2Contact informationClaudio Cortes M. D.V.M., Ph.DMedical Microbiology and ImmunologyThe University of Toledo3000 Arlington Avenue, mail stop 1021Toledo OH, 43614
3Medical Mycology Introduction: Fungal structure and growth 1 SUBJECT CLASSIntroduction: Fungal structure and growth 1Fungal physiology and antifungal 2Subcutaneous pathogens 3Cutaneous pathogens (Dermatophytes) 4Opportunists- Mycoses I 5Opportunists- Mycoses II 6
4“Septate hyphae, intercalary and terminal chlamydospores with rare microconida along hyphae branches were identified. Multiple small budding yeast around a big one was found in BAL sample. Diagnostic: Dimorphic fungi Paracoccidiodes brasiliensis”
5OBJECTIVESTo impart sufficient basic knowledge about the growth of Fungi.TerminologyDistinguish structures/components of several forms of fungiAssist you in diagnosing mycotic diseases.
9Characteristics of fungi cont. EukaryotesFungi are heterotrophic (non-photosynthetic)Do not contain chlorophyllFungal cell membrane have a unique sterol.ErgosterolCell wall similar in structure to plants. Differs in chemical compositionsChitins biosynthesis
10Characteristics of fungi Fungi digest then ingestExoenzymesVegetative body may be unicellular (yeasts) or composed of microscopic thread called Hyphae (singular Hypha)Reproduce by means of spores, usually wind-disseminatedSexual (meiotic) and asexual (mitotic) spores may be produced.
11SIZE COMPARISON OF PATHOGENS Viruses0.08 mBacilli4-6 mCocci0.8 mSpirochetesmProtozoa15 mFungi5 – 15 mNematodes10 mm
17The basic units of growing fungi YeastsHyphae (mold)
18Yeasts Single cells dividing usually by budding (single nucleus) Reproduce by budding (or by fission in some groups)Found where there is plenty of moisture (spread in water films and by turbulence).Yeast cannot push into substrates as do hyphae.Growth in the form of yeasts is quite common for many human pathogens.Growth of the organism within phagocytes and for easy hematogenous spread.Cause cutaneuos candidiasis (AIDS), systemic mycosis (hospitalized patients), and vaginal yeast infection
19Mold growthLong filaments growing at apex branching. (sing. Hypha): MoldApical growthHyphae branch to form myceliumMycelium (plural mycelia)Push into substratesCommon in cutaneous and subcutaneous infectionRingworm-> DermatophytesMYCELIUM
20Classification based on cell division (hyphae) Septate (with septa)Aspergillus and many other species have septate hyphae. Septate hyphae with acute-angle branching important in pulmonary disease caused by Aspergillus spp.Aseptate or coenocytic (without septa)Non-septate hyphae are associated with Mucor, some zygomycetes, and other fungi.SeptateAseptate
22DIMORPHIC FUNGI25°C37°CGrowing both in the form of a yeast and a moldCommon in systemic fungal infectionThe environment determines their morphology.Temperature,CO2, nutrientsThis conversion is associated with a change in cell wall composition.Complete reversal of a morphological change follows return of the fungus to the initial environment.
23Classification based on growth MoldYeastDimorphicUncertainDermatophytesAspergillusZygomycetesFusariumDematiaceousfungal infections (Trauma)- Cromoblastomycosis(Dermatitis verrucosa)- PhaeohyphomycosisMycetomata (Madura foot)(tumor like presentation)Candida sppHistoplasmosisCoccidioidomycosis(Valley fever)Blastomycosis(N. American blastomycosis)Paracoccidioidiomycosis(S. American blastomycosis)PenicilliosisSporotrichosis(Rose-thorn or rose-gardeners)Pneumocystis jiroveci (AID): CystsLacazia loboiCryptococcus neoformans
25Naming fungi Hyphae and Septa Sporulation structures and spores Little variationSporulation structures and sporesVariable and are basis of most identificationsIncreasingly rRNA gene sequencing is being applied
26SporesMany forms of spore production -> allow fungal identificationSpores allow fungi to spread to novel sites.
