Microbiology of French military casualties repatriated from overseas for an open traumatic injury

Multidrug-Resistant and Virulent Organisms Trauma Infections: Trauma Infectious Disease Outcomes Study Initiative

INTRODUCTION

During the wars in Iraq and Afghanistan, increased incidence of multidrug-resistant (MDR) organisms, as well as polymicrobial wounds and infections, complicated the management of combat trauma-related infections. Multidrug resistance and wound microbiology are a research focus of the Trauma Infectious Disease Outcomes Study (TIDOS), an Infectious Disease Clinical Research Program, Uniformed Services University, research protocol. To conduct comprehensive microbiological research with the goal of improving the understanding of the complicated etiology of wound infections, the TIDOS MDR and Virulent Organisms Trauma Infections Initiative (MDR/VO Initiative) was established as a collaborative effort with the Brooke Army Medical Center, Naval Medical Research Center, U.S. Army Institute of Surgical Research, and Walter Reed Army Institute of Research. We provide a review of the TIDOS MDR/VO Initiative and summarize published findings.

METHODS

Antagonism and biofilm formation of commonly isolated wound bacteria (e.g., ESKAPE pathogens-Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.), antimicrobial susceptibility patterns, and clinical outcomes are being examined. Isolates collected from admission surveillance swabs, as part of infection control policy, and clinical infection workups were retained in the TIDOS Microbiological Repository and associated clinical data in the TIDOS database.

RESULTS

Over the TIDOS study period (June 2009 to December 2014), more than 8,300 colonizing and infecting isolates were collected from military personnel injured with nearly one-third of isolates classified as MDR. At admission to participating U.S. military hospitals, 12% of wounded warriors were colonized with MDR Gram-negative bacilli. Furthermore, 27% of 913 combat casualties with ≥1 infection during their trauma hospitalization had MDR Gram-negative bacterial infections. Among 335 confirmed combat-related extremity wound infections (2009-2012), 61% were polymicrobial and comprised various combinations of Gram-negative and Gram-positive bacteria, yeast, fungi, and anaerobes. Escherichia coli was the most common Gram-negative bacilli isolated from clinical workups, as well as the most common colonizing MDR secondary to extended-spectrum β-lactamase resistance. Assessment of 479 E. coli isolates collected from wounded warriors found 188 pulsed-field types (PFTs) from colonizing isolates and 54 PFTs from infecting isolates without significant overlap across combat theaters, military hospitals, and study years. A minority of patients with colonizing E. coli isolates developed subsequent infections with the same E. coli strain. Enterococcus spp. were most commonly isolated from polymicrobial wound infections (53% of 204 polymicrobial cultures). Patients with Enterococcus infections were severely injured with a high proportion of lower extremity amputations and genitourinary injuries. Approximately 65% of polymicrobial Enterococcus infections had other ESKAPE organisms isolated. As biofilms have been suggested as a cause of delayed wound healing, wound infections with persistent recovery of bacteria (isolates of same organism collected ≥14 days apart) and nonrecurrent bacterial isolates were assessed. Biofilm production was significantly associated with recurrent bacteria isolation (97% vs. 59% with nonrecurrent isolates; P < 0.001); however, further analysis is needed to confirm biofilm formation as a predictor of persistent wound infections.

CONCLUSIONS

The TIDOS MDR/VO Initiative provides comprehensive and detailed data of major microbial threats associated with combat-related wound infections to further the understanding of wound etiology and potentially identify infectious disease countermeasures, which may lead to improvements in combat casualty care.

