The Analysis Of Antibiotics-resistance And Genotyping Of Shigella Flexneri In China

Objective:To understand the epidemic tendency and antibiotics-resistance among the Shigella flexneri isolates collected from different regions by antibiotic susceptibility testing, PCR amplification of the resistance genes and genotyping.Methods:The susceptibilities to 21 antibiotics of 1219 S. flexneri strains were determined by the broth microdilution using a 96-well microtiter plate.The amplification of resistance genes was performed by PCR. Pulsed field gel electrophoresis genotyping method was applied to analyze their genetic relationships, and BioNumerics software was used to analyze the PFGE patterns.Results:Almost all the tested S. flexneri strains were resistant to Tetracycline, Trimethoprim/sulfamethoxazole, Ticarcillin, Ampicillin and Gentamicin, while sensitive to Imipenem, Amikacin, Cefepime, Nitrofurantoin and Ceftazidime. A total of 18 different antibiotic resistance genes including blaTEM, blaCTX and etc. were identified in the multidrug-resistant S. flexneri trains. PFGE analysis showed that the isolates from Shenyang area could be divided into 22 unique patterns. Most of the isolates from Shenyang area PFGE patterns showed a high genetic homology.Conclusion:In our study, most of the S. flexneri trains from different regions are resistant to Trimethoprim/sulfamethoxazole and Tetracycline. The same clone cluster detected among strains from Shenyang region indicates the spread of the S. flexneri strains among regions. Therefore, it is of great importance to strengthen the surveillance of S. flexneri from different regions in order to reduce the prevalence of multidrug-resistant strains.