Rapid Detection of Escherichia coli O157 and Shiga Toxins by Lateral Flow Immunoassays.

Jinliang Wang,Chitrita Debroy,Lingling Li,Vivek Kapur,Narasimha Hegde,Robab Katani,Elisabeth Roberts

doi:10.3390/toxins8040092

Abstract

Shiga toxin-producing Escherichia coli O157:H7 (STEC) cause food-borne illness that may be fatal. STEC strains enumerate two types of potent Shiga toxins (Stx1 and Stx2) that are responsible for causing diseases. It is important to detect the E. coli O157 and Shiga toxins in food to prevent outbreak of diseases. We describe the development of two multi-analyte antibody-based lateral flow immunoassays (LFIA); one for the detection of Stx1 and Stx2 and one for the detection of E. coli O157 that may be used simultaneously to detect pathogenic E. coli O157:H7. The LFIA strips were developed by conjugating nano colloidal gold particles with monoclonal antibodies against Stx1 and Stx2 and anti-lipid A antibodies to capture Shiga toxins and O157 antigen, respectively. Our results indicate that the LFIA for Stx is highly specific and detected Stx1 and Stx2 within three hours of induction of STEC with ciprofloxacin at 37 °C. The limit of detection for E. coli O157 LFIA was found to be 105 CFU/mL in ground beef spiked with the pathogen. The LFIAs are rapid, accurate and easy to use and do not require sophisticated equipment or trained personnel. Following the assay, colored bands on the membrane develop for end-point detection. The LFIAs may be used for screening STEC in food and the environment.

Highlights

Worldwide, a large number of foodborne outbreaks are attributable to the consumption of contaminated food due to Shiga toxin-producing Escherichia coli (STEC) [1,2,3]
Since cattle are the primary reservoirs of STEC, it is required that all ground meat samples be tested for STEC O-groups and Shiga toxins (Stx) as these organisms are shed in feces and contaminate the environment for prolonged period of time [5]
Using lateral flow immunoassays (LFIA) and ELISA, Shiga toxin (Stx1 and 2) production could be detected after 3 h of induction

Summary

Introduction

A large number of foodborne outbreaks are attributable to the consumption of contaminated food due to Shiga toxin-producing Escherichia coli (STEC) [1,2,3]. The lateral flow immunoassay (LFIA), is a solid-phase immunoassay, combining the principles of thin layer chromatography and immune recognition reaction that has been effectively used in many fields [19] They are low cost, user-friendly and stable in a wide range of applications, for the detection of pathogens and diseases [20,21,22,23,24,25,26,27], and various environmental and agricultural contaminations [28,29,30,31]. The LFIA devices can be used with little training and require only an assessment of colored lines on the membrane for end-point detection

Results and Discussion

Bacterial

Materials and Methods

Methods