Most soft-tissue infections from puncture wounds are caused by gram-positive organisms. Which organism is most commonly implicated?

Most soft-tissue infections from puncture wounds are caused by gram-positive organisms. Which organism is most commonly implicated?

• A. Streptococcus pneumoniae
• B. Streptococcus pyogenes
• C. Staphylococcus aureus
• D. Staphylococcus epidermidis

Answer: (C)

Staphylococcus aureus is the most common gram-positive culprit in soft-tissue infections after a puncture wound. It resides on the skin and in the nares, and when the skin barrier is breached, it readily invades the underlying tissues to cause cellulitis or abscess formation. While Streptococcus pyogenes can cause skin infections, it is less frequently the primary offender in puncture wounds compared with S. aureus. Streptococcus pneumoniae is mainly a respiratory pathogen and not a typical cause of skin infections, and Staphylococcus epidermidis, though part of the skin flora, is less likely to cause acute, invasive soft-tissue infections in this context. Therefore, the organism most commonly implicated is Staphylococcus aureus. In practice, consider coverage for S. aureus (including MRSA in appropriate settings) when selecting empiric therapy for puncture wound infections.

Staphylococcus aureus is the most common gram-positive culprit in soft-tissue infections after a puncture wound. It resides on the skin and in the nares, and when the skin barrier is breached, it readily invades the underlying tissues to cause cellulitis or abscess formation. While Streptococcus pyogenes can cause skin infections, it is less frequently the primary offender in puncture wounds compared with S. aureus. Streptococcus pneumoniae is mainly a respiratory pathogen and not a typical cause of skin infections, and Staphylococcus epidermidis, though part of the skin flora, is less likely to cause acute, invasive soft-tissue infections in this context. Therefore, the organism most commonly implicated is Staphylococcus aureus. In practice, consider coverage for S. aureus (including MRSA in appropriate settings) when selecting empiric therapy for puncture wound infections.