Introduction%20Medical%20Mycology

1
Introduction Medical Mycology

• Prof. Dr. Asem Shehabi
• Faculty of Medicine
• University of Jordan

2
General Fungi-1

• Medical Mycology deals with fungi cause human
  diseases directly (mycoses, allergies) or
  indirectly food poisoning.. Mycotoxins.
• About 100 Fungi are opportunistic pathogens.. Few
  Fungi are true pathogens.. Part of environmental
  flora
• Fungi are Aerobic Eukaryotic microorganisms..
  Larger than bacteria (0.5-2 um) occur as
• Yeasts (unicellular oval cells) or Molds (
  multi-cellular cells), hyphae/ branching
  filament or combination of both forms ..Various
  spores.. Yeasts.. Part human normal flora.. Oral
  -intestine-Genitals-Skin.. Incidence 5-20 in
  normal humans.

3
Hypha (tubular Cell)-Yeast Cell structure
4
Yeast Cells-Candida/Budding yeast
5
2/ Cell Growth

• Dimorphic Fungi.. grow as Yeast (in vivo) or
  Molds (in vitro).
• Molds /Multicellular fungi composed of Hyphae
  Spores are widely distributed in nature..
  decomposing organic/ inorganic materials.
• Hyphae are found in randomly tangled masses
  called mycelia (aerial/vegetative mycelium).
• In molds, the mycelia often spread with their
  spores to fill the available space, limited only
  by available nutrients.
• Fungi are widely spread live in nature,
  environment, soil, surface water, dust.. in
  association with plants ..often as harmful
  organisms, or as free saprophytes on dead organic
  substances.. Human can easily contaminated/inhaled
  spores.

6
(No Transcript)
7
Aminata Toxic Mushroom-Non-Toxic Mushroom in
Nature
8
/3

• All Fungi are Aerobes.. have Chemoheterotrophic
  metabolisms, obtaining nutrients through
  enzymatic/ chemical absorption/ degradations of
  large chemical molecules complex compound ( dry
  wood plants, mineral).
• Certain Fungi .. Producer Antibiotics..
  Fermentation of food, Vitamens, Decompose organic
  materials.. Fresh dry food.. sugar/protein
  molecules.
• Molds reproduction rapidly/slowly by various
  spores and hyphae by apical extension of cells..
  Most asexually by mitosis.
• Yeast Mostly reproduce asexually by budding..
  although a few reproduce by binary fission (cell
  growth rapid 12-15 minutes) .

9
Yeast Growth by Budding
10
/4

• Pathogenic Yeasts are single oval cell forms
  reproduce mostly by budding.. asexual
  reproduction.. Pseudohyphe forming a nest
  produced in infected tissues.
• Baker's yeast/ Saccharomyces cerevisiae.. Ferment
  Sugar during production bread.. Vitamins,
  Proteins, Drugs Like Hepatitis vaccine.. Used
  in Genetic studies
• They are not susceptible to antibacterial
  drugs..phages
• Fungi Cell wall Long chain Polysaccharides,
  mostly chitin (Polymers of N-acytelglucosamine)..
  Less ß-glucan, mannan), lipid-phosphate-protein.
  
• Certain Yeast ( Candida spp.).. secret specific
  proteases, phospholipases, hemolysins..help
  tissue invasion.
• Fungi plasma membranes containing Ergosterol,
  Cytoplasm contains microtubules composed of
  tubulin/Specific Protein

11
Budding Yeast/Germ Tubes
12
Filaments Fungi/ Molds

• Whereas molds form multicellular filaments/
  hyphae .. non-septate/ septate hyphae.. spores of
  different sizes.. color.. arrangement .. A mass
  of hyphae represent Aerial Vegetative Mycelium
• Dimorphic Pathogenic fungi grow as Yeasts or
  Yeast-like structure in vivo at 37C, but as
  Molds at 25C in vitro .
• Lab Identification Depend mainly on their way of
  reproduction.. Conidia are asexual spores hyphae
  (reproductive units) formed in various morphology
  structures.. Microconidia. Spores may be either
  asexual or sexual in origin. Asexual spores are
  produced in sac-like cells called Sporangia/
  Macroconidia.

13
Microconidia-Macroconidia
14
Human Mycosis-1

• Superficial Mycoses/ Cutaneous Mycoses Involve
  superficial keratinized/ dead tissues.. skin,
  hair, Nails..
• Dermatophytes.. Worldwide distribution.. Spores,
  Hyphae fragments.. Common in nature, skin human,
  animals.
• Dermatophytosis - Ringworm / Tinea
• Skin-Body Tinea corporis.. Most common.. Tinea
  versicolor / Pityriasis versicolor..
  Pityrosporum/Malassezia furfur or ovale . These
  Lipophilic yeast is normally found on the human
  skin and only becomes pathogenic under certain
  conditions.. causing chronic mild superficial
  infection in stratum corneum increased in
  warm- humid environment.. under stress
  conditions.. Fever, Unknown Factors.. Allergic
  reaction.. Other dermatophytes may cause very
  similar infection.

