Complex sentence: Of the over 100 documented species in the genus "Mycoplasma", 14, including "Mycoplasma orale", are known to infect humans; this is to be expected as the class Mollicutes are common commensals or pathogens of several different organisms.
Split into simpler sentences: Of the over 100 documented species in the genus "Mycoplasma", 14 are known to infect humans. This is expected as the Mollicutes are common commensals or pathogens of several different organisms.