[A study of Kirby-Bauer method of antimicrobial sensitivity test and resistant plasmid assay with 486 strains of Shigella isolated clinically].

486 cases of bacillary dysentery admitted to an army hospital during the peak season (July to September) from 1986 to 1988 were studied. The pathogens in 452 cases were tested for antimicrobial sensitivity with 14 kinds of antibiotics by using Kirby-Bauer method recommended by WHO. The results showed that the number of antibiotics to which the dysentery bacteria became resistant had increased. In 1986 the number was 9, while in 1987 and 1988 it increased to 12 and 13 respectively. Among the resistant strains of bacteria, 331 had been assayed for resistant plasmids. 88.8% was positive with more than three resistant plasmids. The result of antimicrobial sensitivity test coincided well with that of resistant plasmid assay.