ata were 3,7 x 10(4): 4,8 x 10(3) and 1,1 x 10(3) respectively and on day 7 10(5) CFU were present in all three specimen types. The liver and spleen o f dead birds were contaminated with more than 10(7)CFU per g. The endotoxin from S. gallinarum was found to have an activity of 1,5; 12,0 and 15,0 end otoxin units (EU)/ml on day 1, 4 and 7 after infection, respectively. No en dotoxin activity was established in the blood of the control group (before infection) by the LAL test. This is the first time the connection between t he amount of live S. gallinarum in the blood, liver and the circulating lev el of endotoxin in the blood during the infectious stage of experimental ac ute fowl typhoid, has been demonstrated.