This increased virulence is assumed to be associated with higher amounts of toxin production by fluoroquinolone-resistant strains belonging to PCR ribotype 027, toxinotype III and PFGE NAP1.
Deze toegenomen virulentie wordt verondersteld verband te houden met de hogere productie van toxine (gifstof) door fluorchinolonresistente stammen behorend tot PCR-ribotype 027, toxinotype III en PFGE NAP1.