Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
VET140- Microbiology
Mycology
| Term | Definition |
|---|---|
| Heterotrophs | non-photosynthetic fungi |
| Saprophytic | fungi that gets nourishment from dead organisms or decaying organic material. |
| Fungi Characteristics | -parasitic or saprophytic -multicellular except yeasts -contain eukaryotic cells -consisted of hyphae -digest food externally through exoenzymes |
| Eukaryotic Cell Parts | -nuclei with membranes, mitochondria, cell walls contain chitin (insect exoskeletons, lobster). |
| Hyphae | webs of slender tubes which grow toward food sources. These make up a branching web called a mycelium. |
| Mold Morphology | this is a morphological form that contains hyphae and mycelium from masses of interlacing hyphae. |
| Unicellular Yeast Morphology | this is a morphological form that is oval or spherical. |
| Dimorphic Fungi | This form occurs in both mold and yeast, form depends on environmental factors. |
| Mycelium | a mass of hyphae. |
| Fungal Ecology | -aerobic -tolerate high osmotic pressures and low pH -temp: 25-37*C -Saprophytes are spread in environment -Parasitic (Ringworm) -Yeasts are commensals on skin/MM. |
| Mold Structure | Structure: nuclei, mitochondria, microtubular network, hyphae, spores, no budding, large colonies, growth and extension at edge, sexual and asexual reproduction. |
| Yeast Structure | Structure: nuclei, mitochondria, microtubular network, no hyphae, no spores, asexual reproduction only via budding, soft smooth round colonies. |
| Predisposing Factors to Disease | -immunosuppression, prolonged abx tx, immunological defects, aging, malnutrition, heavy challenges of fungal species, trauma to tissues, persistent moisture on skin, neoplasia, immunosuppression 2nd to viral disease. |
| Arthroconidia | arthrospores; formed and released during the process of hyphal fragmentation. Spores may be formed successively as in dermatophytes or with intervening empty cells as in Coccidioides immitis. |
| Blastoconidia | blastospores; conidia which are produced by budding, as in Candida albicans, from a mother cell from hyphae or from pseudohyphae |
| Chlamydoconidia | chlamydospores; thick walled resistant spores which contain storage products. These structures are formed b some fungi in unfavorable environmental conditions. |
| Macroconidia | large multi=celled conidia which are produced by dermatophytes in culture. |
| Microconidia | small conidia which are produced by certain dermatophytes |
| Phialoconidia | conidia produced from phialides, the phialides of Aspergillus species arise from a vesicle. |
| Sporangiospores | spores formed by zygomycetes such as Rhizopus species, and are released when a mature sporangium ruptures. |
| Sexual Spores | spores that are for the fusion of protoplasm and nuclei of two cells by meiosis |
| Asexual Spores | spores for molds |
| Meiosis | a type of cell division that results in four daughter cells each with half the number of chromosomes of the parent cell, as in the production of gametes and plant spores. |
| Arthoconidia sp. : Coccidioides immitis | arthrospores |
| Clastoconidia sp. : Candida albicans | blastospores (budding), are from mother cell, hyphae, or pseudohyphae |
| Chlamydoconidia sp. | Chlamydoconidia sp. Thick walled, water resistant, contain storage products, formed during unfavorable conditions. |
| Conidiospores | spores that form on condiophores |
| Sporangiospores | spores that form within a sporangium |
| Differentiating Fungi | -type of spore (conidial/sporangium) -physical features of hyphae (vegetative growth) -colony features |
| Fungi Treatments | -Polyene drugs: nystatin, amphotericin B -Antifungals: the –azoles -Griseofulvin for ringworm: accumulates in keratinized tissues -Terbinafine for ringworm and sporotrichosis |
| Fungal Disease Mechanisms | -Tissue invasion (mycosis), release enzymes which kill, digest and invade host cells -Toxin production (mycotoxicosis) -Induction of hypersensitivity |