27Sexual forms (Teleomorph) Naming fungi cont.Asexual forms(Anamorphs)Sexual forms (Teleomorph)Ascospores (Ascus)Basiodiospores (Basidium)Zygospores (Zygosporangium)Conidiospores/conidia(conidiophores)Blastic conidiogenesisAspergillus, Penicillium, candidaThallic conidiogenesisDermatophytes (Microsporum)Coccidioides immitis (arthospores)Sporangiospores(sporangium; sporangiophore)Zygomycetes
28Conidiospores (conidia) Asexual forms(anamorphs)Conidiospores (conidia)Blastic conidiogenesiswhere the spore is already evident before it separates from the conidiogenic hyphaBlastoconidia are pushed out of conidiophore (specialized structure). New wall is formed as the conidium balloons out.Penicillium, Aspergillus, Fusarium, Stachybotrys, Trichoderma, Candida albicans, etc
30Asexual forms (anamorphs) MacroconidiumThallic conidiogenesis (Spores produced by modifying an existing hypha. Wall is remodeled.)Systemic mycosis Dimorphic;Coccidioides immitisDermatophytes(Microsporum canis)arthospores
31Asexual forms (anamorphs) Sporangiospores (sporangium; sporangiophore)Spores produced following cytoplasmic cleavage within a sporangium. Zygomycetes -> zygomycosissporangiosporessporangiumsporangiophore
32Sexually produced spores (teleomorph) Ascospores -> ascomycetes (ascus sing = asci plural)Basidiospores produced BasidiomycetesZygospores produced by zygomycetes**Basidium
33Life cycle of black bread mold (Rhizopus stolonifer) zygomycetes SporangiumSporangiophoreAsexual reproduction by spores(Sporangiospore)Meiotic during GerminationSexual reproduction(Zygospores)ZygosporangiumFertilizationBiology of plant 5th edition. Raven PH. 1992
34Naming yeasts Often little morphologic differences Yeasts grouped by morphology, pigment and how they divide, then put into distinct species on basis of a metabolic profile.Most features of metabolic profile associated with different patterns of sugars and forms of nitrogen (nitrate, nitrite, ammonium etc) usedDNA sequencing coming on fast
35Mycology: PF. LehmannSporesOctober 8, 2008Many forms of spore production -> allow fungal identificationSpores allow fungi to spread to novel sites.Coccidioides
38Species of Fungi>1,000,000 species~400 pathogenic
39Classification Mycosis diseases Systemic MycosesCutaneous MycosesSubcutaneous MycosesOpportunistic fungiInvolve skin and deep visceraSkin, hair and nails.Rarely invade deeper tissueSubcutaneous tissueRarely spread systemicallyMay become widely disseminated.Predilection for specific organsUbiquitous saprophytesPredisposing diseases/conditionDermatophytesAthlete’s footJock itchRingworm diseasesCutaneous candiadiasis*Candida: patients with AIDSChromomycosis(Dermatitis verrucosa)Mycetoma (actinomycetes)(Madura foot)Sporotrichosis*(rose-thorn or rose-gardeners' disease)Histoplasmosis(Darling’s diseases)Coccidioidomycosis(Valley fever)Blastomycosis(North American blastomycosis)Paracoccidioidiomycosis(South American blastomycosis)PenicilliosisSporotrichosis *Candidiasis *Aspergillosis,Pneumocystosis,ZigomycosisCryptococcosis.
40Cutaneous Mycoses Skin, hair and nails Rarely invade deeper tissue DermatophytesAthlete’s foot or tinea pedisJock itch or tinea crurisRingworm diseases (tinea corpora, faciei, capitatis, manuum, unguium)Cutaneous candiadiasisSkin and mucosal; Oral thrush and Candida esophagitis, are extremely common in patients with AIDS.
