Mycoplasma elephantis sp. nov., a New Species from Elephants

This paper describes the identification and characterization of a new mycoplasma species isolated from the genital tracts of female elephants during a survey of arthritic animals in circuses and zoos. Two strains (E42T and E73) were isolated from approximately 60% of female elephants belonging to Elephas maximus and Loxodonta africana. Using serological methods including growth inhibition tests, metabolic inhibition tests, indirect immunofluorescence, and immunobinding assays, the researchers demonstrated that these organisms were distinct from all previously described Mycoplasma, Entomoplasma, Mesoplasma, and Acholeplasma species. The new organism, designated Mycoplasma elephantis, exhibits characteristic mycoplasma features including absence of a cell wall, fried-egg colony morphology, and coccoid cell shape. It ferments glucose, fructose, maltose, mannose, and sucrose; produces films and spots; requires cholesterol or serum for growth; and has a DNA G+C content of 24.0 mol%. The organism lyses but does not adsorb avian, ovine, and guinea pig erythrocytes, with optimal growth at 37°C. While isolated from arthritic elephants with serum antibodies against the mycoplasma, the organisms' role in disease pathogenesis remains unclear.

Key findings

• Mycoplasma elephantis is a novel mycoplasma species isolated from female elephant genital tracts, representing a previously unrecognized species distinct from all existing Mycoplasma, Entomoplasma, Mesoplasma, and Acholeplasma species.
• The organism demonstrates typical mycoplasma characteristics: absence of cell wall, fried-egg colonies, cholesterol/serum requirement for growth, DNA G+C content of 24.0 mol%, and fermentation of multiple sugars (glucose, fructose, maltose, mannose, sucrose).
• Serological testing using multiple methods (growth inhibition, metabolic inhibition, immunofluorescence, and immunobinding assays) confirmed the two elephant strains (E42T and E73) belong to the same species and are serologically distinct from known mycoplasmas.
• While mycoplasmas were detected in approximately 60% of surveyed female elephants and antibodies were present in both male and female elephants with arthritis, the pathogenic role of M. elephantis in elephant arthritis could not be definitively established.