Invasive Mold Infections Following Trauma

Abstract & Commentary

By Dean L. Winslow, MD, FACP, FIDSA, Chairman, Department of Medicine, Santa Clara Valley, Medical Center; Clinical Professor, Stanford University School of Medicine, is Associate Editor for Infectious Disease Alert.

Dr. Winslow is a consultant for Siemens Diagnostic

Synopsis: Invasive mold infections were encountered in 37 patients following combat injuries sustained between June 2009 and December 2010. Mucorales, Aspergillus and Fusarium species predominated in this series. A second report describes 13 patients who developed necrotizing cutaneous Mucormycosis following injuries sustained in a tornado in Joplin, Missouri in 2011.

Sources: Warkentien T, et al. Invasive mold infections following combat-related injuries. CIin Infect Dis 2012; 55:1441-9.

Fanfair, RN, et al. Necrotizing cutaneous mucormycosis after a tornado in Joplin, Missouri, in 2011. New Engl Jrl Med 2012; 367:2214-25.

Thirty-seven cases of invasive fungal infection (IFI) were identified among US military personnel injured during combat in Afghanistan from June 2009-December 2010. Of these, 20 demonstrated histopathological angioinvasion, 4 showed nonvascular tissue invasion, and 13 had positive fungal cultures without histopathological evidence of tissue invasion. During the last quarter of 2010 rates of IFI reached 3.5% of trauma admissions. Blast injury was the etiology of injury in 100% of patients and occurred while conducting foot patrols in 92%. Ninety-four percent of the injuries were sustained in southern Afghanistan. Eighty percent sustained lower extremity amputation and 97% of patients underwent large volume blood transfusion. Mold isolates were recovered in 83% of cases (order Mucorales, n=16; Aspergillus species, n=16; Fusarium species, n=9; and multiple mold species in 28% of cases). Outcomes included 3 infection-related deaths (8%), additional debridements were required in 11 cases and amputation revisions in 58%.

Thirteen cases of invasive cutaneous Mucor infections were identified following the 2011 tornado which struck Joplin, Missouri. Five patients (38%) died. Case patients sustained a median of 5 wounds, 11 patients had at least 1 fracture, 9 sustained blunt trauma and 5 had penetrating trauma. Sequencing of D1-D2 region of 28S rDNA was consistent with Apophysomyces trapeziformis in all 13 case patients.

Commentary

Invasive fungal infections are emerging as an increasingly important trauma-related infection. In both case series extensive soft tissue and/or cutaneous trauma was the most important underlying factor. As in the recently-concluded war in Iraq, more than 75% of combat injuries and deaths in Afghanistan are due to blast injuries from improvised explosive devices (IED’s). In Iraq after about 2005 most of the serious injuries were due to sophisticated explosively-formed penetrator (EFP) devices (generally fielded by Iranian-backed Shia splinter groups) often triggered by passive infrared (PIR) windows and the injuries were often sustained by soldiers in tactical vehicles. In Afghanistan, apparently EFP’s are still relatively uncommon, but soldiers on dismounted (foot) patrols are commonly gravely injured by huge relatively primitive IED’s (Calcium ammonium nitrate is readily available for agricultural use in Afghanistan) with pressure-plate triggers. In both cases soldiers injured by IED’s often sustain multiple limb amputations and extensive burns.

Modern combat injury management includes aggressive debridement of devitalized tissue and irrigation, as often as every 48 hours with delayed wound closure. The 3.5% rate of IFI’s in this population seems remarkably low. Gross contamination of these wounds at the time of injury with dirt and other organic material is almost universal and is obviously the source of molds in these patients. While the 1.3% rate of IFI’s seen among the approximately 1,000 patients injured in the Joplin tornado seems low, it is probably comparable to the US military experience if controlled for degree of injury severity and soft tissue damage.

In any case, awareness of IFI as a complication of severe soft tissue injury is important. Appropriate management includes aggressive surgical debridement and when appropriate early institution of systemic antifungal therapy. Pending identification of the fungal pathogens in these cases, empiric use of both liposomal Amphotericin B plus an antifungal triazole such as voriconazole seems appropriate since Mucor species are often resistant to triazoles and Aspergillus terreus is resistant to Amphotericin B.