Fungi of Relevance to Dentistry
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Transcript of Fungi of Relevance to Dentistry
Fungi of Relevance to Dentistry
Department ofBasic Science College of Dentistry University of Mosul
Eman A. Mustafa Fungi of Relevance to Dentistry Department of Basic
Science
College of Dentistry University of Mosul Fungi are classified in
to: 1-Yeast(unicellular) 2-Mould(filamentous fungi) 3-Dimorphic
fungi #Hyphae(singular hypha or hyphum) #Mycelium(mass of hyphae
that form the mould colony) #Mould (multicellular form have
filaments separated by cross wall (septa)which divide the hyphae)
thus forming multicelular type of structure. #Pseudomycelium of
C.albicans appear under semianaerobic conditions and consist of
elongated cells that may remain end to end in chain. . Yeasts
SELECTED GENERA Candida Cryptococcus Department of Basic Science
College of Dentistry University of Mosul
Candida albicans in oral cavity: *Yeastof the genus candida are the
most important fungal pathogen in the oral cavity *Yeast are
unicellular ,oval or spherical organisms. 2 -5 in diameter ,stain
positively by gram method .Most yeast develop pseudohyphae (chains
of elongatedbudding cells devoid of septa). *Candida is a commensal
organisms found in 40-80% of normal humans, and is present in the
mouth ,gut and vagina. *The predominantfungi isolated from human
mouth belong to the genus Candida while there are more than 350
Candida species approximately 10 of these colonize the oral cavity.
More than 90 of yeast infectionsare caused by C albicansCandida is
found in the mouth of of healthy people . . . Department of Basic
Science
College of Dentistry University of Mosul . Several species in the
genus Candida are found in humans including C. albicans C.
tropicalis C. krusei C. laborata but C. albicans is responsible for
majority of infections. . Department of Basic Science
College of Dentistry University of Mosul Characteristics: Candida
albicans typically grows as spherical to oval budding yeast cell, 3
-5 in size, these are also called blastospore. Candida albicans is
adimorphic fungus ,it can take two forms ,most of time it exist as
oval ,single yeast cells which reproduce by budding, but under
physiological conditionsit may develop in to hyphal form .
Department of Basic Science
College of Dentistry University of Mosul Culture and
Identification: * Cultures grow on sabouraud medium as a
creamywhite colonies that have a yeasty odor . Department of Basic
Science
College of Dentistry University of Mosul *Candida albicansand
C.dubliniens ismay be differentiated from Candida species by their
ability to producegerm tubes and chlamydospore. Department of Basic
Science
College of Dentistry University of Mosul Germ tubes: When yeast
cell are incubate for 3hrs. at 37 in serum both C.albicans and
C.dubliniensisform germ tubes Department of Basic Science
College of Dentistry University of Mosul *Both C.albicans and
C.dubliniensis form round ,thick , wall resting structures called
chlamydospores ,when incubated at 22 _25 with degreased O2on an
nutritionally poor medium(corn meal agar). Department of Basic
Science
College of Dentistry University of Mosul Blastospore and
Chlaymdospore of C. albicanis Differential diagnosis of candida
species
Department ofBasic Science College of Dentistry University of Mosul
Differential diagnosis of candida species Lactose Sucrose Maltose
Glucose - A AG C. albicans C. tropicalis C.pseudotropicalis C.
krusei C. dubliniensis Diagnoses 1. Demonstration of yeasts in
Gram-stained smear, followed
by culture of specimen on Sabouraud agar. 2. Serology or novel
PCR-based molecular methods or blood culture (in suspected
candidaemia) are helpful in the diagnosis of disseminated
candidiasis. 3. Histopathological examination of a biopsy of the
lesion . Department of Basic Science
College of Dentistry University of Mosul C.albicans possesses a
number virulent attributes, including #The ability to adhere to
host tissue and prostheses(e.g.denture) # The ability to form
hyphae that help in tissue invasion. #The potential to switch (e.g.
roughto smooth colony formation and modify the surface antigen.
