General Mycology
Question 1. Amphotericin B acts on
- Cell wall
- Cell membrane
- Ribosome
- mRNA
Answer. (2) (Cell membrane)
Amphotericin B binds to ergosterol and disrupts fungal cell membranes; used for systemic mycoses (all invasive fungal infections) and Topical use (skin infections).
Read And Learn More: Micro Biology And Immunology Multiple Choice Question And Answers
Question 2. Which of the following is not a dimorphic fungus?
- Penicillium marneffei
- Pneumocystis jirovecii
- Blastomyces dermatitidis
- Histoplasma capsulatum
Answer. (2) (Pneumocystis)
- Pneumocystis jirovecii is not a dimorphic fungus.
Question 3. Which of the following is wrongly matched regarding the mechanism of action of antifungal drugs?
- Azoles (fluconazole, itraconazole, miconazole): Inhibit lanosterol alpha demethylase thereby preventing ergosterol synthesis
- Flucytosine: Inhibit microtubule synthesis thus preventing mitosis
- Echinocandins (Caspofungin): Act by inhibiting beta l,3 glucan synthesis
- Amphotericin B binds with ergosterol resulting in disruption of the cell membrane causing micropore leakage of ions and cell death.
Answer. (2) (Flucytosine: Inhibit microtubule synthesis thus preventing mitosis)
- Flucytosine is converted to fluorouracil inside body. Fluorouracil inhibits thymidylate synthetase, thus inhibiting DNA synthesis.
- Griseofulvin disrupts mitotic spindle by binding to fungal cell tubulin thus preventing mitosis.
Question 4. Which of the following is/are dimorphic fungi?
- Cryptococcus neoformans
- Histoplasma capsulatum
- Aspergillus species
- Penicillium marneffei
- Rhizopus species
Answer. (2, 4) (Histoplasma, P.marneffei)
Histoplasma and P. marneffei are dimorphic fungi.
Question 5. albicans is:
- Yeast
- Yeast like
- Dimorphic
- Mold
Answer. (2) (Yeast like) albicans is a yeast-like fungus showing pseudohyphae.
Question 6. Commonly used stain(s) for identifying fungus include(s):
- Periodic acid-Schiff (PAS) stain
- von Kossa stain
- Mucicarmine stain
- Gomori’s methenamine silver
- Giemsa stain
Answer. (1, 3, 4, 5) (PAS, Mucicarmine stain, Gomori’s methenamine silver, Giemsa stain)
- von Kossa stain is used to quantify mineralization in cell culture and tissue section.
Question 7. Fungi of medical importance belong to:
- Basidiomycetes
- Ascomycetes
- Phycomycetes
- Deuteromycetes
Answer. (4) (Deuteromycetes)
- Most of the fungi of medical importance belong to: Deuteromycetes or fungi imperfectii.
Question 8. Special stain fungus:
- Masson trichrome
- Silver methenamine stain
- Alizarin red
- Congo red
Answer. (2) (Silver methenamine stain)
- The stains most commonly used to identify fungi are periodic acid–Schiff and Gomori methenamine silver.
- Masson Trichrome stain was used for stool samples to demonstrate the parasites.
Question 9. A fungus which cannot be grown on artificial media/ not cultivable fungi is:
- Rhinosporidium seeberi
- Penicillium marneffei
- Aspergillus flavus
- Sporothrix schenckii
Answer. (1) (Rhinosporidium seeberi)
- Not cultivable Fungi-Rhinosproridium, Pneumocystis jerovecii and Locazia.
- R. seeberi cannot be grown on artificial culture media; however it grows in vivo in epithelial carcinoma cell culture lines.
Question 10. Fungal spores formed by condensation of hyphal elements:
- Arthrospores
- Conidiospore
- Basidiospores
- Ascospores
Answer. (1) (Arthrospores)
- Arthrospores are asexual spores that are formed along the mycelium/hyphae by segmentation and condensation of hyphae.
Question 11. Which dye is most suitable for fungus demonstration in biopsy?
- Alizarin red
- Veirhoff dye
- Manson’s trichome
- PAS
Answer. (4) (PAS)
- PAS: Very useful for demonstrating fungi in tissues, as they are stained darker than surrounding tissues.
- The nuclei stained blue and the fungi were magenta.
