Micriamoeba tesseris nov. gen. nov. sp.: a new taxon of free-living small-sized Amoebae non-permissive to virulent Legionellae.
Investigation of soil amoebae in 11 cooling towers allowed us to isolate a major unknown small-sized amoeba population (SZA). However, SZA did not appear to be specific to cooling tower ecosystems since they are also a major amoeba population found in muds isolated from different points of a water treatment plant. The SSU-rDNA sequences from SZA strains did not match any known database sequences, suggesting that SZA constitutes a new amoeba taxon. We isolated and further described one of the SZA that we named Micriamoeba tesseris. The phylogenetic analyses showed that Micriamoeba tesseris belongs to the Amebozoa and branched together with genus Echinamoeba+Vermamoeba vermiformis. Phylogenetic analyses within the Micriamoeba group distinguished different subgroups of Micriamoeba strains according to their origin, i.e. cooling tower or mud. Although Micriamoeba are able to feed on viable E. coli cells, they do not uptake virulent Legionella pneumophila strains, thus enabling them to avoid infection by Legionella. Consequently, Micriamoeba is not directly involved in L. pneumophila multiplication. However, an indirect role of Micriamoeba in Legionella risk is discussed.
Université de Lyon, CNRS UMR 5240, Université Lyon 1 F-69622 Villeurbanne, France.
Danièle
D
Atlan
Bénédicte
B
Coupat-Goutaland
Arnaud
A
Risler
Monique
M
Reyrolle
Maud
M
Souchon
Jérôme
J
Briolay
Sophie
S
Jarraud
Patricia
P
Doublet
Michel
M
Pélandakis
D000656:Amoeba / Q000145:classification* / Q000302:isolation & purification / Q000382:microbiology; D016000:Cluster Analysis; D016054:DNA, Protozoan / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D004783:Environmental Microbiology; D004926:Escherichia coli / Q000302:isolation & purification; D005247:Feeding Behavior; D020459:Genes, rRNA; D016952:Legionella pneumophila / Q000302:isolation & purification; D008969:Molecular Sequence Data; D010802:Phylogeny; D016053:RNA, Protozoan / Q000235:genetics; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D017422:Sequence Analysis, DNA
D016054:DNA, Protozoan; D004275:DNA, Ribosomal; D016053:RNA, Protozoan; D012337:RNA, Ribosomal, 18S