Scanning electron micrograph (SEM) of oral bacteria (bacilli and cocci) and yeast. In this image are: Streptococcus mutans with surrounding dextran polysaccharide mucilage (glucan). S. mutans is a coccoid, Gram-positive, facultative anaerobic bacterium that is part of the normal bacteria flora of the mouth. It metabolizes sucrose to lactic acid and is a leading cause of tooth enamel decay. Porphyromonas gingivalis (formerly Bacteroides gingivalis) is part of the normal flora of the mouth, intestine and urogenital tract. It is a rod shaped, Gram-negative, anaerobe associated with gingivitis (gum disease), periodontal infections, ulcerative gingivitis and mouth abscesses. Candida albicans, yeast stage (large cell and yeast bud amongst bacteria). A yeast-like fungus commonly occurring on human skin, upper respiratory, alimentary and female genital tracts. It causes oral thrush (candidiasis). Magnification: x2, 000 when shortest axis printed at 25 millimetres. |