摘要：Infectious diseases present a significant health burden affecting the immunocompromised as well as immunocompetent subjects throughout the world. Most of these diseases are due to the invasion of the host cells and organs by the microorganisms. Common widespread diseases of the respiratory system occur when the organisms invade the respiratory tract of the host. The infectious respiratory diseases are globally observed as a major health concern because they can rapidly become severe and lead to death. Streptococcus pneumoniae is a medically important bacterium that has been commonly linked to causing respiratory infections in individuals with a weakened immune system. Streptococcus pneumoniae, also known as pneumococcus, can survive in both aerobic and anaerobic conditions. The organism has the potential to produce pneumonia, bacteremia, meningitis, acute otitis media, and sinusitis. It colonizes the upper respiratory tract particularly the nasopharynx. Streptococcus pneumoniae, like many other bacterial species, produce toxins that are harmful to its host, has several surface proteins and physical structures, which play a very crucial role in its pathogenesis.