- It stains only the live fungi.
Question 12. Correctly matched stain:
- Mucicarmine – Cryptococcus
- Giemsa – Candida
- Methenamine silver -Histoplasma
- Gram’s – Pneumocystis carinii
Answer. (1, 3) (Mucicarmine – Cryptococcus and Methenamine silver -Histoplasma)
Question 13. Patients with rashes in the groin region as shown in the figure below. Which of the following cannot be the cause?
- Aspergillus
- Microsporum
- Epidermophyton
- Trichophyton
Answer. (1) (Aspergillus)
- Rashes in the groin area are suggestive of Taenia cruris, which can be caused by dermatophytes such as Microsporum, Epidermophyton, or Trichophyton. Aspergillus does not produce rashes in groins.
Question 14. Which of the following antifungal drugs is developing drug resistance and has not been prescribed for tinea cruris and tinea corporis for the last 2 years?
- Griseofulvin
- Terbinafine
- ltraconazole
- Voriconazole
Answer. (1) (Griseofulvin)
Because of the development of drug resistance, Griseofulvin has not been prescribed for dermatophytic infections.
Question 15. Most common dermatophyte associated with Majocchi granuloma:
- Trichophyton rubrum
- Epidermophyton
- Microsporum canis
- Trichophyton mentagrophyte
Answer. (1) (Trichophyton rubrum)
- Majocchi granuloma is deep folliculitis seen in cutaneous dermatophyte infection.
- Agent—Most commonly due to Trichophyton rubrum. Other agents include
- Trichophyton violaceum, Trichophyton mentagrophytes and Epidermophyton floccosum.
- Tends to occur in—(1) young women who frequently shave their legs, (2) use of potent topical steroids on unsuspected tinea.
Question 16. Boggy swelling of the scalp in children is caused by:
- Trichophyton mentagrophyte
- Trichophyton verrucosum
- Microsporum canis
- Microsporum furfur
Answer. (2) (Trichophyton verrucosum)
- Boggy inflammatory swelling of the scalp is a feature of a kerion, a type of tinea capitis.
- Among the given options, Trichophyton verrucosum commonly causes kerion.
- Favus (cup-like crust formation around the infected hair follicles), another type of tinea capitis is caused by Trichophyton schoenleinii.
Question 17. An athlete complains of itching and redness in the groin region. The clinical photograph is given below. All of the following can be caused except:
- Trichophyton
- Microsporum
- Epidermophyton
- Aspergillus
Answer. (4) (Aspergillus)
- It is a case of dermatophyte infection (tinea cruris).
Question 18. Seborrheic dermatitis – causative agent is:
- Candida
- Dermatophytes
- Cryptococcus
- Malassezia furfur
Answer. (4) (Malassezia furfur)
Question 19. Feature(s) of Taenia capitis is/are all except:
- May presents as a boggy swelling
- Most commonly occurs in the elderly
- May present as a black dot
- Caused by Trichophyton and Microsporum but not by Epidermophyton
- Scutula formation
Answer. (2) (Most commonly occurs in the elderly)
- Tinea capitis occurs most commonly in children 3–7 years old.
- Tinea capitis exists in various forms – Favus (as a cup-like crust or scutula), Keroin (as boggy swelling), ectothrix, and endothrix (as black dot due to hair break and alopecia).
Question 20. Trichophyton species which is zoophilic:
- T. tonsurans
- T. violaceum
- T. schoenleinii
- T. mentagrophytes
Answer. (4) (T. mentagrophytes)
Zoophilic species: Trichophyton mentagrophyte and Microsporum canis.
Question 21. Wood’s Lamp used in:
- Tinea pedis
- Pityriasis versicolor
- Sporotrichosis
- Vitiligo
Answer. (1, 2, 4) (Tinea pedis, Pityriasis versicolor, Vitiligo)
- Wood’s lamp is a device that detects fluorescence structures that give different colors.
- In fair-skinned individuals, Wood’s Lamp detects Vitiligo (and other depigmentations) even when it is not visible under normal light conditions.
- List of Wood’s lamp positive fungi
Question 22. Which of the following fungi is/are difficult to isolate culture?
