Laboratory of Aquatic Ecology and Evolutionary Biology, Zoological Institute, K.U.Leuven, Ch. Deberiotstraat 32, 3000 Leuven, Belgium.
Water Res. 2010 Feb;44(3):703-10. doi: 10.1016/j.watres.2009.09.062. Epub 2009 Oct 7.
The objectives of this study were to (1) examine the effect of power ultrasound on the viability of both Legionella pneumophila and Acanthamoeba castellanii trophozoites and cysts, (2) investigate if intracellular Legionella replication in trophozoites positively affects bacterial resistance to ultrasound and (3) study if Legionella renders viable but non-culturable (VBNC) due to ultrasound treatments. Using laboratory scale experiments, microorganisms were exposed for various time periods to power ultrasound at a frequency of 36 kHz and an ultrasound power setting of 50 and 100%. Due to a fast destruction, trophozoite hosts were not able to protect intracellular Legionella from eradication by ultrasound, in contrast to cysts. No significant effects of ultrasound on cyst viability could be detected and power settings of 100% for 30 min only made intracellular Legionella concentrations decrease with 1.3 log units. Due to intracellular replication of Legionella in trophozoites, ultrasound no longer affected bacterial viability. Concerning the VBNC state, ultrasound treatments using a power setting of 50% partly induced Legionella (+/-7%) to transform into VBNC bacteria, in contrast to power settings of 100%. Promising results obtained in this study indicate the possible application of power ultrasound in the control of both Legionella and Acanthamoeba concentrations in anthropogenic water systems.
（1）考察功率超声对嗜肺军团菌和棘阿米巴滋养体和包囊活力的影响；（2）研究滋养体中细胞内军团菌的复制是否会对细菌抵抗超声产生积极影响；（3）研究超声处理是否会导致军团菌变为活但非可培养状态（VBNC）。采用实验室规模的实验，将微生物在 36 kHz 频率和 50%和 100%的超声功率设置下暴露于功率超声中不同的时间段。由于快速破坏，滋养体宿主无法保护细胞内军团菌免受超声的清除，而与包囊不同。未检测到超声对囊泡活力的显著影响，仅在 100%的功率设置下 30 分钟，才能使细胞内军团菌浓度下降 1.3 个对数单位。由于细胞内军团菌的复制，超声不再影响细菌的活力。关于 VBNC 状态，与 100%的功率设置相比，使用 50%的功率设置的超声处理部分诱导军团菌（+/-7%）转化为 VBNC 细菌。本研究获得的有希望的结果表明，功率超声可能在控制人为水系统中军团菌和棘阿米巴浓度方面具有应用潜力。
