Yersinia pestis B. Clark F2013 Modified by DYH Bacteria responsible for the Black Death, which killed over 1/3 of European population from 1347-1353 Gram negative, rod shaped coccobacillus Unique morphology between cocci and bacilli Obligate intracellular pathogen Facultative anaerobe Primary carriers are the Oriental rat flea and infected rodents Produce antiphagocytic slime layer in its path Genome size of strain CO92 is 4.65 Mbp and strain KIM is 4.6 Mbp 4,198 total ORFs http://en.wikipedia.org/wiki/Yersinia_pestis http://www.rkm.com.au/bacteria/Yersinia-pestis.html

Yersinia pestis Can produce loose capsule in some cases B. Clark F2013 Modified by DYH Can produce loose capsule in some cases Lacks O-side chain due to disrupted O-anitgen gene cluster Called a “rough mutant” Infection takes three main forms: pneumonic, septicemic, & bubonic plagues All pathogenic species contain pCD1 virulence plasmid Uses a Type 3 Secretion System to inject bacterial proteins into host immune cells LPS chains mediate antibody resistance Expression of yadBC gene is similar to adhesin function Adherence and invasion of epithelial cells Proliferates in lymph nodes where is can avoid destruction by immune system http://www.ppdictionary.com/bacteria/gnbac/pestis.htm