Collective Flashcard

Fusobacterium necrophorum

4 biotypes or biovars: A, B, AB and C

Fusobacterium necrophorum

Commensal of alimentary tract and mucous membranes

Fusobacterium necrophorum

Invades and multiplies in anaerobic environment provided by damaged tissues

Fusobacterium necrophorum

Infections characterized by necrotic process that are frequently mixed such as liver abscesses in cattle with Archanobacterium pyogenes

Fusobacterium necrophorum

Endotoxin and a potent leukotoxin

Fusobacterium necrophorum

Extracellular products such as hemolysin, hemagglutinin, adhesin, platelet aggregation factor, protease and Dnase

Fusobacterium necrophorum

Capsulated strains more virulent for mice

F. necrophorum infection

necrobacillosis

Fusobacterium necrophorum

Secondary invader in necrotic stomatitis, pharyngitis and enteritis, most commonly in swine

Fusobacterium necrophorum

In numerous infections initiated by a variety of wounds and injuries in all domestic animals

Fusobacterium necrophorum

Metritis, cellulitis, mastitis and calf diphtheria in cattle

Fusobacterium necrophorum

Primary cause of liver abscesses and foot rot

Fusobacterium necrophorum

Found in necrotic areas of the mouth, pharynx, and trachea in cattle

Fusobacterium necrophorum

Together with Archanobacterium pyogenes (now Truepella pyogenes), causes foot abscesses or ovine interdigital dermatitis, abortion in sheep

Fusobacterium necrophorum

Principal cause of “bull nose” from injury caused by ringing boars in swine

Fusobacterium necrophorum

2ndary invader in swine dysentery and necrotic enteritis

Fusobacterium necrophorum

Involved in avian diphtheria, primary cause is fowl pox virus

Fusobacterium necrophorum

Diagnosis: Gram negative rods, initially pleomorphic: short rods, long filaments and moniliform bodies seen

Fusobacterium necrophorum

Colonies are small, smooth, convex and whitish yellow in color with narrow zone of alpha or beta hemolysis

Fusobacterium necrophorum

Definitive id based on biochemical test

Fusobacterium necrophorum

Primary media: hemin with menadione, blood agar, selective media to suppress facultative anaerobes and bile esculin agar

Fusobacterium necrophorum

Colony morphology, pigmentation, fluorescence and antimicrobial susceptibility may indicate genus

Fusobacterium necrophorum

treatment: Amoxicillin, ampicillin, tetracyclines, chloramphenicol, metronidazole, clindamycin, clavulanic acid-amoxicillin, cephalosporinTylosin most effective as food additive

Fusobacterium necrophorum

Vaccination not successful

Bacteroides fragilis group

Comprises 10 species, all recovered from clinical specimens

Bacteroides fragilis group

Most common anaerobe causing infections in humans, occasionally in farm and companion animals

Bacteroides fragilis group

Produces endotoxin which causes accumulation of fluid in ligated intestinal loops of lambs and calves

Bacteroides fragilis group

Enterotoxin is fragilysin, an extracellular zinc metalloprotease

Bacteroides fragilis group

Enterotoxins implicated as cause of diarrheal diseases in calves, lambs, foals, piglets and humans

Candida albicans

• disease-causing; a normal inhabitant of the digestive tract, oral cavity and vagina

this genus occurs saprophytically

CANDIDIASIS

many species invloved in bovine mastitis

Candida parapsilosis

species involved in Bovine abortion

Candida rugosa

species involved in Pyometra in mares

Candidiasis (C. albicans)

possess adhesins consisting of fibrillar peptide_ mannans with affinity to fibronectin on the surface of host cells

Candidiasis

Yeast forms responsible for tissue damage; secreted

aspartic proteinase (Saps) important virulence factor

which contributes to tissue damage

candidiasis

• Inhibition of yeast cell division results in hyphal elements

  which is considered to be a virulence factor associated

  with ability to penetrate host tissue and localize

  infections

candidiasis

Virulence factors: cell wall protein, proteases, neuraminidase, chitin, mannoprotein and lipids

candidacidal

Neutrophils and macrophage have _______ activity

Candida albicans

Pathogenicity

• Infections by____ ______ frequently on mucous

  membranes of digestive and genital tract

candidiasis

occasionally associated with immunocompromised conditions and prolonged antibiotic therapy

candidiasis

Mycotic stomatitis, and enteritis with white to gray patches of pseudomembranous inflsmmation

candidiasis

in swine, Infection of lower esophagus and esophageal region of

the stomach

candidiasis in swine

Diarrhea and cutaneous candidiasis

candidiasis in poultry

Infections of the mouth, esophagus and crop with pseudomembranous whitish areas

candidiasis

Crop mycosis (thrush)

