11 – Erysipelothrix Flashcards
Microbiological characteristics
- Biocontainment level 2
- Non-spore forming Gram-positive rods
o Slender, non-branching rods
o Irregular cells, curved - Facultatively anaerobic
- Grows better with 5-10% CO2
- Gamma-hemolytic or weakly alpha-hemolytic on blood agar
- Catalase negative
Morphology
- ‘kinky’ or ‘cheese doodle’
- Rougher the colony=smoother the individual bacteria
Natural host or habitat
- Widely disseminated
o Can be found in environment (resistant to salt, drying and pickling)
o Associated with many species (found in slime of fish) - Agricultural context=healthy carriers are primary SOURCE
Agricultural context: healthy carriers are primary source
- Shed in feces and secretions
o Directly infect others
o Contaminates environment (up to 6months in pig feces)
E. ruhsiopathiae and tonsillarum biochemical difference
- Ability to ferment sucrose
Virulence factors
- Capsule
- Neuraminidase
- Hyaluronidase
Capsule
- Resistance to phagocytosis
- Experimentally, capsule deficient strains UNABLE to cause disease in mice
Neuraminidase
- Promotes attachment, aids in invasion
- Virulence related to level of expression
Hyaluronidase
- Role in invasion
E. ruhsiopathiae (pigs)
- Older than 3 months (due to waning of maternal immunity)
- Exposure through mouth (food or water)
- Maintained in herd healthy cariiers
- Enters body through palatine tonsils followed by systemic spread (bacteremia)
- Divided into acute, subacute and chronic syndromes
E. ruhsiopathiae (pigs); acute
- Depression, inappetence, pyrexia and sometimes death
- Development of characteristic DIAMOND skin lesions (2-3 days after exposure)
- If severe, diamond lesions may not have time to develop before death
E. ruhsiopathiae (pigs): subacute
- disease less severe than acute
E. ruhsiopathiae (pigs): chronic
- long term sequelae following acute disease
- arthritis, stiffness
- possibly cardiac insufficiency if serious damage to heart valves during acute phase
E. ruhsiopathiae (pigs) : clinical signs
- diamond lesions
- vegetative of mitral valves
- necrosis of ear tip
- chronic proliferative synovitis
E. ruhsiopathiae (turkeys)
- route of exposure not determined: oral
- incubation period in natural infections unknow
- experimentally 2-5 days
- onset is peracute to acute
- mortality from 2-25%
Peracute-acute E. ruhsiopathiae (turkeys)
- begins with death of several birds and others which are ‘droopy’
- toms may have congested, purple snoods
- often death is per-acute, and pathologically lesions may be absent
- in birds that die=endocarditis is frequently the cause
E. rhusiopathiae (wild ungulates)
- associated with large die-offs
o may represent a first encounter of naïve population
o may be secondary to stress of warmer than normal temperatures - *recently recovered from dead caribou in BC
E. rhusiopathiae (humans)
- Occupational exposure (vets, butchers, fish handlers)
- Erysipeloid: mild form
- Systemic infection: severe form
E. rhusiopathiae (humans): erysipeloid
- Skin lesions
o Mild, localized infections
o Typically on fingers of hand
o Lesion 2-7 days after exposure
E. rhusiopathiae (humans): systemic infection
- L sided endocarditis
- High mortality rate
- Typically, debilitated patients
E. rhusiopathiae (dogs)
- Not believed to be pathogenic from pigs
- Recently described as a cause of endocarditis
o Fever
o Recent onset murmur - Treat with high doses of antimicrobial
o Penicillins
o Extended treatment length required
E. piscisicarius (fish)
- Mortality of ornamental fish species in US
- Clinical signs
o Lethargy
o Hovering in water
o Hemorrhage of fins and skins
Specimens to collect
- Necropsy (liver, spleen, kidney, heart, synovial tissues, LONG BONES)
- *measure at least 3 sites!
- Difficult to get from skin lesions
- Blood cultures: dogs with suspect endocarditis
Sample handling
- Do NOT freeze samples
Lab ID
- Standard lab culture methods
- Selective media helpful
o Pre-enrichment useful
o Sodium azide
o Agar with antibiotics - Easily by biochemical methods
- MALDI-TOF
- Pathogenicity testing using mouse infection model (historical)
E. rhusiopathiae zoonotic/interspecies transmission
- Ability to cause disease in wide variety of hosts
- Risk in people is occupational
E. tonsillarum zoonotic/interspecies transmission
- Not know to be associated with disease in people
Treatment options
- Penicillin
- Pathological changes associated with infection may complicate therapy
Drugs to avoid/intrinsic resistance
- Sulfonamides
- Aminoglycosides
- Glycopeptides (vancomycin): not a problem as a VET