Effect of early screening for invasive fungal infections in U.S. service members with explosive blast injuries

A Seminested PCR Method for the Diagnosis of Invasive Fungal Infections in Combat Injured

Background

Among combat injured, invasive fungal infections (IFIs) result in significant morbidity. Cultures and histopathology are the primary diagnostic methods for IFIs, but they have limitations. We previously evaluated a panfungal polymerase chain reaction assay, which was 83% sensitive and 99% specific for angioinvasive IFIs. Here, we evaluated 3 less resource-intensive seminested assays targeting clinically relevant fungi in the order Mucorales and genera Aspergillus and Fusarium.

Methods

Formalin-fixed paraffin-embedded tissue specimens from a multicenter trauma IFI cohort (2009-2014) were used. Cases were US military personnel injured in Afghanistan with histopathologic IFI evidence. Controls were patients with similar injury patterns and no laboratory IFI evidence (negative culture and histopathology). Seminested assays specific to Mucorales (V4/V5 regions of 18S rDNA), Aspergillus (mitochondrial tRNA), and Fusarium (internal transcribed spacer [ITS]/28A regions of DNA) were compared with a panfungal assay amplifying the internal transcribed spacer 2 region of rDNA and to histopathology.

Results

Specimens from 92 injury sites (62 subjects) were compared with control specimens from 117 injuries (101 subjects). We observed substantial agreement between the seminested and panfungal assays overall, especially for the order Mucorales. Moderate agreement was observed at the genus level for Aspergillus and Fusarium. When compared with histopathology, sensitivity and specificity of seminested assays were 67.4% and 96.6%, respectively (sensitivity increased to 91.7% when restricted to sites with angioinvasion).

Conclusions

Prior studies of seminested molecular diagnostics have focused on culture-negative samples from immunocompromised patients. Our findings underscore the utility of the seminested approach in diagnosing soft-tissue IFIs using formalin-fixed paraffin-embedded tissue samples, especially with angioinvasion.

Development of a Combat-Relevant Murine Model of Wound Mucormycosis: A Platform for the Pre-Clinical Investigation of Novel Therapeutics for Wound-Invasive Fungal Diseases

Wound-invasive fungal diseases (WIFDs), especially mucormycosis, have emerged as life-threatening infections during recent military combat operations. Many combat-relevant fungal pathogens are refractory to current antifungal therapy. Therefore, animal models of WIFDs are urgently needed to investigate new therapeutic solutions. Our study establishes combat-relevant murine models of wound mucormycosis using Rhizopus arrhizus and Lichtheimia corymbifera, two Mucorales species that cause wound mucormycosis worldwide. These models recapitulate the characteristics of combat-related wounds from explosions, including blast overpressure exposure, full-thickness skin injury, fascial damage, and muscle crush. The independent inoculation of both pathogens caused sustained infections and enlarged wounds. Histopathological analysis confirmed the presence of necrosis and fungal hyphae in the wound bed and adjacent muscle tissue. Semi-quantification of fungal burden by colony-forming units corroborated the infection. Treatment with liposomal amphotericin B, 30 mg/kg, effectively controlled R. arrhizus growth and significantly reduced residual fungal burden in infected wounds (p < 0.001). This study establishes the first combat-relevant murine model of wound mucormycosis, paving the way for developing and evaluating novel antifungal therapies against combat-associated WIFDs.

Hyphae of Rhizopus arrhizus and Lichtheimia corymbifera Are More Virulent and Resistant to Antifungal Agents Than Sporangiospores In Vitro and in Galleria mellonella

Mucorales species cause debilitating, life-threatening sinopulmonary diseases in immunocompromised patients and penetrating wounds in trauma victims. Common antifungal agents against mucormycosis have significant toxicity and are often ineffective. To evaluate treatments against mucormycosis, sporangiospores are typically used for in vitro assays and in pre-clinical animal models of pulmonary infections. However, in clinical cases of wound mucormycosis caused by traumatic inoculation, hyphal elements found in soil are likely the form of the inoculated organism. In this study, Galleria mellonella larvae were infected with either sporangiospores or hyphae of Rhizopus arrhizus and Lichtheimia corymbifera. Hyphal infections resulted in greater and more rapid larval lethality than sporangiospores, with an approximate 10-16-fold decrease in LD50 of hyphae for R. arrhizus (p = 0.03) and L. corymbifera (p = 0.001). Liposomal amphotericin B, 10 mg/kg, was ineffective against hyphal infection, while the same dosage was effective against infections produced by sporangiospores. Furthermore, in vitro, antifungal susceptibility studies show that minimum inhibitory concentrations of several antifungal agents against hyphae were higher when compared to those of sporangiospores. These findings support using hyphal elements of Mucorales species for virulence testing and antifungal drug screening in vitro and in G. mellonella for studies of wound mucormycosis.

Invasive Non-Candida Fungal Infections in Acute Burns-A 13-Year Review of a Single Institution and Review of the Literature

The past decade has demonstrated increased burn wound infections with atypical invasive fungal organisms. The range of previously regiospecific organisms has expanded, and plant pathogens are increasingly represented. Our institution sought to examine changes in severe fungal non-Candida infections in our patients, via retrospective review of patients admitted to our burn center from 2008 to 2021. We identified 37 patients with atypical invasive fungal infections. Non-Candida genera included Aspergillus (23), Fusarium (8), Mucor (6), and 13 cases of 11 different species, including the second-ever human case of Petriella setifera. Three fungi were resistant to at least one antifungal. Concomitant infections included Candida (19), Staphylococcus and Streptococcus (14), Enterococcus and Enterobacter (13), Pseudomonas (9), and 14 additional genera. Complete data was available for 18 patients, who had a median of 3.0 (IQR 8.5, range 0-15) additional bacteria required a median of 1 (IQR 7, range 0-14) systemic antibacterials and 2 (IQR 2.5, range 0-4) systemic antifungals. One case of total-drug-resistant Pseudomonas aeruginosa required bacteriophage treatment. One case of Treponema pallidum was found in infected burn wound tissue. Every patient required Infectious Disease consultation. Eight patients became bacteremic and one developed Candida fermentatifungemia. There were five patient deaths (13.8%), all due to overwhelming polymicrobial infection. Burn patients with atypical invasive fungal infections can have severe concomitant polymicrobial infections and multidrug resistance with fatal results. Early Infectious Disease consultation and aggressive treatment is critical. Further characterization of these patients may provide better understanding of risk factors and ideal treatmentpatterns.

