Yersinia pasteurella fransicella for undergraduates

1. Yersinia, pasteurella &
francisella

2. PASTEURELLA
YERSINIA
Y.PESTIS
Y.PSEUDOTUBERC
ULOSIS
Y.
ENTEROCOLITICA
PASTEURELLA
P.MULTOCIDA
FRANCISELLA
F.TULARENSIS
GRAM NEGATIVE ,
SHORT BACILLI,
RODENT PATHOGENS
CULTURE,
BIOCHEMICALS

3. YERSINIA PESTIS
PLAGUE BACILLI
DISCOVERED BY YERSIN &
KITASATO IN 1894

4. MORPHOLOGY
• Gram Negative
• Short bacilli with rounded ends
• Appears in singles, short chains or short groups
• Non notile, non sporing
• Non acid fast
• Bipolar staining ( Safety pin appearance)
• Pleomorphism
• Pleomorphism enhanced in media containing
3%NaCl

6. • When smears are stained with giemsa stain or
methylene blue stain the two ends stain
deeply leaving a clear central area.

7. CULTURE
• Aerobic & facultative anerobic
• pH – 5-9.6, optimum pH 7.2
• Temperature – 2-45°
• Best growth at 27 degrees
• Envelope develops best at 35 Degrees

8. Colony morphology
• Nutrient agar – small delicate transparent disc
which becomes opaque on prolonged incubation.
• Blood agar – Dark brown due to absorption of
hemin pigment
• Mac Conkey agar – colorless colonies
• Growth in broth – Flocculent growth at bottom
and side of tube
• Ghee broth – Stalactite growth (Growth hangs
down from the broth surface)

12. Biochemicals
• Catalase – Positive
• Oxidase - Negative
• Indole – Negative
• Methyl red – positive
• VP – Negative
• Citrate – negative
• Urease – positive
• Sugars – Glucose, Maltose and Mannitol
fermented . No Gas production

13. Resistance
• Easily desroyed by heat, sunlight, drying and
chemical disinfectants
• Killed by 55°C
• 0.5% phenol
• Viable in cold moist environments
• All strains lysed by a antiplague bacteriophage
at 22°C

14. Virulence factors
• Protein envelope (F-I)
– Plasmid coded
– Present only in virulent strains
– Heat labile
– Best developed at 37°C
– Inhibits phagocytosis
– Antibody to this antigen is protective in mice
• V and W antigens
– Always produced together
– Plasmid mediated
– Inhibits phagocytosis & intracellular killing of bacilli.

15. Virulence factors
• Bacteriocin
– Pesticin I
– Inhibits Y.pseudotuberculosis, Y.enterocolitica and E.coli
• Coagulase
• Fibrinolysin
• Plague Toxins (Murine toxins*)
– Endotoxin
• LPS
– Protein
• Has both properties of exotoxin and endotoxin
• Thermolabile
• Can be toxoided
• Toxicity predominantly in Rats and Mice*
• Local injection produces edema, necrosis
• Affects peripheral vascular system and Liver

16. Plague
 Pandemics and epidemics
 Black Death – Cutaneous hemorrhage and necrosis.
 41 epidemics in BC era
 109 epidemics in AD
 Last epidemic in 1894
 Reached Bombay in 1896
 Spread all over country with 10million deaths till 1918
 Now endemic foci persists

17. • Human infection
– Bubonic
– Pneumonic
– Septicemic
• BUBONIC PLAGUE
• Incubation period 2-5days
• Draining lymph nodes become infected
• Most common bite is in legs  enlargement of inguinal lymph nodes (BUBONIC –
Bubon – Groin)
• Glands enlarge and suppurate
• Septicemia
• Hemorrhages , DIC  Gangrene of Skin, Fingers and penis
• Case fatality – 30-90%
Plague
PESTIS MINOR

18. PNEUMONIC PLAGUE
• Seen during epidemics of bubonic
plague
• Epidemic of pneumonic plague rare
• Spread by droplet infection
• Hemorrhagic pneumonia.
• Cyanosis.
• Bloody mucoid sputum that is coughed
out is highly infectious
• Mostly fatal
Septicemic PLAGUE
• Terminal event of bubonic / pneumonic plague
• May occur as primary infection rarely
• Meningeal involvement may be present
• asym,ptomatic orophryngeal carrier state has been observed
• No human carriers

19. Infected Rat
Bitten by
Rat flea
Bacilli
multiply in
stomach
Blocks proventiculus
(blocked flea)
Extensive
multiplication
Extrinsicincubationperiod
Tries to bite the
next rodent
Regurgitates the
bacilli along with
bite
Infected
second
rat
Death of rats
( Rat fall)
Flea leaves the
carcass
Rat
Human
Bubonic plague
Contamination of bite wound
with feces of flea

20. Vectors
 Xenopsylla cheopis
• Xenopsylla astia
• Ceratophyllus fasciatus
• Epidemics occur in cool , humid seasons  favors
multiplication of fleas.
• High flea index

21. Epidemiology
• Epizootic in Rattus norvegicus ( sewer rat)
• As the population came down the infection spread to domestic rats.
• Urban cycle / Domestic cycle
• Wild / Sylvatic cycle
• Infected fleas live for an year.
• Y.pestis can live & multiply in soil ( abandoned burrows)  infects
new rodents  re-emergence of disease after a long period.