- Candida
- Dermatophytes
- Cryptococcus
- Malassezia furfur
- Coccidioidomycosis
Answer. (4) (Malassezia furfur)
- It is cumbersome to grow Malassezia furfur in routine SDA, as it is a lipophilic fungus
- Ectothrix hair infection Microsporum spp, T. rubrum
- Endothrix hair infection T.schoenleinii, T.violaceum, T.tonsurans hence lipids like oleic acids are incorporated into SDA.
- Selective culture media used: Dixon agar and modified Dixon medium.
- Other options: Candida, Dermatophytes, Cryptococcus, and Coccidiodes grow on routine SDA.
Question 23. Ectothrix is due to:
- Trichophyton tonsurans
- Micosporum audounii
- Trichophyton schoenleinii
- Trichophyton violaceum
- Mycetoma
Answer. (2) (Micosporum audounii)
- Mycetoma
Question 24. All statements are true about mycetoma except:
- Eumycetoma is caused by bacteria
- Surgery is an important component of treatment
- Usually painless
- Diagnosis can be made by examination of a lesion
- Can affect the lower and upper extremities
Answer. (1) (Eumycetoma is caused by bacteria )
- Eumycetoma is caused by fungi
- Treatment of mycetoma consists of surgical removal of the lesion followed by antifungals.
Question 25. Yellow black granules are seen in which fungal infection:
- Mucormycosis
- Mycetoma
- Aspergillosis
- Rhinosporidiosis
Answer. (2) (Mycetoma)
- All the agents of actinomycetoma produce whitish-yellow granules whereas that of eumycetoma produces white or black granules.
Question 26. The color of granules produced by actinomycetes is:
- Black
- Yellow
- Blue
- White
Answer. (4) (White)
- All the agents of actinomycetoma produce white to yellow granules except Actinomadura Pelletier (red)
Question 27. Actinomycetoma is caused by:
- Actinomyces
- Nocardia
- Streptomyces
- Madura mycosis
Answer. (2, 3) (Nocardia and Streptomyces)
Question 28. Which of the following organisms is implicated in the causation of botryomycosis?
- Staphylococcus aureus
- Staphylococcus albus
- Pseudomonas aeruginosa
- Streptococcus pneumonia
- Streptococcus pyogenes
Answer. (1, 3) (Staphylococcus aureus and Pseudomonas aeruginosa)
- Botryomycosis:
- Chronic, purulent, granule-producing, granulomatous infection of the skin, subcutaneous tissues, and visceral organs by several bacterial spp.
- Neutrophilic reaction is present, (in Mycetoma cement substance present between the agents).
- Clinically and histopathologically, it resembles Mycetoma
- Treatment- susceptible to a variety of antibiotics.
Question 29. A Female had a thorn prick 5 years ago. She presented with a slowly growing 2 × 2 cm verrucous lesion which on KOH mount showed the following image?
- Phaeohyphomycosis
- Blastomycosis
- Sporotrichosis
- Chromoblastomycosis
Answer. (4) (Chromoblastomycosis )
- This is a case of Chromoblastomycosis. The picture shows sclerotic bodies; characterized by brown thick-walled round cells (5-12 µm size) with multiple internal transverse septa.
It’s also called Medlar bodies or muriform cells.
Question 30. Sporotrichoid pattern is seen with:
- Sporothrix schenckii
- Fish tank granuloma
- Erysipelas
- Lupus vulgaris
- Impetigo
Answer. (1, 2, 4) (Sporothrix, Fish tank granuloma, Lupus vulgaris)
- Sporotrichoid lymphocutaneous infection is a syndrome characterized by the development of superficial cutaneous lesions that progress along dermal and subcutaneous lymphatics.
Common causes
- Sporothrix schenckii, Nocardia brasiliensis, Mycobacterium marinum (Fish tank granuloma) or Leishmania brasiliensis.
Rare causes
- Fungal infections: coccidioidomycosis, cryptococcosis, blastomycosis, histoplasmosis.
- Bacterial infections: anthrax, Burkholderia pseudomallei, lepromatous leprosy, lupus vulgaris, Francisella tularensis
- Viral infection: Cowpox virus.
