|
|
| (19 intermediate revisions by 2 users not shown) |
| Line 1: |
Line 1: |
| − | ===Overview=== | + | {{frontpage |
| | + | |pagetitle =Clostridium species |
| | + | |pagebody = |
| | + | <div style="text-align: left; direction: ltr; margin-left: 1em;"> |
| | + | Clostridium organisms are ubiquitously present in the soil, alimentary tract and faeces of many animal species. There are several different pathologies associated with Clostridium species: neurotoxic clostridia such as ''Clostridium tetani'' and ''Clostridium botulinum'' affect neuromuscular function but cause no tissue damage. Histotoxic clostridia can cause localised lesions in tissues and may cause toxaemia. ''C. perfringens'' causes inflammatory lesions in the gastrointestinal tract and enterotoxaemias in sheep. In some species, endospores may be present in the liver which can be reactivated to cause disease periodically. |
| | + | </div> |
| | + | |contenttitle =Content |
| | + | |contentbody =<big><b> |
| | + | <categorytree mode=pages>Clostridium species</categorytree> |
| | + | </b></big> |
| | + | |logo =bugs-logo copy.png |
| | + | }} |
| | | | |
| − | *Organisms present in the soil, alimentary tract and faeces
| |
| − | *Endospores may be present in liver and may be reactivated to cause disease
| |
| − | *Neurotoxic clostridia, ''Clostridium tetani'' and ''Clostridium botulinum'' affect neuromuscular function but cause no tissue damage
| |
| − | *Histotoxic clostridia cause localised lesions in tissues and may cause toxaemia
| |
| − | *''C. perfringens'' cause inflammatory lesions in the gastrointestinal tract and enterotoxaemias in sheep
| |
| | | | |
| | | | |
| − | ===Characteristics===
| + | [[Category:Bacterial Organisms]] |
| − | | + | [[Category:Gram_positive_bacteria]] |
| − | *Large Gram-positive rods
| + | [[Category:Gram Positive Anaerobic Bacteria]] |
| − | *Obligate anaerobes
| + | [[Category:Rods]] |
| − | *Fermentative, catalase negative, oxidase negative
| |
| − | *Straight or slightly curved
| |
| − | *Motile by flagellae
| |
| − | *Require enriched media for growth
| |
| − | *Produce endospores which vary in shape and location and cause bulging of mother cell
| |
| − | | |
| − | | |
| − | ===Pathogenesis and pathogenicity===
| |
| − | | |
| − | *Produce extracellular digestive enzymes and toxic substance known as exotoxins
| |
| − | *Exotoxins cause necrosis, haemolysis and death
| |
| − | *Collagenase, hyaluronidase and DNase enymes facilitate spread through tissues
| |
| − | | |
| − | | |
| − | ===Diagnosis===
| |
| − | | |
| − | *Anaerobic transport medium
| |
| − | *Culture on blood agar enriched with yeast extract, vitamin K and haemin
| |
| − | *Anaerobic culture with hydrogen supplement and 5-10% carbon dioxide for 48 hours
| |
| − | *Colonies of ''C. perfringens'' are 5mm diameter, circular, flat and grey and surrounded by a zone of double haemolysis
| |
| − | *Positive cAMP test with ''Streptococci agalactiae''
| |
| − | *Biochemical tests
| |
| − | *Toxins identified in body fluids by toxin neutralisation or protection tests in lab animals
| |
| − | *Nagler reaction to detect alpha toxin - plate neutralisation test
| |
| − | *Fluorescent antibody tests for histotoxic clostridia
| |
| − | *ELISA, PCR for toxin detection
| |
| − | *Sudden death in unvaccinated farm animals may suggest ''C. perfringens'' types B, C and D
| |
| − | *Post mortem
| |
| − | *Gram positive rods present on intestinal smears suggests clostridial enterotoxaemia
