Pathogenic and free-living protozoa cultured from the nasopharyngeal and oral regions of dental patients.

Protozoa of nose, mouth, and pharynx of 30 randomly chosen female caries patients at an odontological clinic of the National Autonomous University of Mexico, were surveyed by culture from swabs. Culture tubes of swabs from each patient were observed every other day during 5 weeks. Pathogenic protozoa found included Entamoeba histolytica Schaudinn, 1903; Naegleria fowleri Carter, 1970; Acanthamoeba castelanii Douglas, 1930; Acanthamoeba culbertsoni Singh & Das, 1970; and Balantidium coli (Malmsten, 1857) Stein, 1862. This isolation of pathogens suggests that healthy patients may be healthy carriers of cysts of protozoa, mainly amoebae, responsible for several diseases, including primary amoebic meningoencephalitis. Small pathogenic free-living amoebae have not been isolated before from females in Mexico. Many species of free-living protozoa were also cultured from swabs from the patients.