Streptococcal Infections
The bacteria Streptococcus pyogenes and Streptococcus pneumoniae are important human respiratory pathogens. Both organisms are transmitted by the respiratory route. S. pneumoniae is found in the respiratory flora of up to 40% of healthy individuals. Although endogenous strains do not cause disease in most normal individuals, they can cause severerespiratory disease in compromised individuals.
Streptococci are nonsporulating, homofermentative, aerotolerant, anaerobic gram-positive cocci. Cells of S. pyogenes typically grow in elongated chains, as do
many other members of the genus. Pathogenic strains of S. pneumoniae typically grow in pairs or short chains,
and virulent strains produce an extensive polysaccharide capsule.
About half of the clinical cases of severe sore throat are due to Streptococcus pyogenes, with most others due to viral infections. An accurate, rapid determination of the cause of the sore throat is important. If the sore throat is due to S. pyogenes, rapid, complete treatment of streptococcal sore throat is important because untreated streptococcal infections can lead to serious diseases such as scarlet fever, rheumatic fever, acute glomerulonephritis,and streptococcal toxic shock syndrome. Please see Appendix 3. On the other hand, if the sore throat is due to a virus, treatment with antibacterialdrugs (antibiotics) will be useless, and may promote antimicrobial drug resistance.
Pyogenic (ก่อให้เกิดหนอง) Pyrogenic (ก่อให้เกิดไข้)