Humicola Trauma-related Invasive Fungal Infection in an Immunocompetent Patient

The majority of invasive fungal infections arise in immunocompromised patients; however, there exist many clinical interventions and physiologic phenomena in the setting of traumatic injury that induce immunosuppressant states. Enhanced clinical suspicion and early detection of invasive fungal infections has played an increasingly pertinent role in clinical management of patients admitted for traumatic injury, given its substantial morbidity and mortality rates. In this case report, we discuss a case of trauma-related invasive fungal infection by a rare humicola pathogen in a previously immunocompetent patient. We present this case in hopes of instilling a high index of clinical suspicion for trauma-related invasive fungal infections. We also discuss the role of negative pressure wound therapy and aggressive surgical management, including debridement and various levels of amputation to optimize patient outcomes. Clinical management of trauma-related IFI has adopted increasingly aggressive approaches with respect to its formidable morbidity and mortality rates. Multidisciplinary discussions and patient-centered care are essential when making surgical decisions that impact quality of life such as amputation level.

Proposed Treatment Algorithm for Invasive Fungal Infections in Trauma Patients

Background: Invasive fungal infections, most commonly caused by Mucorales species, are an underrecognized sequalae of traumatic injury that can complicate management of patients. The injury mechanism can introduce environmental spores into areas of the body normally not exposed to pathogens and this inoculation can progress rapidly to severe disease. The objective of this study was to present a case series of four trauma patients with invasive fungal infections that was used to develop an algorithm for work-up and treatment of these complex patients in future admissions. Patients and Methods: Four trauma patients who developed mucormycosis from two different hospitals are presented. One patient succumbed to their injuries whereas three were able to clear their infection with medical and surgical intervention. The surviving patients all had an infection of their lower extremity whereas the deceased patient had more extensive disease involving the thorax. Conclusions: Mucormycosis is a rare but significant post-trauma complication with substantial morbidity and mortality. Surgeons should be aware of this complication and maintain a high clinical suspicion because afflicted patients may not match the traditional clinical picture of a mucormycosis-susceptible patient. Close coordination with a pathology service is required for confirmation of the diagnosis and timely intervention can prevent debilitating loss of tissue or death. Additionally, consideration should be given to newer treatment modalities for management such as local tissue irrigation with an antifungal agent.

Department of Defense Trauma Registry Infectious Disease Module Impact on Clinical Practice

BACKGROUND

The Joint Trauma System (JTS) is a DoD Center of Excellence for Military Health System trauma care delivery and the DoD's reference body for trauma care in accordance with National Defense Authorization Act for Fiscal Year 2017. Through the JTS, evidence-based clinical practice guidelines (CPGs) have been developed and subsequently refined to standardize and improve combat casualty care. Data are amassed through a single, centralized DoD Trauma Registry to support process improvement measures with specialty modules established as the registry evolved. Herein, we review the implementation of the JTS DoD Trauma Registry specialty Infectious Disease Module and the development of infection-related CPGs and summarize published findings on the subsequent impact of the Infectious Disease Module on combat casualty care clinical practice and guidelines.

METHODS

The DoD Trauma Registry Infectious Disease Module was developed in collaboration with the Infectious Disease Clinical Research Program (IDCRP) Trauma Infectious Disease Outcomes Study (TIDOS). Infection-related information (e.g., syndromes, antibiotic management, and microbiology) were collected from military personnel wounded during deployment June 1, 2009 through December 31, 2014 and medevac'd to Landstuhl Regional Medical Center in Germany before transitioning to participating military hospitals in the USA.

RESULTS

To support process improvements and reduce variation in practice patterns, data collected through the Infectious Disease Module have been utilized in TIDOS analyses focused on assessing compliance with post-trauma antibiotic prophylaxis recommendations detailed in JTS CPGs. Analyses examined compliance over three time periods: 6 months, one-year, and 5 years. The five-year analysis demonstrated significantly improved adherence to recommendations following the dissemination of the 2011 JTS CPG, particularly with open fractures (34% compliance compared to 73% in 2013-2014). Due to conflicting recommendations regarding use of expanded Gram-negative coverage with open fractures, infectious outcomes among patients with open fractures who received cefazolin or expanded Gram-negative coverage (cefazolin plus fluoroquinolones and/or aminoglycosides) were also examined in a TIDOS analysis. The lack of a difference in the proportion of osteomyelitis (8% in both groups) and the significantly greater recovery of Gram-negative organisms resistant to aminoglycosides or fluoroquinolones among patients who received expanded Gram-negative coverage supported JTS recommendations regarding the use of cefazolin with open fractures. Following recognition of the outbreak of invasive fungal wound infections (IFIs) among blast casualties injured in Afghanistan, the ID Module was refined to capture data (e.g., fungal culture and histopathology findings, wound necrosis, and antifungal management) needed for the TIDOS team to lead the DoD outbreak investigation. These data captured through the Infectious Disease Module provided support for the development of a JTS CPG for the prevention and management of IFIs, which was later refined based on subsequent TIDOS IFI analyses.

CONCLUSIONS

To improve combat casualty care outcomes and mitigate high-consequence infections in future conflicts, particularly in the event of prolonged field care, expansion, refinement, and a mechanism for sustainability of the DoD Trauma Registry Infectious Disease Module is needed to include real-time surveillance of infectious disease trends and outcomes.

