Hospital Environments Act as Reservoirs of Multidrug Resistant Bacteria in Ukraine

Environmental sampling across the Ukrainian medical evacuation chain has revealed that multidrug resistant organisms, which have infected large numbers of wounded soldiers during the ongoing conflict, are largely absent from frontline facilities and evacuation assets but thrive in rear-echelon hospitals. The study, published as peer-reviewed, accepted research in Genome Medicine, points to hospital environments themselves as key reservoirs and amplifiers of these dangerous bacteria during wartime.

The research team collected 127 environmental swabs from surfaces at different points along the evacuation chain: 17 swabs from three frontline hospitals, 12 swabs from two evacuation assets, 23 swabs from a large regional healthcare facility offering full clinical and surgical capabilities, and 75 swabs from three definitive care and rehabilitative hospitals. The swabs were incubated in Brain Heart Infusion broth and then cultured on both non-selective and selective agars. Bacterial growth was recorded from 112 of the swabs, or 88 percent, yielding 280 distinct environmental strains representing 89 bacterial species.

A striking geographic pattern emerged within the country. Multidrug resistant organisms were effectively absent from the frontline facilities and evacuation assets, but were detected in 48 to 56 percent of environmental samples taken from rear-echelon hospitals. This distribution suggests that the heavily damaged and repeatedly wounded patients are not picking up these resistant bacteria at the point of injury or during early evacuation, but later in their care pathway, within the healthcare facilities that provide prolonged treatment.

To characterize the organisms at a genetic level, the researchers performed short-read sequencing on an Illumina NextSeq 2000 and long-read sequencing on a MinION. Genomic analysis showed that the rear-echelon hospital environments were dominated by epidemic lineages of three notorious opportunistic pathogens: Acinetobacter baumannii, Pseudomonas aeruginosa, and Klebsiella pneumoniae.

The team then compared the environmental genomes with a collection of clinical bacteria cultured from patients in healthcare facilities in Denmark, Germany, The Netherlands, and Ukraine, including injured soldiers and refugees receiving care in those hospitals. This genetic comparison revealed high levels of relatedness between the bacteria living on hospital surfaces and the strains infecting patients across multiple countries. The finding supports the conclusion that hospital environments sustain local transmission and contribute to international spread of resistant lineages as patients are evacuated or displaced across borders.

Compounding the problem, plasmidome analysis identified horizontal dissemination of resistance genes across bacterial species within the hospital environment.

The authors conclude that these findings implicate hospital environments as key reservoirs and amplifiers of multidrug resistant organisms during conflict, highlighting their central role in sustaining both local transmission and international spread. Because the reservoirs and transmission routes of these bacteria had previously remained poorly defined despite intense interest and debate, the study provides a direct environmental picture of where the organisms persist along the evacuation chain.

It should be noted that the study is an environmental and genomic survey, and the published version is an early-release, peer-reviewed accepted manuscript that remains subject to further edits before the final Version of Record. The sampling covered a defined set of facilities at specific points in the evacuation chain, and the reported percentages refer to environmental samples rather than patient infection rates. Even so, the work offers a concrete evidence base for the idea that in wartime healthcare systems, hospital environments can serve as key reservoirs and amplifiers of multidrug resistant bacteria, sustaining local transmission and contributing to international spread.

Subject of Research: Environmental reservoirs of multidrug resistant bacteria in Ukrainian hospitals during the ongoing conflict

Article Title: Tracing the origins of multidrug resistant bacteria in Ukraine

Article References: Lebreton, F., Kondratiuk, V., Bartlett, K., Luo, T. L., Kovalchuk, V., Ong, A., Jones, B. T., Maybank, R. A., Sapre, A., Nguyen, E., Kwak, Y. I., Stepanskyi, D., Hammerum, A. M., Fomina, N., Cybulski, R. J., Hasman, H., Hendrickx, A. P. A., Fuchs, F., Gatermann, S., … Mc Gann, P. T. (2026). Tracing the origins of multidrug resistant bacteria in Ukraine. Genome Medicine. https://doi.org/10.1186/s13073-026-01812-w

Image Credits: AI Generated

DOI: 10.1186/s13073-026-01812-w

Keywords: Ukraine, multidrug resistant organisms, Acinetobacter baumannii, Klebsiella pneumoniae, Pseudomonas aeruginosa, carbapenemases, hospital environment, genomic epidemiology, medical evacuation, plasmids, antimicrobial resistance, Tracing