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
Listeria monocytogenes
- Circling disease - neurologic symptom; unilateral facial nerve paralysis
- Facultative intracellular bacteria –> persists in macrophages (intracellular growth)
- Outbreak typically occur after feeding poor-quality silage –> winter-spring disease as more silage is fed during thist time
- Diseases - encephalitis - travels up trigeminal nerve and affects brainstem
- abortions - focal hepatic necrosis
- Septicemia - common in monograstrics
Virulence factors - Internalin (adhesion, entry, phagocytosis)
- Listeriolysin - aids in intracellular multiplication
- Act A - intracellular movement –> actin filmaent utlized to travel between cells
Lesions:
- Microabscesses and glial nodules infiltrated by neutrophils; acute vascular fibrinoid necrosis; leptomeningitis; neuronal necrosis;
Listeria monocytogenes
Diagnosis
Treatment
Control
Diagnosis
- CNS disease
- Circling disease
- Post-mortem - lesions in pons, medullam oblongata, and spinal cord
- Gram stained CSF short intracellular and extracellular gram positive bacteria
Treatment:
- Penicillin, ceftiofur, erythromycin
- high doses are required
Control:
- No vaccines
- Avoid high risk food
- minimize aerosol exposure
Erysipelothrix rheusiopathiae
in swine
- Gram-positive facultative anaerobic bacillus
- Non-sporeforming
- swine are the most susceptible (30 - 50% of healthy swine are carriers)
- Causes polyarthritis, vegetative endocarditis, and septicemia
Transmission and virulence factors:
- Primarily oral transmission –> infection of palatine tonsils
Neuraminidase - adherence to endothelial cells
Heat labile capsule - resistants phagocytosis
Erysipelothrix rheusiopathiae
Sheep
Turkey
Marine mammals
Calves
Humans
Sheep - Fibrinopurulent polyarthritis and osteomyelitis
Turkeys - cyanotic combs, splenomegaly, haemorrhage, polyarthritis, endocarditis
Marine mammals - septicemia and similar skin lesions
Calves - polyarthritis
Humans - erysipeloid - localized skin lesions
Erysipelothrix diagnosis, treatment, and control
Diagnosis: culture
Treatment: antimicrobia treatment - penicillin & tetracycline
Control: treat and isolate infected animals
- vaccination
Bacillus spp.
- Large gram positive rods
- Endospore forming
- Thickpeptidoglycan layer - teichoic and lipo-teichoic acids
- Grows very rapidly
- Aerobic or facultative anerobes
Bacillus anthracis
- Koch’s postulate is based on anthrax bacilli
- Aerobic, non-motile, square-ended gram positive rods in chains
- non-hemolytic –> meusa head colonies
- Stains by McFadyean stain
Virulence factors:
- Capsule - polymers of D glutamic acid; produced in vivo
- Anthrax toxin: Edema factor = inhibition of neutrophils; lethal factors = cell death; Protective antigen = translocation into cells
**BOTH FACTORS ARE REQUIRED FOR VIRULENCE**
What is the pathogensis of Anthrax
Exposure to endospore –> endorespores germinate within phagolysosomes of macrophages –> intracellular survival factors allow growth initiation and phospholipase mediates escape from the phagocytic cell –> capsule and edema factor inhibit phagocytosis of vegetative cells –> cells grow rapdily in the body –> complete anthrax toxin causes cell death and affects vascular permeability
What are the different forms of anthrax and what animals are susceptible?
Ruminants - septicemia
Horses - septicemia
Humans - Wool sorter’s disease - pulmonary distress
Humans - Cutaneous lesions Q
PIgs and dogs - Pharyngeal lesions
Humans, pigs, and horses - Intestinal lesions
What are the pre-mortem and post-mortem signs of antrax baclli in…
Cattle/sheep/deer?
Horses?
Swine?
Carnivores?
