DEPARTMENT OF BIOLOGICAL SCIENCES REDEEMER’S UNIVERSITY MCB 313 PATHOGENIC MYCOLOGY DURUGBO ERNEST UZODIMMA (Ph.D.) COURSE OUTLINE

1. Introduction 2. Structure, reproduction and classification of pathogenic Fungi Eg. , Trichphyton spp., Tinea spp., 3.Superficial systematic mycoses and antimycoses 4. Fungal infections ( , etc) 5. Laboratory methods of study 5. Pathology and immunology 6. Cultivation techniques in Mycology Structure, Reproduction and Classification of Pathogenic Fungi About 30% of the 100,000 known species of Fungi make a living as parasites, or pathogens , mostly of plants. E. g Cryphonectria parasitica, the Ascomycete causes chestnut blight. Fusarium circinatum causes pith pine canker a diseae that threatens pine worldwide. Puccinia graminis causes black stem rust of wheat. Some of the fungi that attack food crops are toxic to humans for example certain species of the ascomycete Aspergillus contaminate improperly stored grain and peanuts by secreting aflatoxins which are carcinogenic. The ascomycete Claviceps purpurea which grows on rye plants forming purple structures called ergots. If diseased rye is milled into flour and consumed it causes ergotism, a condition characterized by gangrene, nervous spasms, burning sensations, hallucinations, and temporary insanity. An epidemic of this around 944 C.E, killed more than 40,000 people in France. Animals are much less susceptible to parasitic fungi than plants. Only about 50 species of fungi are known to parasitize humans and animals . Such fungal infections are . Skin mycoses includes ringworm. The ascomycetes that causes ringworm can infect almost any skin surface. Most commonly, they grow on the feet, causing the intense itching and blisters known as athlete ’s foot. These diseases are highly contagious but can be treated with fungicidal lotions and powders. Systemic mycoses spread through the body and usually cause very serious illnesses. They are typically caused by inhaled spores eg is a systemic mycosis that produces symptoms similar to tuberculosis in the lungs. Some mycosis are opportunistic occurring only when there is a change in the body ’s microbiology, biochemistry, or chemistry e. g a normal inhabitant of the epithelia such as the vaginal lining can grow too rapidly like a newly pregnant woman and become pathogenic leading to infections. Due to the spread of AIDS, in recent times many other opportunistic mycosis have become common due to reduced (compromised) immune systems. 1. Structure, Reproduction and classification of some Pathogenic fungi

Piedra (Beigels ’ disease) White also called Beigel ’s disease or Chignon disease is a fungal of the scalp, beard, pubis, moustache. It is characterized by a soft, grayish, noodle-shaped structures of variable consistency arranged in rows of the shaft to which they adhere. It is caused by a filamentous yeast Trichosporum beigelli that forms blastospores and arthrospores, hyphae and pseudo-hyphae. It is mostly found in young adults of both sexes. A predisposing factor is the development of pubic features. It is readily curable. Diagnosis : It is made by observing the presence of irregular white soft noodles along the hair. Treatment: The simplest method of treatment is by shaving. The application of various topical agents especially 5% salicyclic acid or 1% iodine. Description: White piedra is a superficial cosmetic fungal infection of the hair shaft caused by beigelii . Infected develop soft greyish-white nodules along the shaft. Essentially no pathological changes are elicited. White piedra is found worldwide, but is most common in tropical or subtropical regions. Clinical manifestations : Infections are usually localised to the axilla or scalp but may also be seen on facial hairs and sometimes pubic hair. White piedra is common in young adults. The presence of irregular, soft, white or light brown nodules, 1.0-1.5 mm in length, firmly adhering to the hairs is characteristic of white piedra. Laboratory diagnosis : 1. Clinical Material: Epilated hairs with white soft nodules present on the shaft. 2. Direct Microscopy: Hairs should be examined using 10% KOH and Parker ink or calcofluor white mounts. Look for irregular, soft, white or light brown nodules, 1.0-1.5 mm in length, firmly adhering to the hairs . 3. Culture: Hair fragments should be implanted onto primary isolation media, like Sabouraud's dextrose agar. Colonies of are white or yellowish to deep cream colored, smooth, wrinkled, velvety, dull colonies with a mycelial fringe. 4. Serology: Not required for diagnosis. 5. Identification: Characteristic clinical, microscopic and culture features. Causative agents: Trichosporon beigelii Management: Shaving the hairs is the simplest method of treatment. Topical application of an imidazole agent may be used to prevent reinfection. Again, the application of various topical agents especially 5% salicyclic acid or 1% iodine. )Types of ringworm infections named according to site of body • ……………………… .ringworm infection of the hair, scalp., eyebrows (lashes) • ……………………… smooth body •Tinea manum ……………………… hand •Tinea pedis …………………… foot • ……………………… groin • ……………………… beard •Tinea unguium ……………………… nails •Tinea tavosa ……………………… scalp (mostly hair) are made up of closely related filamentous fungi that infect superficial keratinized tissues of the skin, hair, and nails. The clinical feature they produce is collectively called or ring worm or tinea .

