Molecular Typing of Escherichia coli O157:H7 Isolates from Swedish Cattle and Human Cases: Population Dynamics and Virulence
| Autor: | Cecilia Jernberg, Robert Söderlund, Erik Eriksson, Erik Bongcam-Rudloff, Ingela Hedenström, Anna Aspán, Sofie Ivarsson |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2014 |
| Předmět: |
DNA
Bacterial Microbiology (medical) Genotype Molecular Sequence Data Population Dynamics Population Cattle Diseases Virulence Multiple Loci VNTR Analysis Biology Escherichia coli O157 medicine.disease_cause Microbiology medicine Animals Humans Clade education Escherichia coli Escherichia coli Infections Sweden 2. Zero hunger Genetics Molecular Epidemiology education.field_of_study Molecular epidemiology Genetic Variation Bacteriology Sequence Analysis DNA Molecular Typing Cattle |
| Zdroj: | Journal of Clinical Microbiology |
| ISSN: | 1098-660X 0095-1137 |
| DOI: | 10.1128/JCM.01877-14 |
| Popis: | While all verotoxin-producing Escherichia coli O157:H7 bacteria are considered potential pathogens, their genetic subtypes appear to differ in their levels of virulence. The aim of this study was to compare the distribution of subtypes of E. coli O157:H7 in the cattle reservoir and in human cases with and without severe complications in order to gain clues about the relationship between subtype and relative virulence. A lineage-specific polymorphism assay (LSPA-6), multilocus variable-number tandem-repeat analysis (MLVA), and a novel real-time PCR assay to identify clade 8 were applied to a large and representative set of isolates from cattle from 1996 to 2009 ( n = 381) and human cases from 2008 to 2011 ( n = 197) in Sweden. Draft genome sequences were produced for four selected isolates. The E. coli O157:H7 isolates in Swedish cattle generally belonged to four groups with the LSPA-6 profiles 211111 (clade 8/non-clade 8), 213111, and 223323. The subtype composition of the cattle isolates changed dramatically during the study period with the introduction and rapid spread of the low-virulence 223323 subtype. The human cases presumed to have been infected within the country predominantly carried isolates with the profiles 211111 (clade 8) and 213111. Cases progressing to hemolytic-uremic syndrome (HUS) were mostly caused by clade 8, with MLVA profiles consistent with Swedish cattle as the source. In contrast, infections contracted abroad were caused by diverse subtypes, some of which were associated with a particular region. The work presented here confirms the high risk posed by the clade 8 variant of E. coli O157:H7. It also highlights the dynamic nature of the E. coli O157:H7 subtype composition in animal reservoirs and the importance of this composition for the human burden of disease. |
| Databáze: | OpenAIRE |
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