MEDICAL MYCOLOGY
Medical Mycology Reference Laboratory
Laboratory of Parasitology and Mycology
Institute of Microbiology and Immunology
Medical Faculty in Belgrade, 2010
The goal of teaching:
1.
•
•
•
•
The morphology and biology of the
fungi
Classification of medically
important fungi
Fungal morphology and structure
Antifungals - Mechanisms of action
Fungi - biology and physiology
Fungal infections (FI) - classification
3. Common fungi which causes
superficial / invasive / oprtunistic FI
• Candida - morphology, biology
Pathogenesis
• Cryptococcus - morphology, biology.
Pathogenesis
• Aspergillus - morphology, biology.
Pathogenesis
• Fusarium - morphology, biology.
Pathogenesis
2. Common fungi which primarily cause skin,
hair and nail FI
• Malassezia - morphology, biology
Pathogenesis of pitiriasis versicolor,
Pathogenesis of seborrheic dermatitis
• Trichophyton - morphology, biology
• Microsporum - morphology, biology
• Epidermophyton - morphology, biology
Pathogenesis of dermatophytes
4. Other fungi which cause superficial /
invasive / oprtunistic FI
• Penicillium - morphology, biology
Pathogenesis
• Zygomycetes (Mucor, Rhisopus, Absidia) morphology, biology.
Pathogenesis
• Pneumocystis - morphology, biology.
Pathogenesis
MYCOLOGY WWW
www.mycology.adelaide.edu.au
www.medicalmycology.org
www.edae.gr/myco2.htm
www.pfdb.net
www.doktorfungus.org/mycoses/index.htm
www.lumen.luc.edu/lumen/DeptWebs/microbio/med/review/mycology.htm
www.mikologija.org.rs
Mykos / Fungi Logos/ Science Mycology/ science of fungi
Fungus = fungi
Fungi - eukaryotes
There are about 250 000 species of fungi.
About 100 species are important for people
EMPIRE
FEATURES
EXAMPLE
Monera
Prokaryotes
Protista
Eukaryotes
Fungi
Eukaryotes *
Planta
Eukaryotes
Plants
Animalia
Eukaryotes *
Arthropods / Mammals
Bacteria,
Blue-green algae
Protozoa
Fungi
Man
cell structure
OSNOVNA Fungal
GRAĐA
ĆELIJE GLJIVA
Fungal cell structure
All fungi possess:
- Cell wall (chitin, glucan, mannan, cellulose…)
- Cytoplasmic membrane (ergosterol)
- Nucleus
- Mitochondria
MORPFHOLOGICAL DIVISION OF FUNGI:
YEASTS (unicellular fungi)
MOLDS (multicellular fungi)
DIMORPHIC
(YEASTS/37ºC; MOLDS/25ºC)
Antifungals and primary sites of activity
Mechanisms of action
Cytoplasmic membrane / CM / Polyenes
• Binding to ergosterol CM
(compromise function of CM)
Cell wall / Ehinocandins
• Inhibits the synthesis of glucan
Nucleic acid / 5-Fc
• Inhibits the synthesis of NA
Microtubules/ Griseofulvin
• Inhibits mitosis
Ergosterol / Azoles
• Inhibition of enzymes for the synthesis of
ergosterol
Fungal morphology and biology
YEASTS
Candida
MOLDS
Aspergillus
Fungal morphology and biology
Dimorphic fungi
KVASNICE
PLESNI
Blastomyces (Paracoccidioides) brasiliensis
YEASTS - morphology and biology
Single cell (round / oval / elongated 2-7μm)
•
Asexual reproduction:
blastoconydia / blastospore
pseudohyphae and chlamydospores!!!
•
Sexual reproduction:
ascospores or basidiospores
MOLDS - the morphology and biology
Multicellular / elongated hyphae (5-50 µm)
and conidia / spores:
• conidia (asexual reproduction):
arthroconidia (hyphae segmentation)
macroconidia
microconidia ...