Classification of dermatophytes based on habitat •Anthropophilic • ii) iii) rubrum iv) T. violaceum v) T. tonsurans •Zoophilic • ii) M. nanum iii) Trichophyton mentagrophyte iv) T. verrucosum •Geophilic •Microsporum gypseum ii) Trichophyton ajelloi Sources of ringworm infection •Schools ii) prisons iii) Military camps iv) Warm damp areas like the tropics, moisture accumulation on the clothes and shoes v)Animals such as cats, dogs, cattle, poultry etc. The Main genera of dermatophytes i) Epidermophyton ii) Trichophyton iii) Microsporum

Superficial mycosis refers to infections of the skin and appendages Deep mycosis includes the subcutaneous and systemic mycosis which constitutes the infection of deeper tissues and visceral organs. The Cutaneous and Superficial Mycoses CONDITION COMMON NAME LOCATION ON BODY MAJOR SYMPTOM Tinea corporis ringworm any skin surface except scalp, flaky sores with wellfeet, and male facial areas defined ring shapes Tinea capitis cradle cap scalp scaly, swollen blisters or rash of “black dots” Tinea cruris jock itch genitals, buttocks, and inner raised red sores with thighs well-defined edges Tinea unguium nail fungus nail bed of toes and rarely thickened, discolored fingers nail Tinea pedis athlete’s foot toes and soles of feet red flaky rash Piedraia hortai Black piedra scalp hair hair loss from broken hair shafts Trichosporon White piedra pubic, beard, eyebrow, and hair loss from broken beigelii eyelash hair hair shafts ——— any skin surface red flaky patches ——— any skin surface red flaky patches Tinea pedis (ATHLETE ’S FOOT INFECTION) The infection occurs between the toes or toe which produces a clear fluid most of the time. The 4th and 5th toes are always infected. It brings soreness and itching Mode of transmission They are probably transmitted from host to host through infected materials. There are three causal agents •T. rubrum - the source of the inoculums crosses from people with chronic infections because the fungus is not long lived. •T. mentagrophyte and Epidermophyton floccosum - This source of inoculum comes from long lived arthospores that resides in rugs and carpets. There are three grades of infection Grade 1: subclinical and itching between the toe, skin may be soft and macerated, blisters may occur Treatment: keeping feet dry and clean, drying between the toes lightly each time you bath, application of fungicides or ointment. Grade 2: the host at this level is conscious of burning sensation while walking or standing . Treatment: Use of topical fungicides, dusting powder to keep the feet dry, by the removal of clear liquid from the blisters. Grade 3: Here the problem is compounded by a secondary bacterial infection; Treatment: i) Go to bed ii) The use of systemic antibiotics to fight the bacterial infections iii) use of chemicals as soak iv) the persistent cases normally those by T. rubrum , the use of systemic griseofulvin therapy or other systematic drugs. Athletes feet showing blisters in between the toes Treatment & Management Onychomycosis, also known as tinea unguium , is a fungal infection of the nail. This condition may affect toenails or fingernails, but toenail infections are particularly common. Treatment may be based on the signs. Treatment may be with the medication terbinafine. Treatment of onychomycosis depends on the clinical type of the onychomycosis, the number of affected nails, and the severity of nail involvement.. Topical The use of topical agents should be limited to cases involving less than half of the distal nail plate or for patients unable to tolerate systemic treatment. Agents available in the United States include ciclopirox olamine 8% and efinaconazole 10% nail solutions. Amorolfine and bifonazole/urea are available outside of the United States. Tavaborole, a topical oxaborole antifungal (boron-containing compound) is indicated for onychomycosis of the toenails due to or Trichophyton mentagrophytes . The newer generation of oral antifungal agents (itraconazole and terbinafine) has replaced older therapies in the treatment of onychomycosis “Distal subungual onychomycosis ." Starts at the ends of the nails and raises the nail up : This is called "distal subungual onychomycosis ." It is the most common type of fungal infection of the nails in both adults and children (90% of cases). It is more common in the toes than the fingers, and the great toe is usually the first one to be affected. Risk factors include older age, swimming, athlete's foot, psoriasis , diabetes , family members with the infection, or a suppressed immune system. It usually starts as a discolored area at a corner of the big toe and slowly spreads toward the cuticle. Eventually, the toenails will become thickened and flaky. Sometimes, you can also see signs of athlete's foot in between the toes or skin peeling on the sole of the foot. It is often accompanied by onycholysis. The most common cause is T. rubrum . “Proximal subungual onychomycosis." Starts at the base of the nail and raises the nail up : This is the least common type of fungal nail (about 3% of cases). It is similar to the distal type, but it starts at the cuticle (base of the nail) and slowly spreads toward the nail tip. This type almost always occurs in people with a damaged immune system. It is rare to see debris under the tip of the nail with this condition, unlike distal subungual onychomycosis. The most common cause is T. rubrum and non- . Yeast onychomycosis : This type is caused by a yeast called Candida and not by the Trichophyton fungus .It is more common in fingernails and is a common cause of fungal fingernails. Patients may have associated (infection of the cuticle). Candida can cause yellow, brown, white, or thickened nails. Some people who have this infection also have yeast in their mouth or have a chronic paronychia that is also infected with yeast.

