Novel hemotrophic mycoplasma identified in naturally infected California sea lions (Zalophus californianus)

Abstract

The hemoplasmas are the trivial name for a group of erythrocyte-parasitizing, non-cultivable in vitro bacteria of the genus Mycoplasma that have been described in several mammalian hosts worldwide. This study is the first report of hemoplasmas in marine mammals. EDTA anticoagulated whole blood samples from 137 California sea lions (Zalophus californianus) and 20 northern elephant seals (Mirounga angustirostris) admitted to the Marine Mammal Center (Sausalito, CA; www.marinemammalcenter.org) or live captured in Oregon were collected during 2008. Hemoplasma-specific genomic DNA was detected in blood samples from 12.4% California sea lions tested using PCR. Hemoplasma PCR positive blood specimens also were tested in reverse transcription polymerase chain reaction (RT-PCR) using the hemoplasma-specific primers for the 16S and 23S rRNA genes. The RT-PCR showed the presence the hemoplasmal rRNA, strongly suggesting the presence of potentially viable hemoplasmas in the bloodstream of the animals. BLAST search and phylogenetic analysis of the 16S rRNA sequences of the hemoplasma from California sea lions revealed that the organism is a novel hemoplasma species with only 92.1% of its nucleotide similarity to the 16S rRNA gene of the previously described hemoplasma species of alpacas, Candidatus Mycoplasma haemolamae. Thus, due to low level of genetic similarity of the hemoplasma to other described hemoplasmas and the mammalian host in which the hemoplasma was detected we propose that this novel hemoplasma species has been given the provisional name Candidatus Mycoplasma haemozalophi sp. nov.