Combat-Related Invasive Fungal Wound Infections

INTRODUCTION

During Operation Enduring Freedom in Afghanistan, an outbreak of combat-related invasive fungal wound infections (IFIs) emerged among casualties with dismounted blast trauma and became a priority issue for the Military Health System.

METHODS

In 2011, the Trauma Infectious Disease Outcomes Study (TIDOS) team led the Department of Defense IFI outbreak investigation to describe characteristics of IFIs among combat casualties and provide recommendations related to management of the disease. To support the outbreak investigation, existing IFI definitions and classifications utilized for immunocompromised patients were modified for use in epidemiologic research in a trauma population. Following the conclusion of the outbreak investigation, multiple retrospective analyses using a population of 77 IFI patients (injured during June 2009 to August 2011) were conducted to evaluate IFI epidemiology, wound microbiology, and diagnostics to support refinement of Joint Trauma System (JTS) clinical practice guidelines. Following cessation of combat operations in Afghanistan, the TIDOS database was comprehensively reviewed to identify patients with laboratory evidence of a fungal infection and refine the IFI classification scheme to incorporate timing of laboratory fungal evidence and include categories that denote a high or low level of suspicion for IFI. The refined IFI classification scheme was utilized in a large-scale epidemiologic assessment of casualties injured over a 5.5-year period.

RESULTS

Among 720 combat casualties admitted to participating hospitals (2009-2014) who had histopathology and/or wound cultures collected, 94 (13%) met criteria for an IFI and 61 (8%) were classified as high suspicion of IFI. Risk factors for development of combat-related IFIs include sustaining a dismounted blast injury, experiencing a traumatic transfemoral amputation, and requiring resuscitation with large-volume (>20 units) blood transfusions. Moreover, TIDOS analyses demonstrated the adverse impact of IFIs on wound healing, particularly with order Mucorales. A polymerase chain reaction (PCR)-based assay to identify filamentous fungi and support earlier IFI diagnosis was also assessed using archived formalin-fixed, paraffin-embedded tissue specimens. Although the PCR-based assay had high specificity (99%), there was low sensitivity (63%); however, sensitivity improved to 83% in tissues collected from sites with angioinvasion. Data obtained from the initial IFI outbreak investigation (37 IFI patients) and subsequent TIDOS analyses (77 IFI patients) supported development and refinement of a JTS clinical practice guideline for the management of IFIs in war wounds. Furthermore, a local clinical practice guideline to screen for early tissue-based evidence of IFIs among blast casualties at the Landstuhl Regional Medical Center was critically evaluated through a TIDOS investigation, providing additional clinical practice support. Through a collaboration with the Uniformed Services University Surgical Critical Care Initiative, findings from TIDOS analyses were used to support development of a clinical decision support tool to facilitate early risk stratification.

CONCLUSIONS

Combat-related IFIs are a highly morbid complication following severe blast trauma and remain a threat for future modern warfare. Our findings have supported JTS clinical recommendations, refined IFI classification, and confirmed the utility of PCR-based assays as a complement to histopathology and/or culture to promote early diagnosis. Analyses underway or planned will add to the knowledge base of IFI epidemiology, diagnostics, prevention, and management.

Guidelines for the acute care of severe limb trauma patients

GOAL

To provide healthcare professionals with comprehensive multidisciplinary expert recommendations for the acute care of severe limb trauma patients, both during the prehospital phase and after admission to a Trauma Centre.

DESIGN

A consensus committee of 21 experts was formed. A formal conflict-of-interest (COI) policy was developed at the onset of the process and enforced throughout. The entire guidelines process was conducted independently of any industrial funding (i.e., pharmaceutical, medical devices). The authors were advised to follow the rules of the Grading of Recommendations Assessment, Development and Evaluation (GRADE®) system to guide assessment of the quality of evidence. The potential drawbacks of making strong recommendations in the presence of low-quality evidence were emphasised. Few recommendations remained non-graded.

METHODS

The committee addressed eleven questions relevant to the patient suffering severe limb trauma: 1) What are the key findings derived from medical history and clinical examination which lead to the patient's prompt referral to a Level 1 or Level 2 Trauma Centre? 2) What are the medical devices that must be implemented in the prehospital setting to reduce blood loss? 3) Which are the clinical findings prompting the performance of injected X-ray examinations? 4) What are the ideal timing and modalities for performing fracture fixation? 5) What are the clinical and operative findings which steer the surgical approach in case of vascular compromise and/or major musculoskeletal attrition? 6) How to best prevent infection? 7) How to best prevent thromboembolic complications? 8) What is the best strategy to precociously detect and treat limb compartment syndrome? 9) How to best and precociously detect post-traumatic rhabdomyolysis and prevent rhabdomyolysis-induced acute kidney injury? 10) What is the best strategy to reduce the incidence of fat emboli syndrome and post-traumatic systemic inflammatory response? 11) What is the best therapeutic strategy to treat acute trauma-induced pain? Every question was formulated in a PICO (Patient Intervention Comparison Outcome) format and the evidence profiles were produced. The literature review and recommendations were made according to the GRADE® methodology.

RESULTS

The experts' synthesis work and the application of the GRADE method resulted in 19 recommendations. Among the formalised recommendations, 4 had a high level of evidence (GRADE 1+/-) and 12 had a low level of evidence (GRADE 2+/-). For 3 recommendations, the GRADE method could not be applied, resulting in an expert advice. After two rounds of scoring and one amendment, strong agreement was reached on all the recommendations.

CONCLUSIONS

There was significant agreement among experts on strong recommendations to improve practices for severe limb trauma patients.

Combat trauma-related invasive fungal wound infections

Purpose of review

This review highlights research from the past five years on combat trauma-related invasive fungal wound infections (IFIs) with a focus on risk stratification to aid patient management, microbiology, and diagnostics.

