Objective:The study is to research the prevalence of Shigella in Chongqing. Methods:A total of 349 strains of Shigella isolated from 1997 to 1998 in Chongqing urban district were detected for serotype and plasmid profiles as well as antibiotic resistance. Results:The plasmid profiles of 334 strains showed that 98.8% of the isolates harboured plasmid.Among them 279 Shigella flexneri harboured at least 3 and up to 8 plasmids and contained 7 distinct plasmid patterns.51 Shigella sonnei contained 12 plasmids and were typed 12 plasmid patterns.Antibiotic resistance tests demonstrated that the problem of antibiotic resistance of Shigella was very severe.All isolates had resistance to ten kinds of antibiotics in different degrees;the highest resistance was encountered to rifampin(100%)

followed by tobramycin (96.4%) amikacin (95.8%) norfloxacin (91%)

while the least resistance was observed to caftriazone (1.8).All strains were resistant to at least 3 antibiotics and the multiple resistance of Shigella flexneri was more serious than that of Shigella sonnei. Conclusion:According to the result

Shigella flexneri and Shigella sonnei were the two main epidemic groups in this area currently.The most predominant subtype(93.9%)was 2a serotype of B group.