Tinea corporis Tinea corporis refers to ringworm infection of the smooth skin. It is restricted to the stratum corneum on the smooth skin. The disease is found throughout the world. The symptoms results from fungi metabolites such as toxins and allergies. It produces concentric or ring like lesions and in severe cases the lesions are raised and may become inflamed. All forms of T. corporis are caused by T. rubrum, T. tonsurans, M. canis, M. audouinii are treatable with topical agents can toluaflate, ketoconazole, miconazole etc. The disease is transmitted through infected scale hyphae or arthroconidia and the skin . It is also transmitted through direct contact between infected humans or animals, formites (any agent such as bedding or clothing capable of retaining a pathogen and transmitting into a new host). Can also be transferred from one area of the body to another. Finally T. corporis normally resolves itself in several months.

A typical example of tinea corporis is shown here. Note the circular nature of the infection; hence the common name for the condition, ringworm. Tinea capitis or cradle cap appears most often in children. An abnormally itchy scalp is the most common symptom. Balding patches, as seen here, usually confirm the diagnosis. A case of nail fungus, though cosmetically unappealing, is painless and harmless. It is also quite challenging to cure and can take several months of using topical over-the-counter drugs to treat the condition. The fungus furfur can cause blotches on the skin known as tinea versicolor. While this infection looks bad, like all of the superficial mycoses, it seldom threatens the patient’s health and usually clears up on its own. Prevention and treatment of ringworm infections i) The best way to cope with any of the tineas is prevention, and the key to that is good personal hygiene. ii) Damp, humid, and dirty conditions are just what these fungi are looking for, and so avoiding these conditions goes a long way toward keeping you healthy and itch free. iii) Whenever you shower or bathe, make sure to dry extra carefully between your fingers and toes and your genital area. iv) Don’t share towels, and don’t go around barefoot in locker rooms or public showers—wear some waterproof sandals instead. v) when you do have to wear shoes, you should change socks regularly, vi) Apply some kind of absorbent powder, vii) Keep your nails clipped short to keep them from trapping any moisture under them. viii) Wear loose clothing especially during sporting events and use styling gels sparingly (which slow the evaporation of sweat from your head and trap its moisture there) to keep your skin and hair cool and dry. ix) Tightly braided hair also traps moisture against your head, x) Do not immerse your bare hands in water for prolonged periods can as this expose your skin to too much moisture. is a common yeast found everywhere in the world. Normally a simple saprobe, it lives in the soil decomposing various animal matter and releasing excess nutrients back into the environment. Hence, we might assume that like A. fumigatus and A. flavus, this yeast simply enters through the lungs from disturbed soil, where it would produce similar symptoms. But C. neoformans has a unique physical feature that makes it slightly different from the other pathogenic fungi . i) Each cell of this yeast encases itself in a tough protective capsule made up of acidic starch molecules. None of the other infectious fungi have this acidic layer as part of their spore, making C. neoformans unique from the others in three important ways. First, because of the acidic layer, this fungus can infect people who do not have weakened or stressed immune system. The acidic molecules alter the pH of the blood, hindering the metabolism of the immune cells and slowing down their ability to attack the fungus’ cells. Hence, C. neoformans is the only opportunistic fungus which can occasionally make healthy people sick, too. Second, the acidic layer prevents the fungus from transforming into a form which can generate a biofilm. Third, it enables the disease to spread and to infect people via a carrier rather than only through direct contact with soil. Therefore, cryptococcosis is easier to catch because there are more ways to come into contact with it. The carriers turn out to be birds—especially pigeons —and it is worth taking a moment to explore why. Because birds do not have teeth, they have had to evolve another method for “chewing” their food to grind it up. What they do is eat small bits of earth and tiny stones to store in an organ called the “gizzard.”Here, the stones act just like the millstones people use to grind wheat into flour. Any food a bird eats gets mixed with the hard minerals from the dirt which then mash the food into digestible pulp. But along with the bits of rock found in the soil, the birds are obviously consuming the microbes living there as well. Their digestive juices kill most of these. But the acidic layer of C. neoformans protects it, and the yeast flourish on the food remnants. As a result, the fungus gets concentrated in a bird’s feces, making bird droppings the number one source for this disease. Mere contact with bird droppings, however, does not automatically produce cryptococcosis. A person does have to inhale the spores, and the spores have to survive long enough to infect. In healthy individuals, only between 0.4 and 1.3 out of 100,000 people