Test 3- Campylobacter and Arcobacter Flashcards
Family Campylobacteriaceae
- Both genera were Campylobacter before
- Small, Gram negative, curved rods, no spores
– S-shaped or gull-wing in pairs
– Appear as spirals when in chains
– Polar flagellum at one or both ends- can see in picture
• Associated with disease:
– Reproductive Tract
– Intestinal Tract
Campylobacter species
23 recognized species
Several are significant pathogens of animals and humans
C. coli, C. fetus, C. jejuni- BIG ONE FOR FOOD POISIONING are most important
Campylobacter
• C. fetus (and its subspecies) were originally classified with Vibrio sp.
– Infections are occasionally called “vibriosis”
• C. jejuni and C. coli are leading causes of food- borne bacterial gastroenteritis in humans
– Source:
• Uncooked/undercooked contaminated food (meat/poultry)
- Unpasteurized milk
- Contaminated water
– Other species may be associated less commonly
Cellular Products of Medical Interest
• Cell Wall
– LPS
• Not as immunoreactive as the Enterobacteriaceae LPS
• C. fetus has long O-antigen chains for serum resistance
• C.jejuni does not have LPS- instead it has LOS(lipo-oligiosacchride)
– The LOS is variable depending on location
» Intestine vs. blood
» Mammal vs. avian (temperature)
• Capsule
– Highly variable
– Useful for serotyping
– Shields LOS of C. jejuni
• Adhesins
– CadF in C. jejuni and C. coli
- Mediates adhesion to host cells
• Flagella
– Essential for motility and intestinal colonization
– Mutations in the flagellin genes:
———————- Abolish motility
———————–Prevent secretion of Cia (Campylobacter invasion antigen), thereby impeding cell invasion
• Cytolethal Distending Toxin (CDT)- ONLY TOXIN PRODUCED BY CAMPYLOBACTERIA SPECIES
– Produced by most Campylobacter species
– The only toxin produced in the genus
– Causes apoptosis of host cells
• T2SS
– Binds free DNA for genomic or plasmid incorporation
and replication
– Known as “natural competence”
• T4SS
– A genetic transfer role particular for virulence of C. fetus ssp. venerealis in the bovine reproductive tract
Growth Characteristics
HARD TO GROW!!!!!!
• Microaerobic
– Require 3-10% oxygen
– Require 3-15% carbon dioxide
• Temperature:
– All species grow at 37 ̊C, but some will grow well at 42 ̊C (C.
jejuni, C. coli, C. lari)- can grow at higher temperatures- can be a characterisitic of camplyobacteria
– Poor (or no) growth below 30 ̊C
– Often killed by freeze/thaw cycles
• May remain viable if chilled in organic material- PRODUCT CAN STILL BE INFECTIOUS
– Feces
– Meat
– Milk
Oxidase-positive; but do not oxidize or ferment sugars
Most serotyping is via molecular methods, although LPS antigens have been used
Ecology
• Reservoir
– C. fetus ssp. venerealis- BEEF CATTLE
• Preputial crypts of carrier bulls
• Few cows are persistent vaginal carriers/reservoirs
– C. fetus ssp. fetus- SHEEP AND GOATS
• Intestinal tract and gall bladder of infected ruminants
– C. jejuni (and the other enteric species)- LOTS OF HOSTS
Intestinal tract and gall bladder of carrier sheep,
poultry, cattle, birds, dogs, cats, swine
Pigs and poultry are primary reservoir for C. coli
•
Pathogenesis of Campylobacter
- can disrupt breeding cycles
- loss of condition
- immunity will develop in the herd
Bovine Genital Campylobacteriosis
Reportable Disease
- BOVINE FETAL ANASARCA
_ METRITIS
(Bovine Genital Campylobacteriosis)
Pathogenesis Reproductive Disease
In Sheep and Goats
- can lead to abortion storms
INGESTION OF C. fetus fetus or C. jejuni
Abortion Pathologies
The necrotic target or donut shaped lesions in the fetal liver are considered pathognomonic for ovine Campylobacter infection (C. jejuni or C. fetus ssp. fetus)
Liver is affected most of the organs
Pathogenesis of the Enteric Disease
C. jejuni- MOST COMMON CAUSE OF FOOD POISIONING VIA POULTRY
Epidemiology
Reproductive Disease (Cattle)
– Primarily beef cattle with natural breeding
– Artificial insemination has reduced prevalence in dairy cattle
Reproductive Disease (Sheep/Goats)
– Causes abortions wherever these animals (particularly sheep)
are raised in high numbers
– C. jejuni and C. fetus ssp. fetus (occasionally C. coli)
Enteric Disease
– Feces from infected animals are source of infection for other
animals
– The ceca of ~50% of chickens contain C. jejuni
• Slaughter house environmental contamination may contaminate all poultry meat products even to point-of-sale
– Shelter dogs and cats and dogs fed homemade diets are more likely to carry C. jejuni
Immunologic Aspects
• Reproductive Disease(Cattle)
– Active immune response in uterus and normal flora of vagina often clear the organism
– Serum (IgM, IgG) and secreted (IgA, IgG, IgM) antibodies prevent adherence of organisms
– Antibodies specific for flagellar antigens prevent movement of bacteria from vagina to the uterus
– Older bulls may be infected (carriers) for life • Deep preputial crypts
– Vaccination may prevent or eliminate infection from males and females
• Reproductive Disease (Sheep/Goats)
– Immune after abortion or vaccination
– IgM and IgG antibodies
• Promote opsonization and complement-killing
• Enteric Disease
– Effective circulating and mucosal antibodies
develop to protect mucosa (but not lumen)
– Usually self-limiting; but recolonization may occur without clinical signs
Laboratory Diagnosis
• Sample Collection
– Reproductive Disease (Cattle)
• Samples from males more likely to be positive
• Smegma or preputial scrapings
• All bulls and 10% of females should be sampled
– Reproductive Disease (Sheep)
• Abomasal fluid, lung, liver from aborted fetuses- BEST SAMPLES
• Placenta and associated fluids are often over-contaminated
– Enteric Disease
• Fecal samples
Direct Examination
– Reproductive Disease (Cattle)
• Difficult to find organisms (low numbers)
• Fluorescent stains useful
– Reproductive Disease (Sheep)
• Visualization of small curved rods with tumbling motility
– Enteric Disease
• Numerous slender, curved, gram-negative rods
Isolation
– Reproductive Disease
• Selective media to decrease growth of contaminants
– Vancomycin
– Polymixin
– Trimethoprim
These antibotics will help Campyblobacter grow without contamination or overgrowing of other bacteria
– Enteric Disease
• Similar to above
• Skirrow medium
– Antibiotics as above with lysed horse blood
• Biochemical characterization is difficult and often avoided in lieu of molecular methods
Treatment
Reproductive Disease (Cattle)
– VACCINATION!
– Artificial insemination
– Streptomycin can be used topically and/or systemically to treat bulls, then VACCINATE
Reproductive Disease (Sheep/Goats)
– Vaccination may reduce severity or occurrence of abortion
storms
– Tetracycline resistance has developed
• Consider tilmicosin, erythromycin, tylosin, florfenicol
Enteric Disease
– Usually self-limiting
– Macrolides are drugs of choice
——————-Clarithromycin, erythromycin, tylosin
——————-Hygiene!
– No vaccines available for C. jejuni
