Biotechnology Bulletin ›› 2024, Vol. 40 ›› Issue (2): 55-64.doi: 10.13560/j.cnki.biotech.bull.1985.2023-0841

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Establishment of A Bacterial Model of CRISPR/Cas9 Mediated adeG Gene Knockout in Escherichia coli

ZHU Tian-yi1,2(), KONG Gui-mei1,2(), JIAO Hong-mei1,2, GUO Ting-ting1,2, WU Ri-han1,2, LIU Cui-cui1,2, GAO Cheng-feng1,2, LI Guo-cai1,2()   

  1. 1. Medical College of Yangzhou University, Yangzhou 225100
    2. Jiangsu Key Laboratory of Zoonosis, Yangzhou 225100
  • Received:2023-08-29 Online:2024-02-26 Published:2024-03-13
  • Contact: KONG Gui-mei, LI Guo-cai E-mail:15705273927@163.com;gmkong@yzu.edu.cn;gcli@yzu.edu.cn

Abstract:

【Objective】 Acinetobacter baumannii is one of the important opportunistic pathogens that cause hospital infections, and the highly resistant A. baumannii is currently a thorny issue in prevention and treatment. Due to the fact that bacterial efflux pumps are one of the important causes of drug resistance, the distribution of the efflux pump gene adeLFGH in the resistance-nodulation-division(RND)of A.baumannii was detected by PCR to explore its relationship with drug resistance. Next, an adeG resistance gene model was established and preliminary targeted knockout studies using the CRISPR/Cas9 system was conducted. 【Method】 Broth microdilution method was used to detect drug resistance distribution of collected strains. PCR was to screen and analyze the distribution of adeLFGH efflux pump genes in 13 clinical isolates of multidrug-resistant A.baumannii. The key gene adeG of RND efflux pump was amplified and a model of adeG resistant bacteria was constructed. Specific sgRNA was designed, CRISPR/Cas9 system was used for targeted knockout, and drug sensitivity experiments were conducted to detect its knockout effect. 【Result】 13 clinical strains of A.baumannii were sensitive to polymyxin E, with a low resistance rate to levofloxacin, only 38.5%. The resistance rate to ceftazidime was 92.3%, the resistance rate to tobramycin was 84.6%, and the resistance rate to other common clinical drugs was 100%.The carrier rate of adeLFGH in 13 strains of multidrug-resistant A.baumannii was 100%. The drug sensitivity test results showed that the adeG model bacteria showed a transition from sensitive to resistant to piperacillin, ticarcillin/clavulanic acid, and piperacillin/tazobactam, while from sensitive to intermediary to chloramphenicol, meropenem, and minocycline. The targeted knockout efficiency of the CRISPR/Cas9 system mediated by specific sgRNA varies. The resistance of pCas9-sgRNA1(adeG)to piperacillin/tazobactam was reversed, and the resistance to tobramycin, tetracycline, doxycycline, and minocycline reduced to varying degrees. pCas9-sgRNA2(adeG)and pCas9-sgRNA3(adeG)restored the resistance of piperacillin/tazobactam from resistant to intermediary, but the reversal effect on other drugs was not significant. 【Conclusion】 The specific CRISPR/Cas9 system can specifically knock out drug-resistant genes and provide new ideas and methods for the treatment of drug-resistant bacteria.

Key words: CRISPR/Cas9, drug resistance, sgRNA, adeG