Hyaluronic acid capsule modulates interactions of group A streptococci with human epidermal keratinocytes.

Abstract

Group A Streptococcus (GAS) remains an important cause of human diseases ranging from mild pharyngitis and pyoderma to life-threatening, invasive soft tissue and systemic infections. The streptococcal and host factors that determine the pathogenesis of the wide variety of clinical manifestations remain incompletely understood. GAS infection begins at one of two anatomic sites: in the pharynx or in the external skin, often in association with a break in the skin from a surgical or traumatic wound, varicella infection, or a trivial injury such as an insect bite. Development of clinical pharyngitis or skin infection requires that the organisms attach to the epithelium, then breach the epithelial barrier to establish a nidus of infection within the tissue. Some investigators have found that streptococci enter human cells in vitro and have suggested that entry may represent an early step in the development of invasive infection.2, 5 Entry and proliferation within host cells by intracellular bacteria such as Listeria monocytogenes is necessary for avoidance of host defenses (e.g., opsonins and phagocytes) and for development of disease. By contrast, GAS proliferates not in the intracellular environment, but rather in the extracellular domain causing local suppuration and sometimes spreading to deeper tissues and the blood stream. Therefore, the significance of entry into host cells for GAS is less clear than for obligate intracellular pathogens.KeywordsExternal SkinInvasive SkinInvasive Soft TissueObligate Intracellular PathogenHuman Foreskin KeratinocytesThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.