IMolecular Analysis of AmpC Genomic Polymorphism in Shigella Sonnei Isolated from CLinical Specimens by PCR-RFLP Method

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.

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.

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.

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.