Mycoplasma tullyi sp. nov., isolated from penguins of the genus Spheniscus

Abstract

A mycoplasma isolated from the liver of a dead Humboldt penguin (Spheniscus humboldti) and designated strain 56A97(T), was investigated to determine its taxonomic status. Complete 16S rRNA gene sequence analysis indicated that the organism was most closely related to Mycoplasma gallisepticum and Mycoplasma imitans (99.7 and 99.9% similarity, respectively). The average DNA-DNA hybridization values between strain 56A97(T) and M. gallisepticum and M. imitans were 39.5 and 30 %, respectively and the Genome to Genome Distance Calculator gave results of 29.10 and 23.50 %, respectively. The 16S-23S rRNA intergenic spacer was 72-73% similar to M. gallisepticum strains and 52.2% to M. imitans. A partial sequence of rpoB was 91.1-92% similar to M. gallisepticum strains and 84.7% to M. imitans. Colonies possessed a typical fried-egg appearance and electron micrographs revealed the lack of a cell wall and a nearly spherical morphology, with an electron-dense tip-like structure on some flask-shaped cells. The isolate required sterol for growth, fermented glucose, adsorbed and haemolysed erythrocytes, but did not hydrolyse arginine or urea. The strain was compared serologically against 110 previously described Mycoplasma reference strains, showing that, except for M. gallisepticum, strain 56A97(T) is not related to any of the previously described species, although weak cross-reactions were evident. Genomic information, serological reactions and phenotypic properties demonstrate that this organism represents a novel species of the genus Mycoplasma, for which the name Mycoplasma tullyi sp. nov. is proposed; the type strain is 56A97(T) (ATCC BAA-1432(T), DSM 21909(T), NCTC 11747(T)).