Infection Risk, Identification, and Management
Think in a continuum
Bioburden progresses from contamination to colonization to local (critical) infection to spreading infection to systemic infection. Colonization does not require antibiotics; critical colonization does. Chronic wounds rarely show the classic fulminant picture, so look for indirect signs: stalled healing, increasing exudate, friable red tissue that bleeds easily, debris, odor, new or increasing pain, and breakdown of the periwound skin.
Useful assessment mnemonics
The commonly taught NERDS signs suggest superficial critical colonization: Nonhealing, Exudate, Red and friable tissue, Debris, Smell. STONEES suggests deeper or spreading infection: Size increasing, Temperature elevated, Os (probe to or exposed bone), New breakdown, Erythema/edema, Exudate, Smell. Probing to bone in a pressure injury raises concern for osteomyelitis and warrants imaging and medical escalation.
Diagnosis and treatment
Tissue biopsy is the reference standard for quantitative culture; superficial swabs (Levine technique) sample surface flora and can mislead. Biofilm - a structured microbial community - is not the same as infection and is managed with repeated sharp debridement plus topical antimicrobials, not systemic antibiotics alone. Systemic antibiotics are for spreading or systemic infection and require culture-guided selection. Recognize sepsis as an emergency.
Traps
- Treating colonization or biofilm with systemic antibiotics.
- Assuming a wound is uninfected because pus is absent.
- Relying on a superficial swab to guide therapy for a deep wound.
- Missing atypical signs in immunosuppressed or diabetic patients, who may lack classic erythema and fever.
Rule of thumb
New pain plus stalled healing plus increasing exudate equals critical colonization until proven otherwise - increase local antimicrobial therapy and debridement before reaching for oral antibiotics.