QseBC is involved in the biofilm formation and antibiotic resistance in Escherichia coli isolated from bovine mastitis

PeerJ

article

Wenchang Li¹  Mei Xue²  Lumin Yu¹  Kezong Qi²  Jingtian Ni¹  Xiaolin Chen¹  Ruining Deng¹  Fei Shang¹  Ting Xue¹ 

[1] School of Life Sciences, Anhui Agricultural University;Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, Anhui Agricultural University

关键词: Escherichia coli;    Bovine mastitis;    QseBC two component system;    Efflux pump;    Biofilm;   

DOI  :  10.7717/peerj.8833

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

BackgroundMastitis is one of the most common infectious diseases in dairy cattle and causes significant financial losses in the dairy industry worldwide. Antibiotic therapy has been used as the most effective strategy for clinical mastitis treatment. However, due to the extensive use of antibacterial agents, antimicrobial resistance (AMR) is considered to be one of the reasons for low cure rates in bovine mastitis. In addition, biofilms could protect bacteria by restricting antibiotic access and shielding the bacterial pathogen from mammary gland immune defences. The functional mechanisms of quorum sensing E. coli regulators B an d C (QseBC) have been well studied in E. coli model strains; however, whether QseBC regulates antibiotic susceptibility and biofilm formation in clinical E. coli strain has not been reported.MethodsIn this study, we performed construction of the qseBC gene mutant, complementation of the qseBC mutant, antimicrobial susceptibility testing, antibacterial activity assays, biofilm formation assays, real-time reverse transcription PCR (RT-PCR) experiments and electrophoretic mobility shift assays (EMSAs) to investigate the role of qseBC in regulating biofilm formation and antibiotic susceptibility in the clinical E. coli strain ECDCM2.ResultsWe reported that inactivation of QseBC led to a decrease in biofilm formation capacity and an increase in antibiotic susceptibility of an E. coli strain isolated from a dairy cow that suffered from mastitis. In addition, this study indicated that QseBC increased biofilm formation by upregulating the transcription of the biofilm-associated genes bcsA, csgA, fliC, motA, wcaF and fimA and decreased antibiotic susceptibility by upregulating the transcription of the efflux-pump-associated genes marA, acrA, acrB, acrD, emrD and mdtH. We also performed EMSA assays, and the results showed that QseB can directly bind to the marA promoter.ConclusionsThe QseBC two-component system affects antibiotic sensitivity by regulating the transcription of efflux-pump-associated genes. Further, biofilm-formation-associated genes were also regulated by QseBC TCS in E. coli ECDCM2. Hence, this study might provide new clues to the prevention and treatment of infections caused by the clinical E. coli strains.

【 授权许可】

CC BY