36 Microsporum* Rahul Sharma and Yvonne Gräser Contents 36.1 . Introduction...................................................................................................................................................................... 285 36.1.1. Classification,.Morphology,.Biology,.and.Epidemiology..................................................................................... 287 36.1.1.1. Classification..........................................................................................................................................287 36.1.1.2. Morphology............................................................................................................................................288 36.1.1.3. Biology.and.Epidemiology.....................................................................................................................289 36.1.2. Clinical.Features.and.Pathogenesis......................................................................................................................290 36.1.2.1. Clinical.Features....................................................................................................................................290 36.1.2.2. Pathogenesis...........................................................................................................................................290 36.1.3. Diagnosis.............................................................................................................................................................. 291 36.1.3.1. Conventional.Techniques....................................................................................................................... 291 36.1.3.2. Molecular.Techniques............................................................................................................................291 36.2. Methods............................................................................................................................................................................ 292 36.2.1. Sample.Preparation...............................................................................................................................................292 36.2.1.1. DNA.Extraction.from.Fungal.Colony....................................................................................................292 36.2.1.2. DNA.Extraction.from.Clinical.Specimen..............................................................................................293 36.2.2. Detection.Procedures............................................................................................................................................293 36.2.2.1. Species.Recognition...............................................................................................................................293 36.2.2.2. Strain.Typing..........................................................................................................................................293 36.3. Conclusions.and.Future.Perspectives............................................................................................................................... 295 Acknowledgments......................................................................................................................................................................295 References..................................................................................................................................................................................295 36.1 introdUCtion phytes—plants);.the.other.two.are.Trichophyton.Malmsten5. and.Epidermophyton.Sabouraud6. first.described.in.1845.and. More . has. been. written. about. ringworm. than. any. other. 1910,.respectively..The.name.Microsporum.refers.to.numer- mycotic.disease.of.animals.and.man.and.for.no.other.myco- sis.is.the.older.literature.more.confused. ous.micro-arthrospores.covering.formed.during.its.(ectothrix. type).growth.on.hair.surface.unlike.Trichophyton.that.grows. 1 G.C. Ainsworth and P.K.C. Austwick, 1973 inside.hair.shaft. The.similarity.among.these.dermatophytic.genera.extends. The .above.quote.was.written.when.polymerase.chain.reac- to.their.nutritional.requirement,.which.is.mainly.keratin7. that. tion.(PCR)-based.molecular.methods.have.not.yet.arrived. forms.exoskeleton.covering.in.three.groups.of.higher.verte- at.the.fungal.taxonomic.scene.and.especially.for.mycolo- brates,.i.e.,.birds,.reptiles,.and.mammals..Their.keratinolytic. gists’.studying.dermatophytes..The.PCR.technology.as.we. nature.itself.suggests.that.they.originated.when.life.came.to. know.now.was.only.available.when.Kary.B..Mullis.made. land. from. water. because. aquatic. vertebrates. (e.g.,. whales). a.breakthrough.of.amplifying.DNA.in.vitro,2. and.2.years. lack.exoskeleton.adnexes.like.hair,.feather,.hooves,.which.are. later.the.use.of.thermostable.polymerase3. made.the.whole. primarily.made.of.keratin.and.we.don’t.have.Microsporum. process.automated,.which.revolutionized.biological.inves- (or.other.dermatophyte),.which.is.aquatic.