Streptococci, Pneumococci, and Enterococci

Streptococci, Pneumococci, and Enterococci
Name
Instructor
Course
Date
Streptococci, Pneumococci, and Enterococci
Q1
Streptococci and pneumococci are two types of Gram-positive cocci that can be distinguished based on their microscopic morphology when viewed through a Gram stain. Streptococci usually stains purple when the gram stain technique is applied. This is an indication that it is gram-positive. The same is the case with pneumococci too. Streptococci typically form pairs or chains of cocci, whereas pneumococci are usually observed as pairs of cocci with a lancet shape. The critical distinguishing feature between them is the existence of a capsule in pneumococci that imparts their lancet-like appearance under the microscope, meaning that one of its ends is broad while the other is narrow and pointed. Microscopically, it is around one micrometer in diameter. However, this capsule is absent in streptococci. The streptococci is usually shaped like a sphere or ovoid and are non-motile, meaning that they do not display any form of self-propulsion through metabolism.
Q2
Hemolysis is the destruction of the red blood cells after they reach their ‘expiry date’ usually around 120 days. Streptococcus pneumoniae exhibits alpha-hemolytic activity when grown on blood agar. Alpha-hemolysis is distinguished by a greenish coloration of the agar surrounding the bacterial colony, indicating that red blood cells have been partially damaged. In contrast, beta-hemolysis destroys red blood cells, creating a clear zone around the territory. Nonhemolytic streptococci, on the other hand, do not damage red blood cells at all. Alpha hemolysis usually occurs in aerobic conditions, whereby there is a sufficient supply of oxygen while beta hemolysis occurs in anaerob...