Exam I bacteria Flashcards
Actinomyces spp.
- Virulence not well understood
- Habitat: mucosa of the oropharynx
- Facutative anaerobic & anaerobic spp. & capnophilic
- Catalase negative
- “molar tooth-like”
- Grow as colonies in center of lesion –> often forms draining tracts
What common diseases are caused by Actinomyces spp.?
- Pyogranulomatous disease
- Polymicrobial infection within oropharyngeal flora
- Chronic infections –> bone lysis
Actinomyces bovis
- Causes “Lumpy Jaw” - Pyogranulomatous osteomyelitis
- Gram-positive, club-shaped rods
- Localized, chronic, progressive granulomatous abscess in the mandible, maxillae, or bony tissues in the head
- Introduced via penetrating wounds
- Facial distortions, loose teeth, dyspnea are commonly found
Actinomyces bovis diagnosis, treatment and control
Diagnosis: culture/microscopic exmanation –> must request aerobic and anerobic cultures
Treatment: Susceptible to penicillin G, iodides; long term treatment; surgical removal of froeign bodies
Control: minimize risk of mechanical injury
Dermatophilus congolensis
- Epidermal abscesses with hyperkeratosis
- Filamentous branching –> divides into “tram-tracks”
- Aerobic; Catalase positive
- production of coccoid fragments –> motile zoospores
- zoospores have chemotaxis for CO2; attracted to moist and damaged skin
- all animals can be infected: Rain scald in horses; Strawberry footrot in goats; dermatophilosis in reptiles;
Virulence facotrs: chemotaxis of zoospores, keratinolytic activity
Dermatophilus congolensis diagnosis, treatment, and control
Diagonsis: microscopic examination of scabs; use of Giemsa stain
Treatment: systemic antibitic treatment - penicillin G and tetracycline
Control: Treat and isolate infected invidiausl; eliminate predisposing factors
Trueperella pyogenes
What’s the significance in Cattle?
- Suppurative infection in ruminant and swine
- Facultative anerobe; non-spore forming; non-motile; non-capsulated; capnophilic
- Found on mucous membranes –> most infections are endogenous
In Cattle: involved in most purulent infection of traumatic/opportunistic origin
- Common location - lung, pericardium, liver, uterus, renal, brain, bones
- Causes: abortion and summer mastitis (communicable disease among pasutred daily cattle during the dry period)
Actinobaculum suis
- Causes cystitis and pyelonephritis
- Anaerobic; sexually transmitted pathogen
- Commensal diphteroid organism in prepucial mucosa of boars
- Death often follows as a result of renal failure
Virulence factor: UREASE
Staphylococcus spp.
- Facultative anaerobic; catalase positive; cocci
Exceptions: Anaerobic spp: S. sacharolyticus, S. aureus subsp. anaerobius
- Opportunistic pathogen
- Habitat: Skin and mucous membranes
- Suppurative conditions - production of pus
Toxin mediated diseases (superantigens): Staphylococcal toxic shock syndrome (TSST-1); Staphylococcal food poisoning (enterotoxin); Staphylococcal scalded skin syndrome (Exfoliative toxins)
Virulence factor: Protein A - binds FC portion of IgG; Hemolysins; proteases; hyaluronidase; lipases; leukocidin; biofilm formation
What is coagulase? what does it do?
Coagulase is an enzyme that is sued to convert fibrinogen to fibrin.
It is often used to differenitate between species
Staphylococci pseudintermedius
- Most common isolate found in dogs
- Gram positive cocci in clusters
- Cuases pyoderma and folliculitis
Diagnosis:
- Direct examination of species
- Evidence of inflammation with high # neutrophils
- Culture infection
Staphylococcus hyicus
- Greasy Pig Disease - Exudative epidermitis
Staphylococcus aureus
- cattle
- Humans
- Sheep
- Birds
Cattle - Chronic and acute mastitis/gangrenous mastitis
Humans - Ulcerative pododermatits
Sheep - Cervical lymphadenitis (subsp. anaerobius)
Birds - Bumble Foot
Rodents, humans, horses - Botryomycosis - Chronic pyogranulomatous inflammation
Staphylococcus aureus treatment
- Antimicrobial susceptibility testing is essential
- Common emergence of multidrug resistant staphylococci
- inducible Clindamycin resistance in macrolide resistant staphylococcus - isolates which are macrolide resisant is also clindamycin resistant
- Cephalosporins are first line treatment choice –> quinolones are second line
- Beta-lactamase-mediated resistance is common; Methicillin resistance becoming a problem (MRSA (zoonotic) & MRSP)
Streptococcus spp.
