Difference between revisions of "Campylobacter species"

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<big><center>[[Infectious agents and parasites|'''BACK TO INFECTIOUS AGENTS AND PARASITES''']]</center></big>
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#REDIRECT[[:Category:Campylobacter species]]
<big><center>[[Bacteria|'''BACK TO BACTERIA''']]</center></big>
 
 
 
 
 
* Linked to:
 
** [[Intestines - Catarrhal Enteritis#Undifferentiated Neonatal Calf Diarrhoea|Undifferentiated neonatal calf diarrhoea]], a mixed viral enteritis in calves.
 
 
 
 
===Overview===
 
 
 
*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
 
 
 
 
 
===Characteristics===
 
 
 
*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
 
 
 
 
===Pathogenesis and pathogenicity===
 
 
 
*''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
 
 
 
 
 
===''Campylobacter fetus'' subspecies ''venerealis''===
 
 
 
*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
 
 
 
 
 
===''Campylobacter fetus'' subspecies ''fetus''===
 
 
 
*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
 
 
 
 
 
===[[Intestines - disease due to pathogens#Campylobacter jejuni|''Campylobacter jejuni'']]===
 
 
 
*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
 
 
 
 
 
===Diagnosis===
 
 
 
*Smears stained with dilute carbol fuschin for 4 minutes
 
 
 
 
 
===Control===
 
 
 
 
 
 
 
===Treatment===
 

Latest revision as of 21:24, 10 May 2010