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Detection of Horizontal Gene Transfer Mediated by Natural Conjugative Plasmids in E. coli
Published on: March 24, 2023
Co-transfer of mcr-8 with blaNDM-1 or tmexCD1-toprJ1 by plasmid hybridisation
Xiaoming Wang1, Yao Wang2, Xiaotong Jiang2
1College of Veterinary Medicine, China Agricultural University, Beijing, China; College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China.
Abstract:
Carbapenems, tigecycline and colistin are three important antimicrobial agents for the treatment of clinical infections caused by multidrug-resistant Enterobacteriaceae. Here we characterised the formation of hybrid plasmids containing mcr-8 and blaNDM-1 or tmexCD1-toprJ1 that could confer resistance to colistin and carbapenems or tigecycline. More specifically, these clinically important genes could be co-transferred through IS26- and ltrA-mediated plasmid fusion to clinical isolates during conjugation under single drug (colistin) selection, following which the recipient strains became carbapenem- or tigecycline-resistant. The transferability and stability of these hybrid multidrug resistance (MDR) plasmids depend on the bacterial host and the presence of antibiotics. Further evolution and adaptation of these hybrid plasmids may facilitate their emergence and spread, which is of great concern for clinical therapy.
Insights
Hybrid plasmids carrying resistance genes for colistin, carbapenems, and tigecycline can emerge and spread. This co-transfer mechanism poses a significant threat to treating multidrug-resistant Enterobacteriaceae infections.
Area of Science:
- Microbiology
- Genetics
- Infectious Diseases
Background:
- Multidrug-resistant Enterobacteriaceae pose a significant threat to public health.
- Carbapenems, tigecycline, and colistin are crucial for treating infections caused by these resistant bacteria.
Purpose of the Study:
- To characterize the formation of hybrid plasmids conferring resistance to colistin, carbapenems, and tigecycline.
- To investigate the mechanisms of co-transfer and spread of these resistance genes.
Main Methods:
- Plasmid characterization
- Conjugation experiments
- Antimicrobial resistance profiling
Main Results:
- Hybrid plasmids containing mcr-8 and blaNDM-1 or tmexCD1-toprJ1 genes were identified.
- Co-transfer of resistance genes occurred via IS26- and ltrA-mediated plasmid fusion.
- Recipient strains acquired resistance to carbapenems or tigecycline under colistin selection.
Conclusions:
- Hybrid MDR plasmids can emerge through plasmid fusion, facilitating the co-transfer of resistance genes.
- The spread of these adaptable plasmids is a major clinical concern.
- Understanding plasmid dynamics is crucial for combating antimicrobial resistance.
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