1 Diagnosis of - PowerPoint Presentation

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Diagnosis of

superfacial

and cutaneous mycoses

Presented : by Dr.

nouripour-sisakhtSlide2
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Medical mycology

Reference

www.mycology.adelaide.edu

mycology online

Medical mycology: Dr. Zainii

Medical mycology: Dr. Shadzie7Slide8

INTRODUCTION TO MEDICAL MYC

OLOGY

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001

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Introduction

Fungus(

Myco

)………… Fungi

Mycology:

genetic and biochemical properties, their taxonomy, and their use to humans as source for medicinals (e.g., penicillin), food (e.g., beer, wine, cheese, edible mushrooms), as well as their dangers, such as poisoning or infection

Medical mycology: study of mycoses of man and their etiologic agents. 400000 ( soil, Air, Water )— Human Pathogen ( 100 up to 200 )

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General characterization

Fungi ( yeast and molds) Eukaryote( true nucleus)

- Size: 2 -10 µ

- PH : 2-9 (6.8)

-Temperature : 25-30 ( A.

fumigatus ) - Humidity : 80-95 % -Devoid of chlorophyll

- Heterotrophic C.N - mineral( Fe, Mn , Zn , p … - Vitamin(B group and biotin) - aerobic

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Fungal structure

Cell wall : polymers of polysaccharide

chitin (70%) – Glucan – Mannan- cellulose

rigid cell wall non-motile

Capsule ( evade phagocytosis)

cryptococcus Plasma membrane………….. Ergostrol

cytoplasm consist of various organell:Ribosome 80S , Mitochondria , Endoplasmic reticulum , lysosom, microtubules and a membrane enclosed nucleus.

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Chitin

is a polysaccharide composed of long chain of n-acetyleglucasamine.

the fungal cell wall contain other polysaccharide,

B-glucan

, which is the

site of action of some antifungal drugs.

Ergosterol is the site of action of antifungal drugs, amphtericin B & azole group

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Life style

Saprophyte

F

eed on dead tissues or organic waste (decomposers)

( Saprophyte…….,,,,,……Opportunist)

Pathogen

Feeding on living tissue of a host

.( pathogen)-Animal - HumanPlantsystemic mycoses and dermatophytes

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Study of fungi

Kind of fungi: Mushroom

Amanita amanitin mycetismus

Microscopic:

Yeast

Mould

Dimorphic

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Hyphal

growth from conidia

mycelium

germinating

spore

Conidia Hyphae Mycelium Colony

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Hypha (hyphae plural) - fundamental tube-like structural units of fungi.

Septate - divided by cross walls.

Aseptate (

coenocytic)

- lacking cross walls.

Mycelium - a mass (mat) of hyphae forming the vegetative portion of the fungus.

Aerial - growing or existing in the air.

Vegetative - absorbs nutrients.Fertile - bears conidia (spores) for reproduction.

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mycelium:

septate

mycelium: non

septate

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Hyphae

may have some

specialised

structure or appearance that aid in identification Some of these are:

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(Mold)Mould colony

Surface:

velvety, powdery

Cottony

Pigmentation

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Yeast

Unicellular

(round-oval)

Bud ( budding)

Pseudohypha

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Dimorphism

Thermal dimorphism

Sporothrix

Non thermal dimorphism

Candida, Malassezia

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Habitat

Exogenous

:

soil, plants, water, air

Endogenous:

Candida albicans Malassezia

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Beneficial Effects of Fungi:

1.

Decomposition - nutrient and carbon recycling.

2. Biosynthetic factories. The fermentation property is used for the industrial production of

alcohols

,

fats, citric, oxalic and gluconic acids.

3. Important sources of antibiotics, such as Penicillin.4. Model organisms for biochemical and genetic studies. Eg: Neurospora crassa

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Beneficial Effects of Fungi:

5.

Some fungi are edible (mushrooms).

6. Yeasts provide nutritional supplements such as

vitamins and cofactors.

7. Penicillium

is used to flavour Roquefort and Camembert cheeses.8. Ergot produced by Claviceps

purpurea contains medically important alkaloids that help in inducing uterine contractions, controlling bleeding and treating migraine.9. Fungi (Leptolegnia caudate and Aphanomyces laevis) are used to trap mosquito larvae in paddy fields and thus help in malaria control

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Harmful Effects of Fungi:

1.

Destruction of food, lumber, paper, and cloth.

2. Animal and human diseases, including allergies.

3. Toxins produced by poisonous mushrooms and within food (Mycetism and Mycotoxicosis).

4. Plant diseases.

5. Spoilage of agriculture produce such as vegetables and cereals in the godown.6. Damage the products such as magnetic tapes and disks, glass lenses, marble statues, bones and wax.

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Fungal Pathogenicity (virulence factors):

Ability to adhere to host cells by way of cell wall glycoproteins

Production capsules allowing them to resist phagocytosis

Ability to acquire iron from red blood cells as in

Candida albicans

Ability to damage host by secreting enzymes such as

keratinase, elastase, collagenase

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Continue

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.

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Host

defence

factors

Physical

barriers, such as skin and mucus membranes

The fatty acid content of the skin

The pH of the skin, mucosal surfaces and body fluidsEpithelial cell turnoverNormal flora

Most fungi are mesophilic and cannot grow at 37oC.Natural Effector Cells (polymorphonuclear leucocytes) and the Professional Phagocytes (monocytes and macrophages)

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Factors predisposing to fungal infections:

Prolonged antibiotic therapy

Underlying disease (HIV infection, cancer, diabetes, etc.)

Age

Surgical procedures

Immunosuppressive drugs

Irradiation therapy

Indwelling cathetersObesityDrug addictionTransplantsOccupation

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Reproduction

A sexual

the major method for the maintenance and dissemination of many fungi.