#The production of extracellularphospholipase and proteinase(which
appear to breakdown physical defense barriers of the host.
Department of Basic Science
College of Dentistry University of Mosul Pathogenicity: Superficial
candidiasis. 1-Mucosal infection. Thrush on buccal mucosa and
vagina, other, manifestation include Erythematous and hyperplastic
candidiasis . 2-Skin infection. 3-Nappy rash in children may be
caused by C. albicans derived from the lower gastrointestinal
tract. 4-Candidal paronychia. Is a colonized inflammation aroundand
under the nails. Department of Basic Science
College of Dentistry University of Mosul Department of Basic
Science
College of Dentistry University of Mosul Mucocutaneous Candidiasis:
Involve both skin and oral and /or vaginal mucosa. Systemic or deep
Candidiasis: This may involve ,the lower respiratory tract,
meninges , bone, kidney and eye is common. Department of Basic
Science
College of Dentistry University of Mosul Oral infections Included
among the oralcandidal infections arethrush hyperplastic
candidiasiserythematous, denture stomatitis. Department of Basic
Science
College of Dentistry University of Mosul Thrush or pseudomembranous
candidiasis: Characterized by white membranes on the surface of
oral mucosa ,tongue and else where. It can easily removed by
wiping. Department of Basic Science
College of Dentistry University of Mosul Hyper plastic Candidiasis
or Candida leucoplakia : The lesion present as chronic discrete
raised areas vary from small translucent ,whitishareasto large
denseopaque plaques. Department of Basic Science
College of Dentistry University of Mosul May be the most under
diagnosedand misdiagnosed oral manifestation of HIV disease. The
clinical presentation is one or more asymptomatic erythematous
areasgenerally on the dorsum of the tongue ,palateor buccal mucosa.
Erythematous: Department of Basic Science
College of Dentistry University of Mosul Median rhomboid glossitis.
Characterized by an area of pappillryatrophy which is rhomboid in
shape ,present centrally at the mid line of the tongue. Department
of Basic Science
College of Dentistry University of Mosul Angular Stomatitis Angular
stomatitis or chellitis: Present as erythema or fissuring of the
corners of the mouth. Department of Basic Science
College of Dentistry University of Mosul Denture Stomatitis The
characteristic presenting signs are erythemaand odema of the mucosa
that is contact with the fitting surface of the upper denture
Department of Basic Science
College of Dentistry University of Mosul Treatment: Candida
infections can be treated by 3 main groups of agents, depending on
the type and sensitivity of infection. # The polyenes(Nystatin or
amphotericin)very effective for oral Candidal #The DNA analogues.
#Azole agent( fluconazole) effective for both superficial and
systemic mycoses Department of Basic Science
College of Dentistry University of Mosul Oral lesions due to fungi
other than Candida are rare Such as: 1-Cryptococcosis caused by
Cryptococcus neoformans,isa budding yeast with thick capsule 5-15
in diameter, identification by sputum and spinalfluid culture on
SAB agar ,India ink preparation of spinal fluid are used in the
demonstrationof endocapsulatedyeastwhich appear as translucent
haloes. Department of Basic Science
College of Dentistry University of Mosul Cryptococcosis A sub-acute
or chronic infectionwhich may affect the lungs(cause an influenza
like syndrome or pneumomia but most commonly manifests as
ameningitis Department of Basic Science
College of Dentistry University of Mosul Serological Tests
Cryptococcosis #Indirect fluorescent antibody # Latex
Agglutination(is used to detect the poly saccharide Ag) in
urine,blood or spinal fluid. Department of Basic Science
College of Dentistry University of Mosul 2-Histoplasmosis caused by
Histoplasma capsulatum. And 3-penicillosiscaused by Penicillium
marneffei.,may be seen in HIV disease and usually respondto
intravenous amphotericin therapy. Department of Basic Science
College of Dentistry University of Mosul Thank you