leptothrix ochracea leptothrix ochracea leptothrix ochracea is a bacterium from the genus leptothrix. it occurs in iron-rich fresh water and wetlands with only low concentrations of organic matter. leptothrix ochracea scientific classification domain: bacteria phylum: pseudomonadota class: betaproteobacteria order: burkholderiales genus: leptothrix species: l. ochracea binomial name leptothrix ochraceakützing 1843, species.