title: Escherichia coli in bacteremia: K and O antigens and serum sensitivity of strains from adults and neonates.
abstract: Comparisons of O- and K-antigenic types and serum sensitivity were carried out with 149 strains of Escherichia coli isolated from adults with bacteremia and 46 strains from neonates with bacteremia. O-antigenic types O6, O4, O2, O16, O18, and O7 were observed most frequently, but their relative prevalence did not differ materially between adult and neonatal bacteremias. A greater proportion of strains from neonatal bacteremia contained K1 antigen and were autoagglutinable compared with strains from adult bacteremia, although K1 was the most frequent K antigen found in strains from adults. K-antigen-containing strains did not appear to be associated with enhanced severity of bacteremia, but nontypable strains, auto-agglutinable strains, and strains of O-antigenic types O4, O6, and O8 were associated with a greater frequency of shock and fatal outcome in adults. No differences could be detected between the serum sensitivities of E. coli isolated from adult bacteremia and those from neonatal bacteremia. K antigen did not affect serum sensitivity, but E. coli strains of O types O18, O2, O4, and O7 were more serum-resistant than other E. coli. Bacteremia caused by serum-sensitive E. coli was less often associated with shock and death than bacteremia caused by serum-resistant E. coli.
mesh_terms: D000328:Adult; D000372:Agglutination Tests; D000942:Antigens, Bacterial / Q000302:isolation & purification*; D001770:Blood Bactericidal Activity; D004926:Escherichia coli / Q000472:pathogenicity; D004927:Escherichia coli Infections / Q000276:immunology*; D006801:Humans; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases / Q000276:immunology*; D018805:Sepsis / Q000276:immunology* / Q000401:mortality; D012703:Serotyping; D012772:Shock, Septic / Q000453:epidemiology; D014774:Virulence
chemical_list: D000942:Antigens, Bacterial