Wound infection under occlusive dressings.

It is often supposed that occlusive dressings potentiate wound infection. However, even though heavy colonization by skin and wound flora is often seen under certain types of occlusion, clinical infection is not a frequent occurrence. Commensal wound flora consists of a variety of Gram-positive and Gram-negative organisms and fungi which do not appear to be detrimental to healing. Certain aspects of wound healing may in fact be promoted by bacterial colonization, although clinical infection can lead to wound breakdown and systemic infection. Wounds compromised by devitalized tissue, drains or sutures are more susceptible than clean wounds to clinical infection. Occlusive dressings may help prevent infection by presenting a barrier to potential pathogens, and hydrocolloid occlusive dressings have been shown to prevent dissemination of methicillin-resistant Staphylococcus aureus. The rate of clinical infection as deduced from published trials of dressings is lower under occlusion than when non-occlusive dressings are used, and this is likely to be a result of normal activity of the host defences under occlusive dressings.