Objective: To understand the epidemic tendency and antibiotics-resistance among Shigella sonnei isolates collected from different regions by antibiotic susceptibility testing, PCR amplification of the resistance genes and genotyping.
Methods: The susceptibilities to 21 antibiotics of 54 S. sonnei strains were determined by 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: All tested S. sonnei strains were resistant to Trimethoprim/Sulfamethoxazole, Tetracycline, Ticarcillin, Ampicillin and Gentamicin, whereas sensitive to Imipenem, Cefepime, Levofloxacin, Norfloxacin and Amikacin. A total of 7 different antibiotic resistance genes including blaTEM, blaCTX and intI were identified in the multidrug-resistant S. sonneis strains. PFGE patterns of all the isolates showed a high genetic homology.
Conclusion: It is of great importance to strengthen the surveillance of S. sonnei from different regions in order to reduce the prevalence of multidrug-resistant strains.