Identification and differentiation of E. coli and Shigella from other Enterobacteriaceae sp. by lamB gene amplification

Metallic green sheen and lactose fermentation has been used for identification and differentiation of E. coli from other enterobacteriaceae in laboratories for many years. However, these methods defect to accurate diagnosis of E. coli.  This study employed lamB gene PCR amplification to distinguish E. coli and Shigella from other enterobacteriaceae isolated from clinical samples and surface waters, collected in Babol, Iran.

In this cross-sectional study, 100 clinical samples from patients attending health centers and 30 surface water samples were gathered in Babol . All samples were grown on blood agar and Eosin methylene blue. After first biochemical identification, DNA of the samples were extracted and lamB gene was amplified using the PCR reaction.

After cultivation of the samples on blood agar and eosin methylene blue media and biochemical identification of the strains, it has been shown that all 40 isolated E. coli and 30 Shigella carry the lamB gene. However, none of the Salmonella and Klebsiella strains showed the related band.

According to the findings of this study, investigation of lamB gene is an appropriate method for initial isolation of E. coli and Shigella from other enterobacteriaceae.