Question 31. A cutaneous lesion with sporotrichosis pattern is seen with:
- Nocardia
- Candida
- Measles
- Influenza
Answer. (1) (Nocardia)
- Nocardia is sometimes presented as lymphocutaneous syndrome characterized by subcutaneous nodules appearing along lymphatics, a condition seen with Sporothrix schenckii.
Question 32. Rhinosporidium seekers belong to:
- Fungus
- Bacteria
- Aquatic protistan protozoa
- Virus
Answer. (3) (Aquatic protistan protozoa)
- Rhinosporidium seeberi, a lower aquatic fungus. Its taxonomic status is controversial; some believe that it may be a hydrophilic protist.
Question 33. Asteroid bodies are seen in:
- Sporotrichosis
- Blastomycosis
- Coccidioidomycosis
- Cryptococcosis
Answer. (1) (Sporotrichosis)
Question 34. The causative agent of recurrent ulcers in the sub-Himalayan region is: AI 2012,
- Cladosporium
- Sporothrix
- Chromoblastomycosis
- Mucor
Answer. (2) (Sporothrix)
- Multiple recurrent ulcers and a history of the sub-Himalayan region are suggestive of Sporotrichosis.
Question 35. Cigar body is seen in:
- Cryptococcosis
- Sporotrichosis
- Histoplasmosis
- Aspergillosis
Answer. (2) (Sporotrichosis)
- A cigar-shaped asteroid body is seen in Sporotrix schenkii infection.
Question 36. Sclerotic bodies are found in:
- Rhinosporidiosis
- Histoplasmosis
- Coccidioidomycosis
- Chromoblastomycosis
Answer. (4) (Chromoblastomycosis)
- Skin scrapings from a patient with chromoblastomycosis show characteristic brown-walled, globose bodies 5–13 µ in size, called sclerotic bodies or muriform cells/Medlar bodies.
Question 37. A gardener has multiple vesicles on hand and multiple eruptions along the lymphatics.
- The most common fungus responsible is:
- Sporothrix schenckii
- Cladosporium
- Histogram
- Candida
Answer. (1) (Sporothrix schenckii)
- Multiple vesicles on hand and multiple eruptions along the lymphatics in a gardener suggest typical clinical manifestations of Sporotrichosis.
- Sporotrichosis is caused by thermally dimorphic fungi, Sporothrix schenckii
- Infection is introduced in the skin by trauma (thorn prick injury), hence Sporotrichosis also called ‘Rose Gardener’s disease’. Draining lymphatic system involvement is characteristic.
Question 38. True about Rhinosporidium selbri:
- Fungi
- Bacteria
- Ketoconazole –treatment
- Present in coastal India
Answer. (4) (Present in coastal India)
- Rhinosporidium seeberi was thought to be a fungus but based on molecular studies it is now considered to be a hydrophilic protistian parasite, hence called a pseudofungal organism.
- R.seeberi cannot be cultured in cell-free artificial media.
- Infection is acquired by coming in contact with fresh or stagnant water and hence it is believed a hydrophilic organism.
- Common in India (Tamil Nadu, Kerala, and Andhra Pradesh) and Sri Lanka.
Question 39. The HIV patient presented with fever and diarrhea for 3 weeks. The patient was started on Sulphamethoxazole-trimethoprim. His diarrhea responded but he continued to have a fever. Bone marrow aspirate showed the following picture of what is not correct for the fungal organism.
- It is an intracellular yeast
- It does not grow on SDA medium
- It can cause disseminated infection
- The infective agent is spores
Answer. (2) (It does not grow on SDA medium)
- It’s a case of histoplasmosis. Bone marrow biopsy revealed intracellular (inside macrophage) 2-4 µm yeast cells with narrow-based budding.
- Histoplasma grows on the SDA medium.
Question 40. Intracellular fungus:
- Histoplasma
- Candida albicans
- Cryptococcus
- Sporothrix
Answer. (1) (Histoplasma)
Question 41. An HIV patient presents with a cough for 10 days. Sputum culture by SDA reveals broad budding yeast with a thick mucoid wall. Diagnosis:
- Histoplasmosis
- Coccidioidomycosis
- Blastomycosis
- Penicillium marneffei
Answer. (3) (Blastomycosis)
- Broad budding yeast cells of 8-15 µm (figure 8 appearance) are a characteristic feature of Blastomyces dermatitidis.
