Analysis of serotype and antimicrobial-susceptibility in clinical isolates of Shigella in some parts of the Tianjin

Objective: To compare the serotype of Shigella spp.and the change pattern of antimicrobial resistance in Tianjin area.Methods: Serotypes of 154 clinical isolates of Shigella spp.were identified,and 12 antimicrobial agents were tested for drug resistance by K-B disk diffusion method.Results:The isolated rate of Shigella sonnei isolated from 2009-2011(90.91%,140/154) had obviously increased than that of in the early 1980s,and became a recent preponderant bacterialtype.Susceptibility results showed that all Shigella strains isolated from 1981-1983 were sensitive to third-generation cephalosporin,imipenem,amikacin and quinolones,the resistance rates to tetracycline,streptomycin were higher,accounted for 93.10%(27/29) and 72.41%(21/29) respectively.The resistance rates of the Shigella spp.isolated from 2009-2011 to ampicillin,gentamicin,sulfamethoxazole and trimethoprim increased,accounted for 96.75%(149/154),77.27%(119/154) and 96.10%(148/154) respectively.The resistance rates of Shigella sonnei to part of the third-generation cephalosporin,norfloxacin were higher than that of S.flexneri,and were less to gentamicin.Multidrug resistance rate of Shigella strains isolated from 2009-2011 was 96.10%(148/154),and significantly higher than that of from 1981-1983(31.03%,9/29).Conclusion:The preponderant serotype of Shigella spp.have changed in some parts of the Tianjin,multidrug resistance strains increased.