Gram negative anaerobes Flashcards by Gabby Leighow

Important genera

-Bacteroides
-Dichelobacter
-Fusobacterium
-Porphyromonas
-Prevotella
-Brachyspira

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Foot rot in sheep

Dichelobacter nodosus

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Calf diphtheria, Foot rot, liver abscesses in cattle

Fusobacterium necrophorum

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Swine dysentery

Brachyspira hyodysenteriae

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UTIS in sows

Acinobaculum suis

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Entercolitis in horses

Clostridium

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Gram negative anaerobe infection

-Part of normal flora
-Generally abscess and necrotic
-Involve mucous membranes
-Often polymicrobial infections

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Characteristics of infections

Located close to mucosal surface
Putrid odor
Gas often
Negative aerobic culture

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Virulence factors

-LPS
-Hemolysin
-Platelet aggregation factor
-Synergy with facultative bacteria
-Superoxide dismumutase
-Catalase
-Exotoxins
-Enzymes
-Fermentation products (acids, ammonia)

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Exotoxins

Enterotoxin, hemolysin, leukotoxin

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Synergism between anaerobes and non anaerobes

Supply essential growth factors
Protect agains phagocytosis
Creation of anaerobic conditions

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Synergism between anaerobes and non anaerobes

Supply essential growth factors
Protect agains phagocytosis
Creation of anaerobic conditions

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Dichelobacter nodosus morphology

Dumb bell shaped and heavily fimbriated

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Dichelobacter nodosus habitat

Obligate pathogen of the epidermal tissues of the hoof of sheep, goats, cattle

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Virulence factors of D. nodosus

-Fimbriae for adhesion
-Protease for tissue destruction
-Endotoxin for inflammation

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Pathogenesis of D. nodosus

Enter through breaks in the skin and colonize with pili. Invade using proteases and have synergy with other bacteria

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Forms of foot rot

-Virulent
-Intermediate
-Benign

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Symptoms of foot rot

Lameness and loss of body weight

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Treatment of foot rot

-Trim affected hoof and remove necrotic tissues
-Topical antiseptics and antibiotics
-Foot baths

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Antibiotics for foot rot

-Penicillin and aminoglycosides
-Tetracyclines
-Fluoroquinolones
-Macrolides

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Vaccines for foot rot

-Prominant in Australia and New Zealand
-Bacterins or fimbraiae based

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Fusobacterium necrophorum

Pleomorphic rods that cause necrotic lesion

Habitat of F. necrophorum

GI, respiratory, urinary and genital tracts
-Soil

Subspecies of F. necrophorum

-Necrophorum: phosphatase, agglutination, and leukotoxin positive
-Funduliforme: sedimentation in browth, waxy and sticky colonies

Virulence factors of necrophorum

-Leukotoxin -LPS -Hemolysin -Hemagglutinin -Adhesins -Dermonecrotic toxin -Platelet aggregation factor -Proteases

Necrobacillosis in horses

1. Thrush 2. Necrotic dermatitis 3. Pneumonia 4. Septicemia

Necrobacillosis in sheep

1. Lip and leg ulceration 2. Infectious bulbar necrosis 3. Foot rot

Necrobacillosis in swine

1. Ulcerative stomatitis 2. Necrotic enteritis 3. Necrotic enteritis 4. Secondary invader in swine dysentery

Necrobacillosis in chickens

Respiratory infection secondary invader to fowl pox

Necrobacillosis in humans

-Sore throat -Lemierrie's syndrome

Necrobacillosis in cattle

1. Diptheria 2. foot rot 3. Liver abscess 4. Metritis in dairy cows

Calf diptheria

Happens in young calves especially if they have a breach in the mucus membrane. Can be acute or chronic

Clinical signs of calf diptheria

-Fever -Dyspnea -Cough -Loss of body weigh -Necrosis of mucus membranes, larynx or adjacent tissues

Treatment of calf diptheria

-Penicillin -Tetracyclines -Tylosin

Clinical signs of foot rot from fusobacterium

-Cellulitis -Swelling between digits -Exudate and pus

Treatment of necrobacillosis foot rot

Tetracyclines

What bacteria causes the highest prevalence of liver abscesses in cattle

Fusobacterium necrophorum

Diagnosis of liver abscesses

No clinical signs diagnosed after slaughter

Control of liver abscesses

-Proper feed management -Antimicrobial feed additives -Bacterin vaccine

FDA guidance for antimicrobial use

Limit the use to assure animal health under veterinary oversight -Tylosin requires VFD

Metritis from necrobacillosis

-See fetid uterine discharge -Fever -Drop in milk production

What type of animals do we see necrobacillosis liver abscesses in

High grain fed cattle

Fusobacterium equinum

Opportunistic infection in horses causing abscesses and necrotic infections in the oral and lower respiratory tract

Virulence factor of fusobacterium equinum

Leukotoxin

Fusobacterium gastrosuis

Normal inhabitants of the oral cavity, and upper stomach in pigs. Leads to gastric ulcerations with Helicobacter suis.

Pathogenesis of liver abscesses

Cows fed high-grain diets leads to high acid production and acidosis leading it susceptible to rumen invasion. Bacteria live in ruminal abscesses they then get into the portal blood and into the liver to cause liver abscesses

Bacteroides fragilis

Gram negative anaerobic rods that are normal flora of the colon of animals. Leads to abscesses and soft tissue infections.

Virulence factors of Bacteroides fragilis

Capsular polysaccharide

B. fragilis enterotoxin

Fragilysin- stimulates fluid secretion and causes enteritis

Black pigmented anaerobe

Porphyromonas

Sugar fermenting anaerobe

Prevotella

Porphyromonas gingivalis infection

Periodontal infections

Porphyromonas levii

abscesses and foot rot with other bacteria