(marine).in.nature. tigations.. This. single. method. has. undoubtedly. had. more. because.it.has.been.shown.that.growth.of.human.pathogenic. application. in. biology. today. than. any. other. technique. in. fungi.(including.dermatophyte.M. gypseum).is.inhibited.by. whole. of. biological. sciences. including. diagnosing. human. high.salt.concentrations.8. Also,.rhexolytic.dehiscence.mech- fungal.infections. anism.is.found.among.fungi.that.have.dry.spores.as.in.all. The. genus. Microsporum. established. by. Gruby. in. 18434. Microsporum. species. (and. not. in. mucilaginous. mass. as. in. was.the.first.genus.to.be.described.among.the.three.genera. Fusarium.spp.,.which.form.blastospores)..Among.the.three. commonly. referred. to. as. dermatophytes. (dermal—skin;. dermatophytic.genera,.Microsporum.is.well.adapted.to.soil. *. The.authors.dedicate.this.chapter.to.Prof..Libero.Ajello,.the.man.who.knew.so.well.the.natural.history.of.dermatophytes. 285 © 2011 by Taylor & Francis Group, LLC 286 Molecular Detection of Human Fungal Pathogens as .(except.a.few.that.have.newly.evolved.as.anthropophilic. dermatophytes.. The. gene(s). responsible. for. triggering. or. species).its.entire.species.produce.macroconidia,.which.have. inhibiting.the..production.of.macroconidia.and.the.extent.of. rough.surfaces.unlike.their.Trichophyton.counterparts. this.inactivation.in.anthropophiles.is.yet.to.be.investigated.. The.member.of.the.genus.can.be.grouped.on.the.basis. It.is.seen.in.agar.or.hair.cultures.of.dermatophytes.that.the. of.ecological.preference.as.geophilic.(saprophytes.in.soil),. fungus.forms.spores.once.the.nutrients.are.depleted.(this.is. zoophilic. (adapted. to. lower. animals),. or. anthropophilic. true. for. the. formation. of. sexual. stages,. i.e.,. sexual. repro- (adapted.to.human).9. These.ecological.groupings.of.various. duction. and. formation. of. ascomata. as. in. Takashio. dilute. species.are.reflected.in.the.phylogenetic.clusters.obtained.by. Sabouraud.agar20) .and.the.phenomenon.is.not.uncommon.in. mtDNA10. and.rDNA.studies.11. This.suggests.that.they.all.were. wide.range.of.fungi..Once.a.fungus.gets.human.skin.(which. previously.soil.dwellers.and.used.to.thrive.on.shed.keratin.. is. still. attached. to. human. body),. it. can. ideally. grow. over. Close.or.direct.contact.with.live.animals.and.later.humans. its.whole.body,.but.due.to.variable.microenvironment.and. made. them. well. adapted. to. their. zoophilic. and. anthropo- medical.arrangements,.the.fungus.is.prevented.from.spread- philic.lifestyle,.respectively..Also,.the.anthropophilic.mem- ing.and.mostly.controlled;.however,.severe.cases.are.often. bers.(M. ferrugineum.and.M. audouinii).must.have.evolved. reported.when.no.medical.treatment.is.done.or.due.to.altered. along. with. Homo sapiens. (modern. human),. which. have. microclimate.(caused.by.drugs.or.reduced.inherent.immu- sparse. hairs. on. their. body. unlike. its. earlier. hominid. viz.. nity)..Human.skin.is.like.a.continuous.culture.with.regular. Australopithecus afarensis,.Homo habilis.or.related.primate. supply.of.fresh.keratin.from.beneath..The.fungus.anchors.its. like.ancestors..This.hypothesis.needs.further.investigation. mycelia.with.the.fresh.integument.by.spreading.radial.in.a. with.right.molecular.marker.and.algorithm,12,13. which.could. ring-like.fashion.(hence,.the.popular.term.ringworm.coined. precisely.date.and.calibrate.the.divergence.of.M. canis.into. by.Anglo-Saxon.ancestors.in.sixteenth.century),9. and.thus. sibling.species.M. auduoinii.in.Africa.and.M. ferrugineum. ensuring.its.survival.on host. in.East.Asia.to.superimpose.precisely.with.the.divergence. Africa.is.thought.to.be.the.center.of.origin.of.Homo sapi- of.Homo sapiens.from.Africa.to.East.Asia..One.theory.sug- ens. based. on. the. available. evidence.21. Ancestral. dermato- gests.that.modern.Homo sapiens.developed.relatively.hair- phytes.including.young.anthropophiles.also.might.have.their. less.bodies.to.evade.parasites14. which.certainly.would.have. origin.in.Africa.22.f sI .this.i .true,.then.the.separation.of.two. included.dermatophytic.fungi..For.adaptation.to.this.altered. lineage.to.become.distinct.species.of.the.M. canis.clade.after. trait.of.nakedness15.n i .humans,.the.evolving.dermatophytes. early.humans.moved.“out.of.Africa”.to.Southeast.Asia23,24. (geophiles.>.zoophiles.>.anthropophiles).that.produce.mac- is.probable,.thereby.causing.allopatric.speciation25. resulting. roconidia.for.transmission,.slowly.lost.their.ability.by.natural.