More than 180 species have been identified of which 20 distinct Mycoplasma and Acholeplasma species from human, bovine and swine have been isolated from cell culture. There are 6 species that account for 95% of all mycoplasma infections (M.orale, M.arginii, M.fermentans, M.salivarum, M.hyorhinis and A.laidlawii).