- Gram-positive cocci found in pairs/chains
- Facultative anerobe (aerobic or anaerobic)
- Catalase negative; haemolytic activity used for classification (beta = pyogenic; alpha = non pyogenic)
- Some are capsulated
Diseases:
- Acute suppurative
- Subacute endocardidits
- Chronic mastitis
Superantigens:
- Streptococcal toxic shock syndrdome (STSS)
- Necrotizing fasciitis and myositis (NFM)
Streptococcous virulence factors
- Capules
- Peptidoglycan layer with teichoic/lipoteichoic acid
- M protien*
- Ig binding proteins
- Streptokinase
- Streptococcal pyrogenic exotoxins (superantigens)
Streptococcus pyogenes
- Scarlet fever in humans - Rheumatic fever; kidney disease; skin infection; abscesses of the throat; arthritis
Streptococcus canis
- Commonly infects skin and mucous membranes
- Embolic lesions in heart and lung; septicemia; skin ulcerations; meningitis; necrotizing fasciitis; toxic shock-like syndrome
- Kittens and puppies
Streptococcus suis
- gram positive cocci
- ZOONOTIC
- Perdominately infection in pigs (type 2 is most common)
- serositis, meningitis, polyarthritis, endocarditis
Streptococcus iniae
- Infects fish
- zoonotic
- Septicemia in fish; central nervous system disruption
Streptococcus procinus
Jowl abscess in pigs
Streptococcus pneumoniae
Humans - Causes pneumonia, septicemia, and meningitis
Guinea pigs and rodents - pneumonia
Domestic pets - act as carriers
Streptococcous equi
(S. equi subsp. equi)
Strangles in horses!!!
- hyaluronic acid capsule - mucoid appearance
- Use sugar fermentation test to distinguish between different species
- All ages are susceptible, average <2 yrs
- <4 mo are protected by maternal antibodies
- Enlargement of retropharyngeal lymph nodes
- HIGHLY contagious - direct transmission or indirect
Streptococcus equi
Virulence factor
- Hyaluronic acid capsule
- M Proteins
- IgG Fc binding proteins
- Peptidoglycan/teichoic acid
- Streptokinase
- Hyaluronidase
- Streptolysin
- DNAase
- Exotoxins
Streptococcus equi
Clincal signs
- Fever
- Purulent nasal discharge
- Anorexia and dysphagia
- Moist cough
- Lymph node abscessation
- Can survive in pus for 6 - 8 weeks
- Guttural pouch empyema (pus formation)
Bastard strangles - disseminated infection –> infection of lymph nodes in chest cavity
Purpura haemorrhagica
Streptococcus equi
Recovery
Diagnostic
Treatment
Control
Recovery - infected animals usually recover after abscesses mature and rupture
- 75% deelop immunity after recovery
Diagnostic
- Culture
- Serology - ELISA for M protein antibodies
PCR - for M protein
Treatment
- Most recover spontaneously
- symptomatic treatment to relieve pain
- Antibiotics only effective if given soon after exposure
Control
- REPORTABLE DISEASE
- apply isolation, hygiene, and disinfection practice
- Vaccines: Killed –> effetive for pregnant mares and foals to maintain high level of anti-M protein opsonizing antibodies
- Live –> similar to killed except in all other animals
Enterococcus
- inhibit GI tract
- nosocomial infection
- Causes persistant UTI
- Vancomycin resistance
- In vivo resistance
Listeria spp.
- Gram positive facultative anaerobic rods
- capable of growing in a wide range of temperature (4 - 44C) –> what you find in your fridge!
- Carried in the GI tract of animals
- Outbreaks typically seen after feeding poor-quality silage –> winter-spring disease as more silage is fed during this time