摘要

       过氧乙酸（PAA）是一种有机化合物，在废水处理中被有效地用作消毒剂。然而，在低剂量下，它可能会引起选择；因此，评估了低剂量PAA作为人类相关微生物废物替代物对屎肠球菌的影响。用增加剂量的PAA（从0到25 mg L-1 min）处理细菌，并在非生长、限制条件和生长、有利条件下在再生实验中培养。评估了细菌丰度、细菌表型（小细胞簇的数量和组成）和抗生素耐药基因（ARG）丰度的变化。实验证明，所选剂量的PAA能有效地去除肠球菌，并在PAA失活后产生长效作用。与接种物相比，实验期间小团簇的相对丰度增加。此外，在生长良好的条件下，随着PAA剂量的增加，小簇的相对丰度降低，每个簇的细胞数增加。结果表明，所测ARG具有很强的稳定性，在整个实验过程中没有显示出任何影响。结果表明，低剂量PAA灭活细菌是可行的。然而，PAA消毒引起的应激促进了细菌的适应，即使可能不会影响ARG的丰度。

        Peracetic acid (PAA) is an organic compound used efficiently as disinfectant in wastewater treatments. Yet, at low doses it may cause selection; thus, the effect of low doses of PAA on Enterococcus faecium as a proxy of human-related microbial waste was evaluated. Bacteria were treated with increasing doses of PAA (from 0 to 25 mg L^-1 min) and incubated in regrowth experiments under non-growing, limiting conditions and under growing, favorable conditions. The changes in bacterial abundance, in bacterial phenotype (number and composition of small cell clusters), and in the abundance of an antibiotic resistance gene (ARG) was evaluated. The experiment demonstrated that the selected doses of PAA efficiently removed enterococci, and induced a long-lasting effect after PAA inactivation. The relative abundance of small clusters increased during the experiment when compared with that of the inoculum. Moreover, under growing favorable conditions the relative abundance of small clusters decreased and the number of cells per cluster increased with increasing PAA doses. A strong stability of the measured ARG was found, not showing any effect during the whole experiment. The results demonstrated the feasibility of low doses of PAA to inactivate bacteria. However, the stress induced by PAA disinfection promoted a bacterial adaptation, even if potentially without affecting the abundance of the ARG.

        https://iris.unito.it/handle/2318/1658948#.XqFKjs29Pak