-
Arcanobacterium pyogenes
- (Actinomyces pyogenes, Corynebacterium pyogenes)
- Mucosal flora of ruminants and swine
- Facultative anaerobe
- Chronic purulent infections - mastitis, endometritis, pneumonia, endocarditis, arthritis, etc..
- Opportunist, polymicrobial infections (+ anaerobes)
- Hemolysin (pyolysin), extracellular-matrix binding proteins, proteases, can invade epithelial cells and survive in M� (how?)
- Therapy - drainage, penicillin
- Actinobaculum suis
- (Actinomyces suis, Eubacterium suis, Corynebacterium suis)
- Anaerobe
- Necrotic purulent pyelonephritis & cystitis in swine
- Actinomyces viscosus
- Oral flora of dogs, humans
- Facultative anaerobe
- Actinomycosis in dogs and cats - chronic pyogranulomatous Infections under the skin or in body cavities (pyothorax)
- Fimbriae
- Microscopic diagnosis: gram stain, immunofluorescence
- Therapy - drainage, penicillin
- Actinomyces bovis
- Oral flora (cattle)
- Anaerobe
- "Lumpy jaw" in cattle - traumatic lesions in the oral cavity leading to chronic granulomas involving bones (� actinobacillosis); fistulation through the skin or oral mucosa
- Microscopy of sulfur granules - 10% NaOH (clubs: proteins & CaPO4), gram stain
- Therapy - drainage, iodine solutions, penicillin
- Nocardia asteroides
- Ubiquitous (soil),
- Aerobe, produce mycolic acid
- Facultative intracellular pathogen � cell-mediated immunity
- Chronic, granulomatous fistulous infections in the oral cavity, the subcutis and internal organs (lungs - aspiration pneumonia); mastitis (iatrogenic)
- Virulence properties
- Bind to and invade endothelial cells (e.g. midbrain)
- Mycolic acid - toxic, inhibits killing by M� and neutrophils; immunostimulant, activates M� (TNF) and induces them to fuse to multinucleate cells
- Lab diagnosis - long branching filaments, weakly gram +, � acid-fast
- Therapy - drainage, sulfonamide-trimethoprim (penicillin-resistant)
- Dermatophilus congolensis
- Obligate parasite of animals
- Aerobe
- Parallel filaments (divides in both directions); release of zoospores (chemotactic for CO2); germ tube formation
-
Streptothricosis (dermatophilosis) in ruminants, horses (dogs, cats, humans) - exsudative dermatitis (� rain rot� or �rain scald� in horses; "lumpy wool", "strawberry foot rot" in sheep)
- Virulence factors - extracellular proteases (keratinase)
- Therapy - hygiene, iodine, penicillin+streptomycin
-
NONSPORE-FORMING ANAEROBES
- (Quinn & Markey, Chapter 30 & 8)
- Oral and gut flora of animals and humans
- Infections require two simultaneous events
- trauma of deep tissues, ischemia, � O2 tension
- fecal contamination (anaerobes), bites
- Polymicrobial (mixed) infections, with facultative anaerobic bacteria, synergistic process (maintenance of a low redox potential)
- Abscesses, gingivitis, peritonitis, tissue necrosis
-
Specimen collection and transport to the lab
Sealed syringe filled with pus (fluid, biopsy better than swab)
-
ACTINOMYCETES
- (Quinn & Markey, Chapters 10-11)
- Gram positive rods and branching filaments
- Chronic purulent and granulomatous infections
- Difficult to
- treat with
- antibiotics
- Arcanobacterium pyogenes
- (Actinomyces pyogenes, Corynebacterium pyogenes)
- Mucosal (nasal and oropharyngeal) flora of ruminants and swine
- Facultative anaerobe
- Chronic purulent infections - mastitis, endometritis, pneumonia, endocarditis, arthritis, etc..
- Opportunist, polymicrobial infections (+ anaerobes)
- Hemolysin (pyolysin), extracellular-matrix binding proteins, proteases, can invade epithelial cells and survive in M� (how?)
