Clinical meaning
Wound infection occurs when microorganisms invade wound tissue, overwhelm host defenses, and cause tissue damage. Understanding the wound infection continuum is essential for practical nurses. All open wounds contain microorganisms, but their presence does not automatically constitute infection. The continuum progresses through four stages: contamination (microorganisms present but not replicating), colonization (microorganisms replicating but not causing tissue damage), local infection (microorganisms invading tissue and causing local tissue damage), and systemic infection/sepsis (organisms or their toxins spreading beyond the wound to cause systemic illness). Two validated clinical frameworks help identify wound infection at different stages. The NERDS criteria identify superficial (localized) wound infection: Non-healing wound despite appropriate care, Exudate that is increasing in volume or changing character, Red and friable granulation tissue that bleeds easily, Debris or dead cells on the wound surface, and Smell or unpleasant odor from the wound. When three or more NERDS criteria are present, topical antimicrobial therapy is indicated. The STONES criteria identify deep and surrounding tissue infection: Size increasing despite appropriate care, Temperature elevated in surrounding tissue, Os (Latin for bone) -- probing to bone...