[The molecular epidemiological analysis of Shigella sonnei isolates from outbreak cases in Yokohama]

We conducted a molecular epidemiological analysis to evaluate the epidemiologic patterns of Shigella sonnei isolates from outbreak cases in Yokohama to clarify the epidemiologic linkages by contact tracing and sources of infection. In the first case (case A), all of the 6 isolates were the colicin 0 type and resistant to both streptomycin (SM) and trimethoprim/sulfamethoxazole (ST). The 5 isolates have plasmid of 230 kb. By RAPD analysis with 2 kinds of primers specific for Shigella, every 6 isolates showed the same pattern. But the DNA fingerprint analysis by PFGE that was performed according to 2 standardized restriction endonucleases revealed a discriminative pattern. However, the resemblance of all isolates, which was calculated by the UPGMA methods, was 0.90 or higher. In the second case (case B), all of the 14 isolates were the colicin 6 type and sensitive to 16 drugs. The serotype of 13 isolates was phase I. The 11 isolates have plasmids of 230 kb and 3 kb. The resemblance of all isolates, which was calculated by the UPGMA methods, was 0.89 or higher. The analysis with a combination of the plasmid, RAPD analysis and PFGE profiles may be effective in investigating detailed epidemiological features of isolates.