intro to fungi and fungal infections Flashcards

1
Q

classification of fungi :
they can be —- like or —– such as:
however they are dimorphic meaning —-

A
  • yeast/yeast like
  • moulds as: hyphen and spore ]- rare both yeast and mould forms
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2
Q

fungal cell structure:
1- contains a —- which is made up of—– and —- ( b-d-glucan and manna’s ) the —- gives it rigidity and is —–
2. it contains cell membrane which is made up of: —— , surrounds —– , and contains —–
3. has —- in some fungi

A
  • cell wall
  • chitin and carbs
  • chitin
  • antigenic
  • phospholipid bilayer
  • cytoplasm
  • ergosterol
  • capsule ( cryptococcus neoformans , polysarcrides , prevents phagocytosis )
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3
Q

—– are tubules made up of fungal cells attached to end to end , the growth = extend in length from tip of tubules ( longitudinal extensions )
—– are the producing bodies of moulds and are different from the bacterial ones

A
  • hyphae
  • spores
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4
Q

yeast - cryptococcurs neofomans are:
— cellular produced by —- and the characteristics are:

A
  • unicellular
  • budding
  • moist , mucoid , waxy colonies
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5
Q

yeast-like fungi : candida species :
- grow partly as — and partly as —- cells resembling —- ( pseudohyphae )
- produced by
- generally ——- colonies

A
  • yeast
  • elongated cells
  • hyphea
  • budding
  • white creamy colones
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6
Q

mould ( filament fungi )
- are — cellular
- made up of clumps of intertwined ——
- growth by —–
- produce —

A
  • multicellular
  • branching hyphae
  • longitudinal extension
  • spores
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7
Q

—- fungi can grow either as yeast or mould depending on —— conditions and —-
- moulds in environment at —- c
- yeast in human tissue at —-
eg. histoplasma capsulatum

A
  • dimorphic
  • environmental and temp
  • 25-30
    35-37
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8
Q

why’s fungal infections important:
1.—- no. of infections
which increases no. of vulnerable immunosuppressed patients
- chemotherapy , organ transplant , immunosupressiant medication
2. cases are more —-
- anti fungal antimicrobial — is increasing as new anti fungal agents available
- immunospressed patients — to treat

A
  • increase
  • complex
  • resistance
  • harder
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9
Q

fungal infections are — which means they are limited to skin only
they are also —- which includes:

A
  • superficial ; limited to outermost layers of skin hair nails and mucosa
    -invasive ( subcutaneous and systemic )
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10
Q

superficial mycoses is limited to the — layers of skins hair nails and mucosa it includes:
diagnosed by —

A
  • outermost
    1. pityriasis versicolor ( pigmented lesions on upper toros )
    2. dermatophytosis ( ringowrm/tinea )
    3. candidas
  • skin scrapping KOH - microscopy
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11
Q

-Malassezia furfur (filamentous fungus)
- Common – patchy rash
* Pale brown/pink macules - Pale patches more
common in darker skin
* Itchy
* Trunk / Neck +/- arms (uncommon in other body
areas)
More common in hot, humid climates or if sweat
heavily.
these are all under:

A

pityriasis verisicolor , its diagnosed by:
1- clinical appearance
2- wood light
3. skin scrapping

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12
Q

—– are skin infection caused by dermatophyte fungi

A

tinae ( ringworm )
- the 2 genera of dermatophytes:
* Trichophyton spp– most common
* Epidermophyton spp
* Microsporum spp
- they might be acquired from humans animals or soil
- treated w topical or systemic antifungals

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13
Q

parts of the body affected by tinea:

A
  • Tinea barbae (beard)
  • Tinea capitis (head)
  • Tinea corporis (body)
  • Tinea cruris (groin)
  • Tinea faciei (face)
  • Tinea manuum (hand)
  • Tinea pedis (foot)
  • Tinea unguium (nail)
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14
Q

tine is diagnosed by —–

A
  • clinical - classical appearance
  • skin scraping/nails clipping confirms diagnosis and identity of pathogens
    – Microscopy (treat first with
    KOH to clear keratin)
    – Culture on selective media -
    Sabouraud agar
  • Slow growing (2-3 weeks)
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15
Q

subcutaneous mycoses refers to — layer of dermis and —- tissue
the sites of trauma acquired from —–

A
  • dermis and subcutaneous tissue
  • soil and thorns
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16
Q

sporotrichosis - rose pickers disease:
Sporothrix schenckii (dimorphic fungus)
* Initial ulcer develops into —–

A

gtandulomatous nodule

17
Q

clinical spectrum of sporotrihosis:
1. —— is most common and enters through break in skin from touching contaminated plant matter
2. —- refers to inhalation of fungal spores
3. —- spread of infection to other parts of the body as: osteoarticular, central nervous system.
Risk factors: Immunodeficiency, COPD, HIV, Alcohol excess

A
  • cutanouse/lymphocutanous
  • pulmonary
  • disseminated
18
Q

sporotrichosis is diagnosed by:
1- microscopy using —-
2- culture ( sabouraud agar) using:
3. histopathology

A
  • KOH
  • tissue biopsy , sputum , body fluid
19
Q

DIMORPHIC FUNGAL INFECTION –
HISTOPLASMA CAPSULATUM :

