Congo red binding by Escherichia coli isolates from chickens.
An attempt was made to use a recently reported special Congo red medium to determine the pathogenicity of Escherichia coli isolates obtained from chickens. The inclusion of bile salts in the Congo red medium as described in previous reports by others was found in the current experiments to cause the production of red colonies from almost all E. coli cultures tested, including known Congo red-negative control cultures. Cultures of E. coli, regardless of their pathogenic history, rarely produced red colonies on the Congo red medium without added bile salts. Numerous isolates of other bacterial genera were examined and found to produce red colonies on the Congo red medium with or without added bile salts.
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USDA, ARS, Southeast Poultry Research Laboratory, Athens, Georgia 30605.
D000818:Animals; D001419:Bacteria / Q000378:metabolism; D001647:Bile Acids and Salts / Q000494:pharmacology; D002645:Chickens / Q000382:microbiology*; D003224:Congo Red / Q000378:metabolism*; D003470:Culture Media; D004926:Escherichia coli / Q000302:isolation & purification / Q000378:metabolism*; D004927:Escherichia coli Infections / Q000382:microbiology / Q000662:veterinary
D001647:Bile Acids and Salts; D003470:Culture Media; D003224:Congo Red