Success of Escherichia coli O25b:H4 Sequence Type 131 Clade C Associated with a Decrease in Virulence.
Infect Immun
; 88(12)2020 11 16.
Article
em En
| MEDLINE
| ID: mdl-32989036
ABSTRACT
Escherichia coli O25bH4 sequence type 131 (ST131), which is resistant to fluoroquinolones and which is a producer of CTX-M-15, is globally one of the major extraintestinal pathogenic E. coli (ExPEC) lineages. Phylogenetic analyses showed that multidrug-resistant ST131 strains belong to clade C, which recently emerged from clade B by stepwise evolution. It has been hypothesized that features other than multidrug resistance could contribute to this dissemination since other major global ExPEC lineages (ST73 and ST95) are mostly antibiotic susceptible. To test this hypothesis, we compared early biofilm production, presence of ExPEC virulence factors (VFs), and in vivo virulence in a mouse sepsis model in 19 and 20 epidemiologically relevant strains of clades B and C, respectively. Clade B strains were significantly earlier biofilm producers (P < 0.001), carriers of more VFs (P = 4e-07), and faster killers of mice (P = 2e-10) than clade C strains. Gene inactivation experiments showed that the H30-fimB and ibeART genes were associated with in vivo virulence. Competition assays in sepsis, gut colonization, and urinary tract infection models between the most anciently diverged strain (B1 subclade), one C1 subclade strain, and a B4 subclade recombining strain harboring some clade C-specific genetic events showed that the B1 strain always outcompeted the C1 strain, whereas the B4 strain outcompeted the C1 strain, depending on the mouse niches. All these findings strongly suggest that clade C evolution includes a progressive loss of virulence involving multiple genes, possibly enhancing overall strain fitness by avoiding severe infections, even if it comes at the cost of a lower colonization ability.
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Base de dados:
MEDLINE
Assunto principal:
Virulência
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Sepse
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Proteínas de Escherichia coli
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Fatores de Virulência
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Escherichia coli
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Infecções por Escherichia coli
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Escherichia coli Extraintestinal Patogênica
Tipo de estudo:
Prognostic_studies
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Risk_factors_studies
Limite:
Animals
Idioma:
En
Revista:
Infect Immun
Ano de publicação:
2020
Tipo de documento:
Article
País de afiliação:
França