Influence of Growth Temperature on the Development of Escherichia coli Polysaccharide K Antigens

International Escherichia and Klebsiella Centre, Statens Seruminstitut, 2300 Copenhagen S, Denmark ABSTRACT SUMMARY: The established seventy-one Escherichia coli polysaccharide capsular K antigenic test strains were examined for the development of the K antigen after growth at 37 °C and 18 °C. Twentyeight K antigens were not detectable after growth of bacteria at 18 °C, while the remaining 43 antigens were developed at both temperatures. Most of the temperature-dependent antigens belonged to electrophoretically fast-moving K polysaccharides of rather low molecular weight, characteristically found among the common K antigens from extraintestinal disease isolates. Lipopolysaccharide O antigens were developed at both growth temperatures.