Serovar-Distribution and Drug-Resistance of Salmonella Strains Isolated from Domestic and Imported Cases in 1990-1994 in Tokyo

A total of 3, 647 non-typhoidal Salmonella strains consisting of 2, 655 domestic strains and 992 imported strains isolated in Tokyo from 1990 to 1994, were examined for their serovardistribution and their drug-resistance. The serological typing results showed that the domestic strains were classified into 15 0-groups and 96 serovars, and the imported strains were classified into 13 0-groups and 73 serovars. Among the serovars identified, Salmonella serovar Enteritidis (S. Enteritidis), S. Thompson, S. Hadar, S. Litchfield, and S. Tennessee were predominant in the domestic strains, whereas S. Hadar, S. Enteritidis, S. Anatum, S. Derby, and S. Blockley were predominant in the imported strains. The drug-resistance test using 9 drugs (CP, TC, SM, KM, ABPC, ST, NA, FOM, and NFLX) showed that 30.5% of the domestic strains and 40.5% of the imported strains were resistant to any of the drugs examined. The serovars of a high resistant rate during this period were S. Hadar (96.2%), S. Blockley (88.7%), S. Enteritidis (63.4%), S. Virchow (54.3%), and S. Typhimurium (51.3%) in the domestic strains and S. Krefeld (100%), S. Hadar (98.9%), S. Blockley (98.2%), S. Emek (83.3%), S. Kentucky (76.5%), S. Panama (69.2%), S. Derby (63.8%), S. Typhimurium (57.1%), S. Rissen (55.6%), and S. Agona (53.7%) in the imported strains. Drug-resistance patterns of the resistant isolates varied to 62 types. Prevalent patterns recognized were SM, TC & SM, TC & SM & KM, TC, TC & SM & KM & ABPC and CP & TC & SM & KM in the domestic strains and TC & SM, TC, CP & TC? SM & ST, TC & SM & KM, and CP & TC & SM & KM in the imported strains.