Australian researchers report they have engineered monoclonal antibodies that recognize pseudaminic acid—a sugar made by bacteria but not by humans—and used them to help eliminate multidrug-resistant Acinetobacter baumannii infections in mice, a step toward potential passive-immunotherapy treatments for hard-to-treat hospital infections.
Scientists in Australia have reported a strategy aimed at fighting some drug-resistant infections by targeting a bacterial-only sugar on the pathogen surface.
In a study published in Nature Chemical Biology on February 4, 2026, the researchers describe generating “pan-specific” monoclonal antibodies that bind pseudaminic acids (Pse)—a family of carbohydrates found in bacterial lipopolysaccharides, capsular polysaccharides and glycoproteins and linked to the virulence of several human pathogens.
The work was co-led by Professor Richard Payne at the University of Sydney, with collaborators including Professor Ethan Goddard-Borger at the Walter and Eliza Hall Institute (WEHI) and Associate Professor Nichollas Scott at the University of Melbourne and the Peter Doherty Institute for Infection and Immunity, according to a University of Sydney release carried by ScienceDaily.
The team chemically synthesized Pse-bearing glycopeptides to help generate antibodies and to support structural characterization of how the antibodies recognize Pse across different chemical contexts, the paper reports. Using these antibody tools, the researchers also describe a workflow to map Pse-modified molecules in Helicobacter pylori, Campylobacter jejuni and Acinetobacter baumannii strains.
In mouse infection experiments, the researchers report that the antibodies enhanced phagocytosis and helped eliminate infections caused by multidrug-resistant A. baumannii, a bacterium associated with hospital-acquired pneumonia and bloodstream infections.
“This study shows what's possible when we combine chemical synthesis with biochemistry, immunology, microbiology and infection biology,” Payne said in the University of Sydney statement distributed via ScienceDaily. The release said the approach could underpin passive immunotherapy—administering ready-made antibodies to rapidly control an infection or help prevent it in high-risk patients.
“Multidrug resistant Acinetobacter baumannii is a critical threat faced in modern healthcare facilities across the globe,” Goddard-Borger said in the same statement, calling the work a proof-of-concept for passive-immunotherapy development.
Scott said the antibodies may also serve as tools to study bacterial virulence by showing where these sugars appear and how they vary across pathogens.
The researchers said they aim to translate the findings into clinic-ready antibody therapies over the next five years, with a focus on multidrug-resistant A. baumannii, which is among the ESKAPE pathogens—bacteria often highlighted for their roles in hard-to-treat, healthcare-associated infections.
The University of Sydney release said funding included support from Australia’s National Health and Medical Research Council, the Australian Research Council and the U.S. National Institutes of Health, among others, and that animal work was conducted under University of Melbourne ethics oversight.
