Yersinia pestis , the cause of plague, is a recently emerged clone of Yersinia pseudotuberculosis

Abstract

Plague, one of the most devastating diseases of human history, is caused by Yersinia pestis . In this study, we analyzed the population genetic structure of Y. pestis and the two other pathogenic Yersinia species, Y. pseudotuberculosis and Y. enterocolitica . Fragments of five housekeeping genes and a gene involved in the synthesis of lipopolysaccharide were sequenced from 36 strains representing the global diversity of Y. pestis and from 12–13 strains from each of the other species. No sequence diversity was found in any Y. pestis gene, and these alleles were identical or nearly identical to alleles from Y. pseudotuberculosis . Thus, Y. pestis is a clone that evolved from Y. pseudotuberculosis 1,500–20,000 years ago, shortly before the first known pandemics of human plague. Three biovars (Antiqua, Medievalis, and Orientalis) have been distinguished by microbiologists within the Y. pestis clone. These biovars form distinct branches of a phylogenetic tree based on restriction fragment length polymorphisms of the locations of the IS 100 insertion element. These data are consistent with previous inferences that Antiqua caused a plague pandemic in the sixth century, Medievalis caused the Black Death and subsequent epidemics during the second pandemic wave, and Orientalis caused the current plague pandemic.

Genome sequence of Yersinia pestis, the causative agent of plague

“…3)) 1,500±20,000 years ago 4 . Thus Y. pestis seems to have rapidly adapted from being a mammalian enteropathogen widely found in the environment, to a blood-borne pathogen of mammals that is also able to parasitize insects and has limited capability for survival outside these hosts.…”

“…Protective mechanisms to attenuate damage are also set in motion 2 . 2-Arachidonoyl glycerol (2-AG) is an endogenous cannabinoid, identi®ed both in the periphery 3 and in the brain 4 , but its physiological roles have been only partially clari®ed 5±7 . Here we show that, after injury to the mouse brain, 2-AG may have a neuroprotective role in which the cannabinoid system is involved.…”

How old are bacterial pathogens?

“…The Y. pestis evolutionary tree is unambiguously rooted within Yersinia pseudotuberculosis, of which Y. pestis is a genetically monomorphic clade [47]. Branches and populations within that tree that are defined by extant diversity have already been assigned characteristic names [16,30,48], for example branch 0 for the ancestral branch leading from [30], [16] and [31], including additional ancient genomes and genotypes (see below), plus proposed mnemonics for those populations.…”

The importance of the magnesium transporter MgtB for virulence of Yersinia pseudotuberculosis and Yersinia pestis

“…pestis appears to have evolved from Y. pseudotuberculosis relatively recently (Achtman et al, 1999). It has adapted from the enteropathogenic lifestyle to become a fleavectored systemic pathogen by a complex process of gene acquisition and gene loss.…”