41Subcutaneous MycosesSubcutaneous tissue and rarely spread systemically. The causative agents are soil organisms introduced into the extremities by traumaChromomycosis (dermatitis verrucosa)Mycetoma (Madura foot)Sporotrichosis (rose-thorn or rose-gardeners' disease)
42Systemic Mycoses Involve skin and deep viscera May become widely disseminatedPredilection for specific organsHistoplasmosis (Darling’s diseases)Coccidioidomycosis (valley fever, San Joaquin Valley fever, California valley fever, and desert fever)Blastomycosis (North American blastomycosis)Paracoccidioidiomycosis (South American blastomycosis” and "Paracoccidioidal granuloma”)Penicilliosis (south Asia)Systemic candidiasis (Hospital)
43Opportunistic fungiUbiquitous saprophytes and occasional pathogens that invade the tissues of those patients who have:Predisposing diseases:Diabetes, cancer, leukemia.Predisposing conditions:Genetic disorders (cystic fibrosis), Agammaglobulinemia, steroid, contraceptive pills or antibiotic therapy, transplantation.Aspergillosis, Candidiasis, Pneumocystosis, Zigomycosis, Cryptococcosis.
44Diagnosis of fungal infections Clinical recognitionLaboratory SpecimenSkin and nail scraping, urine, sputum, BAL, blood Pleural fluid, Peritoneal fluid, tissue biopsies.Case HistoryPhysical examinationOrgan ImagingSkin test (Dermal Hypersensitivity)DNA probesPCRCulture andidentificationDirect MicroscopyHistopathologySerodiagnostic testWet Mount (10 % KOH)Biopsy
46Histoplasmosis (Histoplasma capsulatum) Lungs, mucocutaneous, pericarditis.Grows in soil and material contaminated with bird or bat droppings.The Central River Valleys in the midwestern and south central United States are endemic for histoplasmosis. Latin America, part of Asia, Europe, Middle East, Africa.Inhaled conidia (spores) small, intracellular, budding yeastYeast(370C)YeastTissueTuberculate conidia(240C)
47Penicillium Marneffei Prominent mycotic pathogen among HIV-infected individual.Southeast Asia. Imported cases in USA and Europe.Lung, lymphadenopathy, hematogenous dissemination.Intracellular (like Hisptoplasmosis).Inhaled conidia convert to yeast form with transverse septa.Yeast transverse septa.Mold: Conidia and red pigments
48Coccidioidomycosis (Coccidioides immitis) California valley feverDesert soil. Southewestern USA, Mexico, region of Central and South AmericaLung. CNS, bones and joins. Cutaneous infectionInhaled arthroconidia convert to spherules (contains endospores).arthroconidiaSpherules with endospores
49Blastomycosis (Blastomyces dermatitidis) “North American blastomycosis”Lung and skinSoil and organic debrisUSA OHIO-Mississippi River Valley. North-AmericaInhaled conidia convert to large broad-based, budding yeast.ConidiaYeast (budding broad-based)
50Multiple small budding yeast around a big one Paracoccidioidomycosis(Paracoccidioides brasiliensis)South American blastomycosis," and "Paracoccidioidal granuloma”Chronic single or multiples organs involvementLungs, mouth, nose, lymph nodesInhaled conidia convert to multipolar budding yeastSeptate hyphae, and terminal chlamydospores (240C)Multiple small budding yeast around a big one(Pilot wheel) (370C)
52Sporothrichosis (Sporothrix schenkii) “Rose-thorn or rose-gardeners”Lungs, joints, bones, and even the brain.Nodules and ulcers along lymphatics at site of inoculation (Lymphatic nodules)Peru, tropical places, USA. ZoonoticInhaled conidia covert to yeastSystemic mycosis (rare)Swollen conidiophores, tear shaped, round conidia, sleeve shapes, rosette form(240C)Yeast/cigar shape(370C)
54Aspergillosis Ubiquitous molds found in organic matter (A. fumigatus, A. niger, A. flavus and A. clavatus )Ubiquitous molds found in organic matterLungsImmunocompromised-> SystemicInhaled conidia Hyphae (in lungs)England, USANeutropeniaAcute angle branching (<45oC)methenamine-silver–stained tissue section of lung. (Figure courtesy of The Geraldine Kaminski Medical Mycology Library, produced by David Ellis and Roland Hermanis, Doctorfungus Corporation.
