Bloodstream Infection with Extended-spectrum Beta-lactamase–producing Escherichia coli: The role of virulence genes

Abstract Background Extraintestinal pathogenic Escherichia coli (ExPEC) strains hold the responsibility for the majority of E. coli infections. Numerous extraintestinal virulence factors (VFs) were possessed by ExPEC which are involved in the pathogenesis of infection. However, the effect of comorbidities or infection syndrome in the association of VFs and mortality remains inconclusive. Method This study addressed whether specific sequence type (ST) and VFs of extended-spectrum beta-lactamase–producing E. coli (ESBL-EC) are associated with different outcomes in patients with bloodstream infection. 121 adults from southern Taiwan with ESBL-EC bloodstream infections were enrolled during a 6-year period. Demographic data, including infection syndromes, underlying disease and outcomes, were collected. The virulence factors in isolates were analyzed by PCR and multilocus sequence typing analyses were also performed. Result Positivity for the virulence genes iha, hlyD, sat, iutA, fyuA, malX, ompT, and traT was associated with ST131 positivity (P  Conclusion In bacteremic patients with UTI, and the ST131 clone was borderline associated with mortality. Positivity for the virulence gene iroN may be linked to mortality in bacteremic patients without UTI.