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Testing the Role of Multicopy Plasmids in the Evolution of Antibiotic Resistance
Published on: May 2, 2018
Spread and evolution of blaKPC-plasmid between Serratia marcescens and Klebsiella pneumoniae
Weiwei Yang1, Chengkang Tang1, Siquan Shen1
1Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China; Key Laboratory of Clinical Pharmacology of Antibiotics, Ministry of Health, Shanghai, China.
Objectives:
blaKPC-carrying Enterobacterales have post great challenges to global healthcare systems. In this study, we reported the evolution and spread of blaKPC between Serratia marcescens and Klebsiella pneumoniae.
Methods:
Four S. marcescens and one K. pneumoniae strains were isolated from the sputum samples of the patient. Antimicrobial susceptibility tests and whole genome sequencing were performed to investigate the phenotype & genotype of strains. Conjugation assays, cloning experiment and kinetic parameters measuring were performed to explore the spread and antimicrobial resistance mechanisms.
Results:
The evolution and transmission of blaKPC-2 occurred during the treatment of ceftazidime-avibactam and trimethoprim-sulfamethoxazole. Analysis of the antimicrobial susceptibility and genetic profiles of the clinical strains showed that blaKPC-2 evolved into blaKPC-71 and blaKPC-44, together with resistance to ceftazidime-avibactam and carbapenems susceptibility recovery under antimicrobial pressure. Cloning and expression of blaKPC-44 & blaKPC-71 in E. coli DH5α showed that KPC-44 and KPC-71 resulted in a 64∼128-fold increase in the MIC value for ceftazidime-avibactam. Meanwhile, the kinetic assays also showed that the enzyme activity of KPC-44 and KPC-71 towards carbapenems was destroyed and couldn't be inhibited by avibactam. Based on the conjugation assay and whole genome sequence analyses, we provided evolutionary insights into the transmission pathway trace of blaKPC-bearing plasmids between S. marcescens and K. pneumoniae.
Conclusions:
Mixed-species co-infection is one of the risk factors leading to the spread of plasmids carrying carbapenem-resistant genes, and increased surveillance of multidrug-resistant Enterobacterales is urgently needed.
Insights
blaKPC-carrying Enterobacterales evolved into new resistance forms during treatment, spreading between Serratia marcescens and Klebsiella pneumoniae. This highlights the need for enhanced surveillance of multidrug-resistant bacteria.
Area of Science:
- Microbiology
- Genetics
- Infectious Diseases
Background:
- blaKPC-carrying Enterobacterales pose significant challenges to global healthcare.
- Understanding the evolution and spread of carbapenem resistance genes is crucial.
Purpose of the Study:
- To investigate the evolution and transmission of blaKPC between Serratia marcescens and Klebsiella pneumoniae.
- To explore antimicrobial resistance mechanisms and plasmid spread.
Main Methods:
- Isolation and characterization of S. marcescens and K. pneumoniae strains from sputum samples.
- Antimicrobial susceptibility testing, whole genome sequencing, conjugation assays, and cloning experiments.
- Kinetic parameter measurements to assess enzyme activity.
Main Results:
- blaKPC-2 evolved into blaKPC-71 and blaKPC-44 under antimicrobial pressure (ceftazidime-avibactam, trimethoprim-sulfamethoxazole).
- New variants conferred high-level resistance to ceftazidime-avibactam and carbapenems, with destroyed enzyme activity.
- Evolutionary insights into blaKPC plasmid transmission between S. marcescens and K. pneumoniae were provided.
Conclusions:
- Mixed-species co-infections facilitate the spread of carbapenem resistance genes.
- Increased surveillance of multidrug-resistant Enterobacterales is urgently needed to combat resistance.
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