Eazyplex® EHEC assay (Amplex Diagnostics, Gars-Bahnhof, Germany), a molecular assay based on loop-mediated isothermal amplification (LAMP), is fast, easy to perform, and provides reliable results as a culture confirmation assay for the diagnosis of infection with Shiga toxin-producing Escherichia coli (STEC), Shigella spp, or enteroinvasive E coli, according to study results published in the European Journal of Clinical Microbiology & Infectious Diseases.

To evaluate the performance of the newly introduced eazyplex enterohemorrhagic E coli (EHEC) completeLAMP assay, researchers used 18 retrospective samples (12 strains of Shiga toxin-producing E coli possessing different Shiga toxin (stx) subtypes and 6 strains of Shigella spp) and 31 prospective samples (16 isolates and 15 enrichment broths cultured from diarrheal stool specimens). Results were compared with real-time polymerase chain reaction (PCR) as a reference standard. Microarray analysis was performed to identify the serovar (O:H), the stx subtype, and additional virulence factors.

In the retrospective evaluation, all strains were correctly identified regarding stx types 1 and 2, adhesion intimin (eae), and enterohemolysin A (ehlyA), which is a characteristic virulence factor especially for classical EHEC strains. The gene was correctly identified in all cases.

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In the prospective evaluation, LAMP eazyplex EHEC assay identified and characterized culture isolates in accordance with the PCR and microarray with only 1 exception of a false-positive eazyplex result for eae [isolate O91:H14 (2)]. All 16 isolates harbored additional virulence factors such as adhesins and toxins. From 15 specimens, Shiga toxin-producing E coli infection was confirmed by positive results from a Gram negative enrichment broth, but no isolate could be recovered from single colonies.

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Combining data from the retrospective analysis and prospective testing, the sensitivities and specificities of the eazyplex EHEC assay were as follows: 94.7% and 100% for stx1, 100% and 100% for stx2, 93.3% and 97.1% for eae, 100% and 100% for ehlyA, and 100% and 100% for invasion-associated plasmid antigen H as Shigella spp/enteroinvasive E coli target, respectively. The time to result of the assay ranged from 8.5 to 13 minutes.

Because the cost for a complete test strip covering 7 specific targets are relatively high, researchers “suggested to implement the eazyplex® EHEC assay as a culture confirmation test and to use a sensitive stx PCR as an initial screening test.”


Penzel A, Schützler K, Dröge J, et al. Rapid culture-based identification of Shiga toxin-producing Escherichia coli and Shigella spp./Enteroinvasive E. coli using the eazyplex® EHEC complete assay [published online September 16, 2019]. Eur J Clin Microbiol Infect Dis. doi:10.1007/s10096-019-03704-x