[Regarding the Shigella flexneri 4 strains isolated in recent years].

A total of 38 strains of Shigella flexneri 4, 14 of which were subserotype 4a but 24 of which were of an undecided subserotype, isolated in recent years, were studied for their biochemical and serological characteristics, and drug susceptibility. Among the biochemical characteristics examined, 21 of the 38 strains (55.3%) were mannitol negative biotype and utilized sodium acetate, meanwhile, 17 of the mannitol positive strains did not utilize sodium acetate. The results of serological tests showed that 22 of the 24 strains, were of an undecided subserotype, basically subserotype 4a. Drug susceptibility was tested for nine drugs (CP, TC, SM, KM, ABPC, ST, NA, FOM and NFLX). Fifteen of the 17 mannitol positive strains (88.2%) and 12 of the 21 mannitol negative ones (57.1%), were found to be resistant to the 5 drugs, such as CP, TC, SM, ABPC or ST. None of the strains were resistant to KM, NA, FOM or NFLX.