Difference between revisions of "Category:Campylobacter species"

Revision as of 21:25, 10 May 2010

Live on mucosa of intestinal and genital tract and can be commensals or pathogens
Enteric species cause disease in humans
Other species cause infertility and abortion in cattle and sheep
Excreted in faeces of birds, (C. jejuni and C. lari) as well as pigs contaminating water and food supplies
C. fetus restricted to bovine prepucial mucosa

Curved, Gram negative rods
Polar flagellum aids motility
Daughter cells remain joined giving gull-wing or spiral appearance
Microaerophilic
Sensitive to drying
Thermophilic species - C. jejuni, C. coli
Non-thermophilic species e.g. C. fetus
Grow on enriched selective media e.g. Skirrow agar in 1-10% carbon dioxide and 5-10% oxygen tension
C. jejuni requires increased temperatures for growth
Many grow on MacConkey
Oxidase positive, non-fermentative
C. fetus subspecies venerealis and subspecies fetus have small, round, smooth, translucent colonies
C. jejuni has small, flat, grey colonies with watery appearance
Smears stained with dilute carbol fuschin for 4 minutes

C. fetus subspecies fetus and subspecies venerealis possess a microcapsule (S layer) which resists phagocytosis and serum-mediated destruction and enhances survival in the genital tract
Antigens of S layer undergoes antigenic shifts in C. fetus subspecies venerealis, allowing persistence in the host
C. jejuni attaches and invades host enterocytes and produces enterotoxin-like substances
Flagellae of C. jejuni required for colonisation

Sporadic abortion in cows and sheep
10% of ovine abortions in the UK
Enteric organism of sheep, goats and cattle; faecal-oral transmission
Ingestion during last trimester of pregnancy causes a bacteraemia
Bacteria reach the uterus
Necrotic placentitis causes late abortion, still birth or weak lambs
Sporadic abortion in cattle
Aborted lambs may have round necrotic lesions on surface of liver
Aborting ewes source of infection for vulnerable animals
Up to 20% of flock may abort
Solid immunity developed
S layer immunodominant antigen
Diagnosis: hepatic lesions in lambs; presence of organisms in foetal abomasum; isolation and identification
Treatment/control: isolate aborting ewes; destroy placenta; move other ewes to clean pasture; vaccinate flock with bacterin during outbreak and prophylactically; chlortetracycline in feed in an outbreak

Widespread on farms - hyperendemic
Carried as commensals in intestines of cattle, sheep, dogs, wild birds and especially chickens
Farm animals regularly exposed via faecal-oral route; maternal antibody protects while active immunity develops
Animals with little exposure are very susceptible, e.g. humans, pets
Most chicken carcasses contaminated, leading to food poisoning and enterocolitis in people from uncooked meat
Colonisation, attachment and invasion of colonic enterocytes; toxin production
Necrosis of colonic absorptive epithelial cells, erosion of mucosa, crypt abscesses, inflammatory infiltrate of neutrophils into mucosa causes colitis
Enteritis and diarrhoea in susceptible dogs; treatment with enrofloxacin
Causes abortion in ewes
Usually asymptomatic infections in chickens and turkeys, but occasional outbreaks of avian hepatitis occur with decreased egg production, loss of condition, haemorrhage and necrosis of liver; phase contrast microscopy demonstrates curved rods in bile; in-feed dihydrostreptomycin sulphate in outbreak
Implicated in undifferentiated neonatal calf diarrhoea, a mixed viral enteritis in calves

The following 5 pages are in this category, out of 5 total.