General Information: Ignicoccus hospitalis Kin4/I was isolated from gravel obtained from the shallow marine hydrothermal system of the Kolbeinsey Ridge, north of Iceland. Hyperthermophilic archaeon. Ignicoccus hospitalis, an anaerobic, hyperthermophilic, chemoautolithotroph, uses hydrogen to reduce elemental sulfur and produce hydrogen sulfide. This organism is also moderately halophilic and acidophilic. Ignicoccus hospitalis is the host organism for Nanoarchaeum equitans.