Objective To investigate changes in the serotype distribution,integrons,and antibiotic resistance of Shigella flexneri at different times in the city of Tianjin. Methods The integrase-encoding regions and variable regions of integrons of S.flexneri strains were amplified with PCR and then sequenced.The serotypes of 56 S.flexneri strains,32 of which were stored in this laboratory and 24of which were isolated at different times from tertiary hospitals in Tianjin, were identified and tested for their sensitivi...