who come into contact with the yeast contract the condition annually. This number is much higher among AIDS victims where between 2 and 7 out of every 1,000 patients gets the disease. But even in these individuals, the disease does not begin to attack the body as severely as can. Consequently, cryptococcosis only has a 12% mortality rate. Unlike other opportunistic fungi, C. neoformans produces almost no symptoms of any kind while in the lungs. It is not until the yeast makes it through the blood barrier and into the central nervous system that the patient begins to feel its effects. Once inside the spinal column, the fungus attacks the meninges, the tough layer of membranes protecting the spinal cord and the brain. Its outside acidic layer alters the pH of the spinal column’s environment, inhibiting the cells there from metabolizing correctly, and then the fungus bombards the body’s cells with digestive enzymes to feed itself, killing off the meninges, causing . As it reproduces and spreads, the fungus eventually penetrates into the nerve tissue of the spinal cord and brain. There, it can kill off whole chunks of the central nervous system. Brain abscesses and permanent neurological damage are common even when treated in time. Medical science has only a couple of “advantages” over cryptococcosis that it does not have over the other opportunistic infections. But they are important ones. The first advantage is that meningitis, unlike flu-like diseases, comes on rapidly and has very limited causes. The bacterial form of it responds within a day or two to treatment. The viral form produces slightly different symptoms. Thus, the fungal form gets diagnosed with a higher rate of accuracy than other opportunistic fungus infections. This allows for proper treatment to begin sooner. Furthermore, because the encapsulated yeast cannot form a biofilm, medicines can attack it more directly. It is therefore easier to kill, and even in the 7% to 10% of AIDS patients who catch this form of meningitis, there is a relatively high rate of recovery. Again, though, recovery does not mean undamaged.Most people who suffer from this leading cause of do not come out of it unscathed. Permanent speech impediments and loss of coordinated muscle control are not uncommon. C. neoformans has a different pathology from the rest of the opportunistic fungi. Here, one of the encapsulated yeast (dark circles with light rings around them) is budding. These budding yeast will use the acidic capsule layer on the outside (the light rings) to kill lung cells for food. Note the cleared areas around each yeast cell on the microscope picture where this process has already happened. The cells in this micrograph have been magnified 160 times. HISTOPLASMOSIS Histoplasmosis is the single most common respiratory fungal infection in the world. Sometimes called “spelunker’s disease” because of its association with bats and caves, its causative agent, , is found everywhere except the polar regions. But the fungus is most endemic in the central and eastern United States . It is so common there that 80% percent of the people who live in the Mississippi and Ohio river valleys possess antibodies against this fungus. A mold often found in bat guano (droppings) and bird droppings (mainly chickens and starlings), it likes to grow in moist, rich soil. In particular, it likes soils with high levels of nitrogen. This appetite for nitrogen, in turn, reinforces the relationship between birds, bats, and H. capsulatum. With birds, they eat the soil with the fungus in it. They then excrete nitrogen wastes in their droppings. That, of course, deposits the fungus with more of its food back in the soil where it can use the food to reproduce and increase its population. Thus, the next bird will consume larger amounts of fungi in the dirt it eats, will spread larger amounts of fungi in its droppings, and the cycle repeats. Bats, on the other hand, deposit the guano where they sleep. The drafts of wind from their wings stir up the soil and old dry guano, spreading H. capsulatum over the fresh food source. The fungi reproduce; the bats produce more guano; their flight stirs up the new fungi; and this cycle repeats as well. Because of this association with soil, birds, and bats, the mold strikes most often in those people who work with these things. Just like valley fever, construction workers and farmers are the people most at risk of infection because of their regular exposure to stirred up dirt. But individuals in the poultry industry and professional spelunkers are also at risk. Anyone working in any of these fields should use protective breathing masks. Histoplasmosis (Darling disease) It is caused by a dimorphic fungi Histoplasma capsulatum. Clinical features: i) The disease is asymptomatic in 90-95% of cases. ii) It is manifested solely by a positive histoplasmin test and by the use of lung calcification. iii) In human beings, the clinical feature is acute pulmonary histoplasmosis which starts with influenza, progresses to fever then profuse sweating, chest pain, cough etc. iv) Chronic progressive pulmonary disease which resembles the acute but remains latent in the body before it produces the same symptoms as the acute. Disseminated histoplasmosis This form may occur at any age but is seen especially in children under two years and elderly adults. Prognosis The prognosis is poor. This is manifested by variable