Prise en charge des brûlures en préhospitalier et aux urgences

Une brûlure est une lésion de la peau ou d’un autre tissu organique principalement causée par la chaleur ou les rayonnements, la radioactivité, l’électricité, la friction ou le contact avec des produits chimiques. Les plus fréquentes, les brûlures thermiques (dues à la chaleur), surviennent lorsque certaines cellules ou toutes les cellules de la peau ou d’autres tissus sont détruites par des liquides bouillants, des solides chauds (brûlures de contact), ou des flammes. En France, l’incidence des brûlures prises en charge à l’hôpital est environ de 13 pour 100 000 habitants. La prise en charge en urgence du brûlé grave par lésion thermique est bien décrite, une recommandation de pratique professionnelle a été publiée en 2019 par la Société française d’anesthésie et de réanimation, en association avec la Société francophone de brûlologie, la Société française de médecine d’urgence et l’Association des anesthésistes-réanimateurs pédiatriques d’expression française. Pourtant, l’urgentiste va être confronté à de nombreuses brûlures de gravité et de nature différentes. Nous faisons ici une mise au point sur les données connues en termes d’épidémiologie, de manifestations cliniques et des différentes thérapeutiques qui peuvent être proposées dans la prise en charge des brûlures. Nous faisons aussi le point sur les localisations à risque particulier que l’urgentiste doit connaître, ainsi que sur les intoxications qui peuvent être associées aux brûlures. Nous détaillons aussi certains contaminants qui sont à connaître.

Ex vivo limb perfusion for traumatic amputation in military medicine

BACKGROUND

Limb loss has a drastic impact on a patient's life. Severe trauma to the extremities is common in current military conflicts. Among other aspects, "life before limb" damage control surgery hinders immediate replantation within the short post-traumatic timeframe, which is limited in part by the ischemic time for successful replantation. Ex vivo limb perfusion is currently being researched in animal models and shows promising results for its application in human limb replantation and allotransplantation.

PRESENTATION OF THE HYPOTHESIS

The current lack of replantation possibilities in military operations with high rates of amputation can be addressed with the development of a portable ex vivo limb perfusion device, as there are several opportunities present with the introduction of this technique on the horizon. We hypothesize that ex vivo limb perfusion will enable overcoming the critical ischemic time, provide surgical opportunities such as preparation of the stump and limb, allow for spare-part surgery, enable rigorous antibiotic treatment of the limb, reduce ischemia-reperfusion injuries, enable a tissue function assessment before replantation, and enable the development of large limb transplant programs.

TESTING THE HYPOTHESIS

Data from in vivo studies in porcine models are limited by the relatively short perfusion time of 24 h. In the military setting, notably longer perfusion times need to be realized. Therefore, future animal studies must focus especially on long-term perfusion, since this represents the military setting, considering the time for stabilization of the patient until evacuation to a tertiary treatment center.

IMPLICATIONS OF THE HYPOTHESIS

The development and clinical introduction of ex vivo limb perfusion in the military setting could lead to a drastic reduction in the number of limb amputations among service members. Ex vivo limb perfusion enables replantation surgery in Role 4 facilities and changes the clinical setting from a highly urgent, life-threatening situation to a highly methodical, well-prepared starting point for optimal treatment of the wounded service member. With its introduction, the principle of "life before limb" will change to "life before limb before elective replantation/allotransplantation after ex vivo limb perfusion".

Treating drug-resistant wound pathogens with non-medicated dressings: an in vitro study

Objective:

To assess the in vitro antimicrobial performance of a non-medicated hydro-responsive wound dressing (HRWD) on the sequestration and killing of wound relevant microorganisms found on the World Health Organization (WHO) priority pathogens list.

Methods:

Suspensions of Pseudomonas aeruginosa, Acinetobacter baumannii and methicillin-resistant Staphylococcus aureus (MRSA) were placed on petri dishes. Dressings were each placed on top, incubated for 30 minutes and then removed from the inoculated petri dish. The surface of the dressings previously in contact with the bacterial suspensions were placed directly onto a tryptone soy agar (TSA) plate and incubated for 24 hours. Dressings were then removed from the TSA plate and the level of bacterial growth on the plates was assessed. Sequestered microorganism viability was assessed using LIVE/DEAD viability kits and visualisation by epifluorescence.

Results:

Our results indicated that HRWDs sequester and retain Pseudomonas aeruginosa, Acinetobacter baumannii and MRSA within the dressing. Non-medicated HRWDs containing bound PHMB (polyhexamethylene biguanide, HRWD+PHMB) killed the microorganisms sequestered within the dressing matrix.

Conclusion:

These data suggest that non-medicated HRWD+PHMB is an effective against WHO priority pathogens and promoting goal of antimicrobial stewardship in wound care.