The increasing prevalence and transmission of the carbapenem resistance gene
bla
NDM–5
has led to a severe threat to public health. So far,
bla
NDM–5
has been widely detected in various species of
Enterobacterales
and different hosts across various cities. However, there is no report on the
bla
NDM–5–
harboring
Morganella morganii.
In January 2016, the first NDM-5-producing
Morganella morganii
L241 was found in a stool sample of a patient diagnosed as recurrence of liver cancer in China. Identification of the species was performed using 16S rRNA gene sequencing. Carbapenemase genes were identified through both PCR and sequencing. To investigate the characteristics and complete genome sequence of the
bla
NDM–5
-harboring clinical isolate, antimicrobial susceptibility testing, S1 nuclease pulsed field gel electrophoresis, Southern blotting, transconjugation experiment, complete genome sequencing, and comparative genomic analysis were performed.
M. morganii
L241 was found to be resistant to broad-spectrum cephalosporins and carbapenems. The complete genome of L241 is made up from both a 3,850,444 bp circular chromosome and a 46,161 bp self-transmissible IncX3 plasmid encoding
bla
NDM–5
, which shared a conserved genetic context of
bla
NDM–5
(ΔIS
3000
-ΔIS
Aba125
-IS
5
-
bla
NDM–5
-
ble
-
trpF
-
dsbC
-IS
26
). BLASTn analysis showed that IncX3 plasmids harboring
bla
NDM
genes have been found in 15 species among
Enterobacterales
from 13 different countries around the world thus far. In addition, comparative genomic analysis showed that
M. morganii
L241 exhibits a close relationship to
M. morganii subsp. morganii
KT with 107 SNPs. Our research demonstrated that IncX3 is a key element in the worldwide dissemination of
bla
NDM
-
5
among various species. Further research will be necessary to control and prevent the spread of such plasmids.