超声、紫外及加温对质粒介导的黏菌素耐药基因mcr-1的影响

The Influence of Ultrasound,Ultraviolet Radiation and Heating on Plasmid-Mediated Colistin Resistance Gene mcr-1

为探讨超声、紫外线照射及加温等方法对质粒介导的黏菌素耐药基因mcr-1的影响,采用四因素三水平正交试验设计,以mcr-1阳性猪场废水样品为研究对象,采用实时荧光定量聚合酶链反应(qRT-PCR)测定mcr-1基因绝对丰度,以处理前后mcr-1基因绝对丰度变化率为指标,考察不同因素及水平对mcr-1基因含量的影响。结果表明,超声对mcr-1丰度有显著影响,其次是温度、加温时间,而紫外线照射对mcr-1的影响甚微。当依次将样品进行超声30 min、紫外线照射15 min、温度40℃作用30 min时,会使mcr-1含量比对照组高5倍多。而当超声时间为15 min、同时提高温度至50℃作用30 min和60℃作用5 min时,可使mcr-1的含量分别降低20.5%和30.6%。可见,不同因素及水平的组合可对mcr-1基因的含量造成相反的影响。因此,在实际中应筛选最佳的条件以尽可能地降低mcr-1基因的含量,减少mcr-1基因的进一步污染和扩散。

To investigate the effects of ultrasound,ultraviolet radiation and heating on plasmid-mediated colistin resistance gene mcr-1,a four-factor and three-level orthogonal experiment was conducted.The absolute abundance of mcr-1 gene in pig wastewater samples before and after treatment was determined by real-time fluorescence quantitative polymerase chain reaction(qRT-PCR).The results showed that ultrasonography had a significant effect on the abundance of mcr-1,followed by temperature and heating time,while ultraviolet irradiation had little effect on it.When the samples were treated with ultrasound for 30 min,ultraviolet radiation for 15min at 40℃ for 30 min,the abundance of mcr-1 was more than 5 times higher than that of control group.When the ultrasonic time was set at 15 min and the temperature was increased to 50℃ for 30min or to 60℃ for 5min,the abundance of mcr-1 was reduced by 20.5% and 30.6%,respectively.This indicate that the combination of different factors and levels showed opposite effects on abundance of mcr-1.Therefore,in practice,conditions should be optimized to reduce mcr-1 gene as much as possible,so as to reduce its further contamination and diffusion.