fever, anorexia, weight loss, deterioration of the general body condition. Epidemiology The source of infection is the soil which acts as the fungi reservoir. Adult men are infected more frequently than women. In children there are no sex related differences. Transfer from human to human, or animals to human is unknown. Infection is mostly through the inhalation of spores. Laboratory diagnosis/ Sample collection Specimens of peripheral blood, sternal bone marrow, sputum, tissues from skin lesions, mucous membrane, lymph node or autopsy. All samples should be placed in sterile containers for lab examination. Smears may be made directly of blood, sputum, bone marrow or other moist specimens. Direct examination The smear is stained with Giemsa or Wright ’s stain. Under the microscope, the fungus appears as small oval yeast-like cells 1-5 µm in diameter. Recently, fluorescent antibody technique is also useful in the diagnosis of histoplasmosis in tissues. Culture The infected material is cultivated on brain heart infusion agar (BHI) and Cycloheximide and Chloramphenicol and incubated at 37 °C. Another set of BHI agar without antibiotic but with 6% blood is inoculated and incubated at 37 °C. Both cultures are examined at 3 weeks of incubation. Slides prepared from cultures grown at room temp shows septate hyphae with small (2-3µm) smooth walled round or pyriform conidia borne on short lateral hyphae or sessile on the side of the hyphae together with the large 8-15 µm diagnostic round to pyriform tuberculate chlamydospores H. capsulatum rarely invades the bloodstream through the cells lining the inside of the lungs. When it does, however, its spores use the blood as a highway to the rest of the body and colonize in blood-rich organs like the spleen and liver where it attacks their cells and can cause fatal damage Prevention is vital because when someone does inhale the mold, they run the risk of a life long infection. In the warm, damp environment of the lung, H. capsulatum turns into a small budding yeast quite similar to the fungus responsible for cryptococcosis. It consumes the cells lining the passageways of the lungs, and in 10% to 25% of infected people, the usual flu-like symptoms appear between three and 17 days later. Correct diagnosis depends on a chest x-ray, TReatment for this acute form employs the usual antifungal therapy. Yet there is no cure. Following treatment, the yeast persists in the lung for the rest of a person’s life. Symptoms can reactivate years later, and over time, permanent lung damage is possible. Furthermore, while it seldom happens, the chronic infection can become a systemic one. In infants, young children, the elderly, and the immunocompromised, H. capsulatum can penetrate into the blood stream. When that happens, the disease spreads and produces lesions in the spleen, liver, and lymph nodes and creates ulcers in the mouth. Left untreated, this version of histoplasmosis is always fatal. Blastomyces dermatitidis is a soil mold endemic to the southern United States and the Midwest but is also found in parts of Africa. It prefers to live in the extremely wet soil of river banks and flood plains. As a result, the major outbreaks of this fungus occur mainly near the Mississippi and Ohio rivers and the Great Lakes region of the United States. One to two out of every 100,000 people living in these areas (or about 0.002% of the total population) contracts the disease at some point in his or her life. Because it is so widespread in this part of the world, the condition is sometimes called “North American blastomycosis.” But, again, many cases occur along African waterways as well. Exposure to B. dermatitidis happens through inhaling of soil especially d isturbed soil, particularly from wooded lots, throws the mold into the air where people inhale it. Once inside the lungs, it turns into a budding yeast. In this case, however, the fungus spreads quickly through the blood stream to the skin (though how quickly varies dramatically from patient to patient and there is no set duration for its dissemination).1 It can produce the usual flu-like symptoms with cough and chest pains. But most often, the lung infection stage manifests nothing. Part of the reason for this is that the immune system regularly stops the disease at this acute stage. Only when B. dermatitidis makes it to the skin and forms its lesions do most people become aware of their infection. Diagnosis Doctors know that its characteristic skin lesions should lead to an x-ray of the lungs. Any mass that appears tells a doctor that the source of infection is internal rather than external. This information, in turn, should lead a doctor to culture the skin sores for B. dermatitidis. Only then can he or she make a correct diagnosis and begin the proper treatment— which, as always, is essential. This fungus can harm an untreated patient significantly. It can cause permanent damage to the lung and lead to bone disintegration and even meningitis without proper therapy. While its systemic version seldom kills (it only has a 5% mortality rate), it can cause lasting disfigurement and life long respiratory problems without the right drugs. What are the right drugs Fortunately, those suffering from most cases of blastomycosis can now take one of the oral azoles to cure the disease. However in severe cases and the immunocompromised, doctors must switch therapies and use intravenous amphotericin B.

