Giardia cysts in wastewater treatment plants in Italy
Giardia cysts in wastewater treatment plants in Italy
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DOI：
10.1128/aem.69.6.3393-3398.2003
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发表时间：
2003-06-01
影响因子：
4.4
通讯作者：
Pozio, E
中科院分区：
文献类型：
--
作者：
Cacciò, SM;De Giacomo, M;Pozio, E
一些区域年降雨量减少和人类消费增加，造成全球水资源短缺。已建议将处理过的废水循环用于某些家庭、工业和农业活动。循环水的微生物和寄生虫学标准的重要性已被反复强调。在水传播的病原体中，已知贾第鞭毛虫属和隐孢子虫属的原生动物对水处理程序具有高度抗性，并通过受污染的原水或经处理的水引起爆发。我们在意大利的四个污水处理厂进行了一项调查，在处理过程的每个阶段对废水进行了为期一年的采样。通过单克隆抗体的免疫荧光来评估寄生虫的存在。虽然隐孢子虫卵囊很少观察到，贾第鞭毛虫包囊检测到全年的所有样本，在秋季和冬季观察到的高峰。处理厂的整体去除率为87.0%至98.4%。当二级处理由O-2活性氧化和沉淀而不是活性污泥和沉淀组成时，孢囊数量的去除效率显着更高（94.5%对72.1至88.0%; P = 0.05，方差分析）。为了在分子水平上表征孢囊，PCR扩增β-贾第菌素基因，并对产物进行测序或通过限制性内切酶分析。包囊被分型为集合体A或B，两者都是人类病原体，强调了与废水再利用相关的潜在风险。
Reductions in annual rainfall in some regions and increased human consumption have caused a shortage of water resources at the global level. The recycling of treated wastewaters has been suggested for certain domestic, industrial, and agricultural activities. The importance of microbiological and parasitological criteria for recycled water has been repeatedly emphasized. Among water-borne pathogens, protozoa of the genera Giardia and Cryptosporidium are known to be highly resistant to water treatment procedures and to cause outbreaks through contaminated raw or treated water. We conducted an investigation in four wastewater treatment plants in Italy by sampling wastewater at each stage of the treatment process over the course of 1 year. The presence of the parasites was assessed by immunofluorescence with monoclonal antibodies. While Cryptosporidium oocysts were rarely observed, Giardia cysts were detected in all samples throughout the year, with peaks observed in autumn and winter. The overall removal efficiency of cysts in the treatment plants ranged from 87.0 to 98.4%. The removal efficiency in the number of cysts was significantly higher when the secondary treatment consisted of active oxidation with O-2 and sedimentation instead of activated sludge and sedimentation (94.5% versus 72.1 to 88.0%; P = 0.05, analysis of variance). To characterize the cysts at the molecular level, the beta-giardin gene was PCR amplified, and the products were sequenced or analyzed by restriction. Cysts were typed as assemblage A or B, both of which are human pathogens, stressing the potential risk associated with the reuse of wastewater.