Mechanism of tigecycline insensitivity of multidrug-resistant Acinetobacter baumannii
10.12138/j.issn.1671-9638.20256579
- VernacularTitle:多重耐药鲍曼不动杆菌对替加环素不敏感的耐药机制研究
- Author:
Junmiao GUO
1
;
Runqi YUAN
;
Xiaolong DENG
;
Pu MAO
;
Guixia QIU
Author Information
1. 广州医科大学附属第一医院医院感染管理科,广东 广州 510120;呼吸疾病全国重点实验室,广东 广州 510120
- Publication Type:Journal Article
- Keywords:
Acinetobacter baumannii;
multidrug resistance;
tigecycline;
RND efflux pump
- From:
Chinese Journal of Infection Control
2025;24(1):45-51
- CountryChina
- Language:Chinese
-
Abstract:
Objective To explore the resistance mechanism of tigecycline insensitivity of multidrug-resistant Acine-tobacter baumannii,and provide reference for clinical rational antimicrobial use as well as prevention and control of healthcare-associated infection.Methods 22 strains of tigecycline insensitive multidrug-resistant Acinetobacter bau-mannii(TIS-MDR-AB)and 22 strains of tigecycline sensitive multidrug-resistant Acinetobacter baumannii(TS-MDR-AB)isolated clinically from the First Affiliated Hospital of Guangzhou Medical University from April 2022 to May 2023 were collected.Efflux pump phenotype inhibition assay was performed using efflux pump inhibitor car-bonyl cyanide m-chlorophenylhydrazone(CCCP).The main efflux pump genes(adeB,adeG,adeJ),as well as tigecycline-resistant gene tet(X),were screened by polymerase chain reaction(PCR)technique,and their mRNA expression levels were detected by real-time fluorescence quantitative PCR.Mutations in the efflux pump regulatory gene adeRS were analyzed by Sanger sequencing analysis.Results The detection rates of efflux pump genes adeB,adeG and adeJ were all above 95％in two MDR-AB groups,and tet(X)gene was not detected.Efflux pump inhibi-tor assay showed that the minimum inhibitory concentration(MIC)of TIS-MDR-AB strains decreased after adding CCCP,3 strains showed positive efflux pump phenotype.The mRNA expression level of MDR-AB adeB in the TIS-MDR-AB group was higher than that in the TS-MDR-AB group(P＜0.01),while the expression of adeG and adeJ genes was no statistically different.Multiple mutations were found in the adeR and adeS genes,the adeS of 2 strains was inserted ISAba1,and 3 strains were inserted ISAba13.Conclusion The overexpression of adeABC in the efflux pump system may play an important role in the mechanism of reduced sensitivity of MDR-AB to tigecycline,and its overexpression may be related to the insertion sequence or mutation in the efflux pump regulatory gene adeRS.