Blastomycosis is a disease that affects the internal organs of the body. But it eventually infects so much of the body that populations of the fungus finally colonize the blood vessels near the surface of the skin, and the fungus literally starts to eat its way out, creating lesions like this one. Permanent scarring occurs regularly when the disease reaches this stage. White piedra Description: White piedra is a superficial cosmetic fungal infection of the hair shaft caused by Trichosporon beigelii . Infected hairs develop soft greyish-white nodules along the shaft. Essentially no pathological changes are elicited. White piedra is found worldwide, but is most common in tropical or subtropical regions. Clinical manifestations: Infections are usually localised to the axilla or scalp but may also be seen on facial hairs and sometimes pubic hair. White piedra is common in young adults. The presence of irregular, soft, white or light brown nodules, 1.0-1.5 mm in length, firmly adhering to the hairs is characteristic of white piedra. Laboratory diagnosis : 1. Clinical Material: Epilated hairs with white soft nodules present on the shaft. 2. Direct Microscopy: Hairs should be examined using 10% KOH and Parker ink or calcofluor white mounts. Look for irregular, soft, white or light brown nodules, 1.0-1.5 mm in length, firmly adhering to the hairs. 3. Culture: Hair fragments should be implanted onto primary isolation media, like Sabouraud's dextrose agar. Colonies of Trichosporon beigelii are white or yellowish to deep cream colored, smooth, wrinkled, velvety, dull colonies with a mycelial fringe. 4. Serology: Not required for diagnosis. Laboratory diagnosis : 1. Clinical Material: Epilated hairs with white soft nodules present on the shaft. 2. Direct Microscopy: Hairs should be examined using 10% KOH and Parker ink or calcofluor white mounts. Look for irregular, soft, white or light brown nodules, 1.0-1.5 mm in length, firmly adhering to the hairs. 3. Culture: Hair fragments should be implanted onto primary isolation media, like Sabouraud's dextrose agar. Colonies of Trichosporon beigelii are white or yellowish to deep cream colored, smooth, wrinkled, velvety, dull colonies with a mycelial fringe. 4. Serology: Not required for diagnosis. 5. Identification: Characteristic clinical, microscopic and culture features. Causative agents: Trichosporon beigelii Management: Shaving the hairs is the simplest method of treatment. Topical application of an imidazole agent may be used to prevent reinfection. CANDIDIASIS MYCOTIC INFECTIONS AND THEIR CONTROL CANDIDEMIA - DISMUKES, ET AL. 2003 Candida are small (4–6 m), oval, thin-walled yeastlike fungi that reproduce by budding or fission. The genus Candida is comprised of over 200 species and constitutes an extremely diverse yeast species whose common bond is the absence of a sexual cycle (Berkhout, 1923). Only a few species cause disease in humans (Odds, 1988). The medically significant Candida species include: Candida albicans, Candida (Torulopsis) glabrata, Candida parapsilosis, , , Candida kefyr, Candida guilliermondii, Candida lusitaniae, C. stellatoidea, and Candida dubliniensis. Candida organisms grow readily in blood culture bottles and on agar plates. In most situations, they do not require special conditions for growth. On culture media, Candida species form smooth, creamy white, glistening colonies (Rippon, 1988; Kwon-Chung and Bennett, 1992). The numerous species of Candida are easily identified on the basis of growth characteristics and commercial kits that evaluate carbohydrate assimilation and fermentation reactions and provide species identification of Candida isolates within 2–4 days. A rapid, but nonspecific identification of C. albicans can be made by testing for germ tube production. This test is performed by growing the yeast in serum at 37°C and observing for the growth of small projections from the cell wall that develop after 60–90 minutes of incubation (Odds, 1988). Candida stellatoidea and C.dubliniensis also generate germ tubes, thus eliciting false-positive results (Sullivan,1995). CHROMagar, a culture media utilized to rapidly identify many common Candida species (Pfaller et al, 1996), employs a chemical colorimetric reaction on agar that allows distinction between C. albicans, C. glabrata, C. krusei, C.tropicalis, and other non-albicans Candida species. While the other opportunistic fungi invade the body through the lungs, C. albicans and its relatives, can penetrate the body’s digestive system, invade the blood stream, and produce a systemic infection. This condition, known as candidemia, is actually the fourth most common blood disease in hospital patients. In 8 out of 100,000 immunocompromised