A
  • Grow as moulds at 25oC, yeasts at 37oC
  • Not common in Ireland, UK or rest of Europe but
    found in North America
  • Found in soil
  • Guano from birds & bats
  • Caves!
20
Q

clinical presentation of histoplasma capsultaum:
diagnosis by:

A
  • Asymptomatic infection
  • Acute/ chronic respiratory infection resembling TB
  • Disseminated, involving liver, lungs, spleen
    (immunosuppressed patients)
  • Fungus lives intracellular in macrophages =>
    immune-evasion
  • diagnosis by:
  • Antigen detection
    – Detects fungal
    components
    – Urine or serum
  • Culture
    – Tissue, blood, body fluid
    – Can take up to 6 weeks
  • Histopathology
  • Microscopy
    – Low sensitivity
  • Serology (looking for
    antibodies to the fungus)
21
Q

candida - pseudo yeast :
characterised by — flora in — and — especially the — GI tract , lower — tract and — tract
- —– pathogens of increasing importance
- is —- and —– infection

A
  • normal flora
  • mouth and intestine
  • upper
  • lower genital tract
  • respiratory trac
  • oppourtistic
  • superficial in skin and mucosal and systemic infection
22
Q

candida is found in —- areas of and skin — as well as:
they are erythema aka —- lesions and — lesions
other info:

A
  • warm and moist
  • skin folds
  • intertrigo (axilla,
    groin, perineum, under
    breasts)
  • plaque like lesions or satellite lesions
  • Napkin dermatitis in
    babies
  • Precipitants
    – Antibiotics
    – Steroids
    – Pregnancy /High oestrogen
    – Immunosuppressiond
23
Q

diagnosis and treatment of candida :

A
  • Diagnosis:
    – Clinical appearance
    – Skin scrapings, swabs
  • Treatment:
    – General measures e.g.
    correct predisposing
    factors, keep skin clean
    and dry
    – Topical antifungal agents
    applied to the skin e.g.,
    clotrimazole cream
    – Oral: fluconazole
24
Q

candida mucosal infection discrete — patches on mucosal surfaces as in —-
the diagnosis are:
treatment by:

A
  • white patches
  • oral vaginal and oesophageal (as HIV )
  • diagnosis: Swab for microscopy
    and culture
  • treatment:
    – Topical (Clotrimazole cream or
    suppository)
    – Oral antifungal mouthwashes
    – Oral systemic antifungal (e.g.
    fluconazole)
25
CANDIDA – INVASIVE INFECTIONS:
* Can cause infection of any system * Urinary tract infections * Candida blood stream infection * Endophthalmitis (infection of the back of the eye) * Infective endocarditis (infection of endocardium) * Peritonitis * Osteomyelitis/Septic Arthritis (rare) * Meningitis (neonates) - Risk factors include: * Haematological malignancy such as leukaemias * Bone marrow or solid organ transplant * Neutropenia * Extremes of age (premature neonates, elderly) * Abdominal surgery * Prolonged intensive care unit admission * Central venous catheter e.g. central line * Use of broad-spectrum antibiotics * Kidney failure
26
---- are mould/ filamentous fungus - unqiuiton - found in soil air plants and decomposing organic matter - hospital environments: construction work the clinal manifestation includes:
aspergillus 1. Allergic aspergillosis – Sinusitis – Allergic Bronchopulmonary Aspergillosis (ABPA) 2. Aspergilloma (fungal mass) 3. Invasive aspergillosis
27
aspergillus pathogenesis can be --- due to reaction to asperigullus antigen in atopic individuals ABPA or it can be by ----- organics which can be:
- allergy - spore forming organisms : – Spores inhaled – Germinate to form hyphae – Destruct blood vessels & disseminate (angioinvasive)
28
ALLERGIC BRONCHO PULMONARY ASPERGILLOSIS (ABPA):
* Hypersensitivity reaction * Asthma, cystic fibrosis (symptoms overlap) * Bronchospasm, obstruction * Wheeze, cough, Shortness of breath (SOB), fever * Eosinophilia, high IgE * Diagnosis –high antibody titres in serum * Fleeting chest x-ray changes * Treat with steroids +/- itraconazole
29
ASPERGILLOMA:
* Damaged lung (TB, CF, COPD) * Asymptomatic, chronic cough, haemoptysis * Sputum culture positive in 66% * Serum antibodies raised in 70% * Fluid filled cavity on CXR/CT Thorax * Surgery in some cases * No role for antifungals
30
invasive aspergillosis ( IA) spread from --- site to other sites as liver spleen kidney and CNS - can invade --- aka angiovasive - high --- and can be difficult to diagnose - high --- of suspicion in sucepticable patient -the risk factors include:
- primary - blood vessels - mortality - index - risk factors: * Bone marrow or solid organ transplant * Neutropenia * Haematological malignancies e.g. acute leukaemia * Haematological disorders such as aplastic anaemia (bone marrow failure) * Intubated patients in intensive care unit * Patients on chemotherapy * Severe lung diseases e.g. end-stage COPD * Patients with advanced HIV infection * Dialysis patients * Patients with severe innate immunodeficiencies
31
diagnosis of Fingal infections depend on -----
clinical presentation and exam ( diagnostic technique discussed in this lecture includes: * Clinical diagnosis * Microscopy and culture * Antigen detection * Serology * Histopathology * Radiology )