Jessu Amélie, Cochard Thierry, Burtin Mélanie, Crapart Stéphanie, Delafont Vincent, Samba-Louaka Ascel, Biet Franck, Moyen Jean-Louis, Héchard Yann
Université de Poitiers, Centre National de la Recherche Scientifique (CNRS), Laboratoire Écologie et Biologie des Interactions (EBI), UMR 7267, Equipe Microorganismes, Hôtes, Environnement, Poitiers, 86000 Poitiers, France.
Laboratoire Départemental d'Analyse et de Recherche de la Dordogne, Coulounieix-Chamiers 24660, France.
FEMS Microbiol Ecol. 2025 Jan 7;101(1). doi: 10.1093/femsec/fiae164.
Free-living amoebae (FLA) are described as environmental reservoirs for some bacteria able to resist their phagocytosis. In the environment, the fate of Mycobacterium bovis (Mbo) and Mycobacterium avium subsp. paratuberculosis (Map) responsible for bovine tuberculosis and paratuberculosis, respectively, remains poorly understood and is considered potentially problematic in the eradication and control of these diseases. We hypothesize that FLA may play a role in the persistence of Mbo and Map in the environment. In this study, 90 samples were collected from herds affected by one or both diseases to investigate the diversity of amoeba and their associated bacteria. Metabarcoding analyses revealed that Acanthamoeba, Copromyxa, Naegleria, and Vermamoeba were the most represented genera of FLA, with Pseudomonadota being the bacteria most commonly found associated with FLA. Although no Mbo and Map DNA were identified by sequencing, traces were detected by ddPCR (digital droplet PCR), specifically targeting these bacteria. In conclusion, we described a wide diversity of FLA and associated bacteria in this environment. It also suggests that Map and Mbo could be associated, even weakly, with FLA in the environment. However, this needs to be confirmed by detecting a highest amount of DNA and, if possible, cultivable Map and/or Mbo associated with these environmental FLA.
自由生活阿米巴（FLA）被描述为某些能够抵抗其吞噬作用的细菌的环境储存库。在环境中，分别导致牛结核病和副结核病的牛分枝杆菌（Mbo）和鸟分枝杆菌副结核亚种（Map）的命运仍知之甚少，并且在这些疾病的根除和控制中被认为可能存在问题。我们假设FLA可能在Mbo和Map在环境中的持续存在中起作用。在本研究中，从受一种或两种疾病影响的牛群中收集了90个样本，以调查阿米巴及其相关细菌的多样性。元条形码分析显示，棘阿米巴属、粪粘菌属、耐格里属和维氏阿米巴属是FLA中最具代表性的属，假单胞菌门是最常与FLA相关联的细菌。尽管通过测序未鉴定出Mbo和Map的DNA，但通过数字液滴PCR（ddPCR）检测到了痕迹，该技术专门针对这些细菌。总之，我们描述了该环境中FLA和相关细菌的广泛多样性。这也表明Map和Mbo在环境中可能与FLA存在关联，即使这种关联很弱。然而，这需要通过检测到更多的DNA以及如果可能的话，检测与这些环境FLA相关的可培养的Map和/或Mbo来证实。
