Mycoviro Part 1

8/13/2019 Mycoviro Part 1

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MLS 302 C - MICROBIOLOGY 3

MYCOLOGY

VIROLOGY


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PRELIMS OUTLINE

General characteristics of fungi

Morphology of fungi

Classification of fungi Laboratory Diagnosis of Fungal Diseases

Classification of Fungal Diseases


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REFERENCES Jawetz, Melnick & Adelbergs Medical

Microbiology

Clinical Mycology by Dismukes, et al.

Bailey & Scotts Diagnostic Microbiology

Clinical Microbiology Made Ridiculously

Simple


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M Y C O L O G Y


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LECTURE 1: OBJECTIVES

1. Define terms used in mycology

2. Discuss the general

characteristics of fungi

3. Describe the morphology andstructure of fungi in general

4. State the medical importance ofthe cellular structures of fungi


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FUNGAL CHARACTERISTIC

Eukaryotic

Facultative anaerobic/strictly aerobic

Chemotrophic; nutrition by absorption Non-photosynthetic; achlorophyllos

pH 5-6 (acidic)

High sugar concn. favors growth


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Widely

distributed in

nature

Saprophytic


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Gastronomic

Delights


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Penicillium notatum

Tolypocladium inflatum


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Mycoses


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TERMINOLOGY

Mykos (Gk): Mushroom

Mycology: Study of fungi

Mycoses: diseases caused by fungi Dimorphism: ability to grow as yeast at

37C and as mold at room

temp. Hyaline fungi: non-pigmented fungi

Dematiaceous fungi:pigment-producing fungi


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Morphologic Classification

of FUNGI

YEAST

MOLD

DIMORPHIC


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YEASTUnicellular fungi

MICROSCOPIC Oval to round

Budding

Bud=Blastospore Pseudohyphae


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BUDDING YEAST


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MACROSCOPIC:

Pasty, opaque, cream-colored colonies


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MONOMORPHIC

YEAST: Candida

albicans

Cryptococcusneoformans

Geotrichumcandidum


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MOLD

Multicellular Hypha [2-10 m]

MYCELIA

Vegetative /Thallus

Reproductive /Aerial


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MOLDS: Mycelia


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MACROSCOPIC:

Cottony, wooly,

velvety, granular,filamentous

MONOMORPHICMOLD:

Microsporum

Epidermophytonfloccosum

Trichophyton


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PIGMENTATION:

observed from the reverse


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A. EXISTENCE OF SEPTA

CLASSIFICATION OF HYPHAE


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In Medically Important Fungi:

3 Types Of Hyphae

1. Coenocytic- sparselyseptated

2. Dematiaceous fungi -dark and pigmentedseptate hyphae

3. Hyaline molds: septate,non-pigmentedhyphae


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B. HYPHAL SHAPES


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DIMORPHIC FUNGI

Thermal dimorphism (a group of pathogenic fungi)

Mold form: 25C to 30CYeast form 35C to 37C


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DIMORPHIC FUNGI

Sporothrix schenckii Histoplasma capsulatum

Blastomyces dermatitidis

Coccidioides immitis

Paracoccidioides brasiliensis

Penicillium marneffei

Subcutaneous

Systemic

Opportunistic


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CAPSULEStructure: PolysaccharideFunctions: Antiphagocytic factor

Cryptococcus neoformans(encapsulated yeast)


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CELL WALL

Antigenic

Multilayereda. polysaccharides poorly degraded by host

activate CF; provokes inflammatory rxn Induce immune hypersensitivity

b. proteins and glycoproteins


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CELL WALL

Functions:

Provides shape, rigidity & strength

protection from osmotic shock

mediates attachment to host cells


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CELLULAR MEMBRANE

Bilayered Structure:

1. Phospholipids-phosphatidylcholine-phosphatidylethanolamine

2. Sterols- ergosterol- zymosterol


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CELLULAR MEMBRANEFunctions:

Protects cytoplasm

regulates intake & secretion ofsolutes

facilitates capsule & cell wallsynthesis


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CYTOPLASM

Nucleus, nuclear membrane, nucleolus,ER, mitochondria, vacuoles


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LECTURE 2: OBJECTIVES

Classify fungi

according to methods of reproduction type of spores they produce.

