Phenotypic modification of the reactivity in human serum of Escherichia coli K1 isolates.
Three Escherichia coli strains producing the K1 antigen and shown to be resistant to the complement-mediated bactericidal action of human serum when grown in batch culture, were cultivated in the chemostat under conditions of carbon-, nitrogen-, magnesium- and phosphate-limitation. All strains were fully serum resistant when grown under carbon-limiting conditions but became phenotypically serum sensitive when limited by magnesium. One strain, belonging to serogroup O7:K1, also displayed serum sensitivity when nitrogen limited and showed an intermediate serum response when phosphate was used as the limiting nutrient.
D000942:Antigens, Bacterial; D000954:Antigens, Surface / Q000235:genetics; D001770:Blood Bactericidal Activity; D002244:Carbon / Q000378:metabolism; D003470:Culture Media; D004926:Escherichia coli / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D008274:Magnesium / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism; D010641:Phenotype; D010710:Phosphates / Q000378:metabolism; D013696:Temperature
D000942:Antigens, Bacterial; D000954:Antigens, Surface; D003470:Culture Media; C030659:K antigens; D010710:Phosphates; D002244:Carbon; D008274:Magnesium; D009584:Nitrogen