Work

Emergence and genomic epidemiology of tigecycline resistant bacteria of fly origin across urban and rural China

Year: 2024

Type: article

Abstract: Plasmid-mediated tigecycline resistance genes, notably the tet(X4) and tmexCD-toprJ genes, have garnered considerable attention due to their transferability. This study aims to investigate the prevalence and resistance mechanisms associated with tet(X) and tmexCD-toprJ in flies, which are important resistance genes reservoirs. A total of 52 tigecycline resistant bacteria were collected, among which 40 (76.9%) and 12 (23.1%) were positive for tet(X) and tmexCD-toprJ, respectively. Tigecycline resistant bacteria were isolated from diverse geographical locations in China, with tet(X4)-positive Escherichia coli and tmexCD-toprJ-positive Klebsiella pneumoniae prevalent among the isolates. The prevalence of tet(X) in rural area was significantly higher than that in urban area (82.5% vs. 17.5%; P< 0.001), while the prevalence of tmexCD-toprJ shows no significant difference between urban and rural areas (58.3% vs. 41.7%; P>0.05). Most tet(X) positive strains (n=40, 100.0%), and 11(91.7%) of the tmexCD-toprJ positive strains exhibited multi-drug resistance. The IncFIB(Mar)/IncHI1B hybrid plasmid carrying tmexCD-toprJ was identified by whole-genome sequencing analysis, which dominated the transmission of tmexCD-toprJ in Klebsiella pneumoniae. Genetic context analysis showed that tmexCD-toprJ was related to IS26, and IS26 may exacerbate the spread of tmexCD-toprJ in different bacteria. In addition, the genetic structure of tmexCD1-toprJ1 also contains several drug resistance genes, including aph(3')-Ic, sul1, blaDHA-1, blaCTX-M-5, etc., showing resistance to aminoglycosides, sulfonamides, and carbapenem drugs. This study provides insights into the epidemiology and transmission dynamics of tigecycline resistance genes, informing targeted intervention strategies to mitigate antimicrobial resistance dissemination.

Source: Environment International

DOI: 10.1016/j.envint.2024.109099