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Staphylococcus infections


Staphylococcus is an opportunistic pathogen that can cause infections through broken skin or when introduced into the body via a catheter or other device. Most Staph infections are skin and surface infections that vary in their presentation depending on the depth and extent of infection. These include impetigo, folliculitis, carbuncles, furuncles and wound infections. Systemic infections (bacteremia, endocarditis, and pneumonia) as well as toxic shock syndrome and food poisoning also occur. Staphylococcus infections cause tissue and cell damage through production of certain virulence factors (e.g. hylaronidase) and exotoxins such as TSST-1.

Staphylococcus aureus

  1. Cause: Staphylococcus aureus
  2. Microscopy: Gram-positive clusters
  3. Diagnosis: Selective media such as Mannitol Salt Agar; coagulase; DNAse
  4. Transmission: Direct contact, fomites, foreign bodies (catheter, prosthetic valve/joint, splinter)

Staphylococcal Scalded Skin Syndrome

Toxic Shock Syndrome

Cutaneous infections:

The production of virulence factors such as lipase and hyaluronidase increases the spread and severity of the infection, especially important in furuncles and carbuncles

Impetigo: All You Need to Know | CDCcarbuncle2-1.jpg image by drbernardchanImage: Bullous Impetigo - Merck Manuals Consumer Version


Systemic Staphylococcus infections

Coagulase-negative Staphylococcus

  1. Endocarditis, esp. of artificial valves
  2. > 50% of all catheter & shunt infections
  3. Prosthetic joints
  4. Urinary tract infections (S. saprophyticus)