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Mycology II
Dr. Courtney Mycology Lecture 2
83
Medical
Graduate
04/14/2011

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Term
T/F the cell immune response is a key factor at staving off opportunistic mycoses?
Definition
True - there is a delicate balance of factors
Term
5 sites of normal Candida colonization
Definition
mucosal surfaces of oral cavity, vagina, lower GI, rectal area and skin surfaces
Term
When are people normally colonized with Candida?
Definition
Shortly after birth
Term
Who gets infected with Candida?
Definition
Those with immune system out of balance
Term
What are 4 morphologies of Candida?
Definition
Yeast, pseudohypahe, germ tube, and Hypha
Term
What is the Germ Tube test?
Definition
Incubate yeast cells @ 37 C - hyphal outgrowth = candida
Term
T/F Germ tube candida are more adhesive?
Definition
True - antigens and proteins on tube have affinity for mucosal cells
Term
What non-biologic surface does Candida attach to? Mechanism?
Definition
Plastic - hydrophobic and electrostatic interactions
Term
3 biological sites of candida albicans attachment
Definition
mucosal cells, vagina, and GI
Term
Other mechanisms for Candida albicans attachment (3)
Definition
Fibronectin binding, proteinase activity, ECM binding
Term
When are infants at risk for mucosal/cutaneous candidiasis?
Definition
Prior to the establishment of normal bacterial flora
Term
What increases the risk of infant candidiasis?
Definition
Maternal vaginal candidiasis
Term
Presentations of infant candidiasis (3)?
Definition
Oral Thrush, severe diaper rash and perianal/genital infections
Term
What is the white material in oral thrush?
Definition
Budding yeast cells and pseudohyphae
Term
What are 5 typical sites of adult cutaneous candidiasis?
Definition
sites of trauma, burn and abrasions, opposing skin folds and underneath nails
Term
T/F Candida albicans can not infect under nails?
Definition
False - it often destroys the nail lining
Term
What is the incidence rate of Vaginal Thrush among women? If pregnant?
Definition
10-17%, double if pregnant
Term
What factors increase the incidence of vaginal thrush?
Definition
Antibiotics, pregnancy, oral contraceptives. All disrupt balance
Term
Who is primarily at risk for adult mucocutaneous candidiasis?
Definition
Those with compromised cell mediated immunity (AIDS patients)
Term
Risk factors for adult mucocutaneous candidiasis?
Definition
Corticosteroid treatment, diabetes (endocrine disturbance), hematologic malignancies, immunosuppressive drugs, and radiation therapy
Term
T/F Candida is the most common systemic MYCOSES?
Definition
True - is also 4th most common nosocomial systemic infector
Term
Name 4 risk factors for systemic candidiasis
Definition
Immunosuppressive treatment, intravenous lines, indwelling catheters, improperly cleaned skin around injection sites
Term
What are the potential systemic problems with systemic candidiasis?
Definition
Endocarditis, meningitis, esophagitis, eyes have patches of candida
Term
What is CMC? C/O? Lasts? Treatment?
Definition
Chronic mucocutaneous candidiasis, predisposed conditions (impaired T cell response), can last lifetime, can treat with antifungals - but will come back
Term
What is the single reservoir of pneumocystis jirovecii? P. carinii?
Definition
Humans, rats
Term
What is the classification of pneumocystic jirovecii (fungus/protozoa)?
Definition
It fits in both, but we categorize it as fungi
Term
What are fungal features of pneumocystic jirovicii?
Definition
morphology, rRNA sequences, mito DNA, Chitin cell wall
Term
What are the protozoan features of pneumocystic jirovecii?
Definition
DNA content/cell, absence of fungal EF3, susceptible to anti-protozoan (not anti-fungal) therapeutics
Term
T/F pneumocystic jirovecii are treated with anti-fungals
Definition
False - use anti-protozoan treatments
Term
T/F Pneumocystic jirovecii human strains can be cultured?
Definition
False
Term
What is the life cycle of pneumocystic jirovecii?
Definition
Begins as cyst with 8 sporozoites which break open the cyst and become feeding trophozoites which form new cyst of 8
Term
Who is at risk for pneumocystic pneumonia?
Definition
Anyone with compromised immune system - almost everyone is colonized by age 4
Term
T/F Pneumocystis pneumonia is an opportunistic, latent infection?
Definition
True - it hangs around till it has a chance to infect - especially in AIDS patients
Term
T/F pneumocystis jirovecii always produces disease on infection
Definition
False - only those with low T cell response
Term
In pneumocystic pneumonia where is the invader found, and what does it do?
Definition
It fills alveoli and causes death by progressive asphyxia
Term
In animal models of pneumocystic pneumonia what initiates infection (2)?
Definition
Corticosteroids and starvation
Term
What is a typical treatment for pneumocystic pneumonia infection?
Definition
Prophylaxis and therapeutics
Term
What are the four primary systemic mycoses?
Definition
Histoplasma capsulatum, coccidioides immitis, blastomyces dermatitidis, and cryptococcus neoformans
Term
In systemic mycoses, where is the site of initial infection and the common symptoms?
