Atypical class 1 integron and multi-drug resistance in Shigella spp.

Objective To investigate the distribution of atypical class 1integron and its relationship to multi drugre sistance in Shigella spp.Methods Suscep tibility test of 8 antimicrobials was determ ined in 90 Shigella strains.PCR and restriction fragment length polymorphism(RFLP)analysis of atypical class 1 integron were applied to all strains.PCR production of representative isolate was selected for sequencing analysis.Results High prevalence of multi drugresistance(86/90,95.6%)was found.Of all isolates,66(73.3%)were resistant to ampicillin,tetracy cline,and chloram phenicol and 65 (72.2%)had a typical class 1 integron.RFLP analysis revealed the identical profile and gene cassettes bla_oxa-30-aadA 1.The multi resistant rate to ampicillin,tetracyc line and chloram phenicol was significantly higher in the isolates positive of atypica l class 1 integron than in those of negative isolates(P<0.05).Conclusion A typical class 1 integron is related to the multi pleresistance to ampic illin,tetracy cline and chloram phenicol and may play a role in the emergence of multi drug resistance in Shigella spp.