1. Introduction: The Renaissance of Wound Antisepsis
The medical community is currently experiencing a critical “renaissance” in the utilization of xenobiotic wound antiseptics. For much of the twentieth century, the initial euphoria surrounding penicillin and the subsequent development of systemic antibiotics led to a decline in antiseptic research. However, several modern clinical realities have necessitated a return to these agents.
The pandemic spread of multidrug-resistant organisms (MDROs) has severely curtailed the efficacy of traditional systemic treatments. Furthermore, the local application of antibiotics is increasingly contraindicated due to high rates of patient sensitization, concentrations that are difficult to adjust precisely, and the significant risk of promoting further resistance. In contrast, modern antiseptics offer a microbicidal—rather than microbiostatic—action, damaging pathogens irreversibly through unspecific mechanisms such as the destruction of the bacterial cell wall or blockage of negative surface charges.
The diagnostic priority for the clinician is to accurately distinguish between superficial critical colonization (the NERDS criteria) and deep or spreading infection (the STONEES criteria). This distinction dictates whether a wound requires local remediation or mandatory systemic escalation.
2. The Microbial Spectrum: From Contamination to Systemic Infection
Microorganisms interact with wound tissue across a spectrum of severity. The clinician must evaluate the wound according to the following classifications to determine the necessity of intervention.
| Term | Clinical Characteristics |
| Contamination | Microorganisms are present and attached to the tissue surface without initial proliferation. |
| Colonization | Microorganisms are present and proliferating, but a clinically significant immunological host reaction is absent. |
| Critical Colonization | The transition point between physiological colonization and pathological infection. Proliferation occurs without classical signs, but toxins cause stagnation. Includes MDRO-colonized wounds. |
| Local Infection | A manifest immunological host reaction. Diagnostic markers include swelling, local heat, pain, functional impairment, and erythema (1–2 cm measured from the wound margin) with a tendency to increase. |
| Systemic Infection | Local inflammatory reactions accompanied by a systemic host response, including fever, elevated C-reactive protein (CRP), and leukocytosis. |
3. Identifying Superficial Bioburden (The NERDS Criteria)
“Critical Colonization” represents a pathological state where microbial proliferation impairs healing despite the absence of classical infection markers. The clinician must evaluate the wound for the following superficial signs:
- N – Non-healing: Stagnation in a previously progressing wound or delayed healing.
- E – Exudate increase: An increase in the quantity of wound fluid or a perceptible change in its viscosity.
- R – Red, Friable Tissue: Granulation tissue that bleeds easily, often due to the impact of bacterial toxin production.
- D – Debris: The presence of slough or necrotic material on the wound surface.
- S – Smell: A perceptible, distinct odor emanating from the wound bed.
While these wounds lack deep tissue involvement, they require immediate microbiological remediation with topical antiseptics to return the wound to a physiological healing state.
4. Identifying Deep and Spreading Infection (The STONEES Criteria)
When microbes penetrate deeper tissues or trigger a systemic response, the clinical markers become more pronounced. These signs represent a high risk of sepsis and tissue loss.
- S – Size increasing: Unexpected expansion of the wound dimensions.
- T – Temperature: Increased local skin/tissue temperature at the site.
- O – Osteitis/Deep Structures: Wounds connected to organs, joints, or where bone is exposed/probed.
- N – New areas of breakdown: Satellite lesions or new undermining of the wound edges.
- E – Erythema: Significant redness extending 1–2 cm from the wound margin with an observable tendency to spread.
- E – Edema: Marked swelling and induration of the surrounding tissue.
- S – Smell: Intense malodor associated with deep tissue necrosis.
Systemic Markers: If the infection spreads, markers such as fever, leukocytosis, and elevated CRP are mandatory indicators for systemic intervention.
5. Risk Assessment: The Wounds-at-Risk (WAR) Score
To determine when prophylactic or therapeutic antisepsis is justified, the clinician should utilize the WAR Score.
