The anti-biofilm effect of silver-nanoparticle-decorated quercetin nanoparticles on a multi-drug resistant Escherichia coli strain isolated from a dairy cow with mastitis

Lumin Yu,Li Yu,Dongdong Sun,Ming Zhang,Fei Shang,Xiaolin Chen,Ting Xue,Jingtian Ni

doi:10.7717/peerj.5711

Abstract

BackgroundEscherichia coli is an important opportunistic pathogen that could cause inflammation of the udder in dairy cows resulting in reduced milk production and changes in milk composition and quality, and even death of dairy cows. Therefore, mastitis is the main health issue which leads to major economic losses on dairy farms. Antibiotics are routinely used for the treatment of bovine mastitis. The ability to form biofilm increases the antibiotic resistance of E. coli. Nanoparticles (NPs), a nanosized, safe, and highly cost-effective antibacterial agent, are potential biomedical tools. Given their antibacterial activities, silver nanoparticles (Ag NPs) have a broad range of applications.MethodsIn this study, we performed antibacterial activity assays, biofilm formation assays, scanning electron microscopy (SEM) experiments, and real-time reverse transcription PCR (RT-PCR) experiments to investigate the antibacterial and anti-biofilm effect of quercetin, Ag NPs, and Silver-nanoparticle-decorated quercetin nanoparticles (QA NPs) in E. coli strain ECDCM1.ResultsIn this study, QA NPs, a composite material combining Ag NPs and the plant-derived drug component quercetin, exhibited stronger antibacterial and anti-biofilm properties in a multi-drug resistant E. coli strain isolated from a dairy cow with mastitis, compared to Ag NPs and Qe.DiscussionThis study provides evidence that QA NPs possess high antibacterial and anti-biofilm activities. They proved to be more effective than Ag NPs and Qe against the biofilm formation of a multi-drug resistant E. coli isolated from cows with mastitis. This suggests that QA NPs might be used as a potential antimicrobial agent in the treatment of bovine mastitis caused by E. coli.

Highlights

Mastitis, an infection or inflammation of the parenchyma of the mammary gland, is considered to be one of the most frequent and troublesome diseases in dairy cows and results in significant economic losses to the dairy industry worldwide (Halasa et al, 2007; Miller et al, 1993)
Since QA NPs were synthesized with the raw material Qe and Ag NPs, the survival rates of E. coli strain ECDCM1 exposed to Qe and Ag NPs were firstly detected
These data indicated that QA NPs had a higher antibacterial activity against E. coli strain ECDCM1 than Qe and Ag NPs

Summary

Introduction

An infection or inflammation of the parenchyma of the mammary gland, is considered to be one of the most frequent and troublesome diseases in dairy cows and results in significant economic losses to the dairy industry worldwide (Halasa et al, 2007; Miller et al, 1993). Due to the extensive use of antibacterial agents in bovine mastitis, the emergence of antibiotic-resistant bacteria and the frequent reoccurrence of chronic bovine mastitis has become a critical issue (Chambers, 2001; Gomes & Henriques, 2016) Another major reason for antibiotic resistance and recurrence of inflammation is bacterial biofilm formation inside the udder tissue (Atulya et al, 2014; Davies, 2003; Olson et al, 2002). This study provides evidence that QA NPs possess high antibacterial and anti-biofilm activities They proved to be more effective than Ag NPs and Qe against the biofilm formation of a multi-drug resistant E. coli isolated from cows with mastitis. This suggests that QA NPs might be used as a potential antimicrobial agent in the treatment of bovine mastitis caused by E. coli

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Conclusion