The importance of fungi in the chronic-wound microbiome

While the role of microorganisms as pathogens of infection in wounds has centred in the majority around bacteria, fungi may also play a role. Kalan and colleagues report an approach using molecular techniques to amplify the Internal Transcribed Spacer (ITS1), a specific point on fungi DNA to identify the presence of fungi in wounds that have experienced delayed healing.

The authors summarise that fungi play a significant role and may act as pathogens of infection in diabetic foot wounds. They further identify that fungi interact with bacterial pathogens to form potential synergistic effects in causing a delay in wound healing or as co-pathogens of infection. The data presented are, however, difficult to interpret within the context of clinical management. Kalan and colleagues report the sampling of chronic wounds undertaken using the Levine technique with a swab. This culture method has been the subject of great debate in the diabetic foot arena, with opinions divided. Some expert groups promote tissue biopsy as the most appropriate sampling method for identifying pathogens of infection and for exploring both the microbiome and the role of biofilms. However, the use of swab samples from superficial tissue makes it difficult to ascertain whether any fungi identified merely resided on wound surfaces as colonizers or whether the fungi were invasive and involved deeper tissue (this may suggest a more pathogenic involvement).

At present the ability to grow fungi from routine wound samples is arduous and requires selective and exhaustive measures. For this reason the likelihood of clinicians adopting practices to identify fungi in wounds is probably going to remain limited.