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Poster Presentations
Day 4, June 25（Wed.）
Room P (Maesato East, Foyer, Ocean Wing)
- 4P-AM-01（3C-O1-1155）
Towards Rapid and Accurate Bacterial Serotyping Using MALDI Glycotyping
(Hokkaido Univ.)
oShogo Urakami, Hiroshi Hinou
MALDI-TOF MS is widely used in clinical microbiology for bacterial identification. However, conventional methods primarily focus on protein analysis and struggle to differentiate bacterial serotypes, which are crucial for epidemiological investigations. Among serotypes of gram-negative bacteria, O-antigens are highly diverse and play a key role in serotyping. To overcome this limitation, we developed MALDI glycotyping, a novel approach that directly detects O-antigen glycans. In this study, we applied MALDI glycotyping to 71 Escherichia coli and Shigella strains, achieving O-antigen identification in 80% of cases using both positive and negative ion modes. Acidic O-antigens, previously undetectable in positive mode, were successfully identified in 28% of strains in negative mode. Additionally, MALDI glycotyping distinguished eight O-antigen variants that conventional serology could not resolve and identified O-antigens different from the reported serotypes in some commercial strains. These findings demonstrate that MALDI glycotyping is a rapid and effective method for bacterial serotyping. This approach has the potential to enhance microbial identification and epidemiological investigations by providing a faster and more accurate alternative to conventional serotyping techniques.