| Dermatophytes | ringworm, caused by Microsporum and Trichophyton sp. Fungi that invade superficial keratinized structures (skin/hair/claws). Arthrospores are the infectious form. Can grow on Saboraud dextrose agar and Dermatophyte test media (DTM) @ room temp. |
| Aspergillus species | opportunistic infection, mycotoxins. |
| Yeasts | commensal on skin or MM, opportunistic infection. |
| Dimorphic Fungi | mold in the environment, yeast in tissue, opportunist infection. |
| Zygomycetes | saprophytes, opportunistic infection. |
| Mycotoxin Producing Species | toxic metabolites in growing crops or stored feed. |
| What is the best method to obtaining a sample when attempting to determine whether dermatophytes are present? | take hair from the periphery of the lesion. |
| Lyme disease if transmitted via: | Deer Tick |
| -philic | "love or liking," "unnatural attraction," or "tendency." |
| Dermatophyte Diseases in dogs | M. canis, M. gypseum, Trichophyton sp. mentagrophytes. |
| Dermatophyte Diseases in cats | Microsporum canis |
| Microsporum canis | most common isolated in dogs and cats, zoonotic dermatophyte. CS: alopecia, scaling, broken hairs surrounded by inflammatory zone, miliary dermatitis, generalized lesions are rare and associated w/ Cushing's/immunosuppression. |
| Miliary | (of a disease) accompanied by a rash with lesions resembling millet seed. |
| Trichophyton verrucosum | dermatophyte in calves. Causes: lesions around face/eyes, alopecia, white crusts. Most common in winter bc of housing, can control with vaccination. |
| Trichophyton equinum | dermatophyte in horses from direct contact or fomite exposure. Horses less than 4 year olds are most susceptible. |
| Microsporum gallinae | dermatophyte in poultry |
| Microsporum nanum | dermatophyte in swine |
| Dermatophyte Diagnosis | Dx: not possible by CS alone (all look alike), need samples, 10% potassium hydroxide (KOH), culture on sabouraud dextrose agar can be up to 5 wks, colony morphology, microscope exam of microconidia, DTM, Wood's Lamp (can have up to 50% false negatives). |
| KOH Steps | -cover plucked hairs/specimen with KOH -sit for several minutes + exam under microscope -KOH will dissolve skin/hair, but not the hyphae. |
| Lactophenol Cotton Blue Stain | staining method- phenol will kill any live orgnisms; lactic acid preserves fungal structures and cotton blue stains the chitin in the fungal cell walls, works better than KOH with transparent specimens. |
| Aspergillosis species | saprophytic molds that are widespread in the environment, aerobic, grow rapidly, colonies on Saboraud agar are often velvery/fluffy/green/black/yellowish. |
| Aspergillosis Effects | -respiratory infection -hyphal invasion of blood vessels (vasculitis and thrombus formation) -mycotic granulomas in lungs -uncommon/sporadic -immunosuppression related -2nd most common fungal infection in humans |
| Aspergillus in poultry | bacteria in poultry that causes Brooder Pneumonia. CS: lethargic, anorexia, high mortality in chicks, yellow nodules in lungs, air sacculitis. Dx: histopath ad culture. |
| Guttural Pouch Mycosis | disease in horses caused by Aspergillus species. Is usually unilateral, causes plaque-like lesions in mucosa, and is Dx by an endoscopy and/or x-ray. |
| Nasal Aspergillosis | dz in dogs that occurs in young to middle-aged dolicocephalic breeds. CS: sneezing, epistaxis, possible turbinate damage, unilateral, persistent, sanguine-purulent discharge. |
| Doliocephalic | having a relatively long skull |
| Sanguine | blood-red color |
| Aspergillus species in cats | rarely causes infections in cats, only immunosuppressed animals. |
| Mycotic Abortion | condition in cattle from Aspergillus. Is sporadic, associated w/ poor quality hay, silage, brewer's grains, no CS illness in cows, aborted fetuses have ringworm-like lesions. |
| Aspergillus Diseases in Cattle | -mycotic pneumonia (housed calves) -mycotic mastitis (use of contaminated IMM abx tubes) -intestinal (acute to chronic diarrhea in calves. |
