Hong Yingying, Schmidt Kyle, Marks Danielle, Hatter Samantha, Marshall Anne, Albino Luiz, Ebner Paul
1 Department of Animal Sciences, Purdue University , West Lafayette, Indiana.
2 Department of Food Microbiology, Federal University of Viçosa , Viçosa, Minas Gerais, Brazil .
Foodborne Pathog Dis. 2016 Dec;13(12):679-688. doi: 10.1089/fpd.2016.2172. Epub 2016 Oct 21.
Numerous studies have assessed the efficacy of phage-based methods to inhibit Salmonella contamination in food products. As with most antibacterials, bacteria can develop resistance to phage in vitro. Here, we applied a single broad-spectrum Salmonella phage, vB_SalS_SJ_2 (SJ2; 10 PFU; MOI = 10), to Salmonella-contaminated meat and eggs to quantify the development of resistance in actual food matrices. Treatment with a single phage significantly reduced Salmonella Typhimurium contamination in both ground pork and liquid egg at various time points. Similarly, the same phage significantly reduced Salmonella Enteritidis in both food matrices. Efficacy was temperature dependent as larger reductions were seen at higher temperatures (21°C) versus lower temperatures (4°C) at 24 h. Following phage treatment, over 10,000 Salmonella isolates were examined for resistance to the treatment phage. The percentages of phage-resistant Salmonella (either serovar) recovered from phage-treated versus untreated pork did not differ. Conversely, significantly (p < 0.05) higher percentages of phage-resistant Salmonella Typhimurium (92.50% vs. 0.56% of control) and Salmonella Enteritidis (50.83% vs. 0.56% of control) isolates were observed in phage-treated versus untreated egg samples after incubation at room temperature for 48 h. Taken together, these data indicate that the food matrix may influence the emergence of phage resistance with resistance developing more rapidly in foods with less complex microbial communities. Future studies will focus on the impact the development of resistance in production and processing settings may have on the efficacy of phage treatments for longer term biocontrol of pathogens.
众多研究评估了基于噬菌体的方法抑制食品中沙门氏菌污染的效果。与大多数抗菌剂一样，细菌在体外可对噬菌体产生抗性。在此，我们将一种单一的广谱沙门氏菌噬菌体vB_SalS_SJ_2（SJ2；10噬菌斑形成单位；感染复数=10）应用于受沙门氏菌污染的肉类和蛋类，以量化实际食品基质中抗性的产生情况。用单一噬菌体处理在不同时间点均显著降低了碎猪肉和蛋液中鼠伤寒沙门氏菌的污染。同样，同一噬菌体在两种食品基质中均显著降低了肠炎沙门氏菌的数量。效果取决于温度，在24小时时，较高温度（21°C）下的减少量大于较低温度（4°C）下的减少量。噬菌体处理后，检查了超过10000株沙门氏菌分离株对处理噬菌体的抗性。从经噬菌体处理和未经处理的猪肉中回收的抗噬菌体沙门氏菌（任一血清型）百分比没有差异。相反，在室温下孵育48小时后，在经噬菌体处理和未经处理的鸡蛋样品中，观察到抗噬菌体鼠伤寒沙门氏菌（92.50%对对照组的0.56%）和肠炎沙门氏菌（50.83%对对照组的0.56%）分离株的百分比显著（p<0.05）更高。综上所述，这些数据表明食品基质可能影响噬菌体抗性的出现，在微生物群落较简单的食品中抗性发展更快。未来的研究将聚焦于生产和加工环境中抗性的发展对噬菌体处理病原体长期生物防治效果可能产生的影响。
