Opportunistic infection and Saprophytic fungi Flashcards

Question

Who is most at risk for Rhinocerebral zygomycosis?

Answer 1

People in DKA, leukemia patients, and organ transplant recipients are high risk

Answer 2

Follows inhalation of spores (as from moldy foods). The fungus kills lung tissue (necrosis), resulting in the formation of cavities in the lung. People can experience bronchitis, pneumonia, thrombosis, hemoptysis, and hematogenous spread of the infection. It is most commonly found in leukemia patients. Normally diagnosed upon autopsy or by fine needle aspiration cytology (FNAC). Difficult to distinguish from Aspergillosis. The infection can be fatal within 2 to 3 weeks and there is an 83% death rate

Answer 3

Involves ulcers in the intestinal tract (stomach, colon, ileum). Symptoms- abdominal pain, peritonitis, intestinal perforation. Death from bowel infarction, sepsis, and hemorrhagic shock can result. This is a rare finding, but high risk populations includes malnourished infants or children, leukemia/lymphoma patients. Usually diagnosed upon autopsy

Answer 4

Results from the introduction of fungi through the skin after trauma (such as burns, surgery, or needle punctures). Lesions range from pustules and ulcers to abscesses and dead patches of skin. Often does not develop into disseminated disease. The fatality rate is 16%

Answer 5

Follows any of the 4 types of zygomycosis. The most common site of infection is the brain, abscess formation and infarction can occur. The patient's CSF examination appears normal. This type of Zygomycosis is most common in neutropenic patients with pulmonary infection. The fatality rate is 100%, it is diagnosed upon autopsy

Answer 6

Found worldwide in the soil, water, food, or decomposing organic matter, and are wide-spread in the environment. They are common culture contaminants. The infectious inoculum is not clear, as healthy individuals are resistant to infection even when there is substantial exposure

Answer 7

There are 184 species, 40 associated with human infection, 2 species predominate. Inhalation of conidia is the most common exposure. Invasive aspergillosis is a significant cause of morbidity and mortality, with invasive pulmonary Aspergillosis being the most serious form of infection. Disseminated disease fatality rate is 58 to 88%. Rapid identification of infection is vital for survival- species level identification influences treatment and outcomes

Answer 8

Requires consideration of the patient’s medical history- some conditions put people at higher risk than others. When there are large numbers of colonies on culture, it suggests infection

Answer 9

1. Bone marrow transplant 2. Immunosuppressive therapies 3. Leukemia/lymphoma, cancer patients receiving chemotherapy

Answer 10

1. Invasive pulmonary aspergillosis 2. Hypersensitivity, asthma - allergic bronchopulmonary disease 3. Tissue invasion 4. Disseminated disease 5. Ingestion of toxins from contaminated food 6. Diseases without tissue invasion- otomycosis, abscesses 7. Mycotic keratitis

Answer 11

Most common Aspergillosis disease. The destruction of lung tissue causes significant respiratory impairment associated with fever, cough, and pain, may present as pneumonia. A "fungus ball" forms in the tissue- can result in an aspergilloma (granuloma), associated with other disease cavitation (TB, PCP, Histoplasmosis etc)

Answer 12

Ball-like masses of fungal hyphae that grow in the cavities of lung tissue formed as a result of a previous tuberculosis infection. Most cases are asymptomatic, though coughing and blood-tinged sputum may occur.

Answer 13

Form in paranasal sinuses, ear canals, eyelids, the conjunctivas, brain, or eye sockets. These infections are more rare.

Answer 14

Found in the heart, CSF, bone, burn, mycetoma, sinuses

Answer 15

Can cause abscesses or otomycosis (in the ear). Otomycosis is often secondary to bacterial infections, following antimicrobial treatment. Can cause inflammation, scaling, partial deafness, or trauma to the ear.

Answer 16

Rare, usually in AIDS patients, intravenous drug abusers or when introduced into the deep tissue through severe trauma. Around 20% of cases are stem cell transplant cases. Organs affected include the brain, GI tract, and kidneys, and the infection is acute. Organ failure and death can result. There is a 90% mortality rate

Answer 17

Can be caused by Aspergillosis- not an infection but an allergic disease. Patients can experience eosinophilia, asthma, IgE increase

Answer 18

Infection of the cornea

Answer 19

The colony is velvety to granular texture, dark-green to light green, and black. Some species are susceptible to cycloheximide. They grow rapidly, maturing within 3-4 days

Answer 20

aspergillus- base of conidiophore where it merges with hyphae

Answer 21

aspergillus- stalk where conidia (asexual spores) are formed,

Answer 22

aspergillus- enlarged structure at end of conidiophore, bears phialides

Answer 23

aspergillus- cell that produces and extrudes conidia, flask shaped

Answer 24

Has septate hyphae. The conidiophore branches from the foot cell, and the vesicles and phialides branch from the conidiophore.

