Gram Positive Cocci | 合法醫療器材資訊網

Gram-positivecocciareincludedamongsomeofthemostsignificanthumanbacterialpathogens:primarypathogenssuchasStaphylococcusaureus, ...

Streptococci are gram-positive cocci that grow in pairs or chains. Most pathogenic streptococci are facultative anaerobes. Many species of streptococci constitute the normal flora of the respiratory, gastrointestinal, and genitourinary tracts. These organisms cause disease either directly by invasion of tissues or indirectly through the elaboration of toxins.

Streptococci may be classified based on the antigenic composition of cell wall carbohydrates. To date, Lancefield serogroups A to H and K to V have been identified.

Another useful classification scheme is based on the ability of the organism to produce zones of hemolysis around the colony when cultured on blood agar. α-Hemolysis is characterized by a zone of partial hemolysis, which often appears as a greenish hue on the...