| The causative agent of Lyme Disease is: | Borrelia burgdorferi |
| Yeasts | commensals on skin and MM, immunosuppression or factors such as antimicrobial therapy disturbs resident flora on mucosal surfaces may facilitate yeast overgrowth leading to tissue invasion. |
| Candida albicans | colonies, budding oval cells, in tissue they exhibit polymorphism: pseudohyphae and hyphae. Produce oral, GI, and urogenital diseases. |
| Candida albicans Virulence | virulence: molecules that allow adhesion, surface structures that bind fibrinogen, proteases and phospholipases that aid in tissue invasion. |
| Candida | yeast |
| Diseases caused by Yeasts | -mycotic stomatitis, gastro=esophageal ulcers, rumenitis, enteritis, cutaneous lesions, reduced fertility, abortion, mastitis, pyometra, cystitis, pyothorax, eye lesions, and disseminated disease. |
| Cryptococcosis neoformans | forms bud (daughter cells) and has a prominent mucopolysaccharide capsule, aerobic, form mucoid colonies on media. Virulence: antiphagocytic capsule and phenol oxidase production. |
| Phagocytosis | the ingestion of bacteria or other material by phagocytes and amoeboid protozoans |
| Cryptococcosis Infection Cause | cause: inhalation of yeast cells in contaminated dust and like to grow in pigeon droppings. Usually associated with immunosuppression and viral infection. |
| Cryptococcosis in Cats | the most common systemic mycosis in cats, has nasal/cutaneous/neural/ocular forms. Dx: cytology of aspirates, commercial antigen test. Tx: sx removal plus antifungal drugs for at least 2 months. |
| Malassezia pachydermatis | opportunistic skin commensal yeast on birds and mammals in areas that are rich in sebaceous glands. High numbers induce excessive sebaceous secretion. |
| Malassezia pachydermatis in dogs | causes otitis externa and seborrheic dermatitis (over other parts of the body) in dogs. Dermatitis is usually foul-smelling and greasy with matted hair. Treated with topical and oral antifungals. |
| Malassezia pachydermatis predisposing factors | -hypersensitivity disorders -keratinization defects -immunosuppression -persistently moist skin folds -poor ear conformation -wax retention |
| Yeasts Dx and Tx | Dx: stain of organism in exudates, aerobic culture of Sab. Dextrose agar for 4 days. Tx: topical antifungals. |
| Which of the following is an example of a selective medium? | MacConkey |
| Dimorphic Fungi Forms | -mold form: environmental and cultured at 25*C, stable form. Are soil saprophytes and live off decaying vegetation. -yeast form: in animal tissues and cultures at 37*C on brain-heart infusion agar, are opportunistic infections. |
| Disease-causing Dimorphic Fungi | Blastomyces dermatiditis Histoplasma capsulatum, Coccidiodes immitis, Sporothrix schenckii. |
| Dimorphic Fungi Treatment | Tx: Amphotericin B and Ketoconazole, long-term therapy for several months. |
| Blastomycosis | dogs and humans are infected by this from aerosol exposure to fungus changing water levels. Causes: coughing, exercise intolerance, pyrexia, wt loss, anorexia, lameness, lymphadenopathy, skin lesions, uveitis, conjunctivitis, prostatitis. |
| Blastomycosis (Dx and Tx) | Dx: new urine Ag test (very accurate) Tx: Amphotericin B and Ketoconazole, Itraconazole, ,long term treatment up to 1 year in humans and 3-4 months in dogs. |
| Histoplasmosis capsulatum | found in Mississippi and Ohio River valleys, likes soil enrichd with bat/bird feces, dog + cats can be affected, inhalation is primary infection route. CS: chronic cough, persistent diarrhea, emaciation. Dx: rads, cyto, serology. |
| Histoplasmosis Cytology | cyto results: small round intracelluar yeast cells surrounded by light halo |
| Coccidiodes immitis | causes coccidiodomycosis, affects many species including humans, arid regions of southwest USA, common name is "Valley Fever," caused by spore inhalation. CS: cough, fever, inappetence, osteomyelitis, lame. Dx: rads, cyto |
| Coccidiodes Cytology | cyto results: thick double walled spherical bodies. |
