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Jaudou S, Deneke C, Tran ML, Schuh E, Goehler A, Vorimore F, Malorny B, Fach P, Grützke J, Delannoy S. A step forward for Shiga toxin-producing Escherichia coli identification and characterization in raw milk using long-read metagenomics. Microb Genom 2022; 8:mgen000911. [PMID: 36748417 PMCID: PMC9836091 DOI: 10.1099/mgen.0.000911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC) are a cause of severe human illness and are frequently associated with haemolytic uraemic syndrome (HUS) in children. It remains difficult to identify virulence factors for STEC that absolutely predict the potential to cause human disease. In addition to the Shiga-toxin (stx genes), many additional factors have been reported, such as intimin (eae gene), which is clearly an aggravating factor for developing HUS. Current STEC detection methods classically rely on real-time PCR (qPCR) to detect the presence of the key virulence markers (stx and eae). Although qPCR gives an insight into the presence of these virulence markers, it is not appropriate for confirming their presence in the same strain. Therefore, isolation steps are necessary to confirm STEC viability and characterize STEC genomes. While STEC isolation is laborious and time-consuming, metagenomics has the potential to accelerate the STEC characterization process in an isolation-free manner. Recently, short-read sequencing metagenomics have been applied for this purpose, but assembly quality and contiguity suffer from the high proportion of mobile genetic elements occurring in STEC strains. To circumvent this problem, we used long-read sequencing metagenomics for identifying eae-positive STEC strains using raw cow's milk as a causative matrix for STEC food-borne outbreaks. By comparing enrichment conditions, optimizing library preparation for MinION sequencing and generating an easy-to-use STEC characterization pipeline, the direct identification of an eae-positive STEC strain was successful after enrichment of artificially contaminated raw cow's milk samples at a contamination level as low as 5 c.f.u. ml-1. Our newly developed method combines optimized enrichment conditions of STEC in raw milk in combination with a complete STEC analysis pipeline from long-read sequencing metagenomics data. This study shows the potential of the innovative methodology for characterizing STEC strains from complex matrices. Further developments will nonetheless be necessary for this method to be applied in STEC surveillance.
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Affiliation(s)
- Sandra Jaudou
- COLiPATH Unit, Laboratory for Food Safety, ANSES, Maisons-Alfort, France,National Study Center for Sequencing, Department of Biological Safety, German Federal Institute for Risk Assessment, Berlin, Germany,*Correspondence: Sandra Jaudou,
| | - Carlus Deneke
- National Study Center for Sequencing, Department of Biological Safety, German Federal Institute for Risk Assessment, Berlin, Germany
| | - Mai-Lan Tran
- COLiPATH Unit, Laboratory for Food Safety, ANSES, Maisons-Alfort, France,Genomics Platform IdentyPath, Laboratory for Food Safety, ANSES, Maisons-Alfort, France
| | - Elisabeth Schuh
- National Reference Laboratory for Escherichia coli including VTEC, Department of Biological Safety, German Federal Institute for Risk Assessment, Berlin, Germany
| | - André Goehler
- National Reference Laboratory for Escherichia coli including VTEC, Department of Biological Safety, German Federal Institute for Risk Assessment, Berlin, Germany
| | - Fabien Vorimore
- Genomics Platform IdentyPath, Laboratory for Food Safety, ANSES, Maisons-Alfort, France
| | - Burkhard Malorny
- National Study Center for Sequencing, Department of Biological Safety, German Federal Institute for Risk Assessment, Berlin, Germany
| | - Patrick Fach
- COLiPATH Unit, Laboratory for Food Safety, ANSES, Maisons-Alfort, France,Genomics Platform IdentyPath, Laboratory for Food Safety, ANSES, Maisons-Alfort, France
| | - Josephine Grützke
- National Study Center for Sequencing, Department of Biological Safety, German Federal Institute for Risk Assessment, Berlin, Germany
| | - Sabine Delannoy
- COLiPATH Unit, Laboratory for Food Safety, ANSES, Maisons-Alfort, France,Genomics Platform IdentyPath, Laboratory for Food Safety, ANSES, Maisons-Alfort, France,*Correspondence: Sabine Delannoy,
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