Quilez Joaquin, Sanchez-Acedo Caridad, Avendaño Catalina, del Cacho Emilio, Lopez-Bernad Fernando
Department of Animal Pathology, Faculty of Veterinary Sciences, University of Zaragoza, Miguel Servet 177, 50013 Zaragoza, Spain.
Appl Environ Microbiol. 2005 May;71(5):2479-83. doi: 10.1128/AEM.71.5.2479-2483.2005.
Two commercial peroxygen-based disinfectants containing hydrogen peroxide plus either peracetic acid (Ox-Virin) or silver nitrate (Ox-Agua) were tested for their ability to inactivate Cryptosporidium parvum oocysts. Oocysts were obtained from naturally infected goat kids and exposed to concentrations of 2, 5, and 10% Ox-Virin or 1, 3, and 5% Ox-Agua for 30, 60, and 120 min. In vitro excystation, vital dyes (4',6'-diamidino-2-phenylindole and propidium iodide), and infectivity in neonatal BALB/c mice were used to assess the viability and infectivity of control and disinfectant-treated oocysts. Both disinfectants had a deleterious effect on the survival of C. parvum oocysts, since disinfection significantly reduced and in some cases eliminated their viability and infectivity. When in vitro assays were compared with an infectivity assay as indicators of oocyst inactivation, the excystation assay showed 98.6% inactivation after treatment with 10% Ox-Virin for 60 min, while the vital-dye assay showed 95.2% inactivation and the infectivity assay revealed 100% inactivation. Treatment with 3% Ox-Agua for 30 min completely eliminated oocyst infectivity for mice, although we were able to observe only 74.7% inactivation as measured by excystation assays and 24.3% with vital dyes (which proved to be the least reliable method for predicting C. parvum oocyst viability). These findings indicate the potential efficacy of both disinfectants for C. parvum oocysts in agricultural settings where soil, housing, or tools might be contaminated and support the argument that in comparison to the animal infectivity assay, vital-dye and excystation methods overestimate the viability of oocysts following chemical disinfection.
对两种基于过氧化物的市售消毒剂进行了测试，它们分别含有过氧化氢加过氧乙酸（Ox-Virin）或硝酸银（Ox-Agua），以评估其灭活微小隐孢子虫卵囊的能力。卵囊取自自然感染的山羊幼崽，并分别暴露于浓度为2%、5%和10%的Ox-Virin或1%、3%和5%的Ox-Agua中30分钟、60分钟和120分钟。采用体外脱囊法、活性染料（4',6'-二脒基-2-苯基吲哚和碘化丙啶）以及对新生BALB/c小鼠的感染性来评估对照卵囊和经消毒剂处理的卵囊的活力和感染性。两种消毒剂对微小隐孢子虫卵囊的存活均有有害影响，因为消毒显著降低了卵囊的活力和感染性，在某些情况下甚至将其消除。当将体外试验与作为卵囊灭活指标的感染性试验进行比较时，用10%的Ox-Virin处理60分钟后，脱囊试验显示灭活率为98.6%，而活性染料试验显示灭活率为95.2%，感染性试验显示灭活率为100%。用3%的Ox-Agua处理30分钟可完全消除卵囊对小鼠的感染性，不过通过脱囊试验测得的灭活率仅为74.7%，用活性染料测得的灭活率为24.3%（事实证明活性染料是预测微小隐孢子虫卵囊活力最不可靠的方法）。这些研究结果表明，在土壤、圈舍或工具可能被污染的农业环境中，这两种消毒剂对微小隐孢子虫卵囊均具有潜在的消毒效果，同时也支持了这样一种观点，即与动物感染性试验相比，活性染料法和脱囊法高估了化学消毒后卵囊的活力。