| |
| − | | |
| − | | |
| − | | |
| − | | |
| − | ===[[Histotoxic Clostridia]]===
| |
| − | | |
| − | | |
| − | | |
| − | | |
| − | ===Enteropathogenic and enterotoxaemic clostridia===
| |
| − | | |
| − | *General:
| |
| − | **''Clostridium perfringens'' types B, C and D
| |
| − | **Found in soil, feaces and intestinal tract
| |
| − | **Survive in soil as spores
| |
| − | **Husbandry, changes in diet and environment predispose to proliferation in the intestine
| |
| − | **Abrupt changes to rich diets and intestinal hypomotility due to overeating
| |
| − | *Pathogenesis and pathogenicity:
| |
| − | **Clostridial replication and overgrowth in the interstinal tract of sheep
| |
| − | **Production of potent exotoxins which cause local and systemic effects of enterotoxaemia
| |
| − | **Type of toxins produced determine clinical syndrome
| |
| − | **Haemolysins, collagenases and hyaluronidases also produced
| |
| − | | |
| − | | |
| − | ===''C. perfringens'' type A===
| |
| − | | |
| − | *Necrotising enterocolitis in pigs and necrotic enteritis in chickens (alpha toxin with lecithinase activity)
| |
| − | *Canine haemorrhagic gastroenteritis (cytotoxic enterotoxin)
| |
| − | *Typhlocolotis in horses, possibly associated with [[Intestines Fibrinous/Haemorrhagic Enteritis - Pathology#Colitis X|Colitis X]]
| |
| − | | |
| − | | |
| − | ===''C. perfringens'' type B===
| |
| − | | |
| − | *[[Intestines Fibrinous/Haemorrhagic Enteritis - Pathology#Lamb Dysentery (Enterotoxaemia with Blood)|Lamb dysentery]]
| |
| − | *Up to 30% morbidity and high mortality
| |
| − | *Affects lambs in first week of life
| |
| − | *Abdominal distension, pain, bloody faeces, sudden death
| |
| − | *Bacterial overgrowth in the intestine of the lamb due to immature bacterial flora
| |
| − | *Lack of proteases in the immature gut prevents cleavage of the beta toxin, allowing it to cause disease
| |
| − | *Also alpha and epsilon toxins
| |
| − | *Haemorrhagic enteritis and ulceration in the small intestine
| |
| − | *Fluid in the peritoneal cavity and pericardial sac due to increased capillary permeability (beta toxin)
| |
| − | *Fatal haemorrhagic enteritis in newborn foals, calves and adult goats
| |
| − | | |
| − | | |
| − | ===''C. perfringens'' type C===
| |
| − | | |
| − | *Acute enterotoxaemia in adult sheep, 'struck'
| |
| − | *Sudden death or terminal convulsions in sheep at pasture
| |
| − | *Beta toxin (lethal, necrotising) plays major role in pathogenesis of the disease - increases intestinal and capillary permeability
| |
| − | *Also alpha toxin (lecithinase)
| |
| − | *Post mortem: jejunal ulceration; hyperaemia in small intestine; fluid accumulation in peritoneal cavity; congestion of peritoneal vessels; petechial haemorrhages
| |
| − | *Haemorrhagic enteritis in piglets
| |
| − | **Peracute enterotoxaemia often of entire litter with mortality rates 80%
| |
| − | **Infection from sow's faeces
| |
| − | **Death within 24 hours in young piglets
| |
| − | **Chronic disease in older piglets
| |
| − | **Dullness, anorexia, bloody faeces, perianal hyperaemia
| |
| − | **Post mortem: necrosis of terminal small intestinal mucosa, caecum and colon and blood-stained contents; serosanguinous fluid in pleural and peritoneal cavities
| |
| − | *Necrotic enteritis in chickens:
| |
| − | **Broilers under 12 weeks
| |
| − | **Acute enterotoxaemia, sudden onset and high mortality
| |
