MacroPhage

Hi, after long time, Today, we will explain Streptococcus with its structure and classification, so let’s begin: --------------------------------------------------------------------------------------------------------------------- * Pyogenes cocci are those in which the hallmarks (special characteristic) of the infective process results in formation of pus. And they are classified into Gram(+ve) pyogenes such as Streptococcus and staphylococcus tend to cause diseases by exotoxins while Gram (-ve) pyogenes such as Neisseria and Haemophilus causes diseases depending on host’s response to lipopolysaccharides (LPS) (endotoxin) as LPS cause releasing of inflammatory cytokines. * Streptococcus are aerobic and facultative anaerobic Gram-positive cocci, arranged in pairs (diplococci) such as Streptococcus pneumonia or chains such as Streptococcus pyogenes . They are nonmotile, non-sporing, have hyaluronic acid capsules and catalase negative by which they are disting...

Characteristics of Spirochetes: 1)    Vary in size from 5 to 500 µm in length. 2)    Many of them are free-living saprophytes (microorganism that lives on dead), while a few are obligate parasites. 3)    Are thin, helical (0.1–0.5 × 5–20 µm), and Gram negative . 4)    Are also elongated, motile, and flexible bacteria, twisted spirally along the long axis, giving these bacteria the name spirochetes (Spira meaning coiled, chait meaning hair). 5)    The presence of endoflagella . 6)    Exhibit three types of motility: (a) flexion and extension, (b) corkscrew- like rotatory movement, and (c) translatory motion. Examples of genera of Spirochetes: Treponema and Borrelia which causes diseases to human. Common diseases occurred by Spirochetes: Treponema: Are short and slender spirochetes with fine spirals and pointed ends. They are causative agent of syphilis. Morphology: 1)    Is a thi...