Saprophytes are fungi that are capable of getting nourishment from decaying plants in order to live their lives longer. They are known to stay in rich soil and in various dead trees. They often reside in decaying wood as well.
The sexually transmitted diseases are a major threat to the human population as they are caused by microbes and spread during sexual intercourse.
In the given question, the two mentioned sexual disease: bacterial vaginosis and the syphilis are caused by the bacterial species.
Although the disease is caused by the bacteria the species of the disease-causing bacteria differ in these two cases.
The bacterial vaginosis is caused by the <em>Gardnerella vaginalis</em> whereas the syphilis is caused by the <em>Treponema pallidum.