This document discusses the genus Yersinia, focusing on important pathogenic species. It covers Yersinia pestis, the causative agent of plague, describing its isolation, transmission cycle involving rodents and fleas, clinical forms (bubonic, pneumonic, septicemic), diagnosis and treatment. It also briefly discusses Yersinia pseudotuberculosis and Yersinia enterocolitica, which can cause yersiniosis in humans and animals through contaminated food.

1. Yersinieae
MBBS (2016 Batch)
28th Feb, 2018
By
Dr Puneet Kumar Gupta
Assistant Professor, Microbiology

2. Yersinia
Important species :
 Y.pestis:
 Plague in man & rodent
Yersiniosis
 Y.pseudotuberculosis
 Pseudotuberculosis in animals
 Y.enterocolitica
 Enteritis in man & animal

3. Yersinia pestis
 Enterobacteriaceae
 GNB, Cat+ve,
 Oxidase –ve, Glucose
fermenter
 Non sporing non acid
fast.
 Bipolar Staining(safety
pin appearance)

4. Y. pestis
 1894-1st Isolated- Alexandre Yersin (Hong
Kong)

5. No serotypes but biotypes
Biotypes Nitrate
reduction
Glycerol
fermentation
Pandemic
associated
Y. pestis var
antiqua
+ + 1st -Justinian
(AD 541)
Roman Emperor
Justinian
Y. pestis var
medievalis
- + 2nd –Black
Death –Europe
(1347-52)
Killed 1/3rd
population
Y. pestis var
orientalis
+ - 3rd- Hong Kong,
China, India
(1894-1918)
10 million deaths

6. India
1896-1918 Entered India
1918-67 Declined occasional cases
from endemic area
1967-1994 No cases
1994 Surat Epidemic-
Start-Beet Latur belt
(Maharashtra)
>6000 suspects
>60 deaths
2002 Rohru Shimla Outbreak 4 deaths
2004 Dangud village Uttarkashi
outbreak
8 cases
3 deaths

7. 4 Foci
1. Kolar-Trijunction of KAT—(Karnataka, Andra
Pradesh, TN)
2. Beed Latur Belt- Maharashtra
3. Rohru shimla HP
4. Dangud Village Uttarkashi

8. Plague
 Zoonotic disease
 Reservoir :Wild Rodent(Rats)
 Vector :Rat flea
 Xenopsylla cheopsis-North India-Most efficient
 X. astia- South India-less efficient
 X. brasiliensis
 Human Flea-less common

9.  Source of Infection:
 Infected Wild Rodents rat flea
 Pneumonic plague cases
 Cycles
 Domestic/Urban-
 Human-Rat flea-Rodents
 Potential of epidemic
 Wild/Sylvatic-wild rodents----No human

10.  Mode of transmission:
 Infected Rat flea bite (MC)
 Direct contact tissue of infected animal
 Droplet-Pneumonic plague
 Bite by infected human flea (Pulex irritans)
 Cycles
 Domestic/Urban-
 Human-Rat flea-Rodents
 Potential of epidemic
 Wild/Sylvatic-wild rodents----No human

11. Infected Rodent
Flea bite
Bacteria multiply
in gut block
proventriculus
Suck-
Regurgitate
blood to bite site

12. In man
 Plague occur in three form
 Bubonic Plague
 Pneumonic Plague
 Septicaemic Plague

13. Bubonic Plague
 Bubo:groin
 Tender Inguinal LAP
 Rat flea bite on leg
 Fever,chill,malaise with bubo
 Incubation period 2-7 d
 Mortality :30-90%

14. If not treated
 Bacteremia
 IP 2-7 d
 Blood vessel involved
 Hemorrhage in skin & mucosa---
Gangrene of affected area
 Black death
 If crosses blood brain barrier
:meningeal plague

15. Pneumonic Plague
 Most dangerous variety
 Virtually always fatal
 Most infectious (Droplet)
 Involves lung
 Hemorrhagic pneumonia
 Short IP (1-3 d)

16. Specimen:
 Bubonic plague :
 Aspirate from bubo
 Pneumonic Plague/Septicemic Plague :
 Sputum, Blood, Splenic aspirate (Post
mortem)
 Strict Bio safety Precaution is needed.

