21. By contrast, " Yersinia pestis " is a bacterium with a very different biology. 22. The gene map for Y . pestis is published in Thursday's issue of the journal Nature. 23. In addition, " Y . pestis " can spread from the urban environment and back. 24. The bacterium that causes this disease, " Yersinia pestis ", was named after Yersin. 25. Transmission of " Y . pestis " occurs during the futile attempts of the flea to feed. 26. Failure to isolate Y . pestis from any case has been one of the major puzzles of the Indian epidemic. 27. Seven vials of Yersinia pestis , one of the highest-risk materials, had been stored there since 1981. 28. A comprehensive and comparative proteomics analysis of " Y . pestis " strain KIM was performed in 2006. 29. It is also used to visualize the classic " safety pin " shape in " Yersinia pestis ". 30. The Rockefeller team is already working on lysins from viruses that attack cholera and Yersinia pestis , the agent of plague.