Colicine types of Shigella sonnei isolated in Hong Kong

Two-hundred and twenty-five strains of Shigella sonnei isolated from sporadic cases of bacillary dysentery were subjected to colicine typing. The result showed that types 15 and 12 were the prevailing types in Hong Kong and two new types which did not fit in with the colicine patterns of the current types were observed. A marked increase in the numbers of strains concurrently resistant to chloramphenicol, tetracycline, and streptomycin occurred in recent years. However, there was no correlation between drug resistance or biochemical pattern and colicine types. Consistency of colicinogenicity was confirmed by the fact that even a rough variant of a smooth strain had not changed its colicine pattern.