Senderovich Yigal, Gershtein Yana, Halewa Etti, Halpern Malka
Department of Evolutionary and Environmental Biology, Faculty of Science and Science Education, University of Haifa, Haifa, Israel.
ISME J. 2008 Mar;2(3):276-83. doi: 10.1038/ismej.2007.114. Epub 2008 Feb 7.
Species of the genus Aeromonas are native inhabitants of aquatic environments and have recently been considered as an emergent human pathogen. It is estimated that aeromonads cause up to 13% of reported gastroenteritis cases in the United States. Although the autochthonous existence of Aeromonas in the aquatic environment has been established, its natural reservoir is as yet unknown. Chironomids are closely related to mosquitoes except they do not bite and they are the most widely distributed insects in freshwater. They infest drinking water systems in Israel and all over the world. Vibrio cholerae inhabit chironomids and are able to degrade their egg masses. The degradation of the egg masses is followed by failure of the eggs to hatch. In the current study, egg masses from a waste stabilization pond and a river in northern Israel were collected and cultured during a five-month period. Bacterial colonies were randomly chosen and checked for their egg mass degradation abilities. In addition to V. cholerae, most of the other isolates that had the ability to degrade the egg masses were identified as Aeromonas species, thus, demonstrating that Aeromonas species are natural inhabitants of chironomid egg masses. The following virulence-associated genes were detected in Aeromonas species that were isolated from chironomid egg masses: alt (78%); ahpB (76%); act/aerA/hlyA (65%); fla (59%); pla/lipH3/apl-1/lip (43%); and ast (2%). These findings indicate that the Aeromonas species inhabiting chironomid egg masses pose a potential health risk. Understanding the natural reservoir of Aeromonas will help to develop methods to monitor and control the bacteria in fresh and drinking water reservoirs and to better understand the relationships between chironomids, V. cholerae and Aeromonas populations.
气单胞菌属的物种是水生环境的原生居民，最近被认为是一种新出现的人类病原体。据估计，在美国报告的肠胃炎病例中，气单胞菌导致的病例占13%。尽管气单胞菌在水生环境中的原生存在已得到证实，但其天然宿主尚不明确。摇蚊与蚊子密切相关，只是它们不叮咬，是淡水中分布最广的昆虫。它们侵扰以色列和世界各地的饮用水系统。霍乱弧菌栖息在摇蚊体内，并能够降解它们的卵块。卵块被降解后，卵就无法孵化。在本研究中，在五个月的时间里，从以色列北部的一个废水稳定塘和一条河流中收集并培养了摇蚊卵块。随机挑选细菌菌落并检测它们降解卵块的能力。除了霍乱弧菌外，大多数具有降解卵块能力的其他分离株被鉴定为气单胞菌属物种，因此，表明气单胞菌属物种是摇蚊卵块的天然居民。在从摇蚊卵块中分离出的气单胞菌属物种中检测到了以下与毒力相关的基因：alt（78%）；ahpB（76%）；act/aerA/hlyA（65%）；fla（59%）；pla/lipH3/apl-1/lip（43%）；和ast（2%）。这些发现表明，栖息在摇蚊卵块中的气单胞菌属物种构成了潜在的健康风险。了解气单胞菌的天然宿主将有助于开发监测和控制淡水和饮用水水库中细菌的方法，并更好地理解摇蚊、霍乱弧菌和气单胞菌种群之间的关系。
