School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, WA 99164-7520, USA.
J Antimicrob Chemother. 2012 Aug;67(8):1915-26. doi: 10.1093/jac/dks138. Epub 2012 May 1.
Bacterial biofilms pose significant food safety risks because of their attachment to fomites and food surfaces, including fresh produce surfaces. The purpose of this study was to systematically investigate the activity of selected antimicrobials on Campylobacter jejuni biofilms.
C. jejuni biofilms and planktonic cells were treated with ciprofloxacin, erythromycin and diallyl sulphide and examined using infrared and Raman spectroscopies coupled with imaging analysis.
Diallyl sulphide eliminated planktonic cells and sessile cells in biofilms at a concentration that was at least 100-fold less than used for either ciprofloxacin or erythromycin on the basis of molarity. Distinct cell lysis was observed in diallyl sulphide-treated planktonic cells using immunoblot analysis and was confirmed by a rapid decrease in cellular ATP. Two phases of C. jejuni biofilm recalcitrance modes against ciprofloxacin and erythromycin were validated using vibrational spectroscopies: (i) an initial hindered adsorption into biofilm extracellular polymeric substance (EPS) and delivery of antibiotics to sessile cells within biofilms; and (ii) a different interaction between sessile cells in a biofilm compared with their planktonic counterparts. Diallyl sulphide destroyed the EPS structure of the C. jejuni biofilm, after which the sessile cells were killed in a similar manner as planktonic cells. Spectroscopic models can predict the survival of sessile cells within biofilms.
Diallyl sulphide elicits strong antimicrobial activity against planktonic and sessile C. jejuni and may have applications for reducing the prevalence of this microbe in foods, biofilm reduction and, potentially, as an alternative chemotherapeutic agent for multidrug-resistant bacterial strains.
细菌生物膜因其附着在污染物和食物表面（包括新鲜农产品表面）上而对食品安全构成重大威胁。本研究旨在系统研究选定抗菌剂对空肠弯曲菌生物膜的活性。
用环丙沙星、红霉素和二烯丙基二硫处理空肠弯曲菌生物膜和浮游细胞，并结合成像分析用红外和拉曼光谱进行检测。
二烯丙基二硫以摩尔浓度计算，消灭浮游细胞和生物膜中固定细胞的浓度至少比环丙沙星或红霉素低 100 倍。免疫印迹分析观察到二烯丙基二硫处理的浮游细胞发生明显的细胞裂解，并通过细胞内 ATP 的快速减少得到证实。使用振动光谱法验证了空肠弯曲菌生物膜对环丙沙星和红霉素的两种抗性模式：（i）最初阻碍吸附到生物膜胞外聚合物（EPS）中，并将抗生素输送到生物膜中的固定细胞；（ii）生物膜中固定细胞与浮游细胞之间的不同相互作用。二烯丙基二硫破坏空肠弯曲菌生物膜的 EPS 结构，之后以与浮游细胞类似的方式杀死固定细胞。光谱模型可以预测生物膜中固定细胞的存活。
二烯丙基二硫对浮游和固定空肠弯曲菌表现出强烈的抗菌活性，可能适用于减少食品中这种微生物的流行、减少生物膜以及作为多药耐药菌菌株的替代化学治疗剂。
