In vitro growth and characterization of 'Candidatus Sarcina troglodytae' isolated from the brain of a chimpanzee in Sierra Leone.

'Candidatus Sarcina troglodytae' ('Ca. S. troglodytae'), a proposed bacterial species in the family Clostridiaceae, has been epidemiologically associated with a lethal disease in sanctuary chimpanzees in Sierra Leone, epizootic neurologic and gastroenteric syndrome (ENGS). As sarcinae are known to be difficult to culture, a lack of viable in vitro growth conditions has limited further characterization of this bacterium. Such studies are critical to elucidating the relationship between 'Ca. S. troglodytae' and ENGS. Here, we isolate a Gram-stain-positive, endospore-forming coccus and anaerobic bacterial strain, designated JB3T, from brain tissue of a western chimpanzee (Pan troglodytes verus) using a reinforced clostridial medium. We describe the growth of strain JB3T at a pH range of 6 to 9 (optimum 6) at 37 °C in an atmosphere composed of 5% H2, 5% CO2 and 90% N2 and demonstrate endospore production under alkaline conditions, suggesting the possibility of an environmental reservoir. We identify ethanol as the primary non-gaseous fermentation byproduct which we hypothesize to have relevance for ENGS. Antibiotic susceptibility testing shows susceptibility to common antimicrobial agents with notable resistance to ceftriaxone. By establishing in vitro conditions for the viable culture, propagation and storage of 'Ca. S. troglodytae', this study lays the groundwork for future infection studies to test hypotheses about pathogenic mechanisms and prevention/treatment measures for ENGS.