Summary Primarily, three operons, hmsHFRS, hmsT and hmsP , are responsible for the development of a Yersinia pestis biofilm, which is essential for blockage‐dependent transmission of plague from fleas to mammals. Here, using specific antibodies, a polymeric β‐1,6‐ N ‐acetyl‐ d ‐glucosamine‐like polysaccharide was detected in the extracellular matrix of hmsHFRS ‐dependent Y. pestis biofilm. The production of this exopolysacchar...