Oral microbes - Bacteria (bacilli and cocci) and yeast
Copyright 2006 Dennis Kunkel Microscopy, Inc.
Caption: Oral microbes - Bacteria (bacilli and cocci) and yeast. The oral microbes in this image are: 1) Streptococcus mutans with surrounding dextran polysaccharide mucilage (glucan). S. mutans is a coccoid shaped, Gram-positive, facultative anaerobic bacterium that is part of the normal bacteria flora of the mouth. It can thrive in temperatures ranging from 18-40 degrees Celsius. It metabolizes sucrose to lactic acid and is a leading cause of tooth enamel decay. The acidic environment created in the mouth by this process is what causes the highly mineralized tooth enamel to decay. S. mutans is one of a few specialized organisms equipped with receptors for adhesion to the surface of teeth. Sucrose is utilized by S. mutans to produce a sticky, extracellular, dextran-based polysaccharide (glucan) that allows them to adhere to each other forming plaque. It is the combination of plaque and acid that leads to dental / tooth decay. 2) P. gingivalis (formerly know as Bacteroides gingivalis) is part of the normal flora of the mouth, intestine and urogenital tract. It is a rod shaped, Gram-negative, anaerobe found in periodontal lesions and associated with adult periodontal diseases such as: gingivitis (gum disease), periodontal infections, ulcerative gingivitis and mouth abscesses. Approximately 70-90% of young adults and older have associated Porphyromonas gingivalis gingivitis, an oral inflammatory process and a possible precursor to adult periodontal disease. Porphyromonas gingivalisutilizes heme, transferrin and hemoglobin efficiently as sources of iron for growth. 3) Candida albicans - yeast stage (large cell and yeast bud amongst bacteria). A yeast-like fungus commonly occuring on human skin, in the upper respiratory, alimentary & female genital tracts. This fungus has a dimorphic life cycle with a yeast and hyphal stages. The yeast produces hyphae (strands) from which pseudohyphae branch. The pseudohyphae can give rise to yeast cells by apical or lateral budding. Causes candidiasis which includes thrush (an infection of the mouth & vagina) and vulvo-vaginitis. Magnification*: x2,000 Type: SEM
*(Magnifications are based on a 35mm slide image of 24mm in the narrow dimension.)