Affiliation:
1. Universidad San Francisco de Quito, Colegio de Ciencias Biológicas y Ambientales, Instituto de Microbiología, Quito , Pichincha, Ecuador
2. Environmental Health Sciences Division, University of California , Berkeley, California, USA
Abstract
ABSTRACT
The rapid dissemination of extended-spectrum β-lactamase (ESBL)-producing Enterobacterales, mainly
Escherichia coli
carrying
bla
CTX-M
genes, is a major public health concern due to its successful spread in hospital settings as well as among humans and animals in the community. We characterized ESBL-producing
E. coli
isolates from children and domestic animals in semirural communities of Ecuador to assess the contribution of horizontal gene transfer of the
bla
CTX-M
genes among
E. coli
isolates. From 20 selected
E. coli
isolates (from children and domestic animals) harboring
bla
CTX-M
allelic variants, we identified 16 plasmids carrying
bla
CTX-M-55
(
n
= 9),
bla
CTX-M-65
(
n
= 5), and
bla
CTX-M-27
(
n
= 2), as well as four chromosomes carrying
bla
CTX-M-65
. The backbone structure of plasmids, including replication, maintenance, and plasmid transfer genes, and the synteny was conserved in all plasmids carrying the same
bla
CTX-M
allelic variant. In all plasmids and chromosomes, the
bla
CTX-M
genes were bracketed by two IS
26
transposable elements. This study highlights the critical role of the IS
26
transposable element for the current mobility of
bla
CTX-M
genes among plasmids or from plasmids to chromosomes, suggesting that IS
26-bla
CTX-M
brackets could be used to study
bla
CTX-M
transmission between humans, domestic animals, and the environment.
IMPORTANCE
The horizontal gene transfer events are the major contributors to the current spread of CTX-M-encoding genes, the most common extended-spectrum β-lactamase (ESBL), and many clinically crucial antimicrobial resistance (AMR) genes. This study presents evidence of the critical role of IS
26
transposable element for the mobility of
bla
CTX-M
gene among
Escherichia coli
isolates from children and domestic animals in the community. We suggest that the nucleotide sequences of IS
26
-
bla
CTX-M
could be used to study
bla
CTX-M
transmission between humans, domestic animals, and the environment, because understanding of the dissemination patterns of AMR genes is critical to implement effective measures to slow down the dissemination of these clinically important genes.
Funder
HHS | NIH | National Institute of Allergy and Infectious Diseases
Publisher
American Society for Microbiology
Subject
Infectious Diseases,Cell Biology,Microbiology (medical),Genetics,General Immunology and Microbiology,Ecology,Physiology