Bloodstream Infection with Extended-spectrum Beta-lactamase–producingEscherichia coli: the role of virulence genes
AbstractBackgroundVarious bacterial putative virulence factors are involved in the pathogenesis of bacterial infection. However, the effect of comorbidities or infection syndrome in the association of virulence factors and mortality remains inconclusive.MethodThis study addressed whether specific sequence type (ST) and virulence factors of extended-spectrum beta-lactamase–producingEscherichia coli(ESBL-EC) are associated with different outcomes in patients with bloodstream infection.121 adults from southern Taiwan with ESBL-producingE. colibloodstream 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.ResultPositivity for the virulence genes iha,hlyD,sat,iut,fyu,malX,ompT,uspandtraTwas associated with ST131 positivity (P<0.05). Some ESBL-EC virulence genes associated with urinary tract infection (UTI) were revealed. Positivity for ST405 and the virulence genesiroNandisswas significantly associated with increased 30-day mortality (death within 30 days) on univariate analysis (P<0.05). Independent risk factors of 30-day mortality in bacteremic patients with UTI included underlying chronic liver disease and malignancy. ST131 was borderline associated with 30-day mortality. Independent risk factors associated with 30-day mortality among bacteremic patients without UTI included comorbidities andiroNpositivity.ConclusionIn bacteremic patients with UTI, and the ST131 clone was borderline associated with mortality. Positivity for the virulence geneiroNmay be linked to mortality in bacteremic patients without UTI.