Recent Findings

A revised classification scheme stratifies wounds into three risk groups: IFI, High Suspicion of IFI, and Low Suspicion of IFI. This stratification is based on persistence of wound necrosis and laboratory fungal evidence, presence of signs/symptoms of deep soft-tissue infections, and the need for antifungals. Use of this classification could allow for prioritization of antifungal therapy. Further, IFIs delay wound healing, particularly when caused by fungi of the order Mucorales. Lastly, molecular sequencing offers promising and complimentary results to the gold standard histopathology.

Summary

Optimal management of combat-related IFIs depends on early tissue-based diagnosis with aggressive surgical debridement and concomitant dual antifungal therapy. Further research on clinical decision support tools and rapid diagnostics are needed.

Mould Infections of Traumatic Wounds: A Brief Narrative Review

Mould infections may follow traumatic injuries, with direct fungal inoculum in the site of injury and subsequent angioinvasion, possibly resulting in tissue necrosis and systemic dissemination. The pathogenesis of mould infections following trauma injuries presents unique features compared with classical mould infections occurring in neutropenic or diabetic patients, because a large fraction of post-traumatic mould infections is observed in previously healthy individuals. Most of the published clinical experience and research on mould infections following traumatic injuries regards soldiers and infections after natural disasters. However, following trauma and soil contamination (e.g., agricultural or automotive injuries) other immunocompetent individuals may develop mould infections. In these cases, delays in correct diagnosis and treatment may occur if pertinent signs such as necrosis and absent or reduced response to antibacterial therapy are not promptly recognized. Awareness of mould infections in at-risk populations is needed to rapidly start adequate laboratory workflow and early antifungal therapy in rapidly evolving cases to improve treatment success and reduce mortality.

Classification of Trauma-Associated Invasive Fungal Infections to Support Wound Treatment Decisions

The proposed classification, based on diagnostic certainty, provides a framework for determining initial empiric and subsequent targeted therapy.

To evaluate a classification system to support clinical decisions for treatment of contaminated deep wounds at risk for an invasive fungal infection (IFI), we studied 246 US service members (413 wounds) injured in Afghanistan (2009–2014) who had laboratory evidence of fungal infection. A total of 143 wounds with persistent necrosis and laboratory evidence were classified as IFI; 120 wounds not meeting IFI criteria were classified as high suspicion (patients had localized infection signs/symptoms and had received antifungal medication for >10 days), and 150 were classified as low suspicion (failed to meet these criteria). IFI patients received more blood than other patients and had more severe injuries than patients in the low-suspicion group. Fungi of the order Mucorales were more frequently isolated from IFI (39%) and high-suspicion (21%) wounds than from low-suspicion (9%) wounds. Wounds that did not require immediate antifungal therapy lacked necrosis and localized signs/symptoms of infection and contained fungi from orders other than Mucorales.

Molecular Detection of Filamentous Fungi in Formalin-Fixed Paraffin-Embedded Specimens in Invasive Fungal Wound Infections Is Feasible with High Specificity

Trauma-related invasive fungal wound infections (IFIs) are associated with significant morbidity and mortality. Early identification and treatment are critical. Traditional identification methods (e.g., fungal cultures and histopathology) can be delayed and insensitive. We assessed a PCR-based sequencing assay for rapid identification of filamentous fungi in formalin-fixed paraffin-embedded (FFPE) specimens obtained from combat casualties injured in Afghanistan. Blinded FFPE specimens from cases (specimens positive on histopathology) and controls (specimens negative on histopathology) were submitted for evaluation with a panfungal PCR. The internal transcribed spacer 2 (ITS2) region of the fungal ribosomal repeat was amplified and sequenced. The PCR results were compared with findings from histopathology and/or culture. If injury sites contributed multiple specimens, findings for the site were collapsed to the site level. We included 64 case subjects (contributing 95 sites) and 102 controls (contributing 118 sites). Compared to histopathology, panfungal PCR was specific (99%), but not as sensitive (63%); however, sensitivity improved to 83% in specimens from sites with angioinvasion. Panfungal PCR identified fungi of the order Mucorales in 33 of 44 sites with angioinvasion (75%), whereas fungal culture was positive in 20 of 44 sites (45%). Saksenaea spp. were the dominant fungi identified by PCR in specimens from angioinvasion sites (57%). Panfungal PCR is specific, albeit with lower sensitivity, and performs better at identifying fungi of the order Mucorales than culture. DNA sequencing offers significant promise for the rapid identification of fungal infection in trauma-related injuries, leading to more timely and accurate diagnoses.

Severe fungal infections following blunt traumatic injuries: A 5-year multicenter descriptive study

INTRODUCTION

The aggressive and timely treatment of post-traumatic fungal infections is the most efficacious way to reduce morbidity and mortality. Compared to the military trauma population, studies reporting on fungal infections in civilian trauma are not well described. The purpose of this study was to describe characteristics of civilian trauma patients who developed fungal infections and to identify common risk factors and report any delays between injury and treatment.

METHODS

This was a five-year (1/1/2013-3/1/2018) retrospective, descriptive study across six level 1 trauma centers. All consecutively admitted trauma patients (≥18 years) with laboratory-confirmed fungal wound infections were included. Patients with solely candida wound isolates were excluded. Patient demographics, clinical wound and infection characteristics, organisms cultured, treatment modalities, length of stay, in-hospital mortality, and any diagnostic or treatment delays were described.

