Mycoplasma hominis: a review of its role as a respiratory tract pathogen of humans.

Mycoplasma hominis seldom colonizes the human respiratory tract and only rarely causes acute respiratory infection. It can be recovered from the respiratory secretions of 1-3% of healthy persons and of less than or equal to 8% of persons with chronic respiratory disease, but it has not been implicated definitely in the etiology of this disease or in the exacerbations that characterize its course. M. hominis has been isolated from less than or equal to 6% of persons with acute pharyngitis or acute upper respiratory tract illnesses and can induce exudative pharyngitis in susceptible volunteers when administered intranasally and oropharyngeally. Colonization of the respiratory tract by M. hominis occurs in approximately 15% of persons who engage in oral-genital sexual practices, but colonization alone is not necessarily associated with sore throat or other upper respiratory diseases. Although M. hominis has been recovered from adults with pneumonia more often than from controls, a pathogenic role in pneumonia of adults has not been established. Under special conditions, e.g., neonatal pneumonia, M. hominis appears to be pathogenic for the lower respiratory tract. Thus M. hominis probably is only an occasional respiratory pathogen in the adult and a rare "opportunistic" pathogen of the respiratory tract of the neonate.