Genetic Features Differentiating Bovine, Food, and Human Isolates of Shiga Toxin-Producing Escherichia coli O157 in The Netherlands

The frequency of Escherichia coli O157 genotypes among bovine, food, and human clinical isolates from The Netherlands was studied. Genotyping included the lineage-specific polymorphism assay (LSPA6), the Shiga-toxin-encoding bacteriophage insertion site assay (SBI), and PCR detection and/or subtyping of virulence factors and markers [stx1, stx2a/stx2c, q21/Q933, tir(A255T), and rhsA(C3468G)]. LSPA6 lineage II dominated among bovine isolates (63%), followed by lineage I/II (35.6%) and lineage I (1.4%). In contrast, the majority of the human isolates were typed as lineage I/II (77.6%), followed by lineage I (14.1%) and lineage II (8.2%). Multivariate analysis revealed that the tir(A255T) SNP and the stx2a/stx2c gene variants were the genetic features most differentiating human from bovine isolates. Bovine and food isolates were dominated by stx2c (86.4% and 65.5%, respectively). Among human isolates, the frequency of stx2c was 36.5%, while the frequencies of stx2a and stx2a plus stx2c were 41.2% and 22.4%, respectively. Bovine isolates showed equal distribution of tir(255A) (54.8%) and tir(255T) (45.2%), while human isolates were dominated by the tir(255T) genotype (92.9%). LSPA6 lineage I isolates were all genotype stx2c and tir(255T), while LSPA6 lineage II was dominated by tir(255A) (86.4%) and stx2c (90.9%). LSPA6 lineage I/II isolates were all genotype tir(255T) but showed more variation in stx2 types. The results support the hypothesis that in The Netherlands, the genotypes primarily associated with human disease form a minor subpopulation in the bovine reservoir. Comparison with published data revealed that the distribution of LSPA6 lineages among bovine and human clinical isolates differs considerably between The Netherlands and North America

Bibliographic Details

Main Authors:	Franz, E., van Hoek, A.H.A.M., van der Wal, F.J., de Boer, A.G., Zwartkruis-Nahuis, A., van der Zwaluw, K., Aarts, H.J.M., Heuvelink, A.E.
Format:	Article/Letter to editor biblioteca
Language:	English
Subjects:	dairy-cattle, expression, genotypic characterization, human infection, identification, lineages, prevalence, strain origin, virulence factors, vtec,
Online Access:	https://research.wur.nl/en/publications/genetic-features-differentiating-bovine-food-and-human-isolates-o
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