| Sporothrix schenckii | zoonotic, grows on dead vegetation, occurs sporadically in horses/cats/dogs/humans, causes chronic cutaneous or lymphocutaneous disease which rarely becomes generalized. Dx: cigar shaped budding yeasts in cyto |
| Sporothrix schenckii in horses | the spores of this yeast enter horses via abrasions in lower limb, the nodules ulcerate and discharge yellowish exudate, also causes a SQ edema. |
| Zygomycetes | saprophytes in the environment, causes sporadic opportunistic infections called zygomycoses. Uncommon in healthy animals. Predisposing factors: immunodeficiency, corticosteroid therapy, prolonged administration of broad-spectrum abx. |
| Mycotoxins | secondary metabolites of certain fungal species, poisonous substance. |
| Mycotoxin Disease | infection of these involve toxic metabolites and happens through ingestion of contaminated plant material. Diseases are non-contagious, sporadic, and seasonal; tend to be associated with certain batches of feed. |
| Mycotoxin Characteristics | -heat stable even after pelleting temperatures -non-antigenic and have no immune response -active @ low dietary levels -can results in human exposure -effects: immunosuppression, teratogenesis, carcinogenesis. |
| Mycotoxin Clinical Features | -seasonal and sporadic, no lateral spread to animals, associated with certain types of pasture/feed, often ill defined CS's, severity depends on amount ingested, antimicrobial meds are ineffective, confirmation depends if it is found in high enough levels |
| Aspergillus flavus | this mycotoxigenic fungus causes Aflatoxicosis, happens from absorption in the GI tract and it metabolizes in the liver into toxic products. Vague CS's. Dx: chromatography, bioassays, immunoassays |
| Chromatography | the separation of a mixture by passing it in solution or suspension or as a vapor through a medium in which the components move at different rates. |
| Bioassays | measurement of the concentration or potency of a substance by its effect on living cells or tissues. |
| Immunoassays | a procedure for detecting or measuring specific proteins or other substances through their properties as antigens or antibodies. |
| Claviceps purpurea | causes Ergotism, found in ryegrasses/rye/other cereals, convulsions occur in acute form. Causes Gangrene. |
| Tremorgen Intoxications | "ryegrass staggers," causes: muscular tremors, ataxia, incoordination, and convulsive seizures. High morbidity bure rare deaths and recovery is rapid once animals removed from the contaminated pasture. |
| Mycotoxic oestrogenism | the toxic product is a non-sterodal estrogen. Associated with Fusarium graminearum species. Occurs in pigs, cattle, and sometimes sheep. Causes estrogenic activity: hyperemia, edema of vulva, anestrus, small litters, reduced fertility, etc. |
| Fescue toxicosis/ergovaline | disease caused by mycotoxin Neophytodium coenophialum. Occurs in cattle, sheep, and horses. Causes vasoconstriction/dry gangrene in cold weather and fescue foot/hyperthermia/low milk yield in summer. |
| Leukocephalomalacia/fumonisins B1, B2, A1, A2 | caused by the mycotoxin Fusarium monliforme. Occurs in horses and pigs. Causes liquefactive necrosis in the cerebrum and has variable neurological signs. |
| Oestrogenism/zearalenone | dz caused by mycotoxin Fusarium graminearum. Occurs in pigs, cattle, and sometimes sheep. Causes estrogenic activity: hyperemia, vulva edema, precocious mammary development in prepubertal gilts, anestrus, small litters, reduced fertility. |
| Tremorgan Intoxications | development of penicillin |
| Candida albicans may cause many different diseases, especially when there is a predisposing condition such as...? | primary bacterial infection |
| Which of the following would be considered an abnormal finding on healthy canine external ear canal cytology? | Malassezia |
| Phagocytes | type of cell within the body capable of engulfing and absorbing bacteria and other small cells and particles. |
Created by:
Riley.Scherf
Popular Biology sets