candidiasis in cattle

• Mastitids common, genital infections rare

candidiasis

metritis and vaginitis in mares

candidiasis

genital candidiasis in Stallions and bulls

candidiasis

affects Mucous membranes of mouth, tongue, genital tract in humans

candidiasis

Recurring candidal vulvovaginitis in women

candidiasis

Oral form (thrush) characterized by white patches, commonly in infants

candidiasis

Frequent in acquired immune deficiency syndrome and

advanced malignancies

Candidiasis (C. albicans)

can stimulate release of histamine by mast cells and production of IgE antibodies associated with allergies

candidiasis

diagnosis with Oval, thin-walled budding cells and hyphal fragments (pseudohyphae) in Wet mounts (India ink, LCB) and Gram staining (Gram +)

with diagnosis that Cultivation on blood agar and Sabouraud’s agar looks like Soft, creamy colonies resembling staphylococci

candidiasis

diagnosis where Demonstration of large chlamydospores or germ tubes

Candidiasis

identification of its species by carbohydrate fermentation and assimilation tests

Sporothrix schenckii

SPOROTHRICOSIS is caused by

SPOROTHRICOSIS

Dimorphic fungi that occur in soil, wood and vegetation

SPOROTHRICOSIS

• Infection in humans and some animals characterized by

  formation of subcutaneous nodules or pyogranulomas

SPOROTHRICOSIS

• Organisms enter through wounds on the skin and spread via

  the lymphatics

SPOROTHRICOSIS

• Parasitic form of growth is the blastoconidia

sporothricosis

Involvement of bones, joints and visceral organs fatal

sporothricosis

Disease occurs most commonly in horse and seen most

frequently as an ascending lymphocutaneous infection of the

leg

SPOROTHRICOSIS

very difficult to demonstrate in stained smears and wet

mounts of pus and tissue scrapings except in feline

SPOROTHRICOSIS

• FAT, periodic acid-Schiff and calcofluor white staining of

  specimens give positive results

SPOROTHRICOSIS

Characteristic “asteroid bodies” consisting of clusters of

yeast cells with peripheral eosinophilic rays seen in tissue

sections

SPOROTHRICOSIS

genus with tissue and mycelial phase

CHROMOBLASTOMYCOSIS and PHAEOHYPHOMYCOSIS

Infrequent opportunistic fungal infections of animals and humans

CHROMOBLASTOMYCOSIS and PHAEOHYPHOMYCOSIS

Wide variety of dark pigmented (dematiaceous) fungi found widely in soil and vegetation

CHROMOBLASTOMYCOSIS and PHAEOHYPHOMYCOSIS

• organisms single-celled or

  clustered, spherical, thick-walled muriform or sclerotic

  bodies with a black or dark-brown pigment

CHROMOBLASTOMYCOSIS and PHAEOHYPHOMYCOSIS

they multiply by cross-wall formation or splitting rather than budding

phaeohyphomycosis

fungal forms are yeast-like, pseudohyphal, or hyphal and without muriform cells

PYTHIOSIS

SWAMP CANCER< FLORIDA HORSE LEECHES

PYTHIOSIS

Seen mainly in tropical and subtropical areas such as

Australia, New Guinea, Asia, Central and South America

and Southern United States

PYTHIOSIS

Chronic skin disease of horses, cattle and dogs 

PYTHIOSIS

Chronic skin disease of horses, cattle and dogs caused by

soiled borne fungus Pythium insidiosum, formerly

Hyphomyces destruens

PYTHIOSIS

Enters via abrasions or wounds, involves limbs, hoof,

hock, fetlock, head, neck or lips

PYTHIOSIS

Pyo- or fibrogranulomatous reaction with necrosis and formation of fistulous tracts

PYTHIOSIS

Direct examination of smears from exudates, freshly

affected tissues and biopsies

PYTHIOSIS

Isolation and identification of fungus; presence of characteristic zoospores

PYTHIOSIS

Progressive but not systemic

MYCETOMA

A pyogranulomatous, subcutaneous abscess of

animals and humans resulting from traumatic

inoculation of a saprophytic fungus or an

actinomycete

MYCETOMA

• Characterized by the triad: tumefaction

  (swelling), draining sinuses, and grains

MYCETOMA

Microcolonies (grains or granules) frequently

pigmented, can be seen grossly in lesions and

exudates

MYCETOMA

Lesions reveal discrete brown or black fungal

microcolonies embedded I large mass of granulation

tissue

MYCETOMA

Laboratory Diagnosis

• Gross examination of scrapings or biopsy tissue for

characteristic microcolonies “grains”

MYCETOMA

Grains: pressed between coverslips and examined

microscopically reveal mycelia that are 2-4 um in width,

wider than actinomycotic granules; presence of

chlamydospores