Sexual

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Asexual reproduction

anamorph

state (mitosis)

Budding (fission)

Conidia (Microconidia and Macroconidia)

Artroconidia (holoartric, entroartric)

Chlamydoconidia sporogenesis Sporagiospor…sporang

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Sexual

teleomorph

(meiosis

)

Sexual teleomorph (meiosis)

Ascospor

ZygosporBasidiospor

OosporPlasmogamykaryogamymeiosis HomothalicHeterothalic

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Ascospore

- spore formed in a sac-like cell known as an

ascus

. Often eight (8) spores formed. (

Ascomycetes

)

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Zygospore

- a thick-walled spore formed during sexual reproduction (

zygomycetes

)

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Classification of fungi

Zygomycotina

hyphea mostly

aseptate -

Rhizopus, MucorAscomycotina

Arthroderma, Pseudallescheria, Piedraia hortaeBasidiomycotinaCryptococcous neoformanceMushroom poisiningDeutromycotina}Perfect fungi}Imperfect fungi

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Mycoses

Superficial

-

Confined to the outermost layers of the skin and hair.

No host cellular or inflammatory response due to organisms being remote from living tissue. Essentially no pathology; the disease is recognized purely on cosmetic basis.

Cutaneous

- in the keratin of the skin, nails, and hair. These organisms prefer non-living cornified layers. The disease is called a dermatophytosis or dermatomycosis. Host response is patchy scaling or eczema eruptions. They are classified according to the area of the body that is involved. 40Slide41

Mycoses

Subcutaneous

:

Involve the deeper layers of skin and often muscle tissue.

Man is an accidental host following inoculation of fungal spores via some form of

trauma. This type of infection is often identified by the presence of a characteristic tissue reaction

or granule.Systemic : Attack the deep tissues and organ systems; often creating symptoms that resemble other diseases. 41Slide42

Mycoses

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Aspergillus +

osis

=

aspergillosis

Mucor

+ mycosis =

mucormycosis Trush

Tinea versicolor

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Fungal specimen

Skin( scale)-Hair-Nail

clippings

Pus- Exudates-

Sputum- serumen

Urine-Blood- CSF- Bone marrowcorneal scraping,

discharge or pus from lesions and biopsy

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Transported

to the laboratory without

any delay

Biopsy specimens must be transported

in salineSlide45

Diagnosis of fungal infection

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Chemical classes

Drugs

targets

Allylamines

and

thiocarbamates

Terbinafine

, NaftifineTolnaftate,LiranaftateErgosterol synthesisAzolesTioconazole, ClotrimazoleEconazole, MiconazoleKetoconazole, FluconazoleItraconazole , TerconazoleVoriconazole, Posaconazole

Ergosterol

synthesis

Polyenes

Amphotericin B ,

Nystatin

Ergosterol

(membrane function)

Pyrimidine

Flucytosine

DNA and RNA

Synthesis EchinocandinsCaspofungin, MicafunginAnidulafungin Glucan synthesisAntifungal drugs- by structure and mode of action

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Thank You

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mycoses

Superficial

cutaneous

sub cutaneous

SystemicSlide49

Malassezia

 infections

Pityriasis

versicolor

Pityriasis folliculitisSeborrhoeic dermatitis and dandruff: 

Fungaemia:Slide50
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Pityriasis

versicolor

(tinea

versicolor)

Definition

is a common, mild, but often recurrent infection of the stratum corneum due to lipophilic yeasts of the genus

Malassezia.Slide52

Geographical distribution

The disease is worldwide in distribution, but is much more prevalent in tropical and subtropical regions.

Causal organisms (

Malassezia

species)

M. furfur, M. pachydermatis

(non obligate lypophile)M. sympodialis, M. globosaM. obtusa, M. restricta and M. slooffaeSlide53

Normal flora

……… endogenous in

origion

prevalent in hot, humid tropical and subtropical climates, where 30-40%

of the adult population may be affected.Human-to-human transmission of Malassezia species is possible, either through direct contact or via contaminated

clothing or bedding. In practice, however, infection is endogenous in most cases and spread between persons is uncommon. Slide54

The characteristic lesions consist of patches of

fine brown scaling

, particularly on the trunk, neck and upper portions of the arms.

In light-skinned: may appear darker than normal

In dark-skinned or tanned individuals: affected skin loses colour and becomes depigmented.The disease is exacerbated by sunlight and sweating

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The lesions of

pityriasis

versicolor

and

seborrhoeic

dermatitis have a predilection for sites well

supplied with sebaceous glands, such as the chest, Back and upper armsSlide57

Risk factor

Stress

Chronic infection

Hyperhydrosis

MalnutritionBroad spectrum antibioticsOverweightSteroid therapy

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Differential diagnosis

Erythrasma

Seborrhoic

dermatitis

Tinea corporisNaeviVitiligo

chloasmaSlide59

Pityriasis

Versicolor

Diagnosis

Mic

: short hyphae, Yeast cells (spaghetti)

Wood light …..Golden yellowCultureTherapy:

topical selenium Sulfide 2% shampooSlide60
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Wood's ultra-violet lightSlide64
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Malassezia

ovalis

????

Malassezia Species.Slide66

Less

frequently,these

organisms cause serious systemic infection in low-birth-weight infants and other

mmunocompromised

and debilitated individualsSlide67
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Erythrasma

Chronic Bacterial infection (folds)

axillae, interspaces of the toes,

ETIO:

Corynebacterium

minutisimum

Wood light……..Coral redTherapy - ErythromycinSlide70
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Wood light

……..Coral redSlide72