| Popis: |
Publisher Summary Streptococci are Gram-positive cocci that divide in one plane only and so are arranged in chains of varying lengths. Some strains grow poorly on simple media and might be pathogenic to man and animals. Streptococci do not exhibit marked metabolic activities. They ferment many carbohydrates with the production of acid only, but they have few proteolytic properties and pigment formation is not found. The present conception of human streptococcal infections is based on the unitarian hypothesis. This postulates that the various diseases are caused by one species of streptococcus. The different clinical manifestations are because of variations in one or more of the three offensive weapons, and, on the other, to changes in the susceptibility of the infected individual. To illustrate this hypothesis, it is considered that in scarlet fever the erythrogenic toxin, in empyema pyogenicity, and in septicaemia invasiveness are respectively the predominant pathogenic factors. The unitarian hypothesis is supported by serological observations. Disease-specificity by different strains has not been found; serologically identical strains have been isolated from cases of scarlet fever, sore throat, puerperal fever, and otitis media. |
