Experimentation on artificial inoculation studies for persistence of shiga-like toxin-producing Escherichia coli (E. coli O157) in agricultural soils and vegetables using real-time PCR.
Cayalvizhi B SaiNaganandini SrinivasanJohn Kennady ZachariahBalachandar DananjeyanPublished in: Journal of food biochemistry (2019)
Diarrheagenic Escherichia coli O157 is an important reason for largest food borne inflectional outbreaks. E. coli O157 invades into the food chain through contaminated irrigation water and soil causing infectious diseases to humans. In our previous study, we have evaluated the persistence of E. coli O157 through plate count methods. However, conventional cultural procedures are less sensitive to discriminate the pathogenic strain and are time consuming. Therefore, in the present study we have enumerated the persistence of E. coli O157 in soil and vegetables using specific shiga toxin genes (stx1, stx2) through quantitative PCR. Initially, we have standardized a simple Sephadex-based DNA extraction protocol that could detect 2-3 cells/25g of vegetables. Further, quantitative PCR analysis showed a 103 fold difference in the enumeration of persistence as compared to simple plating techniques. Thus, qPCR-based persistence study can be used for rapid and accurate detection techniques for analyzing E. coli O157 contamination. PRACTICAL APPLICATIONS: Our experiment on E. coli O157 expression could be used as a scale for further studies on E. coli O157 pollution in the cropped soils, additionally the DNA extraction protocol experimented by us could be used in all sensitive quantitative assays, as it could detect the expression in lowest cell loads. However, our methodology is a more reliable and sensitive assay compared to normal cultural methods. Our experiment provides a strong evidence of persistence of E. coli O157 prevailing up to half or full cropping season.
Keyphrases
- escherichia coli
- human health
- heavy metals
- real time pcr
- klebsiella pneumoniae
- biofilm formation
- randomized controlled trial
- poor prognosis
- high resolution
- infectious diseases
- stem cells
- high throughput
- loop mediated isothermal amplification
- induced apoptosis
- dna methylation
- drinking water
- mesenchymal stem cells
- bone marrow
- signaling pathway
- cell free
- single molecule
- particulate matter
- single cell
- pi k akt
- multidrug resistant
- pseudomonas aeruginosa
- oxidative stress
- cystic fibrosis
- cell death
- circulating tumor
- binding protein
- sensitive detection
- mass spectrometry
- candida albicans