Antibiotic resistance and pulsed-field gel electrophoresis patterns of Shigella sonnei isolates

Objective To understand antibiotic resistance of Shigella sonnei and establish its DNA fingerprint database in Pudong district by conducting drug resistance test and pulsed-field gel electrophoresis (PFGE) molecular subtyping. Methods The drug resistance of 34 S. sonnei isolates to 12 antibiotics was conducted by K-B method, and the molecular subtyping of the isolates was done by PFGE after the digestion of restriction enzyme XbaⅠ. Results The resistant rates of isolates to streptomycin, nalidixic acid, trimethoprim and sulfamethoxazole were 100%, and the resistant rate was 94.1% to ampicillin, 91.2% to gentamicin, 88.2% to tetracycline and 2.9% to ceftazidime and cefepime, but they were all sensitive to amoxicillin, clavulanic acid, chloramphenicol and ofloxacin. All the isolates showed 13 PFGE patterns and similarity was more than 90%. The isolates with same PFGE patterns showed same antibiotic resistance. J16X01. sh011 were the predominant PFGE patterns. The isolates with same PFGE patterns were detected in different time and place. Conclusion The antibiotic resistance of S. sonnei is becoming more serious. There were closely related pandemic clones of S. sonnei in Pudong district.