Molecular Detection of the RpoS Gene and In Vitro Evaluation of Curcumin Activity Against Escherichia coli Isolated from Children’s Stool Samples

Abstract

Background: Escherichia coli is one of the main bacterial pathogens involved in the gastrointestinal infections in children. Due to the growing emergence of antimicrobial-resistant strains, there is a need for alternative antimicrobials. The rpoS gene is a very significant gene in bacterial stress resistance, survival and pathogenicity. Aims of the study: The aim of this study was to determine the presence of rpoS gene in E. coli strains isolated from children's stool samples and to assess the in vitro antibacterial effect of curcumin against these strains. Methodology: A cross-sectional, laboratory-based study was performed with 33 children who had gastrointestinal symptoms. Conventional bacteriological technique and VITEK® 2 Compact system were used for identification of E. coli. DNA from the genomic DNA was extracted and PCR amplification was carried out for the molecular detection of rpoS. The antibacterial activity of curcumin was then tested by the agar well diffusion method in terms of diameters of inhibition zones formed. Results: Curcumin exhibited considerable antibacterial activity against all tested E.coli isolates with inhibition zone ranging from 13-20 mm. Major response was sensitive or highly sensitive to most isolates. The rpoS gene was successfully detected using PCR in a few isolates with the expected amplicon of 800 bp. Conclusions: In vitro, curcumin was found to be effective against E. coli isolates from children. The presence of rpoS gene indicates higher stress adaptability and pathogenic potential of bacteria. Based on its antimicrobial activity, curcumin could be a potential natural antibiotic against enteric bacterial infections.