Pathogenesis

  • Skin and soft tissue infections (SSTIs) involve microbial invasion of the skin and underlying soft tissues, following a breach in the protective skin barrier from trauma, surgery, or increased tissue tension secondary to fluid stasis.1,2
  • Infectious microorganisms can go on to provoke inflammatory responses and cause tissue damage which contributes to edema and/or induration around the site of the infection and formation of pus.1,3
Pathogenesis
Development
SSTI Pathogenesis

How Do Skin and Soft Tissue Infections (SSTIs) Develop?

The skin serves as the first line of defense against infection by presenting a physical barrier, by secreting sebaceous fluid that inhibits microbial growth and through its own microbiota, which can deter colonization by potentially pathogenic organisms.4 SSTIs can occur following a breach in the protective skin barrier after trauma, surgery or other causes which allows infectious microorganisms to enter.1,2

 

Once microorganisms infect skin structures, a complex cellular response is initiated, which includes mobilization of immune cells to the site of infection and abscess formation.3,4

 

Host cell defense mechanisms aid in killing bacteria but may also cause non-specific damage to host tissue. This contributes to the physical signs observed such as redness, edema and/or induration around the site of the infection and formation of pus.1,3

Illustration of SSTI Pathogenesis

SSTI pathogenesis

Figure adapted from Kobayashi et al. Pathogenesis of Staphylococcus aureus Abscesses. Am J Pathol. 2015; 185(6):1518-1527

Learn about the epidemiology of SSTIs

References

  1. Brandt SL, Putnam NE, Cassat JE, Serezani CH. Innate Immunity to Staphylococcus aureus: Evolving Paradigms in Soft Tissue and Invasive Infections. J Immunol. 2018;200(12):3871–3880.
  2. Ramakrishnan K, Salinas RC, Agudelo Higuita NI. Skin and Soft Tissue Infections. Am Fam Physician. 2015;92(6):474–483.
  3. Kobayashi SD, Malachowa N, DeLeo FR. Pathogenesis of Staphylococcus aureus abscesses. Am J Pathol. 2015;185(6):1518–1527.
  4. Ki V, Rotstein C. Bacterial skin and soft tissue infections in adults: A review of their epidemiology, pathogenesis, diagnosis, treatment and site of care. Can J Infect Dis Med Microbiol. 2008;19(2):173–184.
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