Defining the problem: acquisition and transmission of MDROs in war-related trauma care
Russia’s war against Ukraine has seen unprecedented technological advances in weaponry. What started with conventional legacy systems, tanks, artillery, and ballistic and cruise missiles quickly evolved to Shahed kamikaze drones, Kinzhal hypersonic missiles, artificial intelligence-enhanced autonomous drones, reconnaissance unmanned aerial vehicle platforms, and fiber-optic-controlled first person view drones that bypass radiofrequency jamming.1–4 These developments have increased both the severity of combat injuries and the constraints on timely evacuation. Persistent aerial surveillance and delayed access to care have limited early hemorrhage control and surgical intervention, contributing to a rising case fatality rate approaching levels not seen since World War 1, despite advances in modern trauma combat casualty care frameworks.5
For casualties who survive these delays, the consequences extend beyond polytrauma. Severe, contaminated wounds, prolonged prehospital evacuation, incomplete early wound management, and early broad-spectrum antimicrobial exposure create optimal conditions for the acquisition, amplification, and transmission of multidrug-resistant organisms (MDROs). As a result, MDRO colonization and infection emerge as predictable downstream outcomes of modern conflict-related trauma, propagating along the trauma care pathway and posing risks not only to individual casualties but also to healthcare systems and civilian populations.
The majority of injuries in Russia’s war against Ukraine result from explosive ordnance rather than small arms fire.6–10 These mechanisms cause devastating soft tissue, bone, and neurological damage, compounded by substantial environmental contamination. Movement of the wounded is often delayed 6–12 hours until nightfall or low-visibility conditions, requiring thermal masking and vehicle blackout to evade enemy surveillance.11 Point of injury care, which may include self- or medic-administered intramuscular antibiotic prophylaxis, is extremely limited. Casualties eventually arrive at trauma stabilization points (Role 2 facilities) hours, days, or even weeks after injury (the definitions and capabilities of Role 1 through Role 4 medical care are summarized in figure 1).12 If casualties survive the prolonged evacuation, they arrive at Role 2 in critical condition, dehydrated, malnourished, and heavily contaminated.
As defined by NATO Standard AJP-4.10 Allied Joint Doctrine For Medical Support, the Functions And Capabilities of Military Health Care are described by Roles, with each successive Role building on the minimum capabilities of the previous one.12 This figure describes established doctrine, while actual implementation may skip roles to mesh tactical and medical situations with optimal casualty outcomes.
At the trauma stabilization point (Role 2), patients undergo triage, re-evaluation, damage control surgery, limited irrigation and debridement, and stabilization. Limited resources, such as personnel, time, equipment, and consumables, combined with large casualty numbers, often prevent thorough casualty cleaning and wound irrigation and debridement. Stays at Role 2 are brief, often hours, before further evacuation westward, away from the forward line of battle. Medical records are abbreviated, and adherence to clinical guidelines is sparse secondary to tactical and operational challenges at the Role 2 facilities. Various broad-spectrum antibiotics are given, dependent on what stock is available and the prescriber’s understanding of the appropriate antimicrobial spectrum required for coverage.
The trajectory from battlefield to systemic infection in Ukraine, therefore, tends to follow a predictable pattern. After injury, wounds typically progress through a continuum beginning with contamination, where debris, soil, and organic material are introduced at the point of injury. This is followed by colonization, as bacteria multiply on the wound surface without yet invading tissues. Without timely and effective irrigation and debridement, cleansing, and prophylactic antibiotics, colonization frequently advances to infection, particularly in the context of delayed evacuation, high-risk wounds, hypotension, complex open fractures, and hollow-viscus perforations, inconsistent or inappropriate antibiotic use, malnourishment, and subsequent immunocompromise. Infections in these patients typically begin to present at the Role 3 stage of evacuation.13
The casualties evacuated from Role 2 are distributed across military (Role 3) and civilian hospitals (approximately 20% vs 80% of war-wounded casualties, respectively). Within the civilian hospital system, transferred war-injured casualties are frequently triaged in the emergency department alongside routine civilian presentations. The war-wounded are then sent to the operating room (OR) or are admitted to a ward among civilian patients to await an available surgeon or OR space. During this time, casualties often remain in contaminated clothing and dressings, with their original invasive lines, catheters, or airway devices. While clinicians are cognizant of the pervasiveness of war-wounded infections, and the importance of infection prevention and control (IPC) principles, very little attention can be prioritized to IPC measures to decrease nosocomial transmission of MDROs and mitigation of hospital-acquired infections. The clinical staff are unable to intervene effectively because of severe staffing shortages; with nursing ratios of 1:20–30 patients, there are simply not enough clinicians to wash patients, change clothes and bedding, maintain ward hygiene, or even administer intravenous antibiotics beyond twice daily. In overcrowded multibed wards, sustained close contact and shared care environments and medical equipment facilitate efficient cross-transmission, enabling MDROs to disseminate from war-wounded patients into the broader civilian healthcare population.14
MDRO acquisition in this pathway reflects three overlapping sources: (i) endogenous carriage and battlefield contamination at injury, (ii) patient-to-patient transmission among cohorts of war-wounded casualties during evacuation and ward-based care, and (iii) nosocomial acquisition from prior contaminated healthcare environments, including Role 2 and Role 3 facilities and transport vehicles. These risks are compounded by limited triage for transmission-based precautions, absent or inconsistent MDRO (including fungal) surveillance, and therefore frequent lack of awareness of colonization status on arrival. Consequently, MDRO-positive casualties may enter and circulate within facilities undetected, allowing suboptimal IPC conditions to drive ward-level transmission and downstream spillover into the civilian population through shared hospital infrastructure.