patients, those already suffering from a yeast infection will have that infection develop into full blown candidemia. Cancer patients are particularly vulnerable, and C. albicans is the leading cause of invasive fungal infections in these individuals. Basically, anything that weakens the body’s natural barriers can set up a person for an invasive yeast infection. Surgery, burns, catheters, HIV, antibiotics—they all damage the normal defenses the body uses to protect itself. But oral antibiotics are what really set the stage among the immunocompromised for further infection. These drugs kill off the normal, healthy bacteria which inhabit the gastrointestinal tract. That makes it easier, though, for C. albicans and company to reproduce and colonize larger portions of the digestive system. To make things worse, the immunocompromised need a carbohydrate rich diet to give them the energy to heal in their weakened condition. All those carbohydrates give the yeast extra food they can use instead. Thus, between the decreased competition from the bacteria and the increased supply of nutrients, C. albicans can reproduce like crazy. The result is that almost all cases of candidemia start out as thrush infections in the gastrointestinal tract. From there, the fungi use the blood stream as their highway to the rest of the body. They form biofilms first in the blood rich organs such as the kidney, liver, heart, and spleen. They can move onto the eyes where they often rupture the retina and cause blindness. If left untreated, the yeast will eventually establish biofilms in the central nervous system, the marrow of the bone, the joints, and the lining of the lungs. At this stage, mortality is around 50%, and even with recovery, the damage to all these critical organs leaves a patient severely endangered. Whatever pathogen attacks next will have an easier time, which is why even if candidemia does not kill someone directly, it often starts them down the path toward death anyway.

Most cases of thrush first appear on the back of the tongue and in the oral pharynx region. In the immunocompromised, C. albicans expands into the esophagus where it can more readily penetrate into the blood stream. When this happens, the patient will then develop a case of candidemia (Brock, 2006). Candida albicans (Robin) remains the major fungal pathogen of man and the most common cause of mucosal and systemic fungal infection (Pfaller, 2001), and is the best characterized of the Candida species (Odds, 1994). (Anderson) Meyer and Yarrow, 1978 has become important because of its increasing incidence worldwide and decreased susceptibility to antifungals. Its emergence is largely due to an increased immunocompromised patient population and widespread use of antifungal drugs (Fidel et al, 1999; Gumbo et al, 1999). In the most recent Trial data, C. glabrata emerged as the second most common cause of candidemia following C. albicans (Pfaller, 2001). Candida parapsilosis (Ashford) Camargo, 1934 , C. brumpti, Langeron and Guerra, 1935) in most parts of the world is the third most common cause of candidemia (Pfaller et al, 2001), especially in patients with intravenous catheters, prosthetic devices, and intravenous drug use (Girmenia et al, 1996; Levy et al,1998). Candida parapsilosis is one of the most common causes of candidemia in neonatal intensive care units (Levy et al, 1998). This species produces slime as a virulence factor enabling it to adhere to environmental surfaces and skin of hospital personnel (Sanchez et al, 1993; Girmenia et al, 1996). Candida tropicalis (Castellani) is the third or fourth most commonly recovered Candida species from blood cultures (Pfaller et al, 2001). Leukemia, prolonged neutropenia, and prolonged intensive care unit (ICU) days are major risk factors for C. tropicalis candidemia (Kontoyiannis et al, 2001). Candida krusei (Castellani) is the fifth most common bloodstream isolate. Although less common (1%–2%), C. krusei is of clinical significance because of its intrinsic resistance to fluconazole, and reduced susceptibility to most other antifungal drugs (Pfaller et al, 2001). . Candida krusei is frequently recovered from patients with hematological malignancies complicated by neutropenia (Merz et al, 1986; Wingard et al, 1991; Abbas et al, 2000), and tends to be associated with higher mortality rates (49% vs. 28% with C. albicans), and lower response rates (51% vs. 69% with C. albicans). Candida kefyr (Beijerinck) van Uden et Buckley, 1970 is a rare species that occasionally causes disease in immunocompromised host (Hazen, 1995). Candida guilliermondii (Castellani) Langeron et Guerra, 1938 is another rare species. While infections due to C. guillermondii are uncommon, candidemia