ABSTRACT
Since the initial discovery of
mcr-1
in an
Escherichia coli
isolate from China, the gene has also been detected in
Klebsiella pneumoniae
and
Salmonella enterica
but is rarely reported in other
Enterobacteriaceae
. Here, we report the isolation and identification of a
Shigella flexneri
strain harboring
mcr-1
from stool samples in a pig farm in China from 2009. The MIC of colistin for the isolate is 4 μg/ml. Conjugation assays showed that the donor
S. flexneri
strain has functional and transferable colistin resistance. Sequencing revealed that
mcr-1
was present on a putative composite transposon flanked by inverted repeats of IS
Apl1
.
IMPORTANCE
There are four species of
Shigella
, and
Shigella flexneri
is the most frequently isolated species in low- and middle-income countries (LMICs). In this study, we report a functional, transferable, plasmid-mediated
mcr-1
gene in
S. flexneri
. We have shown that
mcr-1
is located on a novel composite transposon which is flanked by inverted repeats of IS
Apl1
. The host strain is multidrug resistant, and this multidrug resistance is also transferable. The finding of a functional
mcr-1
gene in
S. flexneri
, a human-associated
Enterobacteriaceae
family member, is a cause for concern as infections due to
S. flexneri
are the main
Shigella
infections in most low- and middle-income countries.
Cost‐Effectiveness Analysis of Introduction of Rapid, Alternative Methods to Identify Multidrug‐Resistant Tuberculosis in Middle‐Income Countries
