Bacillus anthracis 2016 2017 original

Bacillus anthracis

By

Prof / Mohamed A. Madany

Assiut University New-Valley branch

Department of Microbiology & Immunity


2Morphology :-

Gram +ve bacteria

Large (3-8 x 1-2 µm) , Encapsulated Bacilli (Polypeptide

capsule)

Spore forming

Non- Motile

Facultative anaerobic

May be Single , paired or long chain


3

The poly peptide capsule consist of D-glutamic acid

* Anti-Phagocytic & Plasmid encoded

* Not good Immunogen ( Resisted to Antibodies)

Morphology :-


4


5

With spore stain spore appear pink & bacilli appear blue .

With Gram stain (or Methylene blue) B. anthracis is violet or blue & surrounded by Hallo zone .

With Polychrome Methylene Blue (Mc Fadyean’s reaction) B. anthracis appear blue bacilli surrounded by purplish bink capsule ( diagnostic for B. anthracis ) .

With fluorescent-labeled antibody B. anthracis become fluorescent .

Staining :-


6

Nutrient broth >>> produce floccular turbidity >>> appear as cotton wool in the tube.

Nutrient agar >>> gray white , irregular colonies >>> “Medusa head “ appearance.

Blood agar >>> produce Non-hemolyic gray-white colonies , with irregular margins (curled hair).

Gelatin stap >>> slow lequification >>> inverted fir tree appearance.

Culture :-


7

(blue)

(red)


8

B. anthracis on Blood Agar


9

B. anthracis is catalase , nitrate reduction , starch hydrolysis , gelatin lequification tests >>> +ve .

On litmus milk>>> soft card is formed and digested quickly.

MR. & V.P. tests are variable , H2S production is -ve .

Biochemical characteristic :-


10

Starch Hydrolysis (Amylase Activity) :-

* Principle : Starch + Iodine >>>>> Blue color Glucose + Iodine >>>>> No reaction

* Procedure :

* Result :

Biochemical characteristic :-


11

B. anthracis contain 2 plasmid encoded virulence factors : 1) Capsule >>> linear γ-D-glutamic acid polymer. 2) Exotoxin (Trimer) consist of : A- Protective Antigen (PA) : It form Membrane channel that allow Edema Factor (EF) and

Lethal Factor (LF) to enter the mammalian cell via endocytosis. B- Lethal Factor (LF) : Both PA and LF are required for lethal activity. C- Edema Factor (EF) : Both PA and EF are required for edema to occur.

Virulence factors :-


12

AnthraxPathogenesis :-

Synonyms : Splenic feverCharacters : - Zoonotic , highly infectious disease - primarily affecting herbivores animals such as cattle , sheep ,

horses , mules and goats & secondary affecting man .Etiology : -B. anthracis which belong to family Bacillaceae


13

Anthrax (cont.)Susceptibility : - herbivores animals such as cattle , sheep , horses , mules ,

goats , pigs , dogs . - human is accidental host while birds are resistant.


14


15Anthrax (cont.)

Mode of transmission & source of Infection :- - Herbivores animals infection by >>>> ingestion or inhalation of spores

in the soil. - Carnivores become infected through consumption of infected animals

that have died from anthrax. - Human infected through : 1) broken skin (injuries). 2) Inhalation anthrax spores from contaminated animal products as

flesh , bones , hides , hair & wool. 3) Ingestion of infected animal meat.** N.B : Accidentally via biting flies ( Minor route ) during sever outbreaks.


16Anthrax (cont.)

Clinical signs :- 1- Peracute course of illness: * Mainly in cattle & sheep. * Lasts approximately

for 1-2 hours. * Characterized by : Sudden death of the animal ( 1st indication for

anthrax ). 2- Acute course of illness: * Mainly in equines. * Lasts approximately 96

hours. * Characterized by : Fever, enteritis, septicemia >>>> death. 3- Subacute / chronic course of illness: * Mainly in swine, dogs and cats. * Characterized by : Dysphagia, dyspnea, sever enteritis.


17Anthrax (cont.)

Post mortem lesions :- - Bloody discharge from natural openings e.g.: nose, mouth, anus,

etc. - Rabid bloating , failure of blood to clot.In MAN anthrax has 3 forms :- - Cutaneous form (malignant pastule). - pulmonary form (wool sorter’s disease). - Gastrointestinal form.


18

Bloody discharge

Bloating


19Anthrax (cont.)

Diagnosis :- 1) Sampling : - Blood sample >>> only taken from

ear , tail vein or natural openings of the dead animals

*** Blood smear stained by : - With Gram stain (or Methylene

blue) - With Polychrome Methylene Blue

(Mc Fadyean’s reaction) 2) Isolation & Identification :

Don’t Open the carcass of the dead animal

!


20Anthrax (cont.)

Diagnosis :- 3) Laboratory animal inoculation : 4) serological test : - ELISA for PA , LF and EF *** Ascoli test : 1- Procedure :- 2- Result :- +ve reaction >>>> formation of a ring of precipitate at the

junction of the 2 fluids in the capillary tube.


21Anthrax (cont.)

Diagnosis :- 5) Fluorescent labeled antibody staining : 6) PCR :


22Anthrax (cont.)

Treatment :- 1- Large doses of antibiotics with immune serum . 2- Penicillin & tetracycline are the most active .


23Anthrax (cont.)

Prevention and control :- 1- Notification of the authorities . 2- Quarantine the area . 3- Don’t open the carcass or examine postmortem & minimize the contact . 4- Passive immunization .*** Vaccination :- 1) Animal Vaccine 2) Human Vaccine - Pasteur Vaccine - Spore Vaccine - Sterne attenuated spore vaccine - UK Vaccine

- US Vaccine *** Simultaneous Method : The best method is to inject 10-20 c.c. of hyper

immune serum in one shoulder & at the same time a dose of used vaccine is injected into the other shoulder .


24

Bacillus anthracis 2016 2017 original

Education

Transcript of Bacillus anthracis 2016 2017 original