15
Human superficial Mycosis-2

• Cause hyper pigmentation / discolored Skin
  spots.. macular patches.. Limited Inflammation
  and irritation.. commonly affect the back,
  underarm, upper arm, chest, lower legs, and neck.
  Occasionally it can also be present on the face.
• The yeasts can often be seen under the microscope
  within the lesions with typically round yeasts
  filaments. Light to Dark patches on skin.
• Hair Tinea capitis, infect Hair shaft scalp,
  Endo-Exothrix, Common in Children.. Rare
  Adults.. Infection Outbreaks .
• Nail Tinea unguium alone hand finger or
  associated with Tinea pedis (Athlete's foot)
  ..Feet fingers, Feet interspace, moist lesions,
  Common in adults/sport ,chronic lesions may
  spread to Groin, contagious fungal
  infection..difficult to eliminate.
• Causative agents Dermatophytes.. Trichophyton -
  Microsporium -, Epidermophyton species.

16
Tinea corporis-
Pityriasis versicolor
17
Tinea unguium Tinea Tine
acapitis
18
Athlete's foot
19
Penicillin-Trichophyton spp.
20
Microsporum Hyphae Spores-Skin filaments/Hyphae
21
Cutaneous subcutaneous Mycosis-2

• Skin Candida spp. , Histoplasma capsulatum,
  Blastomyces dermatitis.. direct in association
  with Systemic Infection.. Inhalation Spores..
  Soil.. Respiratory Tract Infection, Mostly
  Asymptomatic infection. Rare Pneumonia..
  Systemic.. Skin Abscess,
• Sporotrichosis.. Sporothrix schenckii commonly
  found in soil and on decaying vegetation.. Causes
  Skin ulceration, Lymphadenitis..
• Subcutaneous Mycoses/ Mycetoma Chronic,
  localized infections of the skin and subcutaneous
  tissue.. Foot.. following the traumatic
  implantation of the filamentous fungi.. mostly
  Fungal Madurella spp. or bacterial agent..
  Actinomyces, Nocardia species.. soil
  saprophytes.. Mixed infection
• Treatment Surgical Antifungal agents.

22
Yeasts /Candida species

• Candidiasis/ Candidiosis C. albicans, C.
  glabrata, C. tropicalis., C. Krusei.. Others spp.
  ..Less common Yeast Geotrichum spp. ,
  Trichosporon spp.
• Part normal body Flora.. Mouth, Vagina, Skin,
  Intestine, Urinary tract .. Common Opportunistic
  Infection
• Opportunistic Pathogens.. mostly an endogenous
  infection, arising from overgrowth of the fungus
  following intensive use of antimicrobial drugs..
  Inhibiting normal flora.. Underlining diseases,
  compromised host, Radiation, Toxic drugs
• It may occasionally be acquired from exogenous
  sources .. catheters or prosthetic devices..
  Respiratory tubes.. by person-to-person
  transmission.. Nosocomial Infection.

23
Candidiasis -1

• Oral Candidiasis is showing characteristic
  patches of a creamy-white to grey pseudomembrane
  on Tong (Thrush).. Oral-gingival mucosa..
  Throat.. Pharynx, Larynx.. composed of
  Pseudohyphae nest of Candida cells..
• Patients who wear dentures are often susceptible
  to develop Candida stomatitis .. the balance of
  the normal oral flora is disturbed by the
  presence of plastic dentures.. Xerostomia
• Oesophageal Candidiasis.. observed mostly in AIDS
  patients.. If patients not responded to
  first-line anti-Candida treatment, particularly
  fluconazole.. They may be infected with Candida
  dubliniensis .. resistant to this drug.

24
Candidiasis -2

• Candida infections are now the most frequent
  cause of fungal infection in immunocompromised
  patients..
• Lesions in systemic Candidasis may be localized
  in the mucosa of lung, urinary tract, liver,
  heart valves.. skin folds.. Causes pneumonia,
  endocarditis, chronic meningitis, Skin Lesions
• Candida infections may also be widely
  disseminated and associated with a septicaemia /
  candidaemia.
• Systemic candidasis occurs mainly as an
  opportunistic infection in patients with an
  underlying disease
• Deep-seated Candidasis is difficult to
  diagnose and treat, and its prognosis is
  generally poor.

