Sphingopyxis italica, sp. nov., isolated from Roman catacombs

Abstract

A Gram-negative, aerobic, motile, rod-shaped bacterium, strain SC13E-S71T, was isolated from tuff, the volcanic rock where was excavated the Roman Catacombs of Saint Callixtus in Rome, Italy. Analysis of 16S rRNA gene sequences revealed that strain SC13E-S71T belongs to the genus Sphingopyxis, and that it shows the greatest sequence similarity with Sphingopyxis chilensis DSMZ 14889T (98.72%), Sphingopyxis taejonensis DSMZ 15583T (98.65%), Sphingopyxis ginsengisoli LMG 23390T (98.16%), Sphingopyxis panaciterrae KCTC12580T (98.09%), Sphingopyxis alaskensis DSM 13593T (98.09%), Sphingopyxis witflariensis DSM 14551T (98.09%), Sphingopyxis bauzanensis DSM 22271T (98.02%), Sphingopyxis granuli KCTC12209T (97.73%), Sphingopyxis macrogoltabida KACC 10927T (97.49%), Sphingopyxis ummariensis DSM 24316T (97.37%) and Sphingopyxis panaciterrulae KCTC 22112T (97.09%). The predominant fatty acids were C18:1ω7c, summed feature 3 (iso-C15:0 2OH and/or C16:1ω7c), C14:0 2OH and C16:0. Predominant menaquinone was MK-10. Major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine and sphingoglycolipid. These chemotaxonomic data are common to members of the genus Sphingopyxis. However, a polyphasic approach using physiological tests, DNA base ratios, DNA-DNA hybridisation and 16S rRNA gene sequence comparisons showed that the isolate SC13E-S71T belongs to a novel species within the genus Sphingopyxis, for which the name Sphingopyxis italica is proposed. The type strain is SC13E-S71T (=DSM 25229T =CECT 8016T).