liveonearth (liveonearth) wrote,

Microbiology: FUNGUS amongus

Mercola says fungus can cause IBS (Irritable Bowel Syndrome):
This might convince you to stop eating corn--and to eat more gouda cheese, because it's fermented with lactobacillus.

--fungus gets in skin from traumatic puncture
--grows out over time like a little cauliflower wart
--can be any color

--A. fumigatus is sp. most commonly found in pillows (a million spores per pillow)(pillows had between 1.5 and 20 years of regular use) also the most likely to cause disease
--leading infectious cause of death in leukemia patients
--can worsen asthma
--difficult to treat
--usually infects the lungs and sinuses, can spread to other organs such as the brain
--Immuno-compromised patients can easily die of Aspergillus pneumonia or sinusitis
--contaminated pillow can be problematic even for relatively healthy people
--a large spectrum of diseases caused by members of the genus Aspergillus
--three principal entities are: allergic bronchopulmonary aspergillosis, pulmonary aspergilloma and invasive aspergillosis
--Colonization of the respiratory tract also common
--clinical manifestation depends on immunologic state of the patient (debilitating disease, neutropenia chemotherapy, disruption of normal flora, and an inflammatory response due to the use of antimicrobial agents and steroids can predispose the patient to colonization, invasive disease, or both)
--frequently secondary opportunistic pathogens in patients with bronchiectasis, carcinoma, other mycoses, sarcoid, and tuberculosis
--Allergic aspergillosis is typically a chronic entity, but evolves from episodes of acute corticosteroid-responsive asthma to fibrotic end-stage lung disease

--grows on peanuts and corn
--make aflatoxin, a neurotoxin

--general term for fungus that infect the superficial or cutaneous level
--common genera include:
----Microsporum: tinea
----Dpidermophyton: tinea pedis (athlete's food), tinea cruris (jock itch), tinia unguium (toenail fungus)
----Trichophyton: tinea pedis, tinea unguium
----pityriasis (tinea) versicolor (skin patches either lighter or darker than normal)

--most common cause of athlete's foot , jock itch and ringworm
--Trichophyton is one of the leading causes of hair, skin, and nail infections in humans
--Most of the Trichophyton species have teleomorphic forms and these teleomorphs are classified in the genus Arthroderma.
--most common of the dermatophytes causing fingernail fungus infx but there are others.
--Tricophytum mentagrophytes is the second most common source of fungal nail infections from the dermatophyte group
--Diagnosis: Positive, selective diagnosis of T. rubrum is difficult as many members of the genus react similarly with test reagents. The Mycology Unit at the Adelaide Women's and Children's Hospital uses 6 different media to differentiate the various species and strains of Trichophyton. The media in this scheme are Littman Oxgall agar, Lactritmel agar, Sabouraud's agar with 5% NaCl, 1% Peptone agar, Trichophyton agar No. 1, and hydrolysis of urea.
--Distribution: genus includes anthropophilic, zoophilic, and geophilic species. Some species are cosmopolitan. Others have a restricted geographic distribution. Trichophyton concentricum, for example, is endemic at Pacific Islands, Southeast Asia, and Central America.
--slow to moderately rapid growth
--texture is waxy, glabrous to cottony
--from the front, the color is white to bright yellowish beige or red violet. Reverse is pale, yellowish, brown, or reddish-brown.

--blastomyces dermatitis is richly present in slightly acidit soil
--infection is rare except in immuno-incompetent host
--confirm diagnosis via demonstration of the characteristic broad based budding organisms in sputum or tissues by KOH prep, cytology, or histology

--furfur in bone marrow transplants
--esp bad in immunocompromised cancer pts
--genus Malassezia are ubiquitous skin residents of warm-blooded animals
--involved in disorders including dandruff and seborrheic dermatitis, which together affect >50% of humans
--little is known at the molecular level
--tea tree oil works on it
--pathogenicity may be due to unique metabolic limitations and capabilities
--M. globosa shares similar extracellular hydrolases with Candida albicans, which occupies a similar niche
--unusual dependence on external lipids for in vitro growth, explained by apparent absence of a fatty acid synthase gene, multiple secreted lipases aid in harvesting host lipids
--dandruff <-- Malassezia globosa and Malassezia restricta are most commonly isolated species from human scalp

