Bacteriology - fastidious bacteria Flashcards
What is the main feature of fastidious bacteria?
They are difficult to grow so hard to confirm a diagnosis
What are the two main fastidious bacteria?
Chlamydiales
Rickettsiales
Are chlamydiales and rickettsiales gram positive or gram negative?
Appear gram negative - dont have LPS but also dont have peptidoglycan
Where are fastidious bacteria found?
In epithelial cells, blood cells and macrophages - inside cells rather than on surface
Where do fastidious bacteria grow?
Inside cells
What does rickettsia infect?
Endothelial cells lining capillaries - multiply in cytoplasm
What does ehrlichia infect?
Red blood cells (haemolytic anaemia) and immune cells
How are rickettsia and ehrlichia transmitted?
Blood sucking arthropod vectors
Why do fastidious bacteria need to be intracellular to survive?
Missing cofactors and precursors
How is reckettsia treated?
Antibiotics
What is chlamydia associated with?
Mucous membranes - resp, GI, conjunctival, urogenital
How does chlamydia present as a disease?
Subclinical persistence with clinical flares
What are the two forms of chlamydia?
Elementary body
Reticulate body
What are elementary bodies of chlamydia?
Infectious form - has a resistant wall and is metabolically inactive, can be spread outside the body
What are reticulate bodies of chlamydia?
Reproductive form - intracellular, active
How is chlamydia identified?
Lesion smear
PCR
How is chlamydia treated?
Antibiotics - oxytetracycline or chloramphenicol, not penicillin
For 2-3 weeks
How is coxiella burnetii transmitted?
Ticks
Spores in aerosols/dried faeces/milk
What does C. burnetii cause in animals?
Abortion if gets to placenta
Mild gut/udder infection
What does C. burnetii infect?
Macrophages in oropharynx
What disease does C. burnetii cause in humans?
Q fever
What are the symptoms of Q fever?
Pneumonia/flu-like illness
Recurrence of infection causes systemic organ damage
What is the spirochaetes main feature?
Motile - spiral with a flagella
What are the main spirochaetales?
Borrelia - lyme disease
Leptospira
Treponema - syphilis in rabbits
Brachyspira
How are spirochaetes diagnosed?
Serology
Silver based stains
PCR
What type of brachyspira is the only one that causes swine dysentry?
B. hyodysenteriae
How is B. hyodysenteriae spread?
Faecal - oral
What can be reservoirs of B. hyodysenteriae?
Wild rodents
Environment - 3 days
Clinical cases and carriers
How can you prevent swine dysentery?
Eliminate carriers - test using PCR
How is swine dysentery treated?
Antibiotics
Hyperimmune serum
What category of conditions does borrelia need?
Microaerophilic
What are the two types of borrelia disease?
Generalised - anaemia and fever
Deposition and inflammation
What are the three stages of borreliosis/lyme disease?
- Skin rash - bullseye
- Systemic problems
- Chronic problems
What can lyme disease cause in horses?
Laminitis
What are some systemic features of lymes disease?
Fever
Fatigue
Stiff joints - arthritis
Nervous system disorders
How is lyme disease controlled?
Aggressive antibiotic treatment
Tick control
Vaccine in dogs in USA
How does leptospirosis enter the body?
Ingestion
Infected urine
Via mucous membranes or skin cuts
What does leptospirosis cause?
Fever Diarrhoea Haemolyric anaemia Haemorrhage Jaundice Death
What is a major vector of leptospirosis?
Rodents - urine
What is bacillus?
Anthrax
What category of conditions does bacillus need?
Aerobic/facultatively anaerobic
What are the three species of bacillus?
B. licheniformis - abortion
B. cereus - mastitis
B. anthracis - anthrax
How does bacillus anthracis spread?
Spores
What increases the virulence of bacillus anthracis?
Protective antigen - anchor for the oedema factor and the lethal factor
What is the oedema factor of bacillus anthracis?
An enxyme that causes oedema and prevents leucocyte activity
What is the lethal factor for bacillus anthracis?
Toxin that increases vascular permeability and kills macrophages
What are the main signs of cutaneous anthrax?
Painless lesion - from oedema
Very dark crust around lesion - from haemorrhage
What causes septicaemic anthrax?
Inhaling or ingesting spores
What does septicaemic anthrax cause?
Death - bacteria multiply in blood
Haemorrhaging
Pulmonary oedema
Use up oxygen
What is the main sign of septicaemic anthrax?
Dark tar-like blood oozing from all body orifices
How long does anthrax take to kill?
Ruminants - 1-2 hours
Humans/horses - 24hrs
What should you do if you find anthrax?
Inform APHA
Take blood sample
Prepare and stain smear
What will APHA do once notified?
Burn everything
Monitor area
Cull at risk animals
