Is a wound swab for microbiological analysis supportive in the clinical assessment of infection of a chronic wound?

A Host-Directed Approach to the Detection of Infection in Hard-to-Heal Wounds

Wound infection is traditionally defined primarily by visual clinical signs, and secondarily by microbiological analysis of wound samples. However, these approaches have serious limitations in determining wound infection status, particularly in early phases or complex, chronic, hard-to-heal wounds. Early or predictive patient-derived biomarkers of wound infection would enable more timely and appropriate intervention. The observation that immune activation is one of the earliest responses to pathogen activity suggests that immune markers may indicate wound infection earlier and more reliably than by investigating potential pathogens themselves. One of the earliest immune responses is that of the innate immune cells (neutrophils) that are recruited to sites of infection by signals associated with cell damage. During acute infection, the neutrophils produce oxygen radicals and enzymes that either directly or indirectly destroy invading pathogens. These granular enzymes vary with cell type but include elastase, myeloperoxidase, lysozyme, and cathepsin G. Various clinical studies have demonstrated that collectively, these enzymes, are sensitive and reliable markers of both early-onset phases and established infections. The detection of innate immune cell enzymes in hard-to-heal wounds at point of care offers a new, simple, and effective approach to determining wound infection status and may offer significant advantages over uncertainties associated with clinical judgement, and the questionable value of wound microbiology. Additionally, by facilitating the detection of early wound infection, prompt, local wound hygiene interventions will likely enhance infection resolution and wound healing, reduce the requirement for systemic antibiotic therapy, and support antimicrobial stewardship initiatives in wound care.

The diagnosis of infection in chronic leg ulcers: A narrative review on clinical practice

This literature review aimed to provide a narrative review of evidence on validity of clinical and microbial indicators of infection and to gain insights into the diagnosis of infection in chronic leg ulcers (CLUs). A search was conducted in Cinahl, Medline, the Cochrane Library databases, Embase, Web of Science, ScienceDirect, Pubmed, PsycINFO, ProQuest dissertations, and Google Scholar from January 1990 to July 2017. The inclusion criteria were original studies, systematic reviews, and consensus documents focused on "infection" in CLUs, English language, clinical and community settings, and human. The reviewed studies were inconsistent in criteria for infection between investigated wound types and lack of specificity regarding wound types. There were few studies investigating the criteria for diagnosis of infection in leg ulcers. The identification of leg ulcer infection still remains problematic and relies on out-of-date and not uniform evidence. Literature in this area was mostly limited to level III and IV evidence based on The Australian National Health and Medical Research Council Levels of Evidence, or expert opinion. This literature review showed seven clinical signs and symptoms that could be diagnostic for infection in CLUs, including: new, increased, or altered ulcer pain; malodour; increased ulcer area; wound breakdown, delayed or non-healing; and erythema and increased local temperature, whilst the microbial indicators used to diagnose infected leg ulcers were varied and regarded as less important.

The inter-rater reliability between nurse-assessors clinically assessing infection of chronic wounds using the WUWHS criteria

The aim of this study was to determine the inter-rater reliability between one expert-nurse and four clinical-nurses who were asked to clinically assess infection of chronic wounds by using the World Union of Wound Healing Societies (WUWHS) criteria. A quasi-experimental design was used to collect the data. In comparison to phase 1 in which 'open questions' were asked, in phase 2 a pre-printed form (checklist) was introduced. In both phases, 55 chronic wounds were clinically assessed. For each WUWHS criterion the inter-rater reliability of signs and symptoms was expressed by Cohens Kappa (κ). A substantial agreement (κ ≥ 0·6) was considered as adequate. In both phases pocketing (p < 0·02), and erythema (p < 0·004) scored statistically significant results. Phase 2 showed higher inter-rater agreements compared with phase 1 (three substantial agreements (easily bleeding/friable granulation tissue, delayed healing, increasing exudate), an almost perfect- and a perfect agreement for malodour and pain, respectively. According to the results it can be concluded that the clinical assessment of infection of chronic wounds may be better supported by a pre-printed form than making use of an 'open questions' form. To provide this with a higher level of evidence, there is need for more well conducted studies.