Role of lipopolysaccharide and capsule in the serum resistance of bacteremic strains of Escherichia coli.

To define the relative roles of capsule and lipopolysaccharide in the virulence of Escherichia coli obtained from blood, we compared the behavior of K1- and K5-encapsulated strains in serum bactericidal and rat virulence assays. Unencapsulated isogenic mutants selected from five parent strains of E. coli O12:K1, but not of O18:K1 or O7:K1 (all rough-specific phage insensitive), were lysed by normal human sera. In contrast, isogenic mutants from strains of serotypes O6:K5 and O18:K5 retained the serum resistance of the parent strains. There was a greater than 10(5) difference in LD50 in newborn rats between K1-positive and K1-negative pairs of E. coli serotypes O18 and O7 and a greater than 1 log difference between isogenic pairs of serotype O12; however, the K5 isogenic pairs had a similar LD50. Some non-O6 O serotypes, however, required the K5 capsule for serum resistance. We conclude that some O serotypes require encapsulation for optimal virulence but that other O serotypes may not.

[1]  J. Sadoff,et al.  Immunoenzymatic analysis by monoclonal antibodies of bacterial lipopolysaccharides after transfer to nitrocellulose. , 1985, Journal of immunological methods.

[2]  K. Jann,et al.  Escherichia coli O18ac antigen: structure of the O-specific polysaccharide moiety , 1984, Infection and immunity.

[3]  A. Cross,et al.  The importance of the K1 capsule in invasive infections caused by Escherichia coli. , 1984, The Journal of infectious diseases.

[4]  P. Jansson,et al.  Structural studies of the Escherichia coli O-antigen 6. , 1983, Carbohydrate research.

[5]  K. Joiner,et al.  Complement and bacteria: chemistry and biology in host defense. , 1984, Annual review of immunology.

[6]  L. Leive,et al.  Complement activation via the alternative pathway by purified Salmonella lipopolysaccharide is affected by its structure but not its O-antigen length. , 1984, Journal of immunology.

[7]  P. Taylor.  Bactericidal and bacteriolytic activity of serum against gram-negative bacteria. , 1983, Microbiological reviews.

[8]  A. Cross,et al.  Evaluation of immunotherapeutic approaches for the potential treatment of infections caused by K1-positive Escherichia coli. , 1983, The Journal of infectious diseases.

[9]  K. Kim,et al.  Efficacy of trimethoprim/sulfamethoxazole in experimental Escherichia coli bacteremia and meningitis. , 1983, Chemotherapy.

[10]  S. Opal,et al.  K antigen and serum sensitivity of rough Escherichia coli , 1982, Infection and immunity.

[11]  G. Schmidt,et al.  Coliphage K5, specific for E. coli exhibiting the capsular K5 antigen , 1982 .

[12]  P. Mäkelä,et al.  Phagocytosis of bacteria by macrophages: changing the carbohydrate of lipopolysaccharide alters interaction with complement and macrophages. , 1982, Journal of immunology.

[13]  G. K. Scott,et al.  Human serum complement requirements for bacterial killing and protoplast lysis of Escherichia coli ML308 225. , 1981, Journal of general microbiology.

[14]  A. Cross,et al.  K1 antigen-associated resistance to the bactericidal activity of serum , 1980 .

[15]  P. Taylor,et al.  Determinants that increase the serum resistance of Escherichia coli , 1980, Infection and immunity.

[16]  S. Olling.  Sensitivity of gram-negative bacilli to the serum bactericidal activity: a marker of the host-parasite relationship in acute and persisting infections. , 1977, Scandinavian journal of infectious diseases. Supplementum.

[17]  P. Taylor.  Genetical studies of serum resistance in Escherichia coli. , 1975, Journal of general microbiology.

[18]  U. K. Laemmli,et al.  Cleavage of Structural Proteins during the Assembly of the Head of Bacteriophage T4 , 1970, Nature.

[19]  C. Howard,et al.  The sensitivity to complement of strains of Escherichia coli related to their K antigens. , 1970, Immunology.

[20]  D. Feingold.  The serum bactericidal reaction. IV. Phenotypic conversion of Escherichia coli from serum-resistance to serum-sensitivity by diphenylamine. , 1969, The Journal of infectious diseases.

[21]  H. Kuritz,et al.  Locus of the Action of Serum and the Role of Lysozyme in the Serum Bactericidal Reaction , 1968, Journal of bacteriology.

[22]  D. Rowley.  Sensitivity of Rough Gram-negative Bacteria to the Bactericidal Action of Serum , 1968, Journal of bacteriology.

[23]  R. J. Roantree.  Salmonella O antigens and virulence. , 1967, Annual Review of Microbiology.

[24]  O. Westphal.  Bacterial lipopolysaccharides : extraction with phenol-water and further applications of the procedure , 1965 .

[25]  A. Wardlaw.  THE COMPLEMENT-DEPENDENT BACTERIOLYTIC ACTIVITY OF NORMAL HUMAN SERUM: II. CELL WALL COMPOSITION OF SENSITIVE AND RESISTANT STRAINS , 1963 .

[26]  L. H. Muschel.  Bactericidal Activity of Normal Serum Against Bacterial Cultures. II. Activity Against Escherichia coli Strains , 1960, Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine.

[27]  R. J. Roantree,et al.  A STUDY OF THE RELATIONSHIP OF THE NORMAL BACTERICIDAL ACTIVITY OF HUMAN SERUM TO BACTERIAL INFECTION. , 1960, The Journal of clinical investigation.

[28]  L. Reed,et al.  A SIMPLE METHOD OF ESTIMATING FIFTY PER CENT ENDPOINTS , 1938 .