- Therapy - drainage, penicillin
- Kidney - Abscessation
- Actinobaculum suis
- (Actinomyces suis, Eubacterium suis, Corynebacterium suis)
- Anaerobe
- Necrotic purulent pyelonephritis & cystitis in swine
- Actinomyces viscosus
- Oral flora of dogs, humans
- Facultative anaerobe
- Actinomycosis in dogs and cats - chronic pyogranulomatous infections under the skin or in body cavities (pyothorax)
- Fimbriae
- Microscopic diagnosis: gram stain, immunofluorescence
- Therapy - drainage, penicillin
-
Actinomyces bovis
- Oral flora (cattle)
- Anaerobe
- "Lumpy jaw" in cattle - traumatic lesions in the oral cavity leading to chronic granulomas involving bones (� actinobacillosis); fistulation through the skin or oral mucosa
- Microscopy of sulfur granules - 10% NaOH (clubs: proteins & CaPO4), gram stain
- Therapy - drainage, iodine solutions, penicillin
-
Nocardia asteroides
- Ubiquitous (soil),
- Aerobe, produce mycolic acid
- Facultative intracellular pathogen � cell-mediated immunity
- Chronic, granulomatous fistulous infections in the oral cavity, the subcutis and internal organs (lungs - aspiration pneumonia); mastitis (iatrogenic)
-
Virulence properties
- Bind to and invade endothelial cells (e.g. midbrain)
- Mycolic acid - toxic, inhibits killing by M� and neutrophils; immunostimulant, activates M� (TNF) and induces them to fuse to multinucleate cells
- Lab diagnosis - long branching filaments, weakly gram +, � acid-fast
- Therapy - drainage, sulfonamide-trimethoprim (penicillin-resistant)
-
Dermatophilus congolensis
- Obligate parasite of animals
- Aerobe
- Parallel filaments (divides in both directions); release of zoospores (chemotactic for CO2); germ tube formation
-
Streptothricosis (dermatophilosis) in ruminants, horses (dogs, cats, humans) - exsudative dermatitis (� rain rot� or �rain scald� in horses; "lumpy wool", "strawberry foot rot" in sheep)
- Virulence factors - extracellular proteases (keratinase)
- Therapy - hygiene, iodine, penicillin+streptomycin
-
NONSPORE-FORMING ANAEROBES
- (Quinn & Markey, Chapter 30 & 8)
- Oral and gut flora of animals and humans
- Infections require two simultaneous events
- trauma of deep tissues, ischemia, � O2 tension
- fecal contamination (anaerobes), bites
- Polymicrobial (mixed) infections, with facultative anaerobic bacteria, synergistic process (maintenance of a low redox potential)
- Abscesses, gingivitis, peritonitis, tissue necrosis
-
Specimen collection and transport to the lab
- Sealed syringe filled with pus (fluid, biopsy better than swab)
- Anaerobic transport media
- Blood culture (3x/24 hrs)
-
Lab techniques - gram stain, gas chromatography; slow growth (O2-sensitive: thioglycolate media, anaerobic jar or glove box)
- Therapy
- Surgery (drainage)
- Antibiotics
- (resistant to
- aminoglycosides,
- fluoroquinolones)
-
GRAM negative - Fusobacterium necrophorum
Gram stain - beaded filaments
-
Mixed infections with A. pyogenes, Bacteroides spp., etc..
- Necrobacillosis
- Phlegmonous and ulcerative necrotic stomatitis in cattle and swine (fights - bull nose), calf diphtheria
- Rumenitis (grain-rich diet, rumen acidosis, ulceration), liver abscess
-
Pericarditis (foreign body)
- Footrot in cattle
- Interdigital phlegmonous
- infections (ulceration)
-
Thrush in horses
- Prevotella, Porphyromonas, Bacteroides
- Leukotoxin (hemolysin)
- LPS
- Penicillin-susceptible, no effective vaccines
- Hygiene - survives for months in humid bedding or soil
-
Pr. melaninogenica, Po. asaccharolytica, B. fragilis
Mixed with other anaerobes; oral infections, aspiration pneumonia, pyothorax (cats), castration wounds, umbilical infections, sepsis
-
Capsule - activates complement, chemotactic for leukocytes
- Proteases - collagenase, IgA protease
- Nontoxic LPS
- Some - enterotoxin, hemolysin
- Superoxide dismutase, catalase
- (� susceptibility to O2)
- Therapy - metronidazole, clindamycin; antibiotic-resistance (penicillin!)
- Dichelobacter (Bacteroides) nodosus
- Obligate parasite of hooves of ruminants (short life in soil)
- Contagious footrot in sheep - predisposing factors
- (humidity, trauma)
- Frequently with A. pyogenes, F. necrophorum, etc�
- Fimbriae (antigenic variability: multivalent vaccines)
- Heat-stable protease (= keratinase)
- Penicillin-susceptible
- Trimming of the hooves, disinfectant baths
- Capnocytophaga canimorsus
- Oral cavity commensal in dogs & cats
- Bite wounds � complications (sepsis)
- Virulence factors: sialidase, block M� killing, LPS
- Gram positive
- Anaerobic streptococci
- Abscess
- Mastitis in cows
- Mixed with other anaerobes
- CLOSTRIDIA
- Spore-forming anaerobes
- (Quinn & Markey, Chapters 14-15)
- Large gram positive rods
- Spores killed only by 121�C, 20 min.