Question 42. Fever with pneumonia, sputum smear showing broad-based budding fungi with double contoured cell wall. What is the diagnosis?
- Histoplasma
- Blastomyces
- Coccidioides
- Penicillium marneffei
Answer. (2) (Blastomyces)
- History of pneumonia with sputum smear showing broad-based budding (figure of 8) yeast cells- suggestive of Blastomyces
Question 43. An HIV-positive patient came with pain in the hip region. Aspiration stained with Giemsa staining shows multiple monocytes and macrophages with yeast-like organisms of 4-6 µm size in the cytoplasm of cells. The organism might be:
- Candida
- Blastomyces
- Histoplasma
- Cryptococcus
Answer. (3) (Histoplasma)
- Case of osteomyelitis in HIV infected patient, with intracellular yeast of 4-6 µm size – most likely diagnosis is histoplasmosis.
Question 44. The histopathological image given below belongs to which of the following fungus?
- Blastomyces
- Histoplasma
- Coccidioides
- Paracoccidioides
Answer. (1) (Blastomyces)
- Yeast cells with Broad-based budding (Figure 8 appearance) are seen in the yeast form of Blastomyces.
Question 45. Darling disease is caused by:
- Histoplasma
- Candida
- Cryptococcus
- Rhizopus
Answer. (1) (Histoplasma)
Darling’s disease is the other name of histoplasmosis. Named after the scientist Samuel Taylor Darling.
Question 46. What is true about Histoplasmosis?
- In the early stage, it is indistinguishable from TB
- Culture is not diagnostic
- Mycelial forms are infectious form
- Person-to-person spread occurs by droplet infection
Answer. (3) (Mycelial forms are infectious form)
- Chronic cavitary histoplasmosis is seen in smokers who have structural lung disease (for example., bullous emphysema) and is characterized by upper-lobe infiltrates, cavitation, and pleural thickening- mimics cavitary tuberculosis.
- Isolation of fungi by culture and demonstration of dimorphism is diagnostic.
- Reservoir of infection: Soil
- Microconidia (spores) are the infective form and the mode of infection is inhalation.
- Person-to-person or animal-to-man transmission is not known so far for Histoplasmosis.
Question 47. Endemic fungal infection:
- Coccidioides immitis
- Cryptococcus
- Histoplasmosis
- Aspergillus
- Blastomycosis
Answer. (1, 3, 5) (Coccidioides immitis, Histoplasmosis, Blastomycosis)
Endemic Mycosis- Fungal infection which is confined to a particular geographical area.
Question 48. What is the management for the given case:
- Dapsone plus steroids
- Stop smoking and screen for carcinoma
- Vitamin supplements
- Antifungal treatment for oral candidiasis
Answer. (4) (Antifungals treatment for oral candidiasis)
White, adherent, painless patches in the mouth are suggestive of Oropharyngeal candidiasis (oral thrush). Therefore, antifungal treatment for oral candidiasis is the most appropriate answer.
Question 49. A patient presented with complaints of dysphagia UGI Endoscopy a diagnosis of esophageal candidiasis was made. The organism obtained from the sample was cultured on a specialized media and the below findings were visible on microscopy the cultural phenomenon is shown below.
- Germ tube formation
- Spore formation
- Mold to yeast formation
- Budding
Answer. (1) (Germ tube formation)
The above picture demonstrates Germ tube formation (also called Reynolds Braude phenomenon), which differentiates Candida albicans (and dubliniensis), which is germ tube test positive from other Candida species (germ tube negative).
- Colonies are mixed with human or sheep serum and incubated for 2 hours. Wet mount preparation is examined under a microscope
- Germ tubes are formed, described as long tube-like projections extending from the yeast cells
- It is differentiated from pseudohyphae as there is no constriction at the origin.
Question 50. An HIV-positive patient presents with a cough for 10 days. Sputum culture by SDA reveals broad budding yeast, diagnosis:
- Histoplasma capsulatum
- Blastomycosis
- Coccidioidomycosis
- Paracoccidioidomycosis
Answer. (2) (Blastomycosis)
- Broad-based budding yeasts….suggestive of Blastomyces.
Question 51. The (1, 3)-ß-D-Glucan pan fungal detection assay is useful in the diagnosis of which ONE of the following infections?
