Which organism is a normal skin flora that produces biofilm and is a common cause of prosthetic joint and IV catheter infections?

Which organism is a normal skin flora that produces biofilm and is a common cause of prosthetic joint and IV catheter infections?

• A. Staphylococcus aureus
• B. Staphylococcus epidermidis
• C. Streptococcus pyogenes
• D. Enterococcus faecalis

Answer: (B)

Normal skin inhabitants that readily adhere to foreign surfaces can cause device-related infections because they form protective biofilms. Staphylococcus epidermidis is a coagulase-negative staphylococcus that is part of the normal skin flora. It excels at sticking to plastic and metal implants and catheters, creating a biofilm composed of extracellular polysaccharide matrix. This biofilm acts as a shield, making bacteria harder to eradicate with antibiotics and immune responses, which explains why infections involving prosthetic joints and IV catheters are often linked to this organism. While Staphylococcus aureus is more virulent and tends to cause acute infections, the scenario described—biofilm formation on implanted devices leading to persistent infections—points to Staphylococcus epidermidis. Streptococcus pyogenes and Enterococcus faecalis are associated with different infection patterns and do not fit this device-related biofilm scenario as neatly.

Normal skin inhabitants that readily adhere to foreign surfaces can cause device-related infections because they form protective biofilms. Staphylococcus epidermidis is a coagulase-negative staphylococcus that is part of the normal skin flora. It excels at sticking to plastic and metal implants and catheters, creating a biofilm composed of extracellular polysaccharide matrix. This biofilm acts as a shield, making bacteria harder to eradicate with antibiotics and immune responses, which explains why infections involving prosthetic joints and IV catheters are often linked to this organism. While Staphylococcus aureus is more virulent and tends to cause acute infections, the scenario described—biofilm formation on implanted devices leading to persistent infections—points to Staphylococcus epidermidis. Streptococcus pyogenes and Enterococcus faecalis are associated with different infection patterns and do not fit this device-related biofilm scenario as neatly.