Further colicin types of Shigella sonnei detected with specific indicator strains.

When 1420 isolates of Shigella sonnei recovered in Dundee, Scotland between 1971 and 1976 were examined with indicator strains of known immune status, four new colicin types, not previously described among the 26 types of Horák (8), were observed. The types were: 11 variant (colicins B, M), 4 variant (Ib, B, M), SH1 (E3) and SH3 (E5). Only type 4 variant strains were of epidemiological significance in the Dundee area.