The Collaborative International Dictionary
Leptothrix \Lep"to*thrix\ (l[e^]p"t[-o]*thr[i^]ks), n. [NL., fr. Gr. lepto`s small + qri`x hair.] (Biol.) A genus of bacteria, characterized by having their filaments very long, slender, and indistinctly articulated.
Leptothrix \Lep"to*thrix\, a. [See Leptothrix, n. ] (Biol.) Having the form of a little chain; -- applied to bacteria when, as in multiplication by fission, they form a chain of filiform individuals.
Wikipedia
Leptothrix is a genus of Gram-negative Comamonadaceae bacteria that occur in standing or slow-flowing, ferruginous, neutral to slightly acidic fresh waters with only low concentrations of organic matter. The energy metabolism of Ideonella is strictly aerobic, oxidative, and chemoorganoheterotrophic. Five species are known: L. ochracea, L. discophora, L. cholodnii, L. lopholea, and L. mobilis.