[Analysis of the drug resistance and the integron resistance gene cassette's characteristics of Shigella flexneri].

OBJECTIVE: To investigate the correlation between Shigella flexneri multi-drug resistance and drug resistance gene cassette of integrons. METHOD: All 79 strains of Shigella flexneri were isolated from the feces of children ranged in age from 6 months to 14 years in some hospitals of Jinan, between May 2009 and April 2012.The resistance was detected by Kirby Bauer agar diffusion method, 1, 2 and 3 integron gene was amplified by PCR, the variable region of positive strains treated with enzyme digestion and determined by Series Analysis. RESULT: Among 79 Shigella flexneri strains, the resistance rate was 91% (72/79) to ampicillin, chloramphenicol, tetracycline, streptomycin, 70% (55/79) to sulfamethoxazole/trimethoprim, 30% (24/79), 23% (18/79), 33% (26/79) and 32% (25/79) to cefotaxime, ceftazidime, ciprofloxacin and levofloxacin.All 79 strains were susceptible to cefoxitin, imipenem, cefoperazone/sulbactam. The common drug resistance pattern is ampicillin tetracycline-chloramphenicol-streptomycin, accounted for 91% (72/79); 91% (72/79) strains carried integrons of class 1, 86% (68/79) strains carried integrons of class 2, No intI3 was detected. The resistance to ampicillin, streptomycin, tetracycline, chloramphenicol of atypical class 1 integron positive strains was significantly higher than the negative strains (χ² = 35.96, P<0.01). The sequencing results:dfrV was detected in class 1 integron variable regions of 9 strains, dfrA17-aadA5 in 2 strains, blaOXA-30-aadA1 in 70 strains, 2 strains were not detected resistance gene cassette, all resistance gene cassettes were dfrA1-sat1-aadA1 in class 2 integron variable regions. CONCLUSION: The muti-drug resistance of Shigella flexneri in Jinan was closely associated with integrons.