- Widely distributed
- saprophytes -
- soil, intestine
- Some produce
- potent exotoxins -
- life-threatening
- diseases
- Clostridium tetani
- Widespread - intestines of animals and humans, soil
- Tetanus - human and horses are most susceptible, pigs, ruminants, (dogs)
- Wound infections (castration, umbilicus), anaerobic conditions for spore germination, exotoxin production
-
Neurotoxin (tetanospasmin)
- Highly toxic protein
- Binds to peripheral nerves near wound (irreversible binding to gangliosides of nerve cells),
- Transmitted to cranial nerve nuclei
- Protease activity on specific vesicle-associated membrane proteins
- Blocks release of inhibitory transmitters (e.g.GABA)
-
Spastic paralysis (protrusion of the nictitating membrane, sawhorse stance; in humans, "sardonic smile", lockjaw - trismus); death by respiratory failure
- Hemolysin (tetanolysin)
- Toxoid vaccine
- Sedation; surgical debridement, penicillin (antitoxin - frequently too late)
-
Clostridium botulinum
- Habitat - soil and marine sediment
- Food contamination by spores (meat, vegetables, fish)
- Botulism
- Intoxication by exotoxins previously produced in food, after germination of spores under anaerobic conditions, e.g. spoiled silage, rotting vegetables or carcasses, contaminated cans
-
Wound botulism
- Infant botulism; shaker foal syndrome
- Neurotoxins (8 serotypes)
- Most potent known toxins!
- Heat-labile proteins, resistant to enteric proteases
- Bind to gangliosides at motor-neuromuscular junctions
- Protease activity on specific vesicle-associated membrane proteins
- Block the release of the neurotransmitter acetyl-choline, inhibition at peripheral cholinergic synapses
-
Cattle, horses & birds are highly susceptible (� carnivores and swine)
- Suspicious food - 100�C, 10 min inactivates the toxin
- Toxoid vaccines for cattle
- Therapy - ASAP tracheotomy and antitoxin
-
Histotoxic Clostridia
- Clostridium perfringens (welchii)
- Types A to E - � 2 major lethal toxins (out of 4)
- Gas gangrene - Type A (most widespread)
-
-
Deep wound infections
- Anaerobic conditions
- 2 hemolysins responsible for leukostasis, vascular dysfunction and capillary leak leading to necrosis and gas formation in muscles (gangrene), toxemia
- a toxin, lecithinase, phospholipase C
- q (theta) toxin, perfringolysin
- Collagenase (pulpy muscles)
- Mixed infections with other Clostridia
- Surgical and antibiotic treatments
-
Food poisoning (type A) in man (meat)
- Enterotoxemia
- Type C - b toxin (protease sensitive), hemorrhagic enteritis in neonatal farm animals
- Type D - e toxin (prototoxin, activated by enteric proteases - necrosis, lethal, plasmid-encoded), "Pulpy kidney" disease of sheep and goats (sudden change to a rich diet); brain edema
- Vaccines (appropriate toxoid), hyperimmune sera (colostrum)
- Clostridium chauvoei (C. feseri)
- More prevalent in certain geographic areas
- Blackleg - ruminants
- Entry through the gut (bacteremia), wounds; germination and multiplication in traumatized muscle tissue; typical lesions rarely found (bubbles, rancid odor)
- Exotoxins - hemolysins, a necrotoxin, etc..
- Diagnostic - immunofluorescence
- Vaccine (formalin-treated cultures)
-
Clostridium septicum
- Worldwide (unlike C. chauvoei)
- Malignant edema: ruminants, horses, pigs
- pathogenesis due to exotoxins, similar to C. chauvoei
- Entry through wounds; cellulitis with � localized large swelling of muscle tissue
- Diagnostic - immunofluorescence
- Vaccine
-
Clostridium novyi (= C. oedematiens)
- Various types produce different toxins (different diseases)
- Gas gangrene (Type A) - sheep, cattle, human
- Extensive edema (rams - "big head")
- Mixed infections with other Clostridia
- Necrotizing infections among injecting-drug users (with other Clostridium sp.)
-
Infectious necrotic hepatitis (Type B) or "Black disease�- sheep, cattle (horse)
- Liver flukes infections cause anaerobic conditions for the germination of spores in the liver
- Exotoxins (4)
- a toxin - gaps between endothelial cells
- b toxin - phospholipase C (hemolysin) release of hemolyzed blood in tissues (blackening) � hypovolemic shock, tissue necrosis, lethal toxemia
- Elimination of the snail (flukes); vaccines
- Clostridium haemolyticum (C. novyi, type D)
- Bacillary hemoglobinuria ("red water") - cattle and sheep
- Pathogenesis: similar to "Black disease" (liver flukes)
- Exotoxins - phospholipase C (b toxin), intravascular hemolysis, lethal anoxia
- Histotoxic Clostridia
- Clostridium difficile
- Pseudomembranous colitis
- Humans, horses (dogs)
- Associated with previous antibiotic (cephalosporins, penicillins, clindamycin) treatment - suppression of the normal anaerobic flora. Unharmed spores can germinate.
- Toxins A and B (cytotoxic - modify small GTPases, actin disassembly) - diarrhea
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