Community transmission in the United States of a CTX-M-15-producing sequence type ST131 Escherichia coli strain resulting in death

Abstract

A middle-aged woman developed fatal urosepsis due to a multidrug-resistant Escherichia coli strain representing sequence type ST131, a recently emerged, disseminated, multidrug-resistant extraintestinal pathogen, after presumably having acquired it from her extensively antibiotic-exposed sister with chronic recurrent cystitis. Susceptibility results (reported on day 4) showed resistance to the initially selected regimen.

Fig. 1.

Dendrogram of XbaI pulsed-field gel electrophoresis (PFGE) profiles. Included in the analysis is a blood isolate from the deceased sister (strain JJ1886), a urine isolate from the surviving sister (strain JJ1887), and four sequence type ST131 reference (ref.) strains. The reference strains are the index isolates from the four most prevalent pulsotypes in a large private PFGE library that comprises 566 ST131 isolates and their 167 distinct pulsotypes (as defined at a 94% Dice coefficient similarity threshold, corresponding with an approximately 3-band profile difference). The 2% band tolerance limit used explains the calculated 100% profile similarity between JJ2142 and JJ1886, despite visible differences. The dashed rectangle encloses the two case isolates and the index isolate for pulsotype 968 (24% of reference library isolates), which cluster at approximately 96% similarity, consistent with them all representing the same strain.