Answer 25

Most common species (90% of the genus). They are also the most common species causing infection. The colonies are velvety and can be white or green. The reverse side is white to tan. Form single phialides and upper half of vesicle. The species grows at 45 degrees Celsius

Answer 26

Associated with mycotoxicosis and produces potent aflatoxins. The colonies are velvety and can be yellow to green or brown. The reverse is gold to red brown. Single and double phialides, entire vesicle - point in all directions

Answer 27

Most common cause of otomycosis. The colonies are wooly, white to yellow then dark brown to black. The reverse can be white to yellow. Double phialides, cover entire vesicle -“radiate” head. Hyaline, septate

Answer 28

1. Aspergillosis 2. Penicilliosis

Answer 29

Ubiquitous in the environment- found in soil, decaying vegetation, compost, wood, dried foodstuffs, spices, dry cereals, fresh fruit and vegetables. They are also growing on building materials in water-damaged environments and are found in indoor air and house dust

Answer 30

200 species identified, no true human pathogens- many of the 200 species will not grow at 37 degrees Celsius. Only repeated isolation of fungus from tissue sections is diagnostic of significant infections Risk factors: Immunocompromised host – Acute leukemia, AIDS

Answer 31

1. Pulmonary infection 2. Keratitis 3. Allergy and hypersensitivity pneumonitis 4. Rarely found BUT case reports: Endocarditis and urinary tract infection

Answer 32

Causes bronchiectasis- airway damage that results in widening and damage of airways, scarring after infection. Mucus is no longer cleared leading to repeated infections

Answer 33

Rapid growth, mature within 4 days. Form septate hyphae. Colonies are greenish-blue with white edges

Answer 34

Branched or unbranched conidiophores – bears metula, which supports phialide. The phialides produces chains of conidia (asexual spores). The colonies resemble a skeleton hand or a paint brush

Answer 35

An ascomycete of the normal respiratory microbiota. 75% of people worldwide have been exposed to the fungus by the age of five. Found in the lungs reside without causing overt infection until the host’s immune system becomes debilitated. In immunocompetent people, the infection is asymptomatic, and generally clearance of the fungus from the body is followed by lasting immunity. However, some individuals may become long-term asymptomatic carriers. Obligate parasite, cannot survive on its own

Answer 36

An interstitial pneumonitis with plasma cell infiltrates. Cysts are found in infected lung tissue and bronchoalveolar lavage, but it does not grow in culture. Before the AIDS epidemic, the disease Pneumocystis pneumonia was very rare observed only in malnourished, premature infants and debilitated elderly patients. Now, the disease is almost diagnostic for AIDS. Once the fungus enters the lungs of an AIDS patient, it multiplies rapidly, extensively colonizing the lungs. Widespread inflammation, fever, difficulty in breathing, and a nonproductive cough are characteristic. If left untreated, lung tissue destruction and death occurs. Extrapulmonary infections of the ear, eye, liver, and bone marrow can also be found in AIDS patients

Answer 37

Worldwide distribution- humans and animals, serology suggests most people have been exposed by age 3. It was originally classified as a protozoan, but later there was identification of sterols in cell membrane through nucleotide sequences and biochemistry. It is an opportunistic pathogen that mainly affects AIDS patients. Causes pneumonia- causative agents are P. jiroveci in humans, P. carinii in other animals

Answer 38

1. Asexual phase- trophic form replicates by (#2 to #3) mitosis 2. Sexual phase

Answer 39

1. Haploid trophic forms conjugate and produce a zygote or sporocyte (#2 early cyst) 2. Zygote undergoes meiosis and subsequent mitosis to produce eight haploid nuclei (#3 late phase cyst) 3. Maturation occurs and the spores exhibit different shapes (spherical and elongate). It is postulated that elongation of the spores precedes release from the spore case. 4. After release, the empty spore case usually collapses, but retains some residual cytoplasm. (form frequently visualized in histology as crushed ping pong balls) 5. Trophic stage, where the organisms probably multiply by binary fission is also recognized to exist.

