Transmission electron microscope study of bacterial morphotypes on the anterior dorsal surface of human tongues

The human tongue has been the subject of many cytological and histological studies. When a literature search disclosed no reports of the ultrastructure of the morphotypes of bacteria residing on the tongue's surface, a transmission electron microscope study of ultrathin sections of bacteria obtained by scraping eight human tongues was undertaken. The scrapings from the anterior dorsal tongue surfaces, processed conventionally for electron microscope study, revealed 33-35 different bacterial morphotypes. Several of the morphotypes were unique to a tongue. Morphotype differences were also related to donor characteristics such as smoking, tongue site, location in centrifuge pellet, diet, and medications. The predominant morphotypes were Gram-positive cocci. These preliminary findings suggest that the microbiota of the human tongue and variations in that microbiota, related to physical condition, lifestyle, medications, and dietary preferences, merit more attention from anatomists.