Abstract:
Global expansion of antimicrobial drug–resistant Escherichia coli sequence type (ST) 131 is unrivaled among
human bacteria. Understanding trends among ST131
clades will help with designing prevention strategies.
We screened E. coli from blood samples (n = 1,784) obtained in Calgary, Alberta, Canada, during 2006, 2012,
and 2016 by PCR for ST131 and positive samples (n =
344) underwent whole-genome sequencing. The incidence rate per 100,000 residents increased from 4.91
during 2006 to 12.35 during 2012 and 10.12 during 2016.
ST131 belonged to clades A (10%), B (9%), and C (81%).
Clades C1-nonM27 and B were common during 2006,
and C2 containing blaCTX-M-15, C1-M27 containing blaCTXM-27, and A were responsible for the increase of ST131
during 2012 and 2016. C2 was the most antimicrobial
drug–resistant subclade and increased exponentially
over time. Eradicating ST131, more specifically the C2
subclade, will lead to considerable public health benefits
for persons in Calgary.
