mycology introduction hpv

INTRODUCTION TO MEDICAL MYCOLOGY

Hari Pankaj VanamAsst ProfessorBhaskar Medical College

Sri Balaji Dental Collegewww.bhaskarmdicalcollege.edu.in

31/3/16 #HariPanVan@Asst Prof@BMC

Objectives

Able to define terms use in mycology basic characteristic of fungi fungal reproduction mycoses laboratory Dx for fungal infection.


• Mycologists--scientists who study fungi • Mycology--scientific discipline dealing with

fungi • Mycoses--diseases caused by fungi

Mycology: Myco=Fungus.

Logy=study


Beneficial Effects of Fungi:1. Decomposition 2. Biosynthetic factories. 3. Sources of antibiotics, ex:Penicillin. 4. Model organisms 5. Some fungi are edible (mushrooms).6. Supplements - vitamins and cofactors. 8. Penicillium is used to flavour cheeses. 9. Ergot -alkaloids that help in inducing

uterine contractions, controlling bleeding and treating migraine.

10. Fungi -trap mosquito larvae-Malaria control 31/3/16 #HariPanVan@Asst Prof@BMC

Harmful Effects of Fungi1. Destruction of food, lumber, paper, and cloth. 2. Diseases, including allergies. 3. Toxins produced by poisonous mushrooms and within food (Mycetism and Mycotoxicosis). 4. Plant diseases. 5. Spoilage of agriculture produce.6. Damage the products such as magnetic

tapes and disks, glass lenses, marble statues, bones and wax.


General FeaturesI: FUNGI

Diverse group of heterotrophs.-many saprophytes Others are parasites.

Most are multicellular, but yeasts-unicellular. Most are aerobes or facultative anaerobes. Rigid Cell walls –chitin ,glucans, mannans Plasma membranes: ergosterol lack of chlorophyll Only about 100 are human or animal pathogen Most human fungal infections are nosocomial

and/or occur in immunocompromised individuals (opportunistic infections).


Characteristic of fungi

1).Vegetative Hypha:Composed of cells involved in catabolism and growth.

2).Reproductive Hypha (aerial)Composed of cells involved in reproduction (produce spores).

Both sexual and asexual spore may be producedStore their food as glycogen


Forms of fungi!!1. Yeast : unicellular, 370C, FAN

2. Non-filamentous– Budding Yeast uneven reproduction–

pseudohypa– Fission yeast-even reproduction

3.Mold :Multicellular, hyphae, 250C4. Dimorphic fungi (thermally dimorphic

fungi) : mold phase & yeast phase


YEAST

Unicellular Micro.:Oval to round

(Dia: 3-15 µm)

Macro.: Pasty colonies

(resemble bacteria)

MOULDMulticellular Micro.: Hypha(e) (dia: 2-10

µm)Spores / conidia. Macro.: Surface texture:

Cottony/ powdery/ wooly/velvety/granular/glabrous

Pigmentation :obverse & reverse


Fungal Structure Thallus-”body”

– Molds & fleshy fungi have these structures– Long filaments of cells (hyphae):

Septate hyphae (cross wall) :most fungi Aseptate hyphae (coenocytic ) :nocross

wall, continous mass with many nuclei .

Mycelium – – Abundance growth of aerial hyphae resulting a

mass can be observed with unaided ayes.


Fungal Taxonomical Classification

Four groups of true fungi1-3 reproduce sexually

1).Zygomycetes (bread mold—Rhizopus)

zygospore- sexual spore class

2).Basidiomycetes (puffballs & mushrooms)

Basidiospore- sexual spore class

3). Ascomycetes (Dutch elm disease/rye smut)

Ascospore- sexual spore class

4).Deuteromycetes (fungi imperfection)

have NO sexual reproduction


Life Cycle Fungal reproduce by 2 way

– Asexual– Sexual– Parasexual –gen.exchange

Asexual– Hyphae fragmentation– Asexual spores

Conidiosphore-Asperigillus Arthroconidia- Coccidioido immitis Blastoconidia- Candida albicans sporangiospore- Rhizopus


