›› 2019, Vol. 39 ›› Issue (9): 1004-.doi: 10.3969/j.issn.1674-8115.2019.09.011

• Original article (Basic research) • Previous Articles     Next Articles

Effect of relA knockout on heterologous resistance of colistin to Acinetobacter baumannii

YU Chun-bo1, LU Ming2, SHAO Lei3, PU Tian4, CHEN Dai-jie4, ZHOU Wei1, 5   

  1. 1. Shanghai Ninth Peoples Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, China; 2. China National Institute of Pharmaceutical Industry & Shanghai Institute of Pharmaceutical Industry, Shanghai 201203, China; 3. Shanghai Health Medical College, Collaborative research center, Shanghai 201318, China; 4. Shanghai Jiao Tong University School of Pharmacy, Shanghai 200240, China; 5. Shanghai Ninth Peoples Hospital, School of Stomatology, Shanghai Jiao Tong University School of Medicine; Laboratory of Oral Microbiota and Systemic Diseases; National Center for Clinical Research of Oral Diseases; Shanghai Key Laboratory of Stomatology & Shanghai Institute of Stomatology, Shanghai 200011, China
  • Online:2019-09-28 Published:2019-11-02
  • Supported by:
    Shanghai Municipal Education Commission—Gaofeng Clinical Medicine Support，20152523）。

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Abstract: Objective · To observe the effect of the (p)ppGpp synthase gene (relA) on the heteroresistance of colistin against Acinetobacter baumannii. Methods · The relA gene in Acinetobacter baumannii ATCC19606 was knocked outRed homologous recombination technique. The biofilm formation of Acinetobacter baumannii was observedcrystal violet staining. The change of heterogeneous colonies of Acinetobacter baumannii under the action of colistin was detectedpopulation analysis profiles (PAP) and the heterogeneity was calculated. The killing curve was used to detect the formation of persistent bacteria in Acinetobacter baumannii under the action of colistin. Results · The relA gene in Acinetobacter baumannii was successfully knocked out, and the relA knockout strain ATCC19606-ΔrelA was obtained. After relA gene knockout, the biofilm formation of Acinetobacter baumannii decreased significantly. After relA gene knockout, Acinetobacter baumannii significantly reduced the heterogeneous colonies and persistent bacteria formation under the action of colistin. Conclusion · The bacterial stringent reaction (p) ppGpp synthase relA may be an important factor affecting the heteroresistance of Acinetobacter baumannii to colistin.

Key words: Acinetobacter baumannii, relA gene, colistin, Red homologous recombination technology, heteroresistance, persistence, biofilm

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