Abstract：
Legionella pneumophila is the causative agent of Legionnaires\' disease, a severe pneumonia. Cooling towers are a major source of large outbreaks of the disease. The growth of L. pneumophila in these habitats is influenced by the resident microbiota. Consequently, the aim of this study was to isolate and characterize bacterial species from cooling towers capable of inhibiting several strains of L. pneumophila and one strain of L. quinlivanii. Two cooling towers were sampled to isolate inhibiting bacterial species. Seven inhibitory isolates were isolated, through serial dilution plating and streaking on agar plates, belonging to seven distinct species. The genomes of these isolates were sequenced to identify potential genetic elements that could explain the inhibitory effect. The results showed that the bacterial isolates were taxonomically diverse and that one of the isolates may be a novel species. Genome analysis showed a high diversity of antimicrobial gene products identified in the genomes of the bacterial isolates. Finally, testing different strains of Legionella demonstrated varying degrees of susceptibility to the antimicrobial activity of the antagonistic species. This may be due to genetic variability between the Legionella strains. The results demonstrate that though cooling towers are breeding grounds for L. pneumophila, the bacteria must contend with various antagonistic species. Potentially, these species could be used to create an inhospitable environment for L. pneumophila, and thus decrease the probability of outbreaks occurring.
摘要：
嗜肺军团菌是军团菌病的病原体，严重的肺炎.冷却塔是该疾病大规模爆发的主要来源。这些栖息地中嗜肺乳杆菌的生长受常驻微生物群的影响。因此,这项研究的目的是从冷却塔中分离和鉴定能够抑制几株嗜肺乳杆菌和一株奎里凡氏乳杆菌的细菌种类。对两个冷却塔进行取样以分离抑制性细菌物种。分离出7个抑制性分离株，通过连续稀释平板接种和在琼脂平板上划线，属于七个不同的物种。对这些分离株的基因组进行测序，以鉴定可以解释抑制作用的潜在遗传元件。结果表明，细菌分离株在分类学上是多样化的，其中一个分离株可能是新物种。基因组分析显示在细菌分离物的基因组中鉴定的抗微生物基因产物的高度多样性。最后,测试不同的军团菌菌株对拮抗物种的抗菌活性具有不同程度的敏感性。这可能是由于军团菌菌株之间的遗传变异。结果表明，尽管冷却塔是肺炎支原体的滋生地，细菌必须与各种拮抗物种抗衡。有可能,这些物种可以用来为嗜肺乳杆菌创造一个恶劣的环境，从而降低爆发的可能性。