RESULTS

Of the 54,521 trauma patients screened for fungal infection, 12 were identified. All patients suffered major injuries after blunt trauma (abbreviated injury score 3-5) and sustained wound contamination, and in nine patients, the cause of injury was motor vehicle. Six had open wounds/fractures on admission. The geographical region with the highest rate of fungal infection was Texas (n = 7), followed by Kansas (N = 3), then Missouri (N = 2). First symptoms of infection (leukocytosis or fever (n = 10)) presented a median of 6.3 (4.1-9.8) days after injury. Wound management entailed a combination of debridements (n = 8), negative pressure wound therapy (n = 9), amputation (n = 6), and antifungal treatment (n = 10). All fungal isolates identified from the wound site were hyphomycetes. A median of 2.1 (1.8-4.0) days passed from diagnosis to first antifungal treatment, and 3 patients died.

CONCLUSIONS

Our study shows the challenges surrounding diagnosis and treatment of fungal infections secondary to trauma. Non-specific fungal infection symptoms, such as leukocytosis and fever, typically presented a week after injury. Vigilance for investigating risk factors and infection symptoms may help clinicians with more timely management of trauma patients with a severe fungal infection.

After the Battlefield: Infectious Complications among Wounded Warriors in the Trauma Infectious Disease Outcomes Study

INTRODUCTION

During recent wars in Iraq and Afghanistan, improved survivability in severe trauma corresponded with a rise in the proportion of trauma-related infections, including those associated with multidrug-resistant organisms (MDROs). Significant morbidity was reported in association with the infections. There is also concern regarding potential long-term impacts of the trauma-related infectious complications. Therefore, to meet the critical need of prospective collection of standardized infection-related data to understand the disease burden and improve outcomes of wounded personnel, the Trauma Infectious Disease Outcomes Study (TIDOS) was developed. Herein, we review accomplishments and key peer-reviewed findings of TIDOS.

METHODS

The TIDOS project is a multicenter observational study of short- and long-term infectious complications following deployment-related trauma. Wounded military personnel medevac'd to Landstuhl Regional Medical Center (LRMC; Germany) before transfer to a participating US military hospital between June 2009 and December 2014 were eligible for inclusion. An infectious disease module to supplement the Department of Defense Trauma Registry by collecting infection-related data from all trauma patients admitted to participating hospitals was developed. Specimens from trauma patients were also collected and retained in a microbiological isolate repository. During the initial hospitalization, patients were given the opportunity to enroll in a prospective follow-up cohort study. Patients who received Department of Veterans Affairs (VA) care were also given the opportunity to consent to ongoing VA follow-up.

RESULTS

A total of 2,699 patients transferred to participating military hospitals in the USA, of which 1,359 (50%) patients enrolled in the TIDOS follow-up cohort. In addition, 638 enrolled in the TIDOS-VA cohort (52% of TIDOS enrollees who entered VA healthcare). More than 8,000 isolates were collected from infection control surveillance and diagnostic evaluations and retained in the TIDOS Microbiological Repository. Approximately 34% of the 2,699 patients at US hospitals developed a trauma-related infection during their initial hospitalization with skin and soft-tissue infections being predominant. After discharge from the US hospitals, approximately one-third of TIDOS cohort enrollees developed a new trauma-related infection during follow-up and extremity wound infections (skin and soft-tissue infections and osteomyelitis) continued to be the majority. Among TIDOS cohort enrollees who received VA healthcare, 38% developed a new trauma-related infection with the incident infection being diagnosed a median of 88 days (interquartile range: 19-351 days) following hospital discharge. Data from TIDOS have been used to support the development of Joint Trauma System clinical practice guidelines for the prevention of combat-related infections, as well as the management of invasive fungal wound infections. Lastly, due to the increasing proportion of infections associated with MDROs, TIDOS investigators have collaborated with investigators across military laboratories as part of the Multidrug-Resistant and Virulent Organisms Trauma Infections Initiative with the objective of improving the understanding of the complex wound microbiology in order to develop novel infectious disease countermeasures.

CONCLUSIONS

The TIDOS project has focused research on four initiatives: (1) blast-related wound infection epidemiology and clinical management; (2) DoD-VA outcomes research; (3) Multidrug- Resistant and other Virulent Organisms Trauma Infections Initiative; and (4) Joint Trauma System clinical practice guidelines and antibiotic stewardship. There is a continuing need for longitudinal data platforms to support battlefield wound research and clinical practice guideline recommendation refinement, particularly to improve care for future conflicts. As such, maintaining a research platform, such as TIDOS, would negate the lengthy time needed to initiate data collection and analysis.

Necrotizing Mucormycosis of Wounds Following Combat Injuries, Natural Disasters, Burns, and Other Trauma

Necrotizing mucormycosis is a devastating complication of wounds incurred in the setting of military (combat) injuries, natural disasters, burns, or other civilian trauma. Apophysomyces species, Saksenaea species and Lichtheimia (formerly Absidia) species, although uncommon as causes of sinopulmonary mucormycosis, are relatively frequent agents of trauma-related mucormycosis. The pathogenesis of these infections likely involves a complex interaction among organism, impaired innate host defenses, and biofilms related to traumatically implanted foreign materials. Effective management depends upon timely diagnosis, thorough surgical debridement, and early initiation of antifungal therapy.

Post-traumatic fatal disseminated Apophysomyces elegans infection

Mucorales infections typically occur in immunocompromised hosts. We describe a case of disseminated post-traumatic Apophysomyces elegans in an immunocompetent patient status-post soil inoculation. Fungi introduced at a deep arm laceration leads to neurovascular invasion and dissemination prior to amputation and systemic treatment. We specify strict post-traumatic wound surveillance protocol and roles of novel tissue tests to improve time to diagnosis and prognosis of frequently fatal post-traumatic Mucorales infections.

