Glycosylation of bacterial cell surfaces is emerging as a critical factor in symbiosis, pathogenesis, cell-cell interactions and immune evasion. The lack of high-throughput analytical tools to examine bacterial glycans has been a major obstacle to the field and has hindered closer examination of the dynamics of carbohydrate variation. We have recently developed a lectin microarray for the analysis of glycoproteins. Herein we present a rapid analytical system based on this technology for the examination of bacterial glycans. The glycosylation pattern observed distinguishes closely related Escherichia coli strains from one another, providing a facile means of fingerprinting bacteria. In addition, dynamic alterations in the carbohydrate coat of a pathogenic E. coli strain are readily observed. The fast evaluation of real-time alterations in surface-carbohydrate epitopes allows examination of the dynamic role of bacterial sugars in response to external stimuli such as the immune system.