Acta Veterinaria et Zootechnica Sinica ›› 2025, Vol. 56 ›› Issue (7): 3507-3518.doi: 10.11843/j.issn.0366-6964.2025.07.042

• Basic Veterinary Medicine • Previous Articles     Next Articles

A Preliminary Study on the Mechanism of Tigecycline Resistance in ESBLs- and Carbapenemase-Producing Klebsiella pneumoniae

WEI Yushi(), SUN Wen, PANG Xiaomin, WANG Yulian*()   

  1. National Reference Laboratory of Veterinary Drug Residues(Huazhong Agricultural University), Wuhan 430070, China
  • Received:2024-09-23 Online:2025-07-23 Published:2025-07-25
  • Contact: WANG Yulian E-mail:joanwei1005@webmail.hzau.edu.cn;wangyulian@mail.hzau.edu.cn

Abstract:

The reports of carbapenem-resistant Klebsiella pneumoniae (CRKP) are increasing annually, and tigecycline has become the last line of defense for treating carbapenem-resistant Klebsiella pneumoniae (CRKP) infections, this article presents a preliminary study on the mechanism of tigecycline resistance in three strains of carbapenem-resistant Klebsiella pneumoniae. Broth microdilution method was used to determine the sensitivity of CRKP to tigecycline and evaluate the effect of efflux pump inhibitor, PAβN, on drug resistance. Combined with the results of the previous whole genome sequencing, polymerase chain reaction (PCR) testing was employed to validate the presence of genes and corresponding regulatory factors, porins (acrAB-tolC, oqxAB, msbA, kexD, kdeA, kpnEF, kpnGH, Ompk37, OmpA, ramA, ramR, marA, rarA, acrR, tet(X4), tetA) associated with tigecycline resistance, and differences in gene expression levels between resistant and sensitive strains were detected by real-time fluorescence quantitative PCR. In vitro drug susceptibility experiments showed that the three CRKP strains KP30535, KP30845 and KP30727 were resistant, intermediate and sensitive to tigecycline respectively. In vivo addition of PAβN increased the resistance of strain to tigecycline. The results of real-time quantitative fluorescence PCR showed that the transcription levels of acrAB, kpnGH and ramA in resistant strain KP30535 and intermediate strain KP30845 were significantly higher (P < 0.05) than those of the control strain ATCC13883, and the transcription level of kpnE in KP30535 was extremely higher (P < 0.01). The transcription levels of acrB, ramA and ramR in KP30727 were significantly higher (P < 0.05) than control. The transcription of porins Ompk37 and OmpA in the three strains were markedly lower (P < 0.001) than control. The results of Spearman correlation analysis showed that acrAB, kpnGH, kexD and the porin OmpA were associated with the antimicrobial resistance phenotype of the strain to tigecycline ($|r|$ ≥0.6). The preliminary research results indicate that the different expression of acrAB, kpnGH, kexD, and porin OmpA may be important factors affecting the resistance of CRKP to tigecycline in this study, which can provide reference for further in-depth research.

Key words: Klebsiella pneumoniae, tigecycline, resistance mechanism, efflux pump, porins, expression regulators

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