Efflux Pump AcrAB Confers Decreased Susceptibility to Piperacillin–Tazobactam and Ceftolozane–Tazobactam in Tigecycline-Non-Susceptible Klebsiella pneumoniae

• Main Authors: Li J, Xu Q, Ogurek S, Li Z, Wang P, Xie Q, Sheng Z, Wang M
• Format: Article
• Language: English
• Published: Dove Medical Press 2020-11-01
• Series: Infection and Drug Resistance
• Subjects: drug efflux pump; enterobacteriaceae; multidrug resistance; β-lactam/β-lactamase inhibitor combinations
• Online Access: https://www.dovepress.com/efflux-pump-acrab-confers-decreased-susceptibility-to-piperacillinndas-peer-reviewed-article-IDR

Junjie Li,1,* Qingqing Xu,2,3,* Sean Ogurek,4 Ziqiang Li,5 Peiyun Wang,5 Qing Xie,5 Zike Sheng,5 Minggui Wang2,3 1Department of Respiratory and Critical Care Medicine, Shanghai Institute of Respiratory Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People’s Republic of China; 2Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, People’s Republic of China; 3Key Laboratory of Clinical Pharmacology of Antibiotics, Ministry of Health, Shanghai, People’s Republic of China; 4Brain Tumor Center, Division of Experimental Hematology and Cancer Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA; 5Department of Infectious Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People’s Republic of China*These authors contributed equally to this workCorrespondence: Qing Xie; Zike ShengDepartment of Infectious Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Building 36, 197 Ruijin Er Road, Shanghai 200025, People’s Republic of ChinaTel [phone] ext 680419; Tel [phone] ext 680403Fax [phone]Email [e-mail]; [e-mail]: Drug efflux pumps are critical for resistance in Gram-negative organisms, but there are limited data on the role they play in decreased susceptibility to β-lactam/β-lactamase inhibitor combinations. In this study, we aimed to investigate the impact of efflux pump AcrAB on piperacillin–tazobactam (TZP) and ceftolozane–tazobactam (C/T) susceptibility in tigecycline-non-susceptible Klebsiella pneumoniae (TNSKP) strains.Methods: A tigecycline gradient was used to obtain various TNSKP strains, and in conjunction with the gradient derived strains, a TNSKP clinical strain (TNSKP24) was also included. Minimum inhibitory concentrations (MICs) of antibiotics were determined by the broth microdilution method, and whole-genome sequencing (WGS) was carried out to analyze genomic changes. PCR and sequencing were performed to confirm mutations in ramR, acrR, and the intergenic region of ramR-romA, and qRT-PCR was applied to evaluate levels of gene expression. In-frame acrB knockout and complementation were performed in 3 TNSKP strains.Results: Two derivatives of K. pneumoniae K2606 (K2606-4 and K2606-16) and TNSKP24 overexpressed efflux pump AcrAB were obtained for further study. The MICs of TZP and C/T exhibited a 4- to 8-fold increase in K2606-4 and K2606-16, respectively, when compared with K2606 (TZP, 2/4 μg/mL; C/T, 0.25/4 μg/mL). Deletion of acrB decreased the MICs of TZP and C/T by 4- to 16-fold in TNSKP24, K2606-4, and K2606-16, respectively, and complementation of acrB increased the MICs of these agents. MICs of clavulanate, sulbactam, and avibactam in the presence of β-lactam compounds did not change after acrB deletion and subsequent introduction of complementation mutants.Conclusion: This study highlights that decreased susceptibility to TZP and C/T could be caused by the multidrug efflux pump AcrAB in TNSKP strains.Keywords: drug efflux pump, Enterobacteriaceae, multidrug resistance, β-lactam/β-lactamase inhibitor combinations