• spores (sexual reproduction):
ascospores or zygospores
Hyphae containing compartments (septaes):
• complete (septated hyphae)
• incomplete (aseptated hyphae)
Mycelium - branched, tubular filaments (hyphae)
• basal / vegetative (in medium)
• aerial / reproductive (above medium)
REPRODUCTION OF FUNGI
Most fungi are haploid
/ heterokaryotic
Mitosis
Dykariotes
(2 haploid
nucleus)
ASEXUAL REPRODUCTION
YEASTS:
budding occur blastoconydia / blastospore
 Unicellular structures (2-7 µm)
MOLDS:
Eg. fragmentation of hyphae - artroconidia
conidiogenesis- conidia:
 multicellular - macroconidia (15-150 µm)
 unicellular - microconidia (2-6 µm)
• Microscopic appearance of hyphae and conidia important to identify
nondermatophytes molds
• Microscopic appearance of macroconidia and hyphae essential for identification of
dermatophytes molds
SEXUAL REPRODUCTION
Zygomycetes, Basidiomycetes, Ascomycetes
Stages:
• merge + (n) - (n) cells → plasmogamy
•
•
resulting zygote (2n) of chromosomes
meiosis → 4 nucleus formed by (n) number of chromosomes
spores
zygospores
ascospores
bazidiospores
Sexual characteristics are key for taxonomy and systematization of fungi
Fungal growth
 macroelements
 microelements
 oxygen
aerobic
microaerophilic
facultative anaerobic
 Water
 CH
Yeast growth curve:
• no well-defined logarithmic
and exponential phase
•
linear growth (7-14 days)
•
counts in colony forming
units / CFU
Mold growth curve:
•
Can not be expressed by
counting the living cells
(7-14 days)
•
measure the weight of the
talus
 pH 2-8
optimum 5.4 - 5.6
TEMPERATURES FOR FUNGAL GROWTH
psychrophiles/0-20˚C
mesophiles/20-45˚C termphfiles/45-90˚C
Dimorphic
Molds
25oC
25°C rise to a mold
37°C in the form of YEASTS
Yeasts
37oC
For isolation of fungi from the patient material it is necessary to use both
25°C and 37°C
Colony growth:
3-7 days (yeasts, non-dermatophytes molds)
14-21 days (molds - dermatophytes)
4-6 weeks (dimorphic fungi)
FUNGAL VIRULENCE FACTORS
ADHERENCE
- attachment to receptors
on cells
ENZYMES
- proteinase,
phospholipase,
elastase, keratinase,
catalase, urease,
coagulase, esterase,
hemolysin, lipase ...
MORPHOGENESIS
- transition from
micelial to yeasts
growth phase, and
the blastospore in
germ tube
FUNGAL DISEASES - classification
MEDICAL MYCOLOGY FIELD
Mycosis (FI)
Mycoallergosis
MEDICAL TOXICOLOGY FIELD
Mycetism
mushroom poisoning
Mycotoxicosis
“fruiting bodies”
CLASIFFICATION OF FUNGI AND FUNGAL
INFECTIONS (FI)
FUNGAL PATHOGENICITY
1. Apathogens (saprophytes)
2.
Pathogens:
CLASIFFICATION OF PATHOGENIC FUNGI
In regard to location and the immune
status of patients
• Opportunistic / IFI ~ 300 species
opportunistic
immunocompromised persons / risk groups
•
•
•
pathogenic
Opportunistic fungi :
- Candida
- Aspergillus
- Fusarium
- Zigomicetes
- Cryptococcus
- Malassezia ...
Skin FI ~ 33 species
Subcutaneous FI ~ 10 species
Endemic FI (dimorphic) ~ 25 species
immunocompetent persons
Pathogenic fungi:
- Dermatophytes
Trichophyton
Microsporum
Epidermophyton
- Dimorphic fungi
MYCOSES - FUNGAL INFECTIONS (FI)
presence and reproduction of fungi on / in the human body
According to the localization:
CLINICAL SIGNS -
CHARACTERISTIC
1. superficial fungal infection (SFI)
- superficial
- cutaneous
- mucocutaneous
onychomycosis
2. deep / systemic / invasive (IFI)
- localized
- disseminated
*subcutaneously (subcutaneous
tissue ...)???
CLINICAL SIGNS -
NO CHARACTERISTIC
(risk group of patients!)
Pulmonary
aspergillosis
BASIC PRINCIPLES FOT THE
DIAGNOSIS OF FI
STANDARD MYCOLOGYCAL METHODS
(conventional methods):
1. Microscopic examination of the
patient samples
-direct microscopic examination (DME)
-histopathology (PH)
IMMUNOLOGICAL
METHODS
Antibodies (Ab) detection
Antigen (Ag) detection
2. isolation of fungi from patient
samples
- mycological cultures (MC)
Other biomarkers
detection
“golden s t a n d a r d”
PROVEN IFI
MOLECULAR METHODS
- DNA detection (PCR)
PROBABLE / POSSIBLE IFI