[Species and serovar distribution, and drug resistance of Shigella strains isolated from imported and domestic cases in 1980-1989 in Tokyo].

A total of 1,189 Shigella strains consisting 804 imported and 385 domestic strains were examined for their species and serovar distribution, and their drug-resistance. In both imported and domestic strains, S. sonnei was found to be the most prevalent species, followed by S. flexneri, S. boydii and S. dysenteriae in order. In imported strains, however, the isolation frequency of S. flexneri, S. boydii and S. dysenteriae were higher than that of domestic strains, and the serovar of each species was distributed in a wider range than that of the domestic strains. The drug resistance test using chloramphenicol (CP), tetracycline (TC), streptomycin (SM), kanamycin (KM), ampicillin (ABPC), sulfamethoxazole-trimethoprim (ST), nalidixic acid (NA), fosfomycin (FOM) and norfloxacin (NFLX) showed that 80.1% of the imported strains and 82.9% of the domestic strains were resistant to any of drugs examined, although frequency of resistance varied by their species. The frequency of resistance to each drugs were SM (74.0%), TC (68.5%), CP (38.8%), ABPC (35.3%), ST (34.1%), NA (1.5%) and KM (1.0%) in imported strains, and TC (79.2%), SM (55.3%), ABPC (40.3%), CP (38.4%), ST (32.4%), NA (30.5%) and KM (4.2%) in domestic strains. No strain resistant to FOM or NFLX was found in both groups. The resistance patterns varied to 32 types. Among those, a multiple drug-resistance type with CP.TC.SM.ABPC was found most frequently in both groups. Frequency of strains carrying transferable R plasmid was tested for 50 strains isolated in 1989 and three (6%) of them had the plasmid.