多种噬菌体单独及混合使用的喷雾灭菌研究

Sterilization of Foodborne Pathogens by Aerosol Spray Treatments with Phages and Their Cocktails

以大肠杆菌噬菌体EK99-C为例分析噬菌体EK99-C在空间的喷雾灭菌效率,5mL、1×104CFU/mL的大肠杆菌K99进行人工喷洒污染,5min后喷洒1×109PFU/mL的噬菌体5mL,并且在喷洒后0.5、1、2h分别检测残存的大肠杆菌K99数量。然后,以与大肠杆菌噬菌体喷雾灭菌实验中所用的相同剂量的细菌和噬菌体数量对其他5株食源性致病菌(其中涉及大肠杆菌、沙门氏菌、志贺氏菌和李斯特菌)的噬菌体进行喷雾灭菌实验,并只在喷洒后2h检测残存的细菌数量。结果表明:喷洒噬菌体EK99-C后,在0.5、1、2h时平板上的残存的细菌数均接近于0CFU,其中2h时噬菌体EK99-C灭菌更彻底;噬菌体单独作用组和按体积比等比例混合作用组,均能有效杀灭宿主菌,其中,噬菌体PSA-116喷雾灭菌效果最好,能杀灭100%的宿主菌,噬菌体EK88-4、EK99-C和FWLLm3的杀灭效率约为99%左右。而噬菌体SS-92和PSA-6以喷雾灭菌的方式可杀灭约80%的宿主菌。6种噬菌体按体积比等比例混合作用后2h时的细菌残存个数少于18.50CFU,杀菌效率大于98.7%。

Five minutes after spraying of 5 mL of 1 × 104 CFU/mL E. coli K99, 5 mL of 1 × 109 PFU/mL its phage, EK99-C, was sprayed into the polluted air and the residual number of viable E. coli K99 was examined at 0.5, 1 h and 2 h after spraying of phage EK99-C to evaluate the efficacy of phage EK99-C to kill E. coli K99. Meanwhile, the sterilization efficiencies of five other foodborn pathogens （E. coli K88, Salmonella enteritidis ATCC13076, Salmonella pullorum Spu-16, Shigella sonnet CMCC51592 and Listeria 2000/47） by their corresponding phages （EK88-4, PSA-6, PSA-116, SS-92 and FWLLm3） at 2 h after spraying were investigated under the same experimental conditions and concentrations as described for K99 and EK99-C. The results showed that the residual number of K99 in the plates was close to 0 CFU at 0.5, 1 h and 2 h after spraying, and complete sterilization was achieved at 2 h. Both phage alone and combination could effectively kill the host bacteria by aerosol spray. Phage PSA-116 had the strongest bactericidal effect, which could kill 100% of the host bacteria. EK88-4, EK99-C and FWLLm3 killed about 99% of their hosts. However, SS-92 and PSA-6 indicated 80% bactericidal efficiency on their host bacteria. The residual number of viable bacteria was smaller than 18.50 CFU when the six phages were mixed in the same volume, providing a bactericidal efficiency above 98.7%.