紫外线和次氯酸钠对Escherichia coli和Poliovirus的消毒作用

本研究选用大肠杆菌(Escherichia coli)和脊髓灰质炎病毒(poliovirus)分别作为典型的细菌和病毒,利用培养和定量PCR的检测技术,对比研究紫外线消毒和次氯酸钠消毒对细菌和病毒的作用特点.结果表明:脊髓灰质炎病毒比大肠杆菌更难被灭活,达到1-log所需的氯剂量分别为19.2 mg·L~(-1)·min和10.14 mg·L~(-1)·min;所需的紫外线剂量分别为6.37 m J·cm~(-2)和1.81 m J·cm~(-2).定量PCR方法检测大肠杆菌和脊髓灰质炎病毒达到1-log的核酸损伤所需的紫外线剂量和氯剂量要比培养法高出1~2数量级,紫外线消毒对脊髓灰质炎病毒的RNA损伤量明显大于对大肠杆菌的DNA损伤,病毒的单链RNA对紫外线的敏感性更强,该结果与培养法正好相反.达到1-log核酸损伤脊髓灰质炎病毒所需的紫外线剂量为135 m J·cm~(-2),大肠杆菌所需的剂量为270.3 m J·cm~(-2),核酸损伤需要更多的消毒剂量,可能由于消毒过程微生物进入活性但处于非可培养状态(VBNC),以及灭活对微生物其他分子的损伤和微生物死后核酸的持续性.

Disinfection Action of Ultraviolet Radiation and Chlorination on Escherichia coli and Poliovirus

We chose Escherichia coli (E. coli) and poliovirus as a typical pathogenic bacterium and virus, respectively. The effects of two typical disinfectants (chlorine and ultraviolet) on each of them were investigated based on microbial culture and quantitative PCR methods. The results showed that Poliovirus was appreciably more resistant to chlorine (required disinfection dose for 1-log microbial reduction:10.14 mg·L^-1·min for E. coli; 19.2 mg·L^-1·min for poliovirus) and ultraviolet (UV) light (required UV dose for 1-log microbial reduction:1.81 mJ·cm^-2 for E. coli; 6.37 mJ·cm^-2 for poliovirus) than E. coli for the microbial culture. For PCR, this study revealed that 1-log gene reduction required UV doses and ct values of at least one to two orders of magnitude higher than that for the microbial culture. The damage of RNA in Poliovirus was more seriously than that of DNA in E. coli. Single-stranded RNA was more sensitive to UV irradiation than DNA. The result evaluated with the quantitative PCR method showed opposite result to that of the traditional culture method in which the Poliovirus was more tolerant. The required UV doses for 1-log nucleic acid reduction were 135 mJ·cm^-2 and 270.3 mJ·cm^-2 for E. coli and poliovirus, respectively. Nucleic acid damage required a higher dose of disinfectants than microbial inactivation, which was probably attributed to the phenomenon of viable but non-culturable (VBNC) cells, other molecular targets of inactivation and the persistence of nucleic acid after cell death.