Yersinia pestis
From DrugPedia: A Wikipedia for Drug discovery
Yersinia pestis
Yersinia pestis (formerly Pasteurella pestis) is a Gram-negative rod-shaped bacterium that can infect humans and other animals. Its closest relative is the gastrointestinal pathogen Yersinia pseudotuberculosis, and more distantly Yersinia enterocolitica.
| Kingdom | Eubacteria |
|---|---|
| Phylum | Proteobacteria |
| Class | Gammaproteobacteria |
| Order | Enterobacteriales |
| Family | Enterobacteriaceae |
| Genus | Yersinia |
| Species | Y. pestis |
| Binomial | Yersinia pestis |
Surface Characteristics
Y. pestis has typical cell wall and whole-cell lipid compositions and an enterobacterial antigen. Its lipopolysaccharide is characterized as rough, possessing core components but lacking extended O-group side chains; while there is no true capsule, a carbohydrate-protein envelope, termed capsular antigen or fraction 1 (F1), forms during growth above 33 C (14, 32, 215). This facultative anaerobe possesses a constitutive glyoxylate bypass and unregulated L-serine deaminase expression but lacks detectable adenine deaminase, aspartase, glucose 6-phosphate dehydrogenase, ornithine decarboxylase, and urease activities, as well as a possible lesion in -ketoglutarate dehydrogenase (32, 33, 125).
Transmission
Initial acquisition of Y. pestis by the vector occurs during feeding on an infected animal. Rat flea (Xenopsylla cheopis), the classical vector for plague will ingest 0.03 to 0.5 µl of blood. Maintenance of the bacteria in the flea digestive tract is contributed by several proteins some of these are hemin storage (Hms) system and Yersinia murine toxin (Ymt). Ymt is important for the survival of Y. pestis in fleas while Hms system plays an important role in the transmission of Y. pestis back to a mammalian host.he Hms system plays an important role in the transmission of Y. pestis back to a mammalian host. In the insect vector, proteins encoded by Hms genetic loci induce biofilm formation in the proventriculus, a valve connecting the midgut to the esophagus.Transmission of Y. pestis occurs during the futile attempts of the flea to feed. Ingested blood is pumped into the esophagus, where it dislodges bacteria growing there and is regurgitated back into the host circulatory system.
