Birtles R J, Rowbotham T J, Raoult D, Harrison T G
Unité des Rickettsies, CNRS EP J 0054, Faculté de Médecine, Marseille, France.
Microbiology (Reading). 1996 Dec;142 ( Pt 12):3525-30. doi: 10.1099/13500872-142-12-3525.
Following a recent phylogenetic analysis of all 39 species of the genus Legionella and related organisms, the name Legionella lytica has been proposed for bacteria previously considered either as Sarcobium lyticum or as 'Legionella-like amoebal pathogens' (LLAPs). To investigate the phylogenetic integrity of this newly proposed species, we determined the 16S rRNA gene sequences of 10 LLAPs isolated from various environmental sources. All 10 isolates clustered within a monophyletic group containing all other members of the genus Legionella. Eight of the 10 isolates formed a monophyletic subgroup within the genus which also included the two previously characterized L. lytica strains. Four of these 10 isolates shared a specific and very close relationship with the L. lytica type strain (> 99% sequence similarity). However, although clearly legionellae, the remaining two LLAP strains bore no specific evolutionary relationship to either L. lytica or any other Legionella species (< 96% sequence similarity). Both isolates lay on their own relatively deep-rooted branches within the radiation of the Legionella cluster. LLAPs do not, therefore, represent a unique species or even a single line of descent within the genus, and investigation of more isolates may reveal them to be as evolutionarily diverse as the other presently recognized Legionella species.
在最近对军团菌属的所有39个物种及相关生物进行系统发育分析之后，有人提议将以前被认为是溶菌性肌球菌或“类军团菌变形虫病原体”（LLAPs）的细菌命名为溶菌军团菌。为了研究这个新提议物种的系统发育完整性，我们测定了从各种环境来源分离出的10株LLAPs的16S rRNA基因序列。所有10株分离菌都聚集在一个包含军团菌属所有其他成员的单系群中。10株分离菌中的8株在该属内形成了一个单系亚群，该亚群还包括之前鉴定的两株溶菌军团菌菌株。这10株分离菌中的4株与溶菌军团菌模式菌株具有特定且非常密切的关系（序列相似性>99%）。然而，尽管这另外两株LLAP菌株显然属于军团菌，但它们与溶菌军团菌或任何其他军团菌物种均无特定的进化关系（序列相似性<96%）。这两株分离菌都位于军团菌簇辐射范围内各自相对根深蒂固的分支上。因此，LLAPs并不代表该属内的一个独特物种，甚至也不是一个单一的谱系，对更多分离菌的研究可能会发现它们在进化上与目前公认的其他军团菌物种一样具有多样性。
