1999 Volume 73 Issue 1 Pages 53-61
To investigate the isolation frequency of O-serotype of Escherichia coil, a total of 1, 563 faecal specimens obtained from patients with sporadic diarrhea in Ishikawa between July 1997 and June 1998, were examined. As a result of O-serotyping of isolated strains using commercially E.coli antisera (43 different types), 247 strains of 29 different O-serotypes were isolated. Isolation rate was 15. %. Most predominant O-serotype was 01 (128 strains, 52%), followed by O18 (26 strains, 11%), 06 (17 strains, 7%), 0111 (16 strains, 6%), and these 4 different O-serotypes took up three quarters of the isolatedE. coli.
Between August 1996 and May 1997, E. coli isolation from faecal samples of 51, 893 healthy persons and O-serotyping of isolated strains using commercial antisera to 6 predominant O-serotypes (O-26, 111, 114, 128, 157 and 01) of VTEC/EHEC were carried out. Among 6 O-serotypes, the most predominant O-serotype was O1 (93% of isolates), followed by O26, 111, 128 (6%) and 0114, 157 (1 %). These isolation frequencies in patients were 80%, 18%, 2%, respectively, have resembled each other in healthy persons in many points.
In a similar way, of these distributions of O-serotype of strains hemolysed on Beutin's blood agar plates, we compared patients with healthy persons. Fifty-six strains (3.6% of the total) of E. coli of different O-serotypes were isolated from 1, 563 patients and 57 strains (2.8% of the total) belonging to 11 serotypes from 2, 036 healthy persons. As a result of O-serotype frequency, both groups resembled each other. 018 and 06, the most predominant O-serotypes, occupied 64% of the isolated strains in patients and 74% in healthy persons. Next in patients, 01, 26 were 7% -level, 028 ac, 152, 157 were 4 % -level, respectively, and in healthy persons, 01 was 5% -level, 028 ac, 55, 146, 152 were 4% -level respectively.
In the comparison of O-serotype frequency of E. coli isolated from sporadic diarrhea in other 5 areas (Kanto district, Tokyo, Oita, Aichi and Ishikawa), 01, 6, 8, 18, 25, 26, 55, 86a, 111, 125, 126, 127a, 128, 146, 148, 157 and 166 (17 types) have covered a wide area. On the other hand, 029, 44, 78, 112ac, 115, 136, 143, 152, 168 and 169 (10 types) have a tendency to distribute in local areas, we believe that there are regional differences even in the same Japanese territory.