and invasive disease in the neutropenic host (Vazquez et al, 1995) are reported occasionally as is endocarditis in intravenous drug addicts. Candida lusitaniae van Uden et do Carmo-Sousa, 1959 ,Although uncommon ( 1%– 2%), C. lusitaniae is of clinical importance because of intrinsic or secondary resistance acquisition to amphotericin B (Hazen, 1995; Yoon et al, 1999) and is typically found in patients with hematological malignancies and patients in intensive care units (Sanchez et al, 1992;Hazen, 1995). Candida stellatoidea (Jones and Martin, 1938) is closely related to C. albicans (Bodey et al, 1993), by producing germ tubes in vitro , a morphologic characteristic seen only in C. albicans and some C. dubliniensis strains (Sullivan et al, 1995). C. stellatoidea is a heterogeneous species with at least two confirmed subtypes, subtype I and II (Kwon-Chung et al, 1989). Type I differs from C. albicans in several genetic characteristics and is not considered a mutant of C. albicans. Type II C. stellatoidea is a sucrosenegative mutant of C. albicans serotype A (Kwon-Chung et al, 1990). Additionally, type II isolates appear to have lower virulence and are slower growers than either type I C. stellatoidea or C. albicans (Kwon-Chung et al, 1988; Kwon-Chung et al, 1989; Rikkerink et al, 1990). Candida dubliniensis is a recently identified species of Candida, previously hidden among the germ tube positive strains of C. albicans. Identified initially from the oral cavity of HIV-positive patients (Sullivan and Coleman, 1998), C. dubliniensis has been recovered from HIV-positive patients throughout the world at rates ranging from 19% to 32% (Sullivan and Coleman,1998), has also been recovered from 3% to 14% of oral cavities of HIV-negative individuals, and rarely is associated with candidemia or invasive disease (Hidalgo et al, 2000). However, recently Candida dubliniensis was recovered from 14 patients with either solid organ or hematological malignancies (Sebti et al, 2001). C. dubliniensis is identified by germ tube and chlamydospore production, by an inability to grow at 45°C, and occasionally by a specific colony color on CHROMagar Candida medium (Pfaller et al,1996). This species can also be identified easily using commercially available yeast identification kits (Jabra-Rizk et al, 1999). A typical case of thrush on the tongue with its characteristic white patches Treatment Part of the problem, of course, is that just like with aspergillosis, this disease’s symptoms are so generic. The patient will usually complain only of fever and chills (and once the biofilm on the heart forms, chest pains). But almost every single pathogen known to science causes these. So it is not until antibiotics fail to clear up these symptoms that doctors have a chance to make the correct diagnosis. Once they do, the standard treatment is to deliver i) amphotericin B or one of the azole drugs intravenously until the symptoms disappear. ii) prevention continues to remain a central theme in the world of infectious fungi. iii) properly maintenance of and reduced use of catheters in hospitals Doing so decreases the likelihood of contracting candidemia a lot. iv) Even more importantly, doctors and nurses now understand the role antibiotics play in catching this disease. They know that excess use and scope of antibiotics is what most probably caused the problem in the first place and that changing how we use them can only make things better. Thus, they now know to reduce how often, how long, and how many antibiotics they give immunocompromised patients. Pathogenic Candida species •Candida krusei ii) C. tropicalis iii) C. parapsilosis C. guilliermondii v) C. pseudotropicalis vi) C. albicans vii) C. brumptii

Predisposing factors to Candida infections i) Impaired immune defenses ii) Menopause iii) Obesity iv) Diabetes mellitus v) Pregnancy •Spontaneous hormonal changes vii) Thyroid insufficiency viii) Adrenal insufficiency •Long term antibiotic therapy x) premature child birth xi) Oral contraceptives xii) Immunosuppression xiii) corticosteroids xiv) preexisting lesions on skin mucosal or internal organs xv) local conditions such as chemical, biological and mechanical irritants xvi) Reduced salivation xvii) Digestive disorders xviii) Remnant of milk left fermented in the mouth of infants.

Though Candida species are opportunistic and yet they cause different infections . Though Candida species are opportunistic, yet they cause such diseases as Candidiasis viscera , thrush, onychia, paronychia, balanitis, vaginitis, granuloma, intestinal candidiasis, septicaemia, brocho pulmonary candidiasis, intertirigo, erythychia, chelitis, erythema mycotium infantile CULTIVATION TECHNIQUES IN MYCOLOGY