Streptococcus pneumoniae Research Paper Example | Topics and Well Written Essays - 1250 words

Streptococcus pneumoniae - Research Paper Example The species name is Streptococcus pneumoniae. Luis Paster discovered the organism in 1800’s. At that time he named it Micrococcus Pasteur. In 1886 and 1920, the name of the organism changed to Pseumococcus and Diplococcus pneumoniae respectively. Finally, in 1974 the micro-organism name became the Streptococcus pneumoniae (Toder, 2012). The micro-organism is Gram-positive, non-spore forming, non-motile and lancet-shaped. Predominantly, the micro-organisms occur in pairs. However, they can form short and straight chains. The micro-organism has a capsule that serves as a protective layer to antibiotics. In addition, the capsule stains positive during Gram staining process. The diameter of individual cells measures 0.5 and 1.25 micrometers. The cell wall of Streptococcus pneumoniae comprises of peptidoglycan and teichoic acid. The peptidoglycan component of the cell wall responds positively to Gram staining technique. This technique identifies and distinguishes different species in the genera streptococci. Steptococcus pneumoniae lacks the catalase activity. In addition, they are facultative anaerobes and metabolizes through lactic acid fermentation (Toder, 2012). There are more than 90 highly antigenic capsular serotypes differentiated in the types of presenting antigen in the capsule. Antibodies to specific types of serotypes are protective. The features responsible for pathogenic nature of organism are innumerable. These include presence of pro-inflammatory cell wall components (C-polysaccharides and F-antigen), IgA2 protease, pneumolysin, adhesins, and enzymes that damages tissue. Pneumolysin is a cytotoxin that stimulates immune response and adhesin bind to cell surface carbohydrates. Some of examples of adhesin include choline binding protein A, and the pneumococcal surface protein A [PspA]. The micro-organism incorporates the genetic material of other micro-organism through a process of transformation. The presence of F-antigen helps in acquiring of genetic material from different sources. Therefore, it means that the organism can change from one serotype to the other. This is quite significant to the development of resistance to antibi otics in the organism. It increases the virulence of the organism. The increasing severity of micro-organism is attributed to its ability to assume different shapes. When the organism acquires genetic material with genes of resistance to antibiotics, it replicates to resist the host defense mechanism. The virulence in these micro-organisms is associated with the capsular material. The capsule resists the hosts’ phagocytosis mechanism thereby surviving and multiplying in the host tissues. The virulence factors of the micro-organism include surface protein A. autolysin, and immunoglobulin A (Toder, 2012). Streptococci pneumoniae are found in the host’s upper airways, nose, or throat. They are part of normal flora in human beings. However, the organism becomes infectious depending on the immunity status of the host. In the immune comprised host, they cause some of the deadly diseases that include pneumonia, meningitis, sinusitis, acute otitis media, peritonitis, and bacte remia. These are diseases of upper and lower respiratory tract. When in the host tissues, pneumococcal undergoes genetic changes that convert the colonies from opaque to transparent ones. However, the rate is very low in number; it is 1 in 105 micro-organisms. The transparent colony is best adapted for proliferation in the nasopharynx. The opaque colonies thrive very well in the host’s blood. The opaque colonies increase their virulence during systemic infections. These differences in