Plasmids Shape the Current Prevalence of tmexCD1-toprJ1 among Klebsiella pneumoniae in Food Production Chains

Abstract

Tigecycline, the first member of the glycylcycline class of antibacterial agents, is frequently used to treat complicated infections caused by multidrug-resistant Gram-positive and Gram-negative bacteria. The emergence of a novel plasmid-mediated efflux pump, TmexCD1-ToprJ1, conferring resistance to multiple antimicrobials, including tigecycline, poses a huge risk to human health.

Emergence of Plasmids Co-Harboring Carbapenem Resistance Genes and tmexCD2-toprJ2 in Sequence Type 11 Carbapenem Resistant Klebsiella pneumoniae Strains

“…in food production chains according to the host range analysis and seemed to be primary vectors for the horizontal dissemination of tmexCD1 - toprJ1 among Klebsiella spp. ( Peng et al., 2021 ). Notably, IncFIB(Mar)/IncHI1B-type plasmid carrying tmexCD1 - toprJ1 gene could not conjugate to E. coli J53 and E. coli C600 strains but could be transformed to E. coli DH5α strains by electroporation ( Peng et al., 2021 ).…”

“…( Peng et al., 2021 ). Notably, IncFIB(Mar)/IncHI1B-type plasmid carrying tmexCD1 - toprJ1 gene could not conjugate to E. coli J53 and E. coli C600 strains but could be transformed to E. coli DH5α strains by electroporation ( Peng et al., 2021 ). However, the two plasmids in this study could not be transferred to recipient E. coli strains by either conjugation or transformation with E. coli strains, indicating that this IncFIB(Mar)-like/IncHI1B-like type plasmids might be more restricted by the host species.…”

“…Interestingly, we found that a genetic structure containing tmexCD2 - toprJ2 gene clusters and two int genes were inserted into the umuC gene in both pNB4_NDM and pNB5_NDM plasmids ( Figure 2 ). The umuC gene appears to be a “hotspot” for tmexCD-toprJ clusters integration in chromosomes and plasmids ( Peng et al., 2021 ). The umuCD gene was the insertion site of variable region III of SXT/R391 ICEs ( Burrus et al., 2006 ; Carraro and Burrus, 2014 ), which consisted of many resistance genes such as tmexCD1 - toprJ1 ( Wang et al., 2021c ), t et(X) ( He et al., 2020 ; Peng et al., 2020 ), and bla NDM-5 ( Kong et al., 2020 ).…”

Coexistence of tmexCD-toprJ , bla NDM-1 , and bla IMP-4 in One Plasmid Carried by Clinical Klebsiella spp.

“…Genetic context analysis revealed that tmexCD-toprJ was positioned in a conserved mobile unit with genetic arrangement int - int - hp - hp - tnfxB - tmexCD - toprJ in the two plasmids. Previous studies have uncovered that similar mobile units containing tmexCD-toprJ were present in many strains ( 23 , 24 ). As yet, no studies have been conducted to demonstrate the mobility such mobile units.…”

“…Interestingly, different variants of tmexCD-toprJ shared a similar genetic structure ( 14 , 15 , 25 ), implying that these tmexCD-toprJ variants originated from a common ancestor and then propagated to different bacteria. It should be noted that IS 26 -mediated movement of tmexCD-toprJ has been detected in many strains ( 24 , 26 ), and we should therefore present an effective way to prevent further dissemination of tmexCD-toprJ . Apart from tmexCD-toprJ , bla IMP-4 and bla NDM-1 were also located in mobile elements.…”