ðə bæktˈɪɹiə kænˈɑːt biː kˈʌltʃɚd ˌɔn lˈæbɹətˌɔːɹi mˈiːdiːə, sˌoʊ ðɪ ˈɔːɹɡənˌɪzəmz jˈuːzd ɑːɹ ɐ lˈaɪəfˌɪlaɪzd səspˈɛnʃən ʌv tˈiː. pælˈɪdəm ɛkstɹˈæktᵻd fɹʌm ɹˈæbɪt tɛstˈɪkjʊlɚ tˈɪʃuː.
The bacteria cannot be cultured on laboratory media, so the organisms used are a lyophilized suspension of T. pallidum extracted from rabbit testicular tissue.