Cattle/sheep/deer
Pre-mortem:
High fever; blooding from orifices; shock; respiratory distress
Post-mortem:
Dark and unclotted blood; incomplete rigour mortis; splenomegaly
Horses
- Colic and diarrhea; edema at point of infection
Swine
- Pharyngeal lesions; ulcerative lesion; lymphadenitis; obstructive edema –> death; ulcerative haemorrhagic enteritis and mesenteric lymphadenitis
Carnivores
- Similar to swine
How do you diagnose Anthrax contamination? how do you treat and control it?
REPORTABLE DISEASE
Diagnosis:
- Blood smear exmaination
- Aerobic culture and PCR from blood
- DO NOT CONDUCT FIELD NECROPSY
- Spleen biopsy
- Staining with McFadyean’s methylene blue
Treatment
- can only treat vegetative cells
- Antimicrobials - penicillin, tetracycline, doxycycline, ciprofloxacin
Control
- Vaccinate healthy animals
Anthrax symptoms/complications in humans
Cutaneous anthrax - subcutaneous edema and septicemia (80 - 90 % recover)
Gastrointestinal anthrax - pharyngeal lesions; lymphadenopathy; vomiting blood and bloody diarrhoea (40 - 75 recover)
Pulmonary or inhalation - pulmonary oedema; pneumonia; meningitis (100% fatality)
Corynebacterium spp.
- Gram positive pleomorphic caultative anaerobe rods
- Non-spore forming, non-motile, catalase positive
- Lipophilic spp - Facultative intracellular bacteria
- Non-lipophilic spp - pyogenic toxic
Corynebacterium renale
Contagious Bovine Pyelonephritis - inflammation of the kidney
- Disease of adult cows
- Antemortem signs - fever; painful urination; ammoniac odour of urine; acute abdominal pain (colic)
Postmortem signs: Multifocal abscess in kidney; enlarged renal lymph nodes; uremia
Corynebacterium pseudotuberculosis
Sheep and Goats
Caseous lymphadenitis
- Effects sheep and goats
- Gram positive facultative intracellular coccobacillus
- Abscess formation in or near major peripheral lymph nodes or within internal organs and lymph nodes
Virulence factor:
- Exotoxin phospholipase D –> damage to endothelial cells and increasing vascular permeability
- External lipid coat –> provides protection from hydrolytic enzymes from host
- “onion skin” apperance in the lymph node
Clincal signs:
- Caseous necrosis of lymph nodes
Corynebacterium pseudotuberculosis
Horses
Pigeon Fever (Colorado strangles or Dry-lan distemper)
- Cattle can also be infected
- Ucerative lymphangitis of lower extremities
- Abscesses in the pectoral region
- Found in western and midwestern states
- Enter through skin abrasions or arthropod vectors
Corynebacterium pseudotuberculosis
Diagnosis
Treatment
Control
Diagnosis:
- Culture of purulent materials
- Synergisitc hemolysin inhibition test (SHI) or you know.. (SHIT) - detects antiboides from phospholipase D exotoxin
- Positive test indicates: past resolved infection, recent exposure, recent vaccination, or active lesions
Treatment:
- Not a “curable” disease
- lancing and draining; surgical excision; systemic antibiotics (penicillin, Rifampin)
Control:
- Biosecurity practice
- Culling of infected animals
Corynebacterium kutscheri
- Murine pseudotuberculosis (old world rats!)
- Lung - suppurative pneumonia
- Lesions in kidney, liver, and heart
- Subcuticular abscess
- Lymphoid hyperplasia
Corynebacterium bovis
dermatitis in MICE!
hyperkertosis
Rhodococcus equi
Foal Pneumonia (1 - 4 month old; rare in > 8 mo old)
- gram-positive aerobic rods/cocobacilli
- Non-spore forming, non-motile, catalse positive
- Facultative intracellular pathogen
- unique lipid-rich cell envelope structure rich in mycolic acid (acid fast positive)
Virulence factor:
- Capsule
- Virulence associated proteins (VAPs)
- Mycolic acid, teichoic acid/peptidoglycan
- Cholesterol oxidase
- Phospholipase C
Clinical signs:
- Lung - multiple coalescing firm casenecrotic foci
- GI - ulcerative enterocolitis over peyer’s patches
Bronchial and mesenteric lymph node - pyogranulomatous lymphadenitis
Bone - Osteomyelitis
Rhodococcus equi in..