| − | **Necrosis of small intestine
| |
| − | **Predisposing factors include diet changes, coccidial infection and intestinal hypomotility
| |
| − | *Acute enterotoxaemia with haemorrhagic enteritis in calves, lambs, foals, goats
| |
| − | *[[Peritoneal Cavity Inflammatory - Pathology#In cattle|Peritonitis in cattle]] - sudden death in feedlot cattle
| |
| − | | |
| − | | |
| − | ===''C. perfringens'' type D===
| |
| − | | |
| − | *[[Intestines Catarrhal Enteritis - Pathology#"Pulpy Kidney" Disease|Pulpy kidney disease]] in well-fed 3-10 week-old lambs
| |
| − | *Follows overeating high grain diet or luchious pasture
| |
| − | *Starch from partially digested food enterering the intestine from the rumen allows rapid clostridial proliferation
| |
| − | *Epsilon toxin activated by proteolytic enzymes causes toxaemia
| |
| − | *Epsilon toxin increases intestinal and capillary permeability; also alpha toxin
| |
| − | *Lambs found dead or with opisthotonos, convulsions, coma in acute phases
| |
| − | *Blindness and head pressing in subacute disease; bloat in later stages
| |
| − | *Hyperglycaemia, glycosuria
| |
| − | *Post mortem: hyperaemia in intestine; fluid in pericardial sac; kidney autolysis with pulpy cortical softening (acute death)
| |
| − | *Subacute death causes symmetrical encephalomalacia and haemorrhage in basal ganglia and midbrain
| |
| − | *Enterotoxaemia in kids and adult goats
| |
| − | | |
| − | | |
| − | ===''C. perfringens'' type E===
| |
| − | | |
| − | *Enteritis in rabbits, haemorrhagic enteritis in calves
| |
| − | *ALpha and iota toxins
| |
| − | | |
| − | | |
| − | ===Treatment and control of enterotoxaemic infections===
| |
| − | | |
| − | *Hyperimmune serum
| |
| − | *Vaccination - vaccinate ewes with toxoid 6 weeks before lambing to allow passive protection of lambs
| |
| − | *Vaccination of lambs with toxoid before 2 months of age to protect against pulpy kidney
| |
| − | *Avoid sudden dietary changes
| |
| − | | |
| − | | |
| − | ===''C. piliforme''===
| |
| − | | |
| − | *Spore-forming filamentous Gram negative intracellular pathogen
| |
| − | *Only grows in tissue culture or embryonated eggs
| |
| − | *Causes Tyzzer's disease - severe hepatic necrosis
| |
| − | *Sporadic disease in foals, calves, dogs, cats
| |
| − | *Foals under 6 weeks, found dead or comatose
| |
| − | *Incubation period up to 1 week
| |
| − | *Depression, anorexia, fever, jaundice, diarrhoea
| |
| − | *Hepatomegaly and necrosis on post mortem
| |
| − | *Diagnosis: Warthin-Starry silver impregnation technique demonstrates organisms in hepatocytes
| |
| − | | |
| − | | |
| − | ===''C. difficile''===
| |
| − | | |
| − | *Dogs with chronic diarrhoea
| |
| − | *New born foals with haemorrhagic enterocolitis
| |
| − | *Possibly associated with acute colitis in adult horses following antibiotic therapy or grain overload
| |
| − | | |
| − | | |
| − | ===''C. colinum''===
| |
| − | | |
| − | *Enteritis in poulty and game birds
| |
| − | *Shed in faeces of clinically affected and carrier birds
| |
| − | *Intestinal ulceration and hepatic necrosis
| |
| − | *Therapeutic antibiotics in drinking water
| |
| − | | |
| − | ===''C. spiroforme''===
| |
| − | | |
| − | *Spontaneous and antibiotic-induced enteritis in rabbits
| |
| − | *Enterotoxaemia, fatal within 48 hours
| |
| − | *Oral antibiotics upset the intestinal flora, allowing overgrowth of clostridia[[Category:Bacteria]][[Category:Gram_positive_bacteria]]
| |
