Mycoplasmas represent the smallest self-replicating organisms that are most closely related to the gram-positive bacterial group that includes streptococci, bacilli, and lactobacilli. Mycoplasma pneumoniae is a member of the family Mycoplasmataceae that causes both the upper and the lower respiratory tract infection both endemically and epidemically worldwide. Most infections are mild, but a small proportion of infected individuals may develop serious pneumonia due to an enhanced host cellular immune response.
