intro to fungi and fungal infections Flashcards
classification of fungi :
they can be —- like or —– such as:
however they are dimorphic meaning —-
- yeast/yeast like
- moulds as: hyphen and spore ]- rare both yeast and mould forms
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
- cell wall
- chitin and carbs
- chitin
- antigenic
- phospholipid bilayer
- cytoplasm
- ergosterol
- capsule ( cryptococcus neoformans , polysarcrides , prevents phagocytosis )
—– 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
- hyphae
- spores
yeast - cryptococcurs neofomans are:
— cellular produced by —- and the characteristics are:
- unicellular
- budding
- moist , mucoid , waxy colonies
yeast-like fungi : candida species :
- grow partly as — and partly as —- cells resembling —- ( pseudohyphae )
- produced by
- generally ——- colonies
- yeast
- elongated cells
- hyphea
- budding
- white creamy colones
mould ( filament fungi )
- are — cellular
- made up of clumps of intertwined ——
- growth by —–
- produce —
- multicellular
- branching hyphae
- longitudinal extension
- spores
—- 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
- dimorphic
- environmental and temp
- 25-30
35-37
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
- increase
- complex
- resistance
- harder
fungal infections are — which means they are limited to skin only
they are also —- which includes:
- superficial ; limited to outermost layers of skin hair nails and mucosa
-invasive ( subcutaneous and systemic )
superficial mycoses is limited to the — layers of skins hair nails and mucosa it includes:
diagnosed by —
- outermost
1. pityriasis versicolor ( pigmented lesions on upper toros )
2. dermatophytosis ( ringowrm/tinea )
3. candidas - skin scrapping KOH - microscopy
-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:
pityriasis verisicolor , its diagnosed by:
1- clinical appearance
2- wood light
3. skin scrapping
—– are skin infection caused by dermatophyte fungi
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
parts of the body affected by tinea:
- Tinea barbae (beard)
- Tinea capitis (head)
- Tinea corporis (body)
- Tinea cruris (groin)
- Tinea faciei (face)
- Tinea manuum (hand)
- Tinea pedis (foot)
- Tinea unguium (nail)
tine is diagnosed by —–
- 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)
subcutaneous mycoses refers to — layer of dermis and —- tissue
the sites of trauma acquired from —–
- dermis and subcutaneous tissue
- soil and thorns
sporotrichosis - rose pickers disease:
Sporothrix schenckii (dimorphic fungus)
* Initial ulcer develops into —–
gtandulomatous nodule
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
- cutanouse/lymphocutanous
- pulmonary
- disseminated
sporotrichosis is diagnosed by:
1- microscopy using —-
2- culture ( sabouraud agar) using:
3. histopathology
- KOH
- tissue biopsy , sputum , body fluid
DIMORPHIC FUNGAL INFECTION –
HISTOPLASMA CAPSULATUM :
- 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!
clinical presentation of histoplasma capsultaum:
diagnosis by:
- 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)
candida - pseudo yeast :
characterised by — flora in — and — especially the — GI tract , lower — tract and — tract
- —– pathogens of increasing importance
- is —- and —– infection
- normal flora
- mouth and intestine
- upper
- lower genital tract
- respiratory trac
- oppourtistic
- superficial in skin and mucosal and systemic infection
candida is found in —- areas of and skin — as well as:
they are erythema aka —- lesions and — lesions
other info:
- 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
diagnosis and treatment of candida :
- 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
candida mucosal infection discrete — patches on mucosal surfaces as in —-
the diagnosis are:
treatment by:
- 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)
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
—- 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
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)
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
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
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
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 )