--most common dermatophytosis in children
--an infection of the scalp and hair shafts
--Transmission by poor hygiene and overcrowding, and can occur through contaminated hats, brushes, pillowcases, and other inanimate objects. After being shed, affected hairs can harbor viable organisms for more than one year!!
--characterized by irregular or well-demarcated alopecia and scaling
--when swollen hairs fracture a few millimeters from the scalp, "black dot" alopecia is produced
--may result in a cell-mediated immune response termed a "kerion," which is a boggy, sterile, inflammatory scalp mass. Cervical and occipital lymphadenopathy may be prominent.
--major cause = Trichophyton tonsurans, which does not fluoresce.
--Before 1950, most tinea capitis cases in North America were caused by fluorescent Microsporum species (bright blue-green).
--today about 90 to 95 percent of tinea scalp infections in adults and children are caused by Trichophyton tonsurans, which does not fluoresce
--Wood's lamp examination has become a less useful diagnostic test for tinea capitis.
--Tinea capitis is generally identified by the presence of branching hyphae and spores on
--If hyphae and spores are not visualized, Wood's lamp examination can be performed
--if KOH microscopy and Wood's lamp examinations are negative, fungal culture may be considered when tinea capitis is strongly suspected
--clinical features can point to the diagnosis
--In one study, tinea capitis was confirmed by culture in 92 percent of children who had at least three of the following clinical features: scalp scaling, scalp pruritus, occipital adenopathy, and diffuse, patchy, or discrete alopecia
--DDx with prominent scaling and inflammation: seborrheic dermatitis (no hair loss), atopic dermatitis (lesions in flexural folds of the neck, arms, or legs), and psoriasis (nail changes and silvery scales on the knees or elbows)
--DDx with prominent alopecia: rule out include alopecia areata (complete, rather than patchy, hair loss), traction alopecia (history of tight hair braiding), and trichotillomania (hairs of differing lengths and a history of obsessive hair manipulation).

--jock itch
--microscopic examination of a potassium hydroxide (KOH) wet mount of scales is diagnostic
--more common where it's warm & humid
-- Risk factors: wearing tight-fitting or wet clothing or undergarments
--most common etiologic agents: Trichophyton rubrum and Epidermophyton floccosum; less commonly Trichophyton mentagrophytes and Trichophyton verrucosum are involved
--Tinea cruris is a contagious infection transmitted by fomites, such as contaminated towels or hotel bedroom sheets, or by autoinoculation from a reservoir on the hands or feet (tinea manuum, tinea pedis, tinea unguium)
--etiologic agents produce keratinases, which allow invasion of the cornified cell layer of the epidermis. The host immune response may prevent deeper invasion.

--commonest cause of fungal meningitis
--BIRDS: found in nature in avian excreta, esp old pigeon droppings
--mostly affects immunocompromised hosts
--worldwide, 7-10% of patients with AIDS are affected when CD4 count below 200/mm3, accounting for 50% of infx
--S/Sx: fever and headache most common
--secondary cutaneous infections in up to 15% with disseminated cryptococcosis and indicates poor prognosis
--lesions usually begin as small papules that ulcerate, may also present as abscesses, erythematous nodules, or cellulitis
--attacks resp or nervous sys
--two varieties split now into 2 sp.
--India Ink Preparation: Positive - distinct, wide gelatinous capsules surrounding the yeast cells are present.
--Dalmau Plate Culture on Cornmeal and Tween 80 Agar: Budding yeast cells only. No pseudohyphae present.
--Germ Tube test is Negative
--Hydrolysis of Urea is Positive
--Growth on Cycloheximide medium is Negative
--Growth at 37C is Weakly Positive
--Negative: Glucose; Sucrose; Lactose; Galactose; Maltose; Trehalose.
Tags: asthma, diabetes, diet, disease, fungus, hiv/aids, ibs, microbes

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