Difference between revisions of "Campylobacter species"

Revision as of 08:32, 18 May 2008

Linked to:
- Undifferentiated neonatal calf diarrhoea, a mixed viral enteritis in calves.
- Food poisoning (Campylobacter jejuni).

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 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

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

Venereal infection of cattle
Infertility in female cattle
Found in glandular crypts of prepuce of bull with no clinical signs - carriers
Causes catarrhal inflammation in female genital tract
Endometritis prevents implantation until infection gone and causes early embryonic death, occasionally sporadic abortion
May remain infertile for 3-5 months before immunity develops, which lasts 4-5 years
Effective immunity includes induction of IgA in the vagina and IgG in the uterus
Bacteria may persist in the vagina and be transmitted to bulls
Diagnosis:
- Fluorescent antibody test on genital discharges from bull/cow
- Vaginal mucus agglutination test
- ELISA to IgA antibodies in vaginal mucus after an abortion
- PCR for detection in semen
Treatment: dihydrostreptomycin intrauterine for cows and systemically or topically for bulls
Vaccination: bacterin in oil adjuvant

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
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
Commensals in intestinal tract of chickens
Most chicken carcasses contaminated, leading to food poisoning in people

@@ Line 79: / Line 79: @@
 ===''Campylobacter jejuni''===
-*
+*Widespread on farms - hyperendemic
+*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
+*Commensals in intestinal tract of chickens
+*Most chicken carcasses contaminated, leading to food poisoning in people