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Experimental infections with group A streptococci in humans
The Journal of Investigative Dermatology
|August 1, 1980
Summary
Group A streptococci do not colonize or infect intact human skin. However, these bacteria can cause localized infections on scarified skin or deeper cellulitis when inoculated intradermally.
Area of Science:
- Microbiology
- Dermatology
- Infectious Diseases
Background:
- Group A streptococci (GAS) are significant human pathogens.
- The role of skin integrity in GAS colonization and infection is not fully understood.
- Understanding GAS skin interactions is crucial for preventing infections.
Purpose of the Study:
- To investigate the ability of Group A streptococci to colonize or infect intact human skin.
- To determine the infective potential of GAS on damaged skin.
- To assess the development of infection following intradermal inoculation of GAS.
Main Methods:
- Experimental inoculation of seven strains of Group A streptococci onto normal intact human skin.
- Inoculation onto skin with suppressed resident microflora and on lipid-rich versus lipid-poor areas.
- Inoculation onto scarified skin and intradermal inoculation in human volunteers.
Main Results:
- Group A streptococci failed to colonize or infect intact skin, rapidly dying on the surface.
- Suppression of normal skin flora did not alter GAS survival on intact skin.
- Inoculation onto scarified skin (≥1 x 10^4 organisms) resulted in localized infections.
- Intradermal inoculation led to localized cellulitis, lymphadenopathy, and fever.
Conclusions:
- Intact skin serves as an effective barrier against Group A streptococci colonization and infection.
- Skin damage, such as superficial scarification, is necessary for GAS to establish localized infections.
- Intradermal inoculation of GAS can lead to invasive localized infections with systemic symptoms.