It has been a year since bacteria from patients injured in the war were analyzed in Ukrainian hospitals. The study revealed that some bacterial strains exhibited complete antibiotic resistance. Now, the same research team has investigated how infectious these bacteria are. “The bacterium *Klebsiella pneumoniae*, which shows resistance to all antibiotics, is particularly aggressive and poses a significant threat,” says the lead author.
Previously, Lund University in Sweden reported on Kristian Riesbeck, a professor of clinical bacteriology and senior consultant at Lund University. He was contacted by Ukrainian microbiologist Oleksandr Nazarchuk to assist in analyzing the level of antibiotic resistance in bacteria from critically wounded and infected patients hospitalized due to war injuries.
The study analyzed samples from 141 wounded individuals, comprising 133 adults and eight newborns with pneumonia. The researchers discovered that several bacterial strains were resistant to broad-spectrum antibiotics, with six percent of samples showing total resistance across all tested antibiotics.
In their published article in the Journal of Infection, the researchers further examined *Klebsiella pneumoniae* to determine if it could cause disease in broader contexts. *Klebsiella* infections can lead to urinary tract infections, pneumonia, skin infections, and sepsis. The team sequenced the entire genome of bacteria samples taken from 37 patients identified to have resistant strains to investigate potential resistance genes.
“All examined bacteria carried known resistance genes. We found that 25% were resistant to all available antimicrobial drugs, a condition referred to as total resistance (pandrug-resistant). Infections from these bacteria are incredibly challenging, if not impossible, to treat with current medications,” explained Professor Riesbeck.
Pandrug-resistant bacteria represent an extreme level of antibiotic resistance and pose a growing challenge in healthcare.
The researchers were also interested in assessing if these bacteria could spread infections further. To explore this, experiments were conducted on mice and insect larvae.
The results showed that the most antibiotic-resistant strains thrived in mice with pneumonia, and these strains killed insect larvae much quicker than less resistant bacterial types.
Genetic analysis confirmed that all *Klebsiella* bacteria exhibiting total resistance contained genes increasing their virulence.
“Typically, bacteria lose their infectious capabilities as they expend their energy resisting antibiotics. However, we may have underestimated these organisms. Many bacteria from Ukraine possess both resistance and virulence genes,” noted Kristian Riesbeck.
Professor Riesbeck warned that the bacteria spreading among the wounded in Ukraine are likely to persist and cause ongoing issues.
“This problem won’t vanish over time. As long as patients cannot be appropriately isolated and treated, infections will continue to spread.”
Riesbeck finds the results alarming, though not surprising, as they illustrate the outcomes of a healthcare system’s collapse, relevant to Ukraine and other war-affected regions worldwide.
“Despite these pandrug-resistant bacteria’s struggles against our antibiotics, they still possess a full array of genes that enable them to cause disease. This is a sobering realization and a concerning indication for our future,” he added.
*Klebsiella pneumoniae is a leading bacterial cause of mortality worldwide, estimated to account for around 20 percent of all deaths associated with antimicrobial resistance.
The research was conducted with support from the Knut and Alice Wallenberg Foundation, the Swedish Research Council, the Swedish Heart Lung Foundation, and ALF funding from Region Skåne.