Definition
Lungs, asymptomatic
Term
When do systemic mycoses become systemic?
Definition
In an immunocompromised person
Term
T/F Each sytemic mycoses has characteristic secondary organ tropism
Definition
True
Term
Which of the four systemic mycoses are dimorphic?
Definition
Histoplasma capsulatum, coccidioides immitis, and blastomyces dermatitidis
Term
T/F systemic mycoses are part of the normal flora?
Definition
False
Term
Describe the growth of Histoplasma capsulatum
Definition
mold grows in soil with bat and bird droppings, using the nitrogen
Term
Who is infected with histoplasma capsulatum?
Definition
Humans and bats - NOT birds
Term
Route of histoplasma capsulatum entry? Site of growth?
Definition
Inhalation into lungs, intracellular (in macrophages)
Term
T/F Histoplasma capsulatum causes lung calcification?
Definition
True - just like TB
Term
The normal pathology of histoplasma capsulatum is?
Definition
nothing beyond a calcified lung lesion, some have fever, malaise, chills, and cough
Term
What are the systemic effects of histoplasma capsulatum?
Definition
Involves the reticuloendothelial (macrophage) system, can also cause lung, bone, heart, meningial, kidney, liver, and intestinal problems and be seen in eye
Term
Where is histoplasma capsulatum geographically common?
Definition
Ohio/Mississippi river areas - most residents have evidence of previous infection
Term
T/F histoplasma capsulatum has a capsule?
Definition
False
Term
What is the morphology and appearance of Coccidioides immitis?
Definition
dimorphic, large distinct spherules in lung containing multiple endospores
Term
How does coccidioides enter body?
Definition
Inhaled conidia that lodge in alveoli
Term
What is the mortality of disseminated coccidioides immitis?
Definition
90% if not treated
Term
Which mycoses is most virulent of all human mycotic pathogens?
Definition
coccidioides immitis
Term
Where does coccidioides immitis grow?
Definition
In deserts - like NV, AZ, and CA and west TX; enhanced by bat/rat droppings; 50% of residents have been exposed
Term
Presentation of systemic coccidioides immitis?
Definition
affect bones, joints, skin, and meninges
Term
When does coccidioides immitis become systemic?
Definition
For the immune compromised (less than 1%)
Term
Normal presentation of coccidioides immitis?
Definition
malaise, cough, chest pain, and fever that lasts 2-6 weeks; aka valley fever, desert rheumatism
Term
What is a physical presentation of coccidioides immitis?
Definition
skin lesions
Term
Where is blastomyces dermatitidis found?
Definition
North america and parts of Africa, primarily the Ohio/Mississippi rivers
Term
Who is most susceptible to blastomyces dermatitidis?
Definition
Dogs and Humans
Term
Morphology of blastomyces dermatitidis?
Definition
dimorphic
Term
What is the physical presentation of systemic blastomyces dermatitidis?
Definition
skin lesions
Term
T/F blastomyces dermatitidis is the last you get, but the worst to have?
Definition
True
Term
How are histoplasma, coccidioides, and blastomyces like TB?
Definition
Inhaled, primary lung infection, lung granulomas/calcification, skin test like PPD, can disseminate, can be asymptomatic, mild, severe, or chronic infection
Term
How are histoplasma, coccidioides, and blastomyces not like TB?
Definition
NO person-to-person transmission, fungi w/spores, NOT acid-fast
Term
Where is Cryptococcus Neoformans typcially found?
Definition
Found worldwide in weathered pigeon droppings and in contaminated soil
Term
What is the resevoir of cryptococcus neoformans?
Definition
soil, humans, birds not infected!
Term
T/F Cryptococcus neoformans is encapsulated?
Definition
True
Term
How is the capsule of cryptococcus neoformans visualized?
Definition
With india ink
Term
What is the most common cause of fungal meningitis?
Definition
cryptococcus neoformans
Term
What is the tropism of cryptococcus neoformans?
Definition
the meninges
Term
Where are cryptococcus neoformans antigens found?
Definition
In the CSF
Term
What is the physical presentation of cryptococcus neoformans that has disseminated?
Definition
skin lesions - especially in immunocompromised
Term
Where is Aspergillosis sp normally found?
Definition
Everywhere in nature, especially in vents - in hospital
Term
What is the organ involvement of Aspergillosis?
Definition
colonization of lungs that can spread to other tissues
Term
What is a fungus ball?
Definition
A collection of aspergillosis within the cavity of the lung, happen in brain
Term
T/F You want an immunocompromised patient inhaling aspergillosis?
Definition
False
Term
T/F Zygomycosis are abundant in nature?
Definition
True
Term
What are the common tissues involved in Zygomycosis infection?
Definition
The blood vessels, eye, central nervous system, nose, sinuses and lungs
Term
Who is most at risk for Zygomycosis infection?
Definition
Diabetes, burns, immunosupression
Term
T/F Zygomycosis is a serious nosocomial infection involved in organ transplants
Definition
True
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