O-Antigen Typing of Escherichia coli by MALDI-TOF MS Analysis of O-Antigen Polysaccharides

Introduction

Microorganism typing is one of the most fundamental techniques for the diagnosis of infectious diseases. For Escherichia coli, the most common method is typing based on the structure of the O-antigen, which is one part of lipopolysaccharides (LPS) located on the surface of cells. That is achieved by an antigen-antibody reaction using an antiserum for the O-antigen (O-serotyping). However, due to the structural diversity in O-antigens of E. coli, O-serotyping requires more than 180 types of antiserum and significant labor. This article describes an example of O-antigen typing of E. coli strains using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), which enables typing with a single reagent and a single assay.

May 26, 2026 GMT