Streptococcus salivarius - Gram-positive, rod prokaryote (bacterium)
Copyright 2009 Dennis Kunkel Microscopy, Inc.
Caption: Streptococcus salivarius - Gram-positive, coccoid, facultatively anaerobic prokaryote (bacterium). Streptococcus salivarius forms chains of cells which are bound together by the capsular material seen around each cell (shown as surface stipulation in this image). It is the principal commensal bacterium of the oral cavity and a normal inhabitant of the upper respiratory tract in humans. It is the first bacterium that colonizes dental plaque, before being joined by numerous other species of various genera. It creates favorable conditions so other species can begin to colonize. It is also a bacterium that plays the role of moderator, permitting the implantation of bacteria that are harmful to the health of the oral cavity. The bacterium colonizes the mouth and upper respiratory tract of humans a few hours after birth, making further exposure to the bacteria harmless. S. salivarius is considered an opportunistic pathogen and when it enters the blood stream it causes septicemia in people with neutropenia. It may cause endocarditis and dental tooth decay. The host's immune response is repelled by the bacteria's ability to alter the proteins on its surface that allow it to be recognized by the body. Magnification*: x5,335 Type: SEM
*(Magnifications are based on a 35mm slide image of 24mm in the narrow dimension.)