65Trichophyton mentagrophytes Hair Perforation TestUrease TestGrowth at 37°CMacro-conidiaMicro-conidiaDistinguishing CharacteristicsTrichophyton rubrumNegativePositivePencil shaped/cigar shapedClub shaped to pyriform, along the sides of the hyphaeRed reverse pigmentHair perf. test neg.Club shaped microconidiaTrichophyton mentagrophytesClub shaped when presentNumerousUnicellular to round in grape like clustersRound microconidia in grape like clusters Spiral hyphaeTrichophyton tonsuransUsually (-)Occasionally +Cylindrical to cigar shaped and sinuous, if presentNumerous, varying in shape and size, club shaped to balloon shapedMicroconidia varying in shape and sizeGrowth enhanced by thiamineTrichophyton verrucosum“Rat-tailed” if presentRare or AbsentChlamydospores in chains typically seenChlamydospores in chainsGrowth better on media with thiamine and inositolTrichophyton terrestre2-8 celled borne at right angles to hyphaeClub shaped with squared-off base on pedicelsMicroconidia with squared-off base on short pedicelsEpidermophyton floccosumClub shaped, often in clustersAbsentKhaki colored colony with brown reverseMicroconidia absentMicrosporumcanisNAFusoid, thick, rough walled with recurved apexTypically absentClub shaped if presentFusoid, rough walled macroconidia with recurved apexMicrosporum gypseumEllipsoidal to fusiform, thin, Rough walledModerately abundant Club shapedThin walled macroconidiaTawny-buff granular colonyMicrosporum nanumTypically 2 celled Pear or egg shapedRough walledClavate when present2 celled pear shaped macroconidia
67Definitions and Nomenclature http://labmed. ucsf Definitions and Nomenclature otheciaAnamorphAsexual or "imperfect" form of a fungus; for example, Scedosporium apiospermum is the anamorphic form of the teleomorph Pseudallescheria boydiiArthroconidiaConidia arising from pre-existing cells in the mycelium; adjacent cells collapse to release the mature form; see, for example, Geotrichum and Coccidioidomycosis
68AscosporeSexual spore produced in a sac-like structure called an ascusBlastoconidiaOne of three types of vegetative "spore" arising directly from the vegetative mycelium; budding form, e.g. seen in yeastsChlamydoconidiaConidia arising from pre-existent cells in the hyphae, which thicken and enlarge; may be intercalary, sessile, or terminalColumellaThe swollen, dome-shaped tip of a sporangiophore that extends into the sporangium
69Conidia(singular conidium) Asexual "spores" of fungusConidiophoreSpecialized hyphal element bearing conidiaHolomorphTaxonomic name including teleomorphic and anamorphic forms of a fungus; the name of the teleomorph also serves as the name of the holomorphHyphae(singular hypha) The fundamental, threadlike structure of moldsMetula(plural metulae) Structure below the phialide in some Penicillium and Aspergillus species; see for example Aspergillus terreus
70Mycelium(plural mycelia) The mass of filaments that constitutes the body of a mold; may be vegetative or aerial (reproductive)PhialideA conidiogenous cell that produces conidia from within its apex, which does not increase in width or length during conidiogenesisRhizoidRoot-like, branched hyphae which usually extend into growth medium; found especially in Zygomycetes. See, for example, RhizopusSporangiaA fruiting body which forms a closed sac; see, for example, Absidia , Rhizopus
71SporangiophoreA specialized hyphal element that bears the sporangiumStolonHorizontal hyphae growing along the surface of growth medium; runnerTeleomorphSexual or "perfect" form of a fungus; see Anamorph and Holomorph, above