1. Yersinia

Yersinia enterocolitica

causes Yersiniosis

Where does Yersinia enterocolitica come from 

raw or undercooked pork 

Yersinia pseudotuberculosis

a rare cause of foodborne illness

Yersinia pestis

Black death plague

Black death 

most fatal pandemic in recorded human history 

Yersinia pestis is transmitted by

oriental rat flea (carried by small rodents)

Is Y. restis only zoonotic transmission

No, also person to person

Bubonic plaque 

transmitted by fleas and affects lymph nodes 

Speticemic plague

enters through break in skin, causes blackened extremities

Pneumonic plague

transmitted person to person by respiratory droplets, causes respiratory failure

which is the most severe and lethal from of pague 

pneumonic plague 

which plague has the best chance of survival 

Bubonic plague 

Plague Buboes

are swollen and painful lymph nodes, characteristic of bubonic plague.

What type of pathogen is yersinia pestis

facultative intracellular pathogen

Alexandre Yersin 

french physician from pasteur institute who co-discovered Yersinia pestis, the causative agent of plague.

Kitasato Shibasaburō

japanese physician who co-discovered Yersinia pestis and contributed to the understanding of infectious diseases.

Can yersinia pestis form biofilms

YES! forms biofilm inside the flea and contributes to its transmission.

Main component of Y. pestis biofilm 

polysaccharide called N-acetyl-D-glucosamine (a derivative of glucose)

N-acetyl-D-glucosamine

produced an exported from cell by gene cluster called hms

Why does y. pestis form biofilm inside flea

blocks the flea’s digestive system and starves them. In an attempt to feed, the flea will bite repeatedly and infect new hosts

How does Y. pestis get from the flea to the host

As the flea bites the human, it regurgitates Y. pestis into host bloodstream

How is Y. pestis regulated 

Cyclic-di-GMP levels are regulated by the hms gene

C-di-GMP production 

by diguanylate cyclase with GGDEF

C-di-GMP degradation 

phosphodiesterase with EAL or HD-GYP amino acid motifs

So c-gi-GMP binds to what

PilZ to inhibit motility and virulence, while promoting biofilm factors

diguanylate cyclase (DGC) specific for y. pestis

HmsT

HmsT 

makes c-di-GMP

phosphodiesterase (EAL) specific to y. pestis

HmsP to break down c-di-GMP

Which protein in Y. pestis actually has the PilZ domain for c-di-GMP to bind

HmsR

Once inside the host, how does Y. pestis replicate 

Intracellular 

What cells does Y. pestis infect

Macrophages

How does y. pestis prevent phagolysosomal fusion

Recruiting Rab proteins to the phagosome

Rab proteins: Rab4a and Rab1b

proteins that are recruited to inhibit phagolysosomal fusion to freely proliferate in a non-acidic phagosome

All pathogenic yersinia have

type 3 secretion system

Type 3 secretion systems are often called

injectosomes because they resemble a needle

The effectors of the Yersinia type 3 secretion system

Yop effectors 

Yersinia Yop effectors

proteins that work together to prevent bacterial phagocytosis from host cells

All Yops and T3SS are encoded by 

plasmid pCD1

Plasmid-encoded virulence factors are often 

acquired by horitzontal gene transfer 

Y. pseudotuberculosis, Y. pestis and Y. enterocolitica

all have the EXACT SAME pCD1 PLASMID!! But cause very diff disease due to niche and transcriptional regulation

Both Y. pseudotuberculosis and Y. enterocolitica are

motile, but Y. pestis is not 

Y. pestis has additional

virulence plasmids that the other yersinia do not have

Which virulce plasmids are only in Y. pestis

pMT1 and pPla

pMT1

contains genes that allow for survival in flea vector 

pPla

encodes plasminogen activator that breaks down blood clots

Y. pestinia induces 

apoptosis of host cells to grow in lymph nodes and spread throughout body 

Quiz next class

Y. pestis biofim in flea