25
Candida Trush
26
Skin Candidasis
27
Candidiasis-3

• Vaginal Candidasis.. inflammation the vaginal
  mucosa.. vaginal discharge, irritation, pain
  during urination, common in pregnant women,
  following use of antibiotics, sexual contact..
  hormonal treatment.
• In healthy individuals, Candida infections are
  usually due to impaired epithelial barrier
  functions .. occur in all age.
• Common Risk Factors Antibiotics, Oral steroids
  , Diabetes, Wearing denture, Immunodeficiency ..
  Leukemia, Cancer or HIV infection.. Radiation,
  Anticancer/immuno-depression drug treatment, Old
  age, Infants, organ transplantation.

28
Candidiasis -4

• Prevention Restore host immunity.. Control
  diabetes, Stop extensive use of Antibiotics,
  removing the underlining cause.. No vaccine is
  available.
• Lab Diagnosis Microscopic Wet preparation..
  Clinical specimens.. Tissue biopsies , Skin,
  Nails, Blood, CSF, Urine, Sputum, Oral swab..
  Presence Budding cells.. Pseudohypha-
  Blastospores-Chlamydospores.
• Culture Sabouraud dextrose agar, ChromCandida
  agar.. Aerobic Incubation Temp. 25-37C, 2 days,
  Sugar fermentation test.. Serological tests not
  significant
• Treatment Topical.. Oral Nystatin, Miconazol,
  Clotrimoxazol .. Systemic fluconazol,
  Amphotercin B, All interact with Ergosterol
  ..causing Fungal Cell membrane disruption.

29
1-Candida Pseudohyphae-Chlamydo-Blastospores
2-Gram-stain
30
Sabouraud /ChromCandida Agar
31
Other Opportunistic Systemic-Mycosis

• Opportunistic Systemic Mycoses Opportunistic
  fungal infections .. occur almost exclusively in
  debilitated patients whose normal defense
  mechanisms are impaired.. AIDS, Extensive use of
  antibiotics, cytotoxins, immunosuppressives
• Few common Fungi are involved .. Saprophytes..
  Widely distributed as in nature.. Plants, Grow
  inside homes .. Transmitted with dust particles..
  have a very low potential of virulence under
  healthy host conditions.. Exogenous Infection ..
  hypersensitivity reactions..Leading to asthma.
• Common Fungal pathogens Aspergillus spp., Mucor
  spp., Alternaria , Cryptococcus spp.

32
Aspergillosis-1

• Aspergillosis / Zygomycosis A. niger, A.
  fumigatus., A. flavus / Producer of aflatoxins..
  Food intoxication.. Rice, Nuts.. Peanuts..
  Grains.. Cause sever liver cirrhosis.. high
  mortality.
• Inhalation of Aspergillus spores may lead to
  colonisation of existing lung nasal cavities
  (Aspergilloma) or may cause hypersensitivity
  reaction (allergic Aspergillosis)..
• Rarely Aspergillus spp. may cause invasive
  disease of the lung, Sinuses, oral cavity ..
  disseminate to other organs.. Meninges /brain
  ..meningitis, brain abscess.. This form of
  disseminated Aspergillosis is seen in patients
  who are severely immun-ocompromised.

33
Aspergillus niger-Conidal head-spores
34
Aspergillus flavus-culture and conidal head-spores
35
Tomato infected with Alternaria
36
Cryptococcosis-2

• Cryptococcosis Encapsulated Yeast C.
  neoformans.. Large polysaccharide capsule..
  Common in Bird droppings/ Pigeons.. Transferred
  by Dust, Human inhalation.. Slowly chronic
  lesions over 1-year sinusitis, pneumonia,
  meningitis.. brain abscess .. mostly
  immuno-Compromised host develop disease or
  following intensive surgery
• Lab diagnosis India ink wet preparation, culture
  on Sabouraud dextrose agar, Aerobic Incubation
  Temp. 25-37C, 4-7 days, Sugar fermentation
  tests.. Detection Cryptococcus antigen in blood.
• Surgical Antifungal systemic treatment

37
Capsulated Yeast / Cryptococcus neoformans
(India ink test)
38
Histoplasmosis Blastomycosis-3

• Histoplasmosis Histoplasma capsulatum..
• Blastomycosis Blastomyces dermatitidis ..Both
  are Dimorphic Fungus.. common in soil enriched
  with birds feces.. Endemic in south-western
  U.S.A., northern Mexico and various parts South
  America..
• Respiratory infection resulting from the
  inhalation of spores/ microconidia.. often
  resolves rapidly leaving the patient with a
  strong specific immunity to re-infection.
• Few person (less 1/1000 ) may develop disease..
  progress to a chronic pulmonary condition or rare
  a systemic disease involving oral cavity,
  meninges, bones, joints, subcutaneous, cutaneous
  tissues.. Antigen Skin test positive.. Not always
  significant in diagnosis.

39
Histoplasma capsulatumin infected White Blood
cells