yersinia mahadi ppt
TRANSCRIPT
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Sharq Elneil College
School of Medical Laboratory Sciences
Department of Microbiology
Medical Bacteriology course
Mr.Mahadi Hassan Mahmoud Bsc, Msc, MIBMS Microbiology
08 April 2014
genus yersinia includes
yersinia pestis, the cause of plauge
y.pseudotuberculosis
y.enterocolitica, important causes of diarrhoeal disease
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francisella tularensis occasionally causes septic infections.
several species of pasteurlla are primarily animal pathogens but also causes human disease.
Gram-negative rod short, pleomorphic
Intracellular pathogen
Zoonotic infection
exhibit bipolar staining.
they are catalase positive,
oxidase negative,
microaerophilic or facultative anaerobic.
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World-wide problem
India has had latest scare (100s infected)
Sporadic cases in the U.S., south-western mostly
Usually associated with contact with squirrels and other urban animals
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Flea bite
Bacilli travel to lymph nodes
Infection results in swelling and pain (Bubo seen in picture below)
High fever, chills, headache, nausea
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Clinical Syndromes (Septicemic Plague)
Can penetrate and invade bloodstream
All organs infected
Lungs (secondary pneumonic plague)
Danger to close contacts
Clinical Syndromes (Primary Pneumonic Plague)
Spread via respiratory droplets
1 bacilli can cause disease in patient
Severe hemorrhaging
Death in hours
100% mortality if untreated, or late treatment
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50-75% mortality when it goes to bloodstream
Endotoxin shock primary problem
Intravascular coagulation
Multi-organ failure
“bruising” on skin……this is how it got the name the ”black death”
See the same thing with Neisseria meningitidis
Yersinia pestis and plauge
Plauge is an infection of wild rodents, rodents, rodents, transmitted from one rodent to another and occasionally from rodent to human by the bites of fleas (black death).
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I. Bubonic Plague: Interhuman Transmission:
> Bubonic Disease >Pneumonic
Plague > Exhales the Organism in
Droplets.
Pestis Minor:
ii. Septicaemic Plague:
iii. Pneumonic Plague:
Symptoms
After i.p of 2-7days,there is high fever and painful lymphadenopathy, common with greatly enlarged, tender nodes (buboes) in the groin of axillae. vomiting and diarrhoea may occur with early sepsis. later D.I.C. lead to hypotension, renal and cardiac failure. y. p, multiplies intravascular and can be seen in B. smears.
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Specimens:
Blood is taken for culture
Aspirates of enlarged lymph nodes for smear and culture.
Acute and convalescent sera may be Examined for antibody level
Pneumonia sputum is cultured,
Meningitis C.S.F is taken for smear and culture.
Stained with giemsa
waysons
I.F stain.
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Culture: all materials are cultured on
B.A
MaCconkey
infusion broth.
on solid media growth is slow but b.
cultures are often positive in 24hrs.
Serology:
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Sensetive to
streptomycin.
Tetracycline
some times given in combination.
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A Quarantinable Disease.
Control of Urban Plague:
Garbage Disposal.
Y. enterocolitica and Y. pseudotuberculosis
These are non lactose fermenting
G-ve rods that are Urase+ and Oxid-.They grow best at 25 cand also motile, but not motile at37c,
Diagnostic tests:
Specimen, culture, serology.
Treatment: most yersiniae infections with diarrheal are self limited.
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Francisella Tularensis and
Tularemia
F.Tularences, is widely found in animal reservoirs and transmitted to human by biting arthropods, inhalation or ingestion of contaminated water or food.
Morphology and identification
F.T, is small G-ve pleomorphic rods, it rarely seen in smears of tissue.
Specimen: blood is taken for serologic tests.
Culture:
growth does not occur in most ordinary media
small colonies appear in 1-3 days on glucose cysteine B.A incubated 37c under aerobic condition.
the organism identified usually by its growth requirement and I.F stain.
Caution: the organism is highly infectious.
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Serology:
there is one or more AG can cross react with brucella.
Diagnostic tests:
generally smears and cultures are not contributory
diagnostic tests rests on serology, paired serum collected 2 weeks apart can show arise in titer, titer of 1:60 is highly suggestive.
Antibiogram
Sensetive to:
Streptomycin
Gentamicin
Tetracycline equally effective, but relapses occur morely frequently.
Ceftriaxone is not effective.
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These are primarily animal pathogens
non motile
G-ve coco bacilli
They are aerobe and facultative
anaerobe they are grow in ordinary
media at 37c .they are O+ve, Cat+ve.
Pathology The most common presentation is a history
of animal bite followed by an acute onset
of redness, swelling and pain, fever is often
low grade, lymphadenopathy is variable.
infections some times present as
bacteremia or chronic respiratory infection
without an evident connection with
animals.
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species routine
nutri-
ent
media
bile
salt
media
Motil
ity
At 22c
At
37 c Acid (no gas)
from
maltose
sucrose
y. pestis + + - -- + -
y. pseudo-
tuberculosis
+ + + - + -
y. enterocolitica + + + - +b +
p. multocida + - - - - +
F tularensis - - - - + -
species slicin indol
e
urea
se
oxidas
e
cat onpg Orithine
decarbo
xylase
Y. pestis + - - - + + -
Y. pseudo
tuberculosis
+ - + - + + -
Y. enterocolitica - - + - + + +
P. multocida - + - -/+ + - +
P. ureae - - + + + - +
F. tularensis … - - … +/- …. -
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