- Rhinosporidiosis
- Invasive candidiasis
- Mucormycosis
- Cryptococcal meningitis
Answer. (2) (Invasive candidiasis)
- β-(1, 3)-β-D-Glucan antigen is an invasive marker for a broad range of invasive fungal infections such as Candida spp., Aspergillus spp., and Pneumocystis jirovecii.
Question 52. Assay for fungi is not used for:
- Aspergillus species
- Candida species
- Cryptococcus species
- Pneumocystis jirovecii
Answer. (3) (Cryptococcus)
- β- (1, 3)-D- antigen is an invasive marker for a broad range of invasive fungal infections such as Candida spp., Aspergillus spp., and Pneumocystis jirovecii.
Question 53. Which fungus gives germ tube test positive?
- Cryptococcus
- Aspergillus
- Candida albicans
- Candida dubliniensis
- All Candida species
Answer. (3, 4) (albicans and dubliniensis)
- Germ tube test is positive for both albicans and dubliniensis
Question 54. Azole group of antimicrobial agents are used in:
- Chlamydia
- Candida
- Trichomonas
- Gardnerella
Answer. (2) (Candida)
Question 55. Raynaud Braude phenomenon is seen in:
- Candida albicans
- Candida pitas
- Histoplasma
- Cryptococcus
Answer. (1) (Candida albicans)
- Raynaud Braude phenomenon is the other name of a positive germ tube test
- Germ tube test is usually positive by Candida albicans, rarely by Candida dubliniensis
Question 56. The most common fungal infection in non-HIV infected (immunocompetent) persons is:
- Candida
- Cryptococcus
- Mucor
- Aspergillus
Answer. (1) (Candida)
- Candida species in immunocompetent hosts can cause infection of any warm and moist parts of the body exposed to the environment. It causes infection of the nail, rectum, and other skin folds.
- Among the given options Candida is most appropriate, as other options Cryptococcus,
- Mucor and Aspergillus are mainly isolated from opportunistic infections.
Question 57. A vitreous aspirate from a case of metastatic endophthalmitis on culture yields Grampositive round to oval cells, 12-14 µm in size. The aspirate on Gram staining shows the presence of pseudohyphaWhich of the following is the most likely etiological agent?
- Aspergillus
- Rhizopus
- Candida
- Fusarium
Answer. (3) (Candida)
- The history provided suggests that it is a case of disseminated fungal endophthalmitis
- The fungal agent has the morphology of yeast cells with pseudohyphae suggesting diagnosis of Candida spp
- Other options provided- Aspergillus, Rhizopus, and Fusarium are molds/filamentous fungi.
Question 58. Which fungal infection spreads in neonates through care giver’s hands?
- Candida albicans
- Candida parapsilosis
- Candida tropicalis
- Candida glabrata
Answer. (2) (parapsilosis)
- EID Journal Volume 10, 2004:Candida parapsilosis Characterization in an Outbreak Setting Parapsilosis is increasingly responsible for hospital outbreaks, and the hands of healthcare workers may be the predominant environmental source.
Question 59. An HIV+ve patient with CD4 Count 20 cells/mm3 came with complaints of headache, mild neck stiffness, and weakness suspected Meningitis and lumbar puncture revealed yeast with no pseudohyphae it might be:
- Candida
- Cryptococcus
- Aspergillus
- Mucor
Answer. (2) (Cryptococcus)
- Case of meningitis in HIV-infected patient- most likely diagnosis is cryptococcosis.
Question 60. The image given below belongs to which of the following organisms?
- Cryptococcus
- Candida
- Histoplasma
- Blastomyces
Answer. (1) (Cryptococcus)
- It is a negative staining (India ink) showing a capsule of Cryptococcus neoformAnswer.
Question 61. The most sensitive and rapid test for diagnosis of cryptococcal meningitis is:
- Culture on SDA
- Culture on Bird Seed Agar
- India Ink
- Latex Agglutination
Answer. (4) (Latex agglutination)
- Latex Agglutination test detecting capsular antigen in CSF is the most sensitive test (95%) for diagnosis of Cryptococcal meningitis
Question 62. Budding is seen with:
- Cryptococcus and Candida
- Candida and Rhizopus
- Rhizopus and Mucor
- Candida and Aspergillus
Answer. (1) (Cryptococcus and Candida)
- Cryptococcus is yeast and reproduces by budding (blastoconidium)
- Candida is a yeast-like fungus; that reproduces by budding and binary fission.