Answer 40

A patient will have a history of a chest x-ray with abnormal features. There are diffuse bilaterally web like extensions. Multiple ill defined small bright patches in the lung are suggestive of pneumocystis pneumonia. Fluid or histology demonstration of cysts or trophs in lower respiratory tract specimens. Stain fluid from lungs or from biopsies with calcofluor white, Giemsa, or GMS. The use of fluorescent antibody on samples taken from patients is more sensitive and provides a more specific diagnosis. Fungi stains black and looks like ping-pong balls

Answer 41

Opportunistic infection associated with trauma, steroid use, glaucoma, and transplant. Clinical presentation- white or cream colored infiltrate. Complications include ulceration, scarring, and blindness. Fusarium species are the most common cause, the fungi are hyaline septate or sparsely septate

Answer 42

Corneal scraping, use direct mounts and culture

Answer 43

1. Repeated isolation of large numbers from the same culture site suggests infection 2. Make judgment taking into consideration patient’s medical history

Answer 44

The second most common saprophytic fungal pathogen (after Aspergillus). It is most commonly found in the US and is found in plants, soil, decomposing organic matter

Answer 45

1. Eye infections 2. Sinusitis, septic arthritis & nails 3. Disseminated infection in neutropenic hosts 4. Fusariosis in allogenic HSCT cases is 4.21 to 5/1000 in HLA matched and 20.19 cases/1000 in HLA mismatched. (Inhalation, ingestion, trauma)

Answer 46

Rapidly growing and takes 4 days to mature. Colonies are wooly, white with pink to lavender center. Septate hyphae and have single or branching conidiophores. Tapering phialides producing banana or canoe shaped macroconidia with 3 to 5 septations, OR small oval microconidia in clusters

Answer 47

1. Acremonium species 2. Chrysosporium species 3. Sepedonium species

Answer 48

Similar to Sporothrix. and growth occurs in 5 to 7 days. Common culture contaminants that are isolated from soil, plant debris, and rotting mushrooms. This fungus does not convert to a yeast at 37 degrees Celsius. Filamentous fungi, can be found as a common saprophyte contaminant but can also be a cause of keratitis

Answer 49

1. Mycetoma 2. Nails 3. Cornea – traumatic implantation 4. Disseminated infection in VERY immunocompromised-entry from skin or lungs most common 5. HAI in patient from surgical suite with contaminated HVAC

Answer 50

Occurs at 25-30 degrees. Forms a delicate, flower-like morphological arrangement. Septate hyphae with long unbranched tapering phialides. Conidia are oblong, in clusters of single or double celled, found at the tip of the phialides

Answer 51

Occurs at 25-30 degrees. Forms a delicate, flower-like arrangement. Narrow, septate hyphae with slender tapering conidiophores swollen at terminal end bearing round to tear-shaped conidia. Conidia form rosette-like arrangements. Converts to a yeast at 37 degrees C

Answer 52

Common culture contaminants. Isolated from soil, plant debris, dung and birds. Causes skin infection of dogs and reptiles, and is associated with skin and nail infections. RARE report of disseminated infection in patient with chronic granulomatous disease (CGD), cerebral infection in HIV. Does not convert to a yeast at 37 degrees C. Similar to Blastomyces dermatitidis and Histoplasma capsulatum

Answer 53

A genetic disorder in which white blood cells called phagocytes are unable to kill certain types of bacteria and fungi. People with CGD are highly susceptible to frequent and sometimes life-threatening bacterial and fungal infections.

Answer 54

Occurs at 25-30 degrees. Slow grower- 6 days to full maturity. Single conidia on short conidiophores - “light bulbs” with arthroconidia sometime present. Can be confused with Blastomyces dermatitidis or Histoplasma capsulatum

Answer 55

Short or long conidiophores, round to pear-shaped conidia, lollipop-like appearance. Converts to a yeast at 37 degrees C

Answer 56

Short branches that bear round to pear-shaped conidia, maybe spiny. Converts to a yeast at 37 degrees C

Answer 57

Common culture contaminant that is isolated from soil and plant material, but is not known to cause disease. Similar to Histoplasma capsulatum. Large conidia (macroconidia) – single-celled, round, thick-walled and rough/knobby/spiny. DOES NOT make microconidia, which are found with H. capsulatum. Does not convert to a yeast at 37 degrees Celsius

Opportunistic infection and Saprophytic fungi Flashcards

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