Yersinia

Question 1

Transmission

Answer 1

ANIMAL PATHOGENS transmitted to humans via FOOD and WATER or INSECT VECTORS

Question 2

Species (3)

Answer 2

Yersinia entercolitica
Yersinia tuberculosis
Yersinia pestis

Question 3

Yersinia entercolitica- General characteristics (2)

Answer 3

Grow on selective medium CIN agar producing PINK “BULLS EYE” colonies

Motile at 25 degrees and Non-motile at 37 degrees

Question 4

Yersinia entercolitica- Diseases (5)

Answer 4

BLOODY DIARRHEA with fever and abdominal pain
PSEUDOAPPENDICITIS —> MESENTERIC LYMPH ADENITIS and TERMINAL ILEITIS

Sequelae- Arthalgia (joint pain), Reactive arthritis / Reiters syndrome, ERYTHEMA NODOSUM

Question 5

Yersinia entercolitica- Virulence (2)

Answer 5

1- INVADE terminal ileum and colon, produce ENTEROTOXIN

2- PLASMID (pYV) encodes OUTER MEMBRANE PROTEINS (Yops) that KILL MACROPHAGES and NEUTROPHILS

Question 6

Yersinia entercolitica- Common?

Answer 6

Cold climate

Question 7

Yersinia entercolitica- Reservoir

Answer 7

Animals (pigs)

Question 8

Yersinia entercolitica- Transmission (2)

Answer 8

MAIN —> Contaminated pork

Transfused blood because organism multiples in refrigerated contaminated blood

Question 9

Yersinia pseudotuberculosis (6)

Answer 9

BIPOLAR staining
SEPTICEMIA and VISCERAL NODULES in animals
Transmitted to humans by contaminated food and water
Causes ACUTE ILEITIS and MESENTERIC LYMPHADENITIS in humans
Virulence factors- PLASMID-ENCODED INVASIN and ENTEROTOXIN
Isolated by COLD ENRICHMENT in BUFFERED SALINE

Question 10

Yersinia pestis- General characteristics (2)

Answer 10

NON-MOTILE

BIPOLAR staining resembles SAFETY PIN

Question 11

Yersinia pestis- Diseases

Answer 11

PLAGUE

BLACK DEATH

Question 12

Forms of Plague (3)

Answer 12

1- BUBONIC plague: Swollen lymph node at area of flea bite; symptoms include rigor, fever, mental confusion, hypotension

2- SEPTICEMIC plague: Organism spread throughout body; symptoms include GI symptoms, hypotension, shock, bleeding from orfices, high mortality

3- PNEUMONIC plague: Complication of above two or primary form acquired through aerosol; individuals develop pneumonia, almost fatal

Question 13

Yersinia pestis- Virulence Factors (4)

Answer 13

1- INTRACELLULAR pathogen —> in phagocytes

2- F1 CAPSULE —> resists phagocytosis

3- V and W ANTIGENS —> contribute to INTRACELLULAR SURVIVAL

4- Yops —> injected into phagocytes inhibit phagocytosis and cytokines production

Question 14

Yersinia pestis- Transmission (2)

Answer 14

RAT FLEAS transmit infections to humans in WILD AREAS (SYLVATIC PLAGUE) and in URBAN AREAS (URBAN PLAGUE)

Transmission from human to human by RESPIRATORY DROPLET

Question 15

Yersinia pestis- Use

Answer 15

WEAPON of BIOLOGICAL WARFARE (can kill large number of people in short time)

Question 16

Yersinia pestis- Vaccination

Answer 16

FORMALIN-KILLED vaccine gives PARTIAL protection against BUBONIC plague

(Vaccine available)

Question 17

Yersinia pestis- Treatment

Answer 17

Gentamicin