histotoxic clostridia

8/13/2019 histotoxic clostridia

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Presented by:

Maheshwari Rathod


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Morphology Clostridiumis a genusof Gram-positivebacteria,

belonging to the Firmicutes.

They are obligate anaerobescapable ofproducingendospores.

Singly or in chains.

Remain viable for thousands of years.
http://en.wikipedia.org/wiki/Genushttp://en.wikipedia.org/wiki/Gram-positivehttp://en.wikipedia.org/wiki/Firmicuteshttp://en.wikipedia.org/wiki/Obligate_anaerobehttp://en.wikipedia.org/wiki/Endosporehttp://en.wikipedia.org/wiki/Endosporehttp://en.wikipedia.org/wiki/Obligate_anaerobehttp://en.wikipedia.org/wiki/Firmicuteshttp://en.wikipedia.org/wiki/Gram-positivehttp://en.wikipedia.org/wiki/Gram-positivehttp://en.wikipedia.org/wiki/Gram-positivehttp://en.wikipedia.org/wiki/Genus


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Histotoxic clostridia The exotoxins produced by these clostridia produce

local tissue necrosis and systemic toxaemia.

Examples include C. chauvoei, the major cause ofblackleg, and C. novyi type B, which causes blackdisease.


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List of clostridia & diseases Clostridium chauvoei Blackleg Clostridium septicum -Malignant oedema

-Braxy (sheep)

Clostridium novyi type A -Big head of rams

Clostridium novyi type B -Black disease (necrotichepatitis)

Clostridium haemolyticum (C.novyi type D)Bacillary

haemoglobinuria

Clostridium sordellii -Gas gangreneAbomasitis


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C. chauvoei Blackleg (gangrenous myositis),caused by C. chauvoei,

is the most common clostridial disease seen in cattle.

Gangrenous myositis occurs less commonly in sheep. However, C.chauvoei commonly causes a

postparturient metritis of sheep.


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Black leg The majority of blackleg cases occur in young cattle (3

months to 2 years of age) during the summer month.

Crepitation is present over affected muscle masses,which are initially warm and painful; later becomingcold and insensitive.

Death usually occurs within 12-24 hours following

signs of systemic toxaemia: dyspnoea, recumbency andcoma.


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Post mortem lesionsAt post-mortem examination lesions are principally

found in the large muscle masses of the fore- andhindquarter.

There is a characteristic rancid odour from recentlydissected lesions.

Visceral lesions due to C. chauvoei infection, such as

pericarditis and pleurisy, are frequently seen.


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Clostridium septicum C. septicum is primarily associated with malignant

oedema in cattle and sheep.

Signs of malignant oedema include subcutaneousaccumulation of f luid, dullness and inappetence.

The lesion may be associated with a wound or mayoccur following intramuscular injections.

C. septicum also causes abomasitis of sheep, known asbraxy.


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C . novyi type D C. novyi type D causes bacillary haemoglobinuria of

cattle.

Clinical disease is characterised by the presence ofdark red urine and fresh blood in the rectal contents.

On post-mortem examination all cases have amahogany-coloured liver in which there is a least one

focal area of necrosis. The urine is dark red and there is blood in the faeces.

Jaundice is present in all cases, but the intensity variesfrom slight to pronounced.


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C. novyi may be identified in the liver lesion by thefluorescent antibody technique.

In order to differentiate C.novyi type D from C.novyi type B, toxin-antitoxin tests are required


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C. Sordellii C. sordellii was traditionally associatedwith gas

gangrene, a wound infection of cattle and sheep.

It has also been associated with acute abomasitis inyoung lambs, 3-10 weeks of age, and sudden death

abomasitis in finishing lambs of 6-12 months of age


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PM Lesions Post-mortem lesions of C. sordellii

abomasitis vary depending on the age

of the sheep. In lambs 3-10 weeks of age the abomasum is partially

distended and displaced.

The abomasal wall is thickened due to a combination

of emphysema and oedema. Erosions and congestion are present in the abomasal

mucosa.


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Erosions and congestion are present in theabomasal mucosa.The main feature of C. sordellii abomasitis in lambs4-6 months of age is abomasal congestion with someulceration.The carcasses appear toxaemic.Post-mortem findings in older ewes are less specific.


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Blood-tinged fluid in the abdominal cavity and a

perforated abomasal ulcer.C. sordellii may be identified in the abomasum by thefluorescent antibody technique.

histotoxic clostridia

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