青霉素菌渣堆肥中β-内酰胺酶基因丰度变化

摘要

为了解抗生素菌渣堆肥中抗生素残留对抗生素抗性基因(ARGs)环境行为的影响,以青霉素菌渣堆肥为对象,采用实时定量PCR方法分析了8种典型β-内酰胺酶基因,bla-TEM、bla-CTX-M-1、bla-CTX-M-9、bla-IMp-1、bla-VIM-2、bla-CMY、bla-OXA-23、bla-NDM-1在整个堆肥过程中的丰度变化.结果表明,高温堆肥处理大大缩短了青霉素的降解时间;bla-NDM-1在所有样品中均未检出.通过比较β-内酰胺酶基因在不同处理中第1d和30d的绝对数量变化,在处理组中除bla-IMP-1、bla-VIM-2基因绝对数量有所增加外;其他基因都明显减少.从相对丰度看,在堆肥前期,青霉素残留对bla-TEM、bla-CTX-M-1、bla-CTX-M-9、bla-CMY、bla-OXA-23、bla-VIM-2基因有一定诱导富集效应.随着堆肥进程及菌渣堆肥中抗生素浓度的降低,到了堆肥末期,各处理组及对照组bla-TEM、bla-CTX-M-1、bla-CTX-M-9、bla-CMY的相对丰度较堆肥前期显著降低;而处理组中bla-IMP-1、bla-VIM-2的相对丰度较堆肥前期显著增加.%In order to reveal the environmental impacts of antibiotic resistance genes (ARGs) during penicillin biomass-residue composting because of the possible antibiotic residues,the relative abundances and distributions of eight typicalβ-lactamase genes(bla-TEM、bla-CTX-M-1、bla-CTX-M-9、bla-IMP-1、bla-VIM-2、bla-CMY、bla-OXA-23、bla-NDM-1)were investigated with quantitative PCR technique.The results indicated that high temperature composting greatly shortened the degradation time of penicillin.No bla-NDM-1 gene was detected in any sample.The abundances of all studied genes were significantly reduced from day 1 to day 30 in the different penicillin biomass-residue composting experiments except those of the bla-IMP-1 and bla-VIM-2 genes which slight increased.The penicillin residue induced the increases of relative abundance of bla-TEM,bla-CTX-M-1.bla-CTX-M-9,bla-CMY,bla-OXA-23,and bla-VIM-2 genes during the early composting stage.With the elongation of the composting process,penicillin residue gradually degraded.At the end of composting,the relative abundances of bla-TEM、bla-CTX-M-1、bla-CTX-M-9、bla-CMY significantly decreased in all treated samples and the control in comparison with those of bla-IMP-1、bla-VIM-2,which greatly increased.