REPRODUCTION


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REPRODUCTION

A. SEXUAL REPRODUCTION opposite gametes mate to form a zygote Sexual spores

3 phases of sexual reproduction:1. Plasmogamyfusion of opposite but

compatible mating types

2. Karyogamyfusion of 2 nuclei.

3. By meiosis, diploid nucleus gives rise to

haploid spores

SEXUAL REPRODUCTION


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SEXUAL REPRODUCTION


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SEXUAL SPORES

ZYGOSPORE

Enclosed in a thickwall

Rhizopus, Mucor


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BASIDIOSPORE

formed externally on abase pedestal called

Basidium mushroom


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ZOOSPOREFusion of cellsfrom 2 diff.hyphae

OOSPORES

thick-walled,

long-survivingspore

Phytophthora

capsici

B ASEXUAL REPRODUCTION


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B. ASEXUAL REPRODUCTION


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SPORE GERMINATION

Fruiting body : Principal structure asexual spores


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CONIDIOSPORE

Unicellular / multicellular

Produced in a chain atthe end of conidiophore

PenicilliumAspergillus

ASEXUAL SPORES


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A. Arthrospore

fragmented septatehyphae

single, slightlythickened cells

Coccidioides

Geotrichum

B Blastospore


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bud

CandidaCryptococcus

B. Blastospore

C. Chlamydospore Thick walled

formed along the

periphery or tip of the

hyphae


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C PARASEXUAL REPRODUCTION


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C. PARASEXUAL REPRODUCTION

Set of events that lead to geneticexchange via mitotic recombination

Initiated by formation of aheterokaryon (thallus w/ 2 haploidnuclei of 2 diff. genotypes)

for genetic analysis of imperfect fungi


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FUNGI TAXONOMIC


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FUNGI-TAXONOMICCLASSIFICATION

Depends primarily on the type ofsexual spore

Phylum -mycotaClass -mycetesOrder -ales

Family -ceaeGenusSpecies


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Fungi-Taxonomic classification

SEXUAL SPORE CLASSZygospore---------- Zygomycetes

Basidiospore--------BasidiomycetesAscospore---------- AscomycetesZoospores---------- Chytridiomycetes

None/Unknown---- Deuteromycetes(Fungi Imperfecti)

ZYGOMYCOTA


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ZYGOMYCOTA

sporangium fungi /common molds

molds & blights

(Rhizopus stolonifer)

coenocytic

rhizoids


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ASCOMYCOTA


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ASCOMYCOTA

sac fungi

Reproduction:

Conidiospores

AscosporesBudding

Ascocarp

Ascus


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BASIDIOMYCOTA


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BASIDIOMYCOTA

club fungi

Some are used asfood; others cause

crop damage Seldom reproduce

asexually


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Basidiocarp

annulus

basidia Volva


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LECTURE 3:


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LECTURE 3:OBJECTIVES

Discuss the laboratorymethods used in the

diagnosis of fungal diseases

as to:

1. proper collection,

handling, transport and

disposal of specimen

2. culture media to use3. methods of identification

SPECIMEN COLLECTION


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SPECIMEN COLLECTION

Aseptic technique

Collect spx from actual infxn site

Adequate quantity

Accurate label; Prompt delivery

CLINICAL SPECIMEN


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CLINICAL SPECIMEN

Blood 5 ml to BHI broth

Bone

Marrow

Aspirate 0.5ml to BHI

CSF Lumbar tapVol. is >2ml: centri, smear,

cultureVol. is


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Direct culture

Biphasic culture bottle Membrane filtration

Lysis centrifugation


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Sputum

Bronchialwashings

Tracheal

aspirate

Collect sputum in a.m. for 3

days

No 24 hr. collections

sterile NSS for washings

Throat

+ few yeast & contaminants

Use 2 sterile swabs

Use tongue depressor if ?

candida


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Urine Midstream, clean-catch,catheter

Centri, smear, culture

(sediments)

Process in 2hrs or refrigerate

>100,000/ml is significant

Vaginal &

cervical

discharges

+few to moderate Candida

colonies

2 swabs: for KOH & culture

CUTANEOUS


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a. Hair May contain contaminants

Pluck hair by roots (forceps)

Select hair that fluoresce, broken,

scaly

b. Nail 70% alc., scrape discolored areas,

collect inner infected nail

Nail clippings: cut into small pcs.

w/KOH

c. Skin Few Candida & contaminants

scrape infected area

w/KOH

Documents

Mycoviro Part 1