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