The Serotypes of Escherichia coli O75 and Their Distribution and Pathogenicity to Man

Abstract

Biochemical and serological studies were carried out on 35 strains of E. coli 0 75 isolated from human stools. The strains were isolated in various parts of Japan, namely, in Mie Prefecture, Tochigi Prefecture, Tokyo, Niigata Prefecture and Nagano Prefecture, from diarrheal cases and normal healthy persons.
The strains showed the typical biochemical characteristics of E. coli with respect to IMViC reactions and carbohydrate fermentation.
It was recognized that at least three serotypes could be distinguished among cultures belonging to 0 group 75 of E. coli tested. The antigenic schemes of the serotypes are 0 75: K-: 115, 0 75: K. (B·): 115 and 0 75: K-: H10, where K-indicates the absence of K antigen and K. (B·) indicates the presence of a K antigen (B antigen) different from the known K antigen 1 to 40.
Some of the strains of serotype 0 75: K. (B·): 1110 were derived from the cases of infantile enteritis (Hamashima enteritis) and from sporadic diarrheal cases, while others from normal healthy persons. All of the strains classified into 0 75: K-: 1110 were the isolates from an outbreak of food poisoning among children in a primary school. It is, however, considered that more concrete evidences shonld de accumulated until the enteropathogenicity of E. coli 0 75 to man is clearly demonstrated, where the serotypes studied in the present work will be helpful.
The authors are indebted to Dr. W.H. Ewing, communicable Disease Center, U.S.A., for his confirmation of the serotypes.