Cattle
Sheep
Goats
Pigs
Cats
Humans
Cattle - Metritis, lymphadenitis, pneumonia
Sheep - Caseous bronchial lymphadenitis
Goats - Pyogranulomatous lesions in liver and lungs; osteomyelitis of the vertebra and skull; entercolitis
Pigs - Tubercuolosis-like lesions in submaxillary and cervical lymph nodes
Cats - Pyogranulomatous skin lesions
Humans - zoonotic in immunocompromised inidividuals
Rhodococcus equi in humans
Lung - Pyogranulomatous pneumonia (alveoli filled with abundant macrophages); septal necrosis and atelectasis
Intestine - pyogranulomatous inflammation of lymphoid tissue
Lymph nodes - pyogranulomatous lymphdenitis
Rhodococcus equi
Diagnosis
Treatment
Control
Diagnosis:
- Evalulte the entire premise
- Screen for early detetion of disease
- Serology tests - Culture or PCR on transtracheal aspirate; cytologic evidence of sepsis
- Smears of affected tissue, transtracheal aspirates, bronchoalveolar lavages
Treatment:
- Prolonged treatment –> expensive and adverse effects
- Combination of macrolide and rifampin
- Hyperimmune plasma and NSAID
Contorl:
- Hyper immune plasma can prevent penumonia
- Early detection, treatment, and environmental management
Norcardia asteroides
- Gram positive pleomorphic facultative intracellular bacterium
- Non-motile and non-sporeforming
- Appears as rods, cocci, or coccobacilli –> long branching filaments
- AEROBIC
- most commonly isolated in species in dogs and cats (more ind ogs than cats)
- Opportunistic, noncontagious, pygranulomatous –> suppurative disease
Norcardia asteroides
Horses
Cattle
Sheep
Swine
Humans
Horses - N. asteroides and N. braziliensis cause fibinopurulent pneumonia and pyothroax
Cattle - Bovine farcy - cutaneous nocardiosis –> lymphangitis and lymphadenitis
Humans - defects with T cell mediated immunity
Horses, cattle, sheep, and swine - abortions
Norcardia asteroides
Diagnosis
Treatment
Control
Diagnosis
- Culture –> acid fast strain –> ID
Treatment:
- aminoglycoside + carbapenem
Control:
- Difficult –> sporadic disease
Clostridium spp.
- Neurotoxic - binds to nerves and causes neuronal damage
- Histotoxic and invasive - invade tissues and causes damage
- Enteric/enterotoxigenic - infects the GI tract and produces toxins
Virulence factors:
- All clostridia produce one or more bacterial protein toxins or etracellular enzyme
- Requirement of anaerobic environment = necrosis as a predisposing factor
Clostridium tetani
TETANUS - “wooden horse syndrome”
- Anaerobic gram positive Rod
- Terminal endospores –> grows in contaminated wounds
- Produces neurotoxin –> spastic paralysis
Pathogensis:
wound infected with C. tetani –> toxin produced –> toxins enter nearest motor nerve –> retrograde transport –> neuromusclar ending –> prevents release of neurotransmitters –> spastic paralysis
Clostridium tetani
Diagnosis
Treatment
Control
Diagnosis:
- Culture is often unrewarding –> takes too long
- Serolog is not very useful
- look for clinical signs: locked jaw + straightened and stiff limbs
Treatment:
- Antitoxin
- Anti-tetanus equine serum (IV or IM)
- Antimicrobial treatment –> only stops production of toxin
- Supportive care
Control:
- Toxoid immunization
- Post exposure prophylaxis
- Prompt wound management
Clostridium botulinum
BOTULISM
- Botulinum neurotoxin –> inhibits neurotransmitter release
- Food intoxication (vegetable and meats) –> toxin absorbed and distributed in bloodstream
- Occasional toxico-infectious forms –> wounds in intestine
- Commonly seen in babies given raw honey –> honey is a good source of C. botulinum spores
- one gram of dried flesh can have enough botulinum to kill a cow
Clinical signs:
- Symmetrical flaccid paralysis
- Cranial nerve impariment (double vision, dysphagia)
- Hind limb paralysis
- Respiratory failure
HUGE problem in aquatic birds
- Maggots can carry C. botulinum –> infect aquatic birds during feeding
Clostridium botulinum
Diagnosis
Treatment
Control
Diagonsis:
- Demonstration of toxin in serum, food/stomach contents
Treatment:
- IV or IM antitoxin –> only use if toxin is still being absorbed
- Therapeutic drugs to enchance cholinergic neurotransmitters
Control:
- Toxoid immunization in high risk animals
- Avoid feeding suspected food
Features of histotoxic clostridial diseases
- mechanical injury –> wounds –> anaerobic environment –> endospore growth
- Toxins cause tissue destruction –> fermentation of msucle glycogen –> gase accumulation
- Deposited endospores may remain dormant in the body for extended periods
What is necrotic myositis?