Question 63. The capsule of Cryptococcus neoformans in a CSF sample is best seen by:
- Gram stain
- India ink preparation
- Giemsa stain
- Methenamine –silver stain
Answer. (2) (India ink preparation)
- Cryptococcus is the capsulated yeast.
- Among the given staining techniques, India ink preparation is the best staining technique used for the demonstration of the capsule (negative staining) – sensitivity of the technique: 60 -75%.
- Other capsular staining techniques are:
- 10% Nigrosin staining
- Modified India ink preparation with 2% chromium mercury
- Alcian blue staining
- Methenamine silver and Periodic acid- Schiff – were used for the tissue sample.
- Sensitivity of various diagnostic tests- Harrison 18/e p1652
- Cryptococcal antigen detection in CSF—90%
- Blood culture: 10—30% in non-HIV patients and 60% in HIV patients
- Sputum culture: 10%
- Sputum antigen detection: 30%.
Question 64. The most common organism amongst the following that causes acute meningitis in an AIDS patient is:
- Streptococcus pneumoniae
- Streptococcus agalactiae
- Cryptococcus neoformans
- Listeria monocytogenes
Answer. (3) (Cryptococcus neoformans)
- Cryptococcosis is the predominant cause of fatal fungal infection and causes acute meningitis in patients with AIDS.
- It may occur most commonly when the CD4+ count falls below 200 cells/mm3.
- The extrapulmonary cryptococcosis is one of the AIDS-defining diseases.
Question 65. A patient came to AIIMS OPD, with acute pain and watering from the eye for 3 days. There was a 3 × 2 mm ulcer on the cornea with ROLLED OUT margins with feathery and finger-like projections with minimal hypopyon:
- Acanthamoeba
- Pseudomonas
- Aspergillus
- HSV-2
Answer. (3) (Aspergillus)
- A corneal ulcer is dry-looking, grayish white, with elevated rolled-out margins, delicate feathery finger-like extensions are present in the surrounding stroma under the intact epithelium are suggestive of Filamentous fungal keratitis.
Question 66. Identify the fungal organism in this slide stained with Gomori methenamine silver stain:
- Acute angle branching, Rhizopus
- Right angle branching, Aspergillus
- Acute angle branching, Aspergillus
- Right angle branching, Mucor
Answer. (3) (Acute angle, Aspergillus)
This is a Gomori methenamine silver-stained smear demonstrating narrow septate hyphae with acute angle branching- suggestive of invasive Aspergillus infection.
Question 67. The following are the main diagnostic criteria for allergic bronchopulmonary aspergillosis:
- Pulmonary infiltrates
- Distal bronchiectasis
- Peripheral eosinophilia
- Bronchial asthma
Answer. (2) (Distal bronchiectasis)
ABPA represents a hypersensitivity reaction to fumigatus; occurs in ~1% of patients with asthma and in up to 15% of adults with cystic fibrosis.
- Presents with coughing fits, pneumonia, pulmonary infiltrates, consolidation, and breathlessness
- Eosinophilia and elevated serum level of total IgE
- Central bronchiectasis is characteristic (but not distal).
Question 68. Drugs used in the treatment of Aspergillosis:
- Itraconazole
- Voriconazole
- Clotrimazole
- Amphotericin B
- Ketoconazole
Answer. (1, 2, 4) (Itraconazole,Voriconazole, Amphotericin B)
- Antifungal drugs active against Aspergillus include voriconazole, itraconazole,posaconazole, caspofungin, micafungin, and amphotericin B.
- Voriconazole is the preferred agent for invasive aspergillosis.
Question 69. Aflatoxins are produced by:
- Aspergillus flavus
- Aspergillus niger
- Candida
- Cryptococcus/Nocardia
Answer. (1) (Aspergillus flavus)
- Mycotoxin is produced by flavus
- It is frequently present in moldy foods, particularly in groundnuts, corn, and peas.
