Characterization of Three Porcine Acinetobacter towneri Strains Co-Harboring tet(X3) and blaOXA-58
Tigecycline is the antibiotic of last resort for the treatment of extensively drug-resistant bacterial infections, mainly those of multidrug-resistant Gram-negative bacteria. The plasmid-mediated tet (X3) gene has recently been described in various pathogens that are resistant to tigecycline. We rep...
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Veröffentlicht in: | Frontiers in cellular and infection microbiology 2020-12, Vol.10 |
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Sprache: | eng |
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Zusammenfassung: | Tigecycline is the antibiotic of last resort for the treatment of extensively drug-resistant bacterial infections, mainly those of multidrug-resistant Gram-negative bacteria. The plasmid-mediated
tet
(X3) gene has recently been described in various pathogens that are resistant to tigecycline. We report three tigecycline-resistant
Acinetobacter towneri
strains isolated from porcine faeces in China, which all contained the
tet
(X3)-harboring plasmids. A broth microdilution method was used to examine the antimicrobial susceptibility of the isolates, and S1-Nuclease digestion pulsed-field gel electrophoresis (S1-PFGE) was used to characterize their plasmid profiles. The whole-genome sequences of the isolates were determined with the Nanopore PromethION platform. The sequence analysis indicated that the strains were
A. towneri.
They showed resistance to multiple antibiotics, and all the resistance genes were located on plasmids. The three
tet
(X3)-harboring plasmids had a similar backbone structure, and all contained
bla
OXA-58
with various insertion elements (IS). IS
CR2
is considered an important factor in
tet
(X3) mobilization. In addition to IS
CR2
, we demonstrate that IS
26
generates a circular intermediate containing the
tet
(X3) gene, which could increase the dissemination risk. To our knowledge, this is the first report of
tet
(X3)- and
bla
OXA-58
-harboring plasmids in
A. towneri
. Because the IS
26
is frequently found in front of
tet
(X3), research should be directed toward the action of IS
26
in the spread of
tet
(X3). |
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ISSN: | 2235-2988 2235-2988 |
DOI: | 10.3389/fcimb.2020.586507 |