Loop-mediated isothermal amplification (LAMP) assay for rapid detection and differentiation of selected Escherichia coli from other Enterobacteriaceae

Abstract

ABSTRACT Background Escherichia coli is a bacterium that lives in both human and animal intestines and it is one of the first bacteria to infiltrate the intestine. The majority of E. coli strains are benign; however, some serotypes can infect people and animals with illnesses. The genomes of E. coli and Shigella spp. are closely related phenotypically, serotypically, biochemically, clinically and molecularly. Methods Loop-mediated isothermal amplification (LAMP) assay was designed to accelerate E. coli detection and verify its specificity for different Shigella species and selected members of Enterobacteriaceae using specific LAMP primers designed along the E. coli fliF gene region. For the E. coli sensitivity test, varying concentrations of betaine and MgSO 4 were used to set up a LAMP reaction to detect 10 E. coli isolates and Enterobacteriaceae. The LAMP results interpretation was based on gel and colour change using SYBR green. Results Results showed that for varying combinations of betaine and MgSO 4 employed, 1.5 μL betaine and 1.0 μL MgSO 4 gave the best amplification. The LAMP reaction amplified all E. coli strains used and did not amplify other Enterobacteriaceae indicating sensitivity and specificity. Conclusion This study showed that this LAMP protocol can be used to detect E. coli among members of Enterobacteriaceae rapidly.