Mycology

1
Mycology Introduction

• Student Lab
• Division of Medical Technology
• Carol Larson MSEd, MT(ASCP)

2
Mycoses

• Superficial
• Subcutaneous
• Systemic
• Opportunistic

3
Characteristics of fungi

• Eukaryotic
• Growth requirements
• Forms
• Mold
• Yeast

4
Hyphae

• Septate

• Aseptate

5
Hyphae

• Hyaline

• Dematiaceous

6
Mycelium

• Mass of branching intertwined hyphae
• Vegetative
• Aerial
• Fertile

7
Vegetative types

• Favic chandeliers

• Nodular organs

• Racquet hyphae

• Spiral hyphae

8
Reproduction

• Identify fungi by
• Morphology of reproductive structures
• Spores from vegetative mycelium or aerial
  fruiting bodies

9
Asexual Reproduction

• Conidia
• Conidiophore

• Arthroconidia

10
Asexual Reproduction

• Blastoconidia
• Pseudohyphae

• Chlamydoconidia
• Chlamydospores

11
Asexual Reproduction

• Macroconidia
• Microconidia

• Phialoconidia
• Phialide

12
Asexual Reproduction

• Annelloconidia
• Annellide

• Sporangiospores
• Sporangium
• Sporangiophore

13
Sexual Reproduction

• Perfect Fungi has a sexual stage
• Fungi Imperfecti no know sexual stage
• Spores

14
Sexual Reproduction

• Ascospores
• Ascus
• Ascocarp

• Basidiospores

• Zygospores

15
In review

• Mycoses fungal diseases
• Characteristics of fungi
• Growth requirements
• Forms (mold, yeast)
• Structures
• Reproduction
• Asexual
• Sexual

16
Fungal Culture Process

• Specimen collection and transportation
• Direct examination of specimen
• Selection and inoculation of media
• Evaluation of fungal growth
• Serological testing
• Antifungal susceptibility testing

17
Specimen Collection

• Specimen types
• Collect from area most likely infected
• Use sterile technique
• Keep specimen moist
• Label container properly
• Transport right away
• Process right away

18
Direct Examination

• Provides preliminary report
• Guides MD in treatment of patient
• Observe yeast phase of dimorphic
• Gives clues to id causative agent
• Inoculate special media
• May require more than one direct examination
  method

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Direct Examination

• Saline wet mount
• Lactophenol cotton blue wet mount
• 10 KOH preparation
• Gram stain
• Acid fast stain
• India ink stain

20
Direct Examination

• Calcofluor white stain
• Wrights stain
• Gomori Methenamine Silver stain
• Periodic Acid Schiff stain

21
Specimen Processing

• Safety
• Tube media preferred over plate media
• Work in safety hood
• Wear gloves and lab coat
• Autoclave specimens and media
• Disinfect work area daily

22
Specimen Processing

• Primary isolation media
• Goal isolate potential pathogens
• Use non-selective and selective media
• Proper ingredients
• Incubation temperature
• Incubation time
• Incubation atmosphere

23
Non-selective Media

• Sabouraud dextrose agar
• Brain heart infusion (BHI) with/without 5 blood
  and 1 glucose

24
Selective Media

• Mycosel agar
• Inhibitory mold agar
• Dermatophyte test medium

25
Subculture / Identification Media

• Neutral Sabouraud dextrose agar (Emmons)
• Cornmeal-Tween 80 agar
• Niger seed agar (Birdseed agar)
• Tween 80 / Oxgall / caffeic acid agar
• Potato dextrose agar

26
Examination of Culture Growth

• Potential pathogens
• Slow growers
• Growth on Mycosel
• Color dull buff, brown, mousy gray
• Dimorphic

27
Examination of Culture Growth

• Growth rate
• Rapid growers 1-5 days
• Intermediate growers 6-10 days
• Slow growers gt10 days

28
Colony Morphology Appearance

• Rugose
• Umbonate
• Verrucose
• Flat

29
Colony Morphology Texture

• Cottony
• Glabrous
• Granular
• Velvety

30
Colony Morphology Pigmentation

• Surface
• Reverse

31
Microscopic Morphology

• Definitive means of identification
• Evaluate
• Shape
• Method of production
• Arrangement of conidia/spores
• Size and color of hyphae

32
Microscopic Techniques

• Tease mount
• Scotch tape preparation
• Slide culture

33
Serological Diagnosis

• Immunodiffusion
• Complement fixation
• EIA
• Latex agglutination

34
Antifungal Susceptibility

• Determine appropriateness
• Standardization of testing
• Methods
• Predictability in vivo
• Antifungal agents

35
In Summary

• Specimen collection and transport
• Specimen processing and culture
• Direct examination of specimen
• Examination of culture
• Serological testing
• Antifungal susceptibility