Glabridin Functions as a Quorum Sensing Inhibitor to Inhibit Biofilm Formation and Swarming Motility of Multidrug-Resistant Acinetobacter baumannii

Hang Lin; Cui Zhou; Kai-Hang Yu; Yi-Shuai Lin; Ling-Bo Wang; Ying Zhang; Shi-Xing Liu; Wen-Ya Xu; Yao Sun; Tie-Li Zhou; Jian-Ming Cao; Jian-Zhong Ye

doi:10.2147/IDR.S417751

Glabridin Functions as a Quorum Sensing Inhibitor to Inhibit Biofilm Formation and Swarming Motility of Multidrug-Resistant Acinetobacter baumannii

Infect Drug Resist. 2023 Aug 30:16:5697-5705. doi: 10.2147/IDR.S417751. eCollection 2023.

Authors

Hang Lin^{1

2}, Cui Zhou¹, Kai-Hang Yu³, Yi-Shuai Lin¹, Ling-Bo Wang¹, Ying Zhang¹, Shi-Xing Liu¹, Wen-Ya Xu¹, Yao Sun¹, Tie-Li Zhou¹, Jian-Ming Cao⁴, Jian-Zhong Ye¹

Affiliations

¹ Department of Clinical Laboratory, Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, People's Republic of China.
² School of the First Clinical Medical Sciences, Wenhzou Medical University, Wenzhou, Zhejiang Province, People's Republic of China.
³ Pathology Department, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, People's Republic of China.
⁴ School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang Province, People's Republic of China.

Abstract

Objective: Acinetobacter baumannii is a hazardous bacterium that causes hospital-acquired nosocomial infections, and the advent of multidrug-resistant A. baumannii (MDR-AB) strains is concerning. Novel antibacterial therapeutic strategies must be developed. The biological effects of glabridin on MDR-AB were investigated in this study.

Methods: The minimum inhibitory concentrations (MICs) of glabridin against eight clinical MDR-AB strains were determined using the broth microdilution technique. Crystal violet staining was used to assess biofilm development, which has significant contribution to bacterial resistance. Swarming motility was measured according to surface growth zone of MDR-AB on LB agar medium. qRT-PCR was used to evaluate the expression of quorum sensing genes abaI and abaR. Glabridin and routinely used therapeutic antimicrobial agents were tested for synergistic action using the checkerboard method.

Results: According to our findings, glabridin suppressed MDR-AB growth at high doses (512-1024 μg/mL). The 1/4 MIC of glabridin significantly decreased MDR-AB biofilm formation by 19.98% (P < 0.05), inhibited MDR-AB motility by 44.27% (P < 0.05), whereas the 1/2 MIC of glabridin dramatically reduced MDR-AB biofilm development by 27.43% (P < 0.01), suppressed MDR-AB motility by 50.64% (P < 0.05). Mechanistically, glabridin substantially downregulated the expression of quorum sensing-related genes abaI and abaR by up to 39.12% (P < 0.001) and 25.19% (P < 0.01), respectively. However, no synergistic effect between glabridin and antibacterial drugs was found.

Conclusion: Glabridin might be a quorum sensing inhibitor that inhibits MDR-AB biofilm development and swarming motility.

Keywords: Acinetobacter baumannii; glabridin; multidrug-resistance; quorum sensing.

Grants and funding

This work was funded by the Major Projects of Wenzhou Science and Technology Bureau (ZY2019011), the Natural Science Foundation of Zhejiang Province (LY20H200004), and Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province (2022E10022).