17. Yersinia pestis
 Enterobacteriaceae
 ?
 GNB,Cat+ve,Oxidase –
ve,Glucose fermenter
 Non sporing non acid
fast.
 Bipolar Staining(safety
pin apperance)

18. Microscopy:
 Gram Stain :
 GNB
 Giemsa/ Methylene
blue (Wayson Stain)
 Bipolar safety pin
appearance.
 Antigen detection:
 F1Glycoprotein
detection from
samples by IF/ELISA

19. Culture Characteristics
 Aerobic /facultative anaerobic
 Grow on ordinary media (slowly)
 Ideal growth temperature :27 degree
 Rapid growth in media containing
blood, body fluid
 Small colorless(?) colony
 Nutrient broth:
 Ghee broth :Stalactites growth

20. Culture Characteristics
 BA: Dark pigmented-Absorption of
hemin
 MA-NLF
 CIN (Cefsulodin Irgasan Novobiocin
Agar)-Selective medium-Sputum
 Animal Inoculation:
 Guinea Pig/ White rat—Badly putrefied
carcasses

21.  Serology
Ab to F1 Ag: ≥128 Titer
 Passive Haemagglutination)
 IgG or IgM ELISA
 Molecular
 PCR targeting F1 Ag gen
 Pesticin gene
 Plasminogen activator gene

22. Diagnosis in Dead Rodent
 Kerosene over
carcasses (to kill the
flea)
 Buboes are present
in the cervical
reason
 Buboes, liver, spleen
are processed like
clinical sample

23. Treatment
 Early start
 Genamicin> Streptomycin
 Other :
 Doxycycline,
 Choramphenicol


24. Prophylaxis
 Vaccine :
 Killed Vaccine (Formalin):
 Killed virulent strains(Haffkin institute Mumbai)
 Short lasting immunity (<6mths)
 Live vaccine: a virulent strains
 Subunit Recombiant Vaccine (Under trial)
 All contacts of pneumonic plague:
Doxy/ Tetracycline x 7days

25. Yersinia
Important species :
 Y.pestis:
 Plague in man & rodent
Yersiniosis
 Y.pseudotuberculosis
 Pseudotuberculosis in animals
 Y.enterocolitica
 Enteritis in man & animal

26. Y. enterocolitica Y.
pseudotuberculosis
Distribution Worldwide Northern Europe &
America
Serotypes (basis) 60 (O Ag)
(6 biotypes)
6 (O & H Ag)
Growth on MA Grow Well NLF Poor growth
Sugar Fermentation Sucrose, Cellobiose,
sorbitol
Rhamnose salicin,
melibiose
Ornithine
decarboxylation
+ -
VP + -
Ab to O Ag Late during
convalescent phase
Appear early in acute
phase
Beta lactamases
production
Nearly always not

27. Yersiniosis
 Zoonotic infection
 Usual host: Pigs, wild/ domestic animals
 Human infection: Consumption of
contaminated food,
 Children>
 Cold climate

28. C/F
 Self limiting gastroenteritis/
Enterocolitis:
 Inflammatory/ non inflammatory
 Intestinal complications:
 Terminal ileitis (Mostly Y. enterocolitica)-
mimic appendicitis
 Septicaemia (Risk factor: DM, Liver ds,
Fe overload)

29. C/F
 Post infective Phenomenon (Adult)
 Due to deposition of non viable
components in joints & Other site
 Reactive arthritis: a/c HLA B 27
 Erythema nodosum
 Grave disease
 SuperAg:
 Scarlet fever in Russia
 Izumi fever- Japan
 Linked to Kawasaki ds childhood

30. Lab diagnosis
 Culture
 BA: Beaten copper colony
 Selective media: CIN: Dark red bull’s eye
colony
 Cold enrichment: Phosphate buffered
saline at 40C x 3 week

31. Treatment
 Self limiting diarrhoea
 Treatment in systemic infection:
 Quinolone/ 3rd generation cephalosporins