22. Lab diagnosis
• In Rats
– May have ectoparasites
– Kerosene/ 3%lysol can be used to eliminate ectoparasites
– Buboes in cervical region – Hard and moves under the skin
– c/s – Congestion, Hemorrhagic points or grey necrosis
– Smear – bipolar staining, pleomorphism
– Fluorescent antibody technique – impression films

23. F- ab stain

24. • Liver – motled with red , yellow or grey stippling
• Spleen – enlarged, granular or nodular
• Pleural effusion – Clear, abundant or straw coloured. Rarely blood
stained
• Culture – from buboes, spleen, heart blood and bone marrow ( in
decomposed carcasses)
• In case of putrefied carcasses – putrified tissue may be rubbed on
shaven abdomen of guinea pig  F1 antigen (immunofluorescence)
Lab diagnosis

25. Lab diagnosis
• In human
– Bubonic plague
• Microscopy
• Culture: blood cultures often positive
• Animal inoculation
– Pneumonic plague
• Bacilli in Sputum microscopy
• Culture
• Animal inoculation
– Serological diagnosis
• Antibidies to F-1 antigen (>128)
• IgM/IgG ELISA
• PCR

26. Prophylaxis
• Control of fleas and rodents
• Vaccines
– Killed – prepared by Haffkine instiute ,Mumbai
• Given s/c , 2 doses, 3 months interval followed by 3rd dose 6
months later
• No protection against pneumonic plague
• Infection gives better immunity compared to vaccination
• At risk patients – cotrimoxazole or tetracycline for 5days
• No use in outbreaks/ mass vaccination
– Live attenuated – Otten’s Tjiwidej strain – Indonesia
Girard’s strain – malagasy
• Not in use due to severe reactions

27. Treatment
• Streptomycin
• Doxycycline
• Chloramphenicol

28. Yersiniosis
Zoonotic infections by Y.pseudotuberculosis & Y.enterocolitica
• Y.pseudotuberculosis
• Resembles Y.Pestis
• Poor growth on Mac Conkey agar
• Motile at 22°C but non motile at 37°C
• Urease – Positive
• Not lysed by antiplague bacteriophage
• 6 serogroups based on somatic and flagellar antigens
• Infected guinea pigs multiple nodules seen in Liver, Spleen and Lungs resembling
tuberculosis  Pseudotuberculosis.
• Human infection – Fatal typhoid like illness with
– Hepatospeenomegaly and purpura
– Mesentric lymphadenitis
– Erythema nodosum
– Gastroenteritis

29. Yersiniosis
Zoonotic infections by Y.pseudotuberculosis & Y.enterocolitica
• Y.enterocolitica
• Biochemical differences
• More than 60 o serotypes
• Most common human infections – 03, 08 & 09
• Self limited gastroenteritis/ enterocolitis
• Mesentric adenitis / inflammatory terminal ileitis
• Systemic disease – Bacteremia, meningitis , arthralgia or erythema nodosum
• People with HLA –B27 are more prone to reactive arthritis

30. Pasteurella multocida
• Hemorrhagic septicemia in animals and birds
– Gram negative bacillus
– Non motile
– Oxidase positive
– Indole positive
– Do not grow on Mac Conkey agar
• May be seen as commensal in animals and humans
• Human infection rare – follows bite/trauma
– Local suppuration
– Meningitis
– Respiratory tract infection
– Appendicitis
• Treatment
• Penicillin, Tetracycline & Streptomycin

31. Francisella tularensis
• Tularemia
• Transmitted by ticks / ingestion of contaminated meat or
water / inhalation of infective aerosols
• Minute GNB, Non motile, Capsulated.
• Multiply by filament formation and budding
• Intracellular parasite – Liver and spleen cells
• FRANCI’S BLOOD DEXTROSE CYSTINE AGAR-
minute colonies after 3-5days

32. Tularemia
• Local ulceration with lymphadenitis
• Typhoid like fever with glandular enlargement
• Influenza like respiratory infection
• Water borne infection
• Diagnosis by culture or inoculation in guinea pigs/mice
• Agglutinating antibodies
• Attenuated vaccine – administered by scarification