Invasive Fungal Infections Secondary to Traumatic Injury

Invasive fungal infection (IFI) is a rare but serious complication of traumatic injury. The purpose of this article is to review the epidemiology, natural history, mycology, risk factors, diagnosis, treatment, and outcomes associated with post-traumatic IFI in military and civilian populations. The epidemiology of post-traumatic IFI is poorly characterized, but incidence appears to be rising. Patients often suffer from severe injuries and require extensive medical interventions. Fungi belonging to the order Mucorales are responsible for most post-traumatic IFI in both civilian and military populations. Risk factors differ between these cohorts but include specific injury patterns and comorbidities. Diagnosis of post-traumatic IFI typically follows positive laboratory results in the appropriate clinical context. The gold standard of treatment is surgical debridement in addition to systemic antifungal therapy. Patients with post-traumatic IFI may be at greater risk of amputation, delays in wound healing, hospital complications, and death as compared to trauma patients who do not develop IFI. More research is needed to understand the factors surrounding the development and management of post-traumatic IFI to reduce the significant morbidity and mortality associated with this disease.

In Vitro activity of Manuka Honey and polyhexamethylene biguanide on filamentous fungi and toxicity to human cell lines

Soft-tissue invasive fungal infections are increasingly recognized as significant entities directly contributing to morbidity and mortality. They complicate clinical care, requiring aggressive surgical debridement and systemic antifungal therapy. To evaluate new topical approaches to therapy, we examined the antifungal activity and cytotoxicity of Manuka Honey (MH) and polyhexamethylene biguanide (PHMB). The activities of multiple concentrations of MH (40%, 60%, 80%) and PHMB (0.01%, 0.04%, 0.1%) against 13 clinical mould isolates were evaluated using a time-kill assay between 5 min and 24 h. Concentrations were selected to represent current clinical use. Cell viability was examined in parallel for human epidermal keratinocytes, dermal fibroblasts and osteoblasts, allowing determination of the 50% viability (LD50) concentration. Antifungal activity of both agents correlated more closely with exposure time than concentration. Exophiala and Fusarium growth was completely suppressed at 5 min for all PHMB concentrations, and at 12 and 6 h, respectively, for all MH concentrations. Only Lichtheimia had persistent growth to both agents at 24 h. Viability assays displayed concentration-and time-dependent toxicity for PHMB. For MH, exposure time predicted cytotoxicity only when all cell types were analyzed in aggregate. This study demonstrates that MH and PHMB possess primarily time-dependent antifungal activity, but also exert in vitro toxicity on human cells which may limit clinical use. Further research is needed to determine ideal treatment strategies to optimize antifungal activity against moulds while limiting cytotoxicity against host tissues in vivo.

Infection After Orthopaedic Trauma: Prevention and Treatment

Trauma to the extremities is disproportionately represented in casualties of recent conflicts, accounting for >50% of injuries sustained during operations in Iraq and Afghanistan. Infectious complications have been reported in >25% of those evacuated for trauma, and 50% of such patients were treated in the intensive care unit (ICU). Osteomyelitis has been reported in 9% (14% of intensive care unit patients), and deep-wound infection in 27% of type III open-tibia fractures. Infections complicating extremity trauma are frequently caused by multidrug-resistant bacteria and have been demonstrated to lead to failure of limb salvage, unplanned operative take-backs, late amputations, and decreased likelihood of returning to duty. Invasive fungal infections of extremities have also presented a unique challenge in combat-injured patients, particularly in those with blast injuries with massive transfusion requirements and high injury severity scores. Infection prevention should begin at the time of injury and, although context-specific depending on the level of care, includes appropriate irrigation, surgical debridement, wound care and coverage, fracture fixation, and antibiotic prophylaxis, in addition to basic infection prevention measures. Clinical practice guidelines to address infection prevention after combat trauma (including extremity infection) were developed in 2007 and revised in 2011, with endorsement from the Surgical Infection Society and the Infectious Disease Society of America. Nevertheless, significant challenges remain, including austere environments of care, multiple transitions of care, and lack of coordinated efforts in prevention. Treatment of established infections is optimally multidisciplinary, particularly when deep wounds, bone, and joints are involved. Surgical debridement of overtly infected or necrotic tissue is necessary, with particularly aggressive margins if invasive fungal infection is suspected. Infected nonunion frequently requires the use of prosthetic materials for fixation, potentiating biofilm formation, and complicating medical therapy. Antibiotic therapy should be targeted at results of deep wound and bone cultures. However, this is complicated by frequent contamination of wounds, requiring differentiation between potential pathogens in terms of their virulence and decreased culture recovery in patient who have frequently received previous antibiotics. Lessons learned in infection prevention and treatment of orthopaedic trauma from combat can serve to inform the care of patients injured in natural disasters and noncombat trauma.

Histopathological techniques for the diagnosis of combat-related invasive fungal wound infections

BACKGROUND

Effective management of trauma-related invasive fungal wound infections (IFIs) depends on early diagnosis and timely initiation of treatment. We evaluated the utility of routine staining, histochemical stains and frozen section for fungal element identification.

METHODS

A total of 383 histopathological specimens collected from 66 combat-injured United States military personnel with IFIs were independently reviewed by two pathologists. Both periodic acid-Schiff (PAS) and Gomori methenamine silver (GMS) stains were used on 74 specimens. The performance of the two special stains was compared against the finding of fungal elements via any histopathological method (ie, special stains or hematoxylin and eosin). In addition, the findings from frozen sections were compared against permanent sections.

RESULTS

The GMS and PAS results were 84 % concordant (95 % confidence interval: 70 to 97 %). The false negative rate of fungal detection was 15 % for GMS and 44 % for PAS, suggesting that GMS was more sensitive; however, neither stain was statistically significantly superior for identifying fungal elements (p = 0.38). Moreover, 147 specimens had frozen sections performed, of which there was 87 % correlation with permanent sections (60 % sensitivity and 98 % specificity). In 27 permanent sections, corresponding cultures were available for comparison and 85 % concordance in general species identification was reported.

CONCLUSIONS

The use of both stains does not have an added benefit for identifying fungal elements. Furthermore, while the high specificity of frozen section may aid in timely IFI diagnoses, it should not be used as a stand-alone method to guide therapy due to its low sensitivity.

