Difference between revisions of "Category:Campylobacter species"

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
• Smears stained with dilute carbol fuschin for 4 minutes

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