Life cycle

Conidiosphore-AsperigillusArthroconidia- Coccidioido immitis Blastoconidia- Candida albi-canssporangiospore- Rhizopus

asex

ual


SEXUAL Spores

1. Zygospore2. Ascospore3. Basidiospore4. Oospore

• Have three stages– Plasmogamy- a haploid nucleus of donor cells– Karyogamy- the (+) and (-) nuclei fuse to form a

diploid zygote– Meiosis – the diploid nucleus give rise to haploid

nuclei (sexual spores) genetic recombinant .31/3/16 #HariPanVan@Asst Prof@BMC

Conidiosphore-AsperigillusArthroconidia- Coccidioido immitis Blastoconidia- Candida albi-canssporangiospore- Rhizopus

1. Zygospore2. Ascospore3. Basidiospore4. Oospore

PlasmogamyKaryogamyMeiosis 31/3/16 #HariPanVan@Asst Prof@BMC

Mycoses-PathogenesisMost fungi are saprophytic or parasitic Risk factors: Conditions are favourable. True pathogens: dimorphic fungi -systemic

mycoses and dermatophytes, which are Primary pathogens,

the rest are only opportunistic. Ex: Candida and Malasezzia have adapted to

human environment and exist as commensals. The complex interplay between fungal virulence

factors and host defence factors will determine if a fungal infection will cause a disease.

Infection depends on inoculum size and the general immunity of the host.


• Ability to adhere to host cells. • Production capsules allowing them to resist phagocytosis • Production of a cytokine -suppress the production of complement.• Ability to acquire iron from red blood cells as in Candida albicans • Ability to damage host by secreting enzymes such as keratinase, elastase, collagenase • Ability to resist killing by phagocytes as in dimorphic fungi • Ability to secrete mycotoxins • Exhibiting thermal dimorphism • Ability to block the cell-mediated immune defences of the host. • Surface hydrophobicity

Fungal Pathogenicity (virulence factors):


• Prolonged antibiotic therapy • Underlying disease (HIV infection,cancer,

diabetes,) • Age • Surgical procedures • Immunosuppressive drugs • Irradiation therapy • Indwelling catheters • Obesity • Drug addiction • Transplants • Occupation

Factors predisposing to fungal infections:


1. Superficial mycoses (Tinea versicolor,piedra etc.,) 2. Cutaneous mycoses

I. Dermatophytosis/& II. Dermatomycosis 3. Subcutaneous mycoses

I. Chromoblastomycosis, rhinosporidiasis III. Sporotrichosis etc.,

4. Systemic (deep) mycoses I. Blastomycosis, II. Histoplasmosis III. Coccid-

ioidomycosis IV. Paracoccidioidomycosis

5. Opportunistic mycoses I. Candidiasis, II. Cryptococcosis III. As-

pergillosis 7. Fungal allergies 8. Mycetism and mycotoxicosis

Fungal diseases (Mycoses):


LABORATORY DIAGNOSIS OF MYCOSES

Direct microscopic examination KOH mount Calcofluor white India ink Culture SDA,PDA, Corn Starch Ag The tease mount Scotch tape preparation The microslide culture technique( slide culture) Serology


Initial observations in the study of fungus isolates

1.Appearance of the growth-Subverse/reverse2. Rate of growth (3-5d),(10d),and (14d)3. Colony pigmentation4. Growth on media containing antifungal agents5.Dimorphic fungi (22-25 OC) & (30-35 OC)


Serology in Diagnosis of MycosesDx Relavence:

only dx sub-cutaneous and systemic mycoses, prognosis and response to anti-fungal drugs. Tests: Immunodiffusion, CIE CFT, IF,RIA and

ELISAAntigen detection:

Dx of cryptococcal meningitis from CSF speci-mens. The Latex Agglutination or immunodiffusion tests.

Detection of Aspergillus and Candida antigens in sys-temic infSkin tests: Demo of DTH reactions to fungal antigens A positive skin does not necessarily indicate an active infection; it only indicates sensitization of the individual. value is in epidemiological These tests may be performed in Histoplasmosis, Can-didiasis. Sporotrichosis, Coccidioidomycosis, and derma-tophytosis. Molecular techniques: DNA hybridization, PCR


THANK YOUPurely for teaching UG and PG’s.


mycology introduction hpv

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