Summary of Risk Factors (Table 3):
- 1 Point Factors: Diabetes mellitus; age >80 years; premature infants/babies; wounds persisting >1 year; size >10 cm²; chronic wounds with a depth >1.5 cm; extended inpatient status >3 weeks; problematic hygiene.
- 2 Point Factors: Severe acquired immune defects (e.g., HIV); heavily contaminated acute wounds; bite/stab injuries penetrating 1.5–3.5 cm.
- 3 Point Factors: Severe innate immunodeficiency (e.g., Wiskott-Aldrich); stem cell transplantation; burns >15% BSA; wounds connected to organs/joints; bite/stab injuries penetrating >3.5 cm.
Clinical Threshold: Antiseptic treatment is clinically justified if the WAR Score reaches or exceeds 3 points.
6. Bedside Application: Choosing the Antiseptic Agent
Selection must be based on tissue compatibility and the specific clinical scenario. As a research-based rule of thumb (the “Eye Test”), clinicians should not apply anything to chronic wounds that should not be applied to the eyes.
| Antiseptic Agent | Clinical Indications | Researcher Notes |
| Polihexanide (PHMB) | 1st Choice: Infected chronic wounds and 2nd-degree burns. | A “virtually detoxified CHD” (lacks 4-chloroaniline). No systemic absorption. Efficacy increases as wound pH rises (6.5–8.5). |
| Octenidine (OCT) | 1st Choice: MDRO decolonization and acute traumatic wounds. | 0.05% concentration preferred for chronic wounds, combined with surface-active ethylhexylglycerin for enhanced wetting. |
| Hypochlorite (NaOCl/HOCl) | 1st Choice: Intensive cleansing, peritoneal lavage, and risk of CNS exposure. | Superior for wounds lacking drainage or when deep structures (peritoneum/CNS) are involved. |
| PVP-Iodine | 1st Choice: Acute bite, stab, and gunshot wounds. | Combined with alcohol for deep penetration. Avoid repeated use in chronic wounds due to cytotoxicity. |
7. Escalation Logic: Topical vs. Systemic Therapy
A clear boundary must be maintained to preserve antibiotic efficacy and prevent patient sensitization.
The Clinical Rule: Local application of antibiotics for confined wound infections or colonization must be strictly avoided. Furthermore, following the guidelines of the German Society for Wound Healing, microbiological diagnostics (swabs) should only be performed if there are signs of a systemic infectious event.
Mandatory Systemic Escalation: Systemic antibiotics are required ONLY when the infection spreads (e.g., positive blood cultures, fever, or systemic host reactions). In these instances, they must always be used in combination with topical antiseptics.
8. Clinical Decision Tree: Therapeutic Pathways
- Assess Wound: Evaluate against NERDS and STONEES criteria.
- Calculate WAR Score: If ≥ 3, initiate antiseptic treatment.
- Determine Intervention Depth:
- Superficial/Critical Colonization: Use 1st choice topical antiseptics (PHMB or OCT).
- Local Infection: Use 1st choice topical agents; reassess progress at 2 weeks. If unsuccessful, the clinician must reassess the underlying etiology and local blood flow.
- Systemic Signs: Escalate to Systemic Antibiotics + Topical Antiseptics.
- Special Considerations: Utilize Hypochlorite if drainage is insufficient or if the CNS/peritoneum is exposed.
9. Clinical Caveats and Safety Rules
- Diagnostic Priority: Correct diagnosis of etiology is paramount; antiseptics cannot compensate for unaddressed vascular insufficiency.
- Mandatory Debridement: Antiseptics are ineffective against microbes shielded by slough, debris, or biofilm.
- Meticulous Aseptic Technique: Meticulous antiseptic rules must be followed during every dressing change.
Critical Safety Warning for Octenidine (OCT): The clinician is strictly forbidden from applying Octenidine under pressure (e.g., via syringe) into deep tissue, puncture wounds, or cavities without guaranteed drainage. Such misapplication has been documented to cause aseptic necrosis and edematous swelling requiring surgical revision. Application must be limited to superficial swabbing or spraying.