Diagnostic criteria for an IFI are:
- Presence of a traumatic wound(s).
- Recurrent necrosis following at least two consecutive surgical debridements.
- Laboratory evidence of fungal infection following at least two surgical debridements (i.e. mold culture positivity and/or histopathology indicating tissue invasion).9,15 This is usually not available at deployed Role 2 or Role 3 Military Treatment Facilities (MTFs), so clinical suspicion is key to early intervention.
- Fungal wound infection is often manifested by ‘tinctorial’ or color changes in a wound; early detection of such changes requires repeated inspection by an experienced clinician.18
- IFIs are often diagnosed through routine histopathological examination of tissue specimens. The evaluation of the performance of periodic acid-Schiff (PAS) and Gomori methenamine silver (GMS) in combat trauma-associated IFI demonstrated that the two stains were 84% concordant with false negative rates of 44% for PAS and 15% for GMS; however, neither stain was significantly superior at identifying fungal elements. Overall, there is no added benefit for increasing diagnostic yield with use of both stains.19
- Where available, pan-fungal PCR, for identification of filamentous fungi evaluation offers promise for rapid identification of IFI which can lead to a more timely and accurate diagnosis. Compared to histopathology, panfungal PCR was specific (99%), but not as sensitive (63%); however, sensitivity improved to 83% in specimens from sites with angioinvasion.19