Necrosis of skeletal muscles
Clostridum chauvoei
BLACK LEG - Necrotic myositis - emphysematous swelling
- Cattle and sheep
- Lesions appear haemorrhagic
- Sudden death is common (100% fatality) –> myocardium and diaphragm effected
Clinical signs:
- Fever, anorexia, depression, lameness
Clostridum novyi
Spores in intestine and reach liver –> traumatic damage by liver fluke provides anaerobic conditions –> germination of spores
Clostridium septicum
What does it cause in all species?
What does it cause specfically in sheep?
Malignant edema
- Fatal toxemia affect in all species of animals
- Local exotoxins = inflammation –> edema, necrosis and gangrene
BRAXY in sheep
- Highly fatal infection
- Toxemia and inflammation of the abomasal wall
Clostridium chauvoei, septicum, novyi
Diagnosis
Treatment
Control
Diagnosis:
- Direct fluorescent antibody staining test (DFA)
Treatment:
- antimicrobial treatment (penicillin)
- Hyperbaric oxygen
Control:
- Routine vaccination
Clostridium perfringens
Necrotizing haemorrhagic enteritis
- Enteric clostridium
- Five types of toxins - Type D is more commonly found in small ruminants
Type D enterotoxemia - similar symptoms as listeria! - Edema and malacia
Clostridium difficile
Enterocolitis
- Affects humans, horses, pigs dogs, cats, laboratory rodents
- Risk factors: recent antibiotic use, increased age, hospitalization
- neonates are resistant
- Dysbiosis - disruption of normal flora –> pseudomembraneous colitis
Tox A - Enterotoxin, fluid loss
*Tox B - Cytotoxin, destroys cells rapidly
Clostridium difficile
Diagnosis
Treatment
Control
Diagnosis:
- Culture - obligate anaerobe –> requires anaerobic median
- Direct toxin detection - antigen for Tox A and B
Treatment:
- Stop antibiotics
- Clindamycin should NOT be used in horses
- give probiotics
- avoid anti-diarrhoeal medication –> accumulates toxin
Clostridum spiroforme
- Found in rabbits (4 - 8 weeks old)
- Entertoxemia –> explosive diarrhoea
- Do not use lincomycin, clindamycin, and erythromycin –> induces clostridium related enterotoxemia
Clostridium piliforme
Tyzzer’s Disease
- GRAM NEGATIVE
- Focal liver necrosis –> fatal diarrheal
Non-sporeforming anaerobes
- usually infects mucous membranes and skin
- require high levels of Vit K, hemin, and growth factors
- Endogenous origin
Virulence factors:
- Catalase and superoxide dismutase –> protection from oxygen
Clinical signs:
- Foul smelling discharge (from necrotic tissue)
- Gas in tissues or discharge
- Pyogranulomatous lesions
- Infetions do NOT repsond to aminoglycosides
Fusobacterium necrophorum
Foot Rot and Liver abscess
- Extensive necrosis and keratinolysis in severe cases
Diagnosis:
- Culture and PCR
Treatment:
- Remove necrotic tissue
- Oxygenation
- Antimicrobials (penicillin, metronidazole, clindamycin chloramphenicol, doxycycline)
Control:
- Very difficult
