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Virulence genes and subclone status as markers of experimental virulence in a murine sepsis model among Escherichia coli sequence type 131 clinical isolates from Spain
OBJECTIVE: To assess experimental virulence among sequence type 131 (ST131) Escherichia coli bloodstream isolates in relation to virulence genotype and subclone. METHODS: We analysed 48 Spanish ST131 bloodstream isolates (2010) by PCR for ST131 subclone status (H30Rx, H30 non-Rx, or non-H30), virule...
Autores principales: | , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Public Library of Science
2017
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5708792/ https://www.ncbi.nlm.nih.gov/pubmed/29190804 http://dx.doi.org/10.1371/journal.pone.0188838 |
Sumario: | OBJECTIVE: To assess experimental virulence among sequence type 131 (ST131) Escherichia coli bloodstream isolates in relation to virulence genotype and subclone. METHODS: We analysed 48 Spanish ST131 bloodstream isolates (2010) by PCR for ST131 subclone status (H30Rx, H30 non-Rx, or non-H30), virulence genes (VGs), and O-type. Then we compared these traits with virulence in a murine sepsis model, as measured by illness severity score (ISS) and rapid lethality (mean ISS ≥ 4). RESULTS: Of the 48 study isolates, 65% were H30Rx, 21% H30 non-Rx, and 15% non-H30; 44% produced ESBLs, 98% were O25b, and 83% qualified as extraintestinal pathogenic E. coli (ExPEC). Of 49 VGs, ibeA and iss were associated significantly with non-H30 isolates, and sat, iha and malX with H30 isolates. Median VG scores differed by subclone, i.e., 12 (H30Rx), 10 (H30 non-Rx), and 11 (non-H30) (p < 0.01). Nearly 80% of isolates represented a described virotype. In mice, H30Rx and non-H30 isolates were more virulent than H30 non-Rx isolates (according to ISS [p = 0.03] and rapid lethality [p = 0.03]), as were ExPEC isolates compared with non-ExPEC isolates (median ISS, 4.3 vs. 2.7: p = 0.03). In contrast, most individual VGs, VG scores, VG profiles, and virotypes were not associated with mouse virulence. CONCLUSIONS: ST131 subclone and ExPEC status, but not individual VGs, VG scores or profiles, or virotypes, predicted mouse virulence. Given the lower virulence of non-Rx H30 isolates, hypervirulence probably cannot explain the ST131-H30 clade's epidemic emergence. |
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