Abstract
In an outbeak of Clostridium perfringens food poisoning, isolates from stool specimens from 29 patients represented five Hobbs' types, ten Tokyo Metropolitan Research Institue of Public Health's types (TW), and untypable from two patients. Isolation of the organisms was attempted from nine stool specimens treated under three different conditions; untreated and heat-treated for 10 min at 100°C and for 60 min at 100°C. The results obtained were as follows:
Among 135 isolates, frequency of isolation of a particular sero-type differed depending upon the condition for heat treatment. After heating for 60 min at 100°C, H12 and H13 organisms were isolated in 11.1% and 77.8%, respectively. After heating for 10 min at 100°C, H6, H12, and H13 organisms were isolated in 55.6%, 22.2%, and 77.8%, respectively. From unheated specimens, H6 organisms were isolated in 100% and H12 in 11.6%. Only the H6 isolates among those of the five Hobbs' sero-types were shown to prouce enterotoxin and to form relatively heat-labile spores. From these results, we concluded that the H6 organisms were the true etiological agent of this outbreak. It seems justified to recommend that unheated in addition to heat-treated stool specimens should be examined for C. perfringens and the isolates be tested for the sero-type and enterotoxigenicity in laboratory diagnosis of C. perfringens food poisoning.