Early Complications and Outcomes in Combat Injury-Related Invasive Fungal Wound Infections: A Case-Control Analysis

OBJECTIVE

Clinicians have anecdotally noted that combat-related invasive fungal wound infections (IFIs) lead to residual limb shortening, additional days and operative procedures before initial wound closure, and high early complication rates. We evaluated the validity of these observations and identified risk factors that may impact time to initial wound closure.

DESIGN

Retrospective review and case-control analysis.

SETTING

Military hospitals.

PATIENTS/PARTICIPANTS

US military personnel injured during combat operations (2009-2011). The IFI cases were identified based on the presence of recurrent, necrotic extremity wounds with mold growth in culture, and/or histopathologic fungal evidence. Non-IFI controls were matched on injury pattern and severity. In a supplemental matching analysis, non-IFI controls were also matched by blood volume transfused within 24 hours of injury.

INTERVENTION

None.

MAIN OUTCOME MEASUREMENTS

Amputation revision rate and loss of functional levels.

RESULTS

Seventy-one IFI cases (112 fungal-infected extremity wounds) were identified and matched to 160 control patients (315 non-IFI extremity wounds). The IFI wounds resulted in significantly more changes in amputation level (P < 0.001). Additionally, significantly (P < 0.001) higher number of operative procedures and longer duration to initial wound closure were associated with IFI. A shorter duration to initial wound closure was significantly associated with wounds lacking IFIs (Hazard ratio: 1.53; 95% confidence interval, 1.17-2.01). The supplemental matching analysis found similar results.

CONCLUSIONS

Our analysis indicates that IFIs adversely impact wound healing and patient recovery, requiring more frequent proximal amputation revisions and leading to higher early complication rates.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Serum Inflammatory Cytokine Markers of Invasive Fungal Infection in Previously Immunocompetent Battle Casualties

BACKGROUND

Invasive fungal infection (IFI) is described increasingly in individuals experiencing high-energy military trauma. Hallmarks of successful treatment involve aggressive surgical debridement and early initiation of systemic antimicrobial therapy. Currently, intravenous anti-fungal therapy commences based on appearance of wounds and patient's clinical course. Whereas some clinical protocols exist to predict which critically injured patients should receive anti-fungal therapies, there are no established serum markers associated with IFI. Our hypothesis is that serum inflammatory cytokines exist that can assist in identifying individuals at risk for IFI.

METHODS

This is a retrospective case control study at a single institution. Nine patients with IFI (Saksenaea vasiformis, Fusarium sp., Graphium sp., Scedosporium sp., Aspergillus sp., Mucor sp., and Alternaria sp.) after battlefield trauma were matched to nine individuals with similar injury patterns whose laboratory results were negative for IFI. The combination of serum inflammatory cytokines from the first and second debridements was examined with multiplex platform proteomic analysis. We defined statistical significance as a two-tailed α<0.05 after adjusting for multiple comparisons using the false discovery rate method. This model was refined further with correlation-based filter selection and the area under the curve of the receiver operating characteristics (AUROC) was tested.

RESULTS

Both groups had similar Injury Severity Scores (ISS) (mean±standard deviation [SD]) (26.8±15.5 vs. 29.2±16.8, p=0.766). Elevated RANTES (regulated on activation, normal T cell expressed and secreted) alone (10,492.8±4,450.1 vs. 5,333.3±4,162.2, p=0.006) correlated with IFI. Also, the combination of persistent elevations in RANTES, interleukin (IL)-2R, and IL-15 was a robust model for predicting IFI with the AUROC being 0.9.

CONCLUSIONS

Elevation in serum cytokines, particularly RANTES, correlated with IFI in this small group of patients. This demonstrates the potential of future rapid serum testing for early initiation and guidance of anti-fungal therapies.

Impact of Mucorales and Other Invasive Molds on Clinical Outcomes of Polymicrobial Traumatic Wound Infections

Combat trauma wounds with invasive fungal infections (IFIs) are often polymicrobial with fungal and bacterial growth, but the impact of the wound microbiology on clinical outcomes is uncertain. Our objectives were to compare the microbiological features between IFI and non-IFI wounds and evaluate whether clinical outcomes differed among IFI wounds based upon mold type. Data from U.S. military personnel injured in Afghanistan with IFI wounds were examined. Controls were matched by the pattern/severity of injury, including blood transfusion requirements. Wound closure timing was compared between IFI and non-IFI control wounds (with/without bacterial infections). IFI wound closure was also assessed according to mold species isolation. Eighty-two IFI wounds and 136 non-IFI wounds (63 with skin and soft tissue infections [SSTIs] and 73 without) were examined. The time to wound closure was longer for the IFI wounds (median, 16 days) than for the non-IFI controls with/without SSTIs (medians, 12 and 9 days, respectively; P < 0.001). The growth of multidrug-resistant Gram-negative rods was reported among 35% and 41% of the IFI and non-IFI wounds with SSTIs, respectively. Among the IFI wounds, times to wound closure were significantly longer for wounds with Mucorales growth than for wounds with non-Mucorales growth (median, 17 days versus 13 days; P < 0.01). When wounds with Mucorales and Aspergillus spp. growth were compared, there was no significant difference in wound closure timing. Trauma wounds with SSTIs were often polymicrobial, yet the presence of invasive molds (predominant types: order Mucorales, Aspergillus spp., and Fusarium spp.) significantly prolonged the time to wound closure. Overall, the times to wound closure were longest for the IFI wounds with Mucorales growth.

Antifungal wound penetration of amphotericin and voriconazole in combat-related injuries: case report

Background

Survivors of combat trauma can have long and challenging recoveries, which may be complicated by infection. Invasive fungal infections are a rare but serious complication with limited treatment options. Currently, aggressive surgical debridement is the standard of care, with antifungal agents used adjunctively with uncertain efficacy. Anecdotal evidence suggests that antifungal agents may be ineffective in the absence of surgical debridement, and studies have yet to correlate antifungal concentrations in plasma and wounds.

