Background & Objective: Shigella is a gram-negative bacillus that has caused serious infection problems in developed and developing countries. The existence of beta-lactamase genes such as AmpC in Shigella species in one country has led to a variety of antibiotic resistance patterns, which can have very serious health risks for the community. The aim of this study was to investigate the prevalence of AmpC β-lactamase gene in S. sonnei strains and determine the prevalence of a spot mutation in this gene by RFLP method.
Materials & methods: Sixty strains of S. sonei were detected using biochemical and microbiological tests. Subsequently, the amplification of ampC gene was performed by PCR method. Then, a point mutation analysis on this gene was performed on ampC gene positive strains. RFLP technique was performed using Hinf1 enzyme.
Results: Among 60 isolates, 30 (50%) isolates were positive for ampC beta-lactamase gene. Furthermore, A to G point mutation was detected in 11 (37%) ampC gene carrying isolates.
Conclusion: The results of this study showed an increasing rate in the prevalence of ampC gene and noticeable prevalence of A to G point mutation in the strains carrying this gene. This mutation may help increase resistance to cephalosporins.