This downstream transmission dynamic creates the conditions for progression from early contamination and colonization to established, often polymicrobial infection by the time casualties arrive at definitive care at Role 3 and 4 military facilities or the secondary and tertiary level civilian hospitals (from 5 days post-injury). The war-wounded polymicrobial infections predominantly involve antibiotic-resistant gram-negative pathogens such as Klebsiella spp., Pseudomonas spp., and Acinetobacter spp.15 16 Recent findings include Pseudomonas aeruginosa (P. aeruginosa) co-producing Klebsiella pneumoniae (K. pneumoniae) carbapenemase in addition to its usual resistance mechanisms, and, for the first time in 2024, a large group of carbapenem-resistant gram-negative bacteria (CR-GNB) that do not carry carbapenemase enzymes.17 18 Notably, these non-carbapenemase CR-GNB were absent in samples from 2022 and 2023, highlighting an emerging shift in resistance mechanisms that complicates detection, treatment, and surveillance efforts.19 This bacterial group shows very broad resistance mechanisms, leading to pan-resistance (resistance to all antibiotics), including to the newest beta-lactam/beta-lactamase inhibitor combinations and cefiderocol (a cephalosporin specifically designed to overcome common resistance mechanisms and preserve activity against CR-GNB, indicating progression toward pan-resistance). All these factors combined create a situation for the emergence of superbugs that not only threaten individual patient survivability but also pose great risk to hospital infection control and cross-transmission to the civilian population.
Systemic infections with MDROs in the war-wounded by this stage are resource-heavy, requiring extensive care of wounds, difficult soft tissue coverage, challenging bone reconstruction, and difficult to impossible antibiotic management. Delayed amputations and prolonged intensive care unit (ICU) stays are a common end result, despite efforts to control, manage, and cure infections to prevent further disability and mortality.
The experience of earlier wars underscores this danger. In previous conflicts such as Iraq and Afghanistan, where medical evacuation was comparatively rapid and deployed teams were highly resourced and trained in IPC and antimicrobial stewardship (AMS), MDRO spread still emerged as a major challenge.20 21 This was especially evident in the rapidly evacuated military casualties, who laid next to civilians that remained in Role 3 facilities. Acinetobacter baumannii (A. baumannii) was transmitted from field hospitals in Iraq to referral centers in Germany and subsequently to the USA, underscoring the ease with which MDROs can disseminate across borders despite robust medical support systems.22 23 In the current war in Ukraine, these issues are further exacerbated by prolonged delays in evacuation due to loss of air superiority, during which contamination and colonization progress to invasive infection. This delay, combined with all the challenges outlined above, amplifies the selective pressure for MDRO infections and underscores their role as a major driver of morbidity and mortality in war-wounded patients and the civilians they encounter on the evacuation pathway.
New approaches to casualty care must be implemented to interrupt the described pathway which ends in predictable failure. Space limitations, an insufficient workforce to deliver care beyond basic functions, and failing antibiotics in a system already stressed by overwhelming patient numbers necessitate implementing new methods. Although Ukraine has strengthened its AMR response, IPC and AMS programs were only introduced in 2021 and require time, stability, and adequate nursing staffing ratios to be effective. Implemented during active conflict, they are insufficient alone to halt the rapid spread of MDRO infections.24 25