Case presentation

Here we report the systemic pharmacokinetics and wound effluent antifungal concentrations of five wounds from two male patients, aged 28 and 30 years old who sustained combat-related blast injuries in southern Afghanistan, with proven or possible invasive fungal infection. Our data demonstrate that while voriconazole sufficiently penetrated the wound resulting in detectable effluent levels, free amphotericin B (unbound to plasma) was not present in wound effluent despite sufficient concentrations in circulating plasma. In addition, considerable between-patient and within-patient variability was observed in antifungal pharmacokinetic parameters.

Conclusion

These data highlight the need for further studies evaluating wound penetration of commonly used antifungals and the role for therapeutic drug monitoring in providing optimal care for critically ill and injured war fighters.

Clinical relevance of mold culture positivity with and without recurrent wound necrosis following combat-related injuries

BACKGROUND

Invasive fungal wound infections (IFIs) are a recognized threat for personnel who sustain combat-related blast trauma in Afghanistan. Blast trauma, particularly when dismounted, has wounds contaminated with organic debris and potential for mold infection. Trauma-associated IFI is characterized by recurrent wound necrosis on serial debridement with histologic evidence of invasive molds and/or fungal culture growth. Wounds with mold growth but lacking corresponding recurrent necrosis present a clinical dilemma of whether to initiate antifungal treatment. Our objective was to assess the clinical significance of fungal culture growth without recurrent wound necrosis.

METHODS

US military personnel wounded during combat in Afghanistan (June 2009 to August 2011) were assessed for growth of mold from wound cultures and/or histopathologic evidence of IFI. Identified patients were stratified based on clinical wound appearance (with/without recurrent necrosis), and the resultant groups were compared for injury characteristics, clinical management, and outcomes.

RESULTS

A total of 96 patients were identified: 77 with fungal elements on histopathology and/or fungal growth plus recurrent wound necrosis and 19 with fungal growth on culture but no wound necrosis after initial debridements. Injury patterns and severity were similar between the groups. Patients with recurrent necrosis had more frequent fevers and leukocytosis during the first 2 weeks after injury, and the majority received antifungal therapy compared with only three patients (16%) without recurrently necrotic wounds. Overall, patients without recurrent wound necrosis had significantly less operative procedures (p = 0.02), shorter stay in the intensive care unit (p < 0.01), and lower rates of high-level amputations (5% vs. 20%) and deaths (none vs. 8%) despite no or infrequent antifungal use.

CONCLUSION

The finding of molds on wound culture among patients with blast trauma in the absence of recurrently necrotic wounds on serial debridement does not require systemic antifungal chemotherapy.

LEVEL OF EVIDENCE

Therapeutic study, level IV. Prognosti/epidemiologic study, level III.

Combat-Related Invasive Fungal Wound Infections

Combat-related invasive fungal (mold) wound infections (IFIs) have emerged as an important and morbid complication following explosive blast injuries among military personnel. Similar to trauma-associated IFI cases among civilian populations, as in agricultural accidents and natural disasters, these infections occur in the setting of penetrating wounds contaminated by environmental debris. Specific risk factors for combat-related IFI include dismounted (patrolling on foot) blast injuries occurring mostly in southern Afghanistan, resulting in above knee amputations requiring resuscitation with large-volume blood transfusions. Diagnosis of IFI is based upon early identification of a recurrently necrotic wound following serial debridement and tissue-based histopathology examination with special stains to detect invasive disease. Fungal culture of affected tissue also provides supportive information. Aggressive surgical debridement of affected tissue is the primary therapy. Empiric antifungal therapy should be considered when there is a strong suspicion for IFI. Both liposomal amphotericin B and voriconazole should be considered initially for treatment since many of the cases involve not only Mucorales species but also Aspergillus or Fusarium spp., with narrowing of regimen based upon clinical mycology findings.

Risk factors associated with invasive fungal infections in combat trauma

BACKGROUND

In recent years, invasive fungal infections (IFI) have complicated the clinical course of patients with combat-related injuries. Commonalities in injury patterns and characteristics among patients with IFI led to the development of a Joint Trauma System (JTS) clinical practice guideline (CPG) for IFI management. We performed a case-control study to confirm and further delineate risk factors associated with IFI development in combat casualties with the objective of generating data to refine the CPG and promote timelier initiation of treatment.

METHODS

Data were collected retrospectively for United States (U.S.) military personnel injured during deployment in Afghanistan from June 2009 through August 2011. Cases were identified as IFI based upon wound cultures with fungal growth and/or fungal elements seen on histology, in addition to the presence of recurrent wound necrosis. Controls were matched using date of injury (±3 mo) and injury severity score (±10). Risk factor parameters analyzed included injury circumstances, blood transfusion requirements, amputations after first operative intervention, and associated injuries. Data are expressed as multivariate odds ratios (OR; 95% confidence interval [CI]).

RESULTS

Seventy-six IFI cases were identified from 1,133 U.S. military personnel wounded in Afghanistan and matched to 150 controls. Parameters associated significantly with the development of IFI multivariate analysis were blast injuries (OR: 5.7; CI: 1.1-29.6), dismounted at time of injury (OR: 8.5; CI: 1.2-59.8); above the knee amputations (OR: 4.1; CI: 1.3-12.7), and large-volume packed red blood cell (PRBC; >20 U) transfusions within first 24 h (OR: 7.0; CI: 2.5-19.7).

CONCLUSIONS

Our analysis indicates that dismounted blast injuries, resulting in above the knee amputations, and requirement of large volume PRBC transfusions are independent predictors of IFI development. These data confirm all the preliminary risk factors, except for genitalia/perineal injuries, utilized by JTS in their IFI CPG. Model validation is necessary for further risk factor specification.