Question 70. A 25-year-old female complains of recurrent rhinitis, nasal discharge, and bilateral nasal blockage for 2 years. She has a history of asthma and allergy. On examination, multiple ethmoidal polyps are noted with mucosal thickening and impacted secretions in both the nasal cavities. A biopsy is taken and the material is cultured which shows the growth of many hyphae and pseudohyphae with dichotomous branching typically at 45. Which of the following is the most likely responsible organism?
- Aspergillus fumigatus
- Rhizopus
- Mucor
- Candida
Answer. (1) (Aspergillu fumigatus)
- The history provided in the question, suggests the involvement of paranasal sinuses with the presence of multiple ethmoidal polyps in an asthmatic patient.
- Septate hyphae with dichotomous branching typically at 45° is observed in the morphology of Filamentous fungi- Aspergillus.
- All of the above points suggest the patient is suffering from fungal sinusitis due to Aspergillus fumigatus.
Question 71. In HIV-infected individuals, the Gram stain of the lung aspirate shows yeast-like morphology. All of the following are the most likely diagnoses except:
- Candida tropicalis
- Cryptococcus neoformans
- Penicillium marneffi
- Aspergillus fumigatus
Answer. (4) (Aspergillus fumigatus)
- Option 1: Correct- Candida tropicalis causes infection in immunocompromised patients and has a gram-positive budding yeast-like morphology
- Option 2: Correct- Cryptococcus neoformans- causes infection in immunocompromised patients and has a gram-positive budding yeast morphology
- Option 3: Correct- Pencillium marneffi – causes infection in immunocompromised patients and is a Dimorphic fungus with yeast morphology in body tissues/at 37°C
- Option 4: Incorrect- Aspergillus fumigatus- Even though can cause infection in immunocompromised patients, it is a filamentous fungus showing hyphae with dichotomous branching typically at 45°C.
Question 72. In a patient, corneal scraping reveals narrow angled septate hyphae, which of the following is likely an etiologic agent:
- Mucor
- Aspergillus
- Histoplasma
- Candida
Answer. (2) (Aspergillus)
- Option 1: Incorrect- Mucor has aseptate hyphae and not septate
- Option 2: Correct-Aspergillus causes fungal keratitis and has narrow angled septate branching hyphae
- Option 3: Incorrect- Histoplasma does not cause fungal keratitis
- Option 4: Incorrect- Candida characteristically shows budding yeast-like cell morphology and also does not cause fungal keratitis.
Question 73. The most common fungus causing orbital cellulitis in diabetic patients:
- Mucor
- Aspergillus
- Candida
- Cryptococcus
Answer. (1) (Mucor).
- Rhinocerebral mucormycosis is commonly seen in patients with diabetic ketoacidosis. It is the most common form; starts as eye and facial pain, and may progress to cause orbital cellulitis, proptosis, and vision loss.
Question 74. Which of the organisms is responsible for orbital cellulitis in a patient with diabetic ketoacidosis?
- Cryptococcus
- Candida
- Mucor
- Aspergillus
Answer. (3) (Mucor)
- Zygomycetes commonly cause orbital cellulitis in a patient with diabetic ketoacidosis.
Question 75. A Diabetic patient suffers from a soft tissue infection and microbiological examination reveals the infection has been caused by fungi with aseptate and broad hyphae.
Which of the following fungus is responsible for this infection?
- Candida
- Aspergillus
- Penicillium
- Apophysomyces
Answer. (4) (Apophysomyces)
- Broad aseptate hype: Belongs to the family zygomycetes or Phycomycetes, e.g.
- Rhizopus, Mucor, Absidia, Apophysomyces
- Narrow septate hyphae, e.g. Aspergillus (belongs to Ascomycetes), Penicillium, Fusarium
Question 76. Which of the following is aseptate fungus?
- Aspergillus
- Candida
- Nocardia
- Rhizopus
Answer. (4) (Rhizopus)
Question 77. True about mucormycosis is:
- Nose is a common site
- Diabetic is a common predisposing factor
- Common in India
- All of the above
Answer. (4) (All of the above)
- Rhinocerebral zygomycosis is the most common and fulminant type of zygomycosis, affecting the nose, paranasal sinuses, orbit, and palate.
- Risk factor- MC is Diabetes followed by the patient on dialysis, iron overload, and Hematopoietic stem cell transplantation
- Mucormycosis is increasