青霉素菌渣堆肥中β-内酰胺酶基因丰度变化

Abundance dynamics of β-lactamase genes in penicillin biomass-residue composting

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 typical β-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.