The genus Shewanella includes saprophytic Gram-negative microorganisms inhabiting warm and temperate regions worldwide and which are part of the marine environment microflora. More than 50 species of Shewanella have been classified thus far, all of which produce yellowish-brown pigmented and mucoid colonies releasing hydrogen sulfide in culture. Several Shewanella species have been recently known to be emerging agents of soft tissue and invasive infections following seawater exposure, and these include Shewanella algae (which is the most common), Shewanella haliotis, Shewanella putrefaciens and Shewanella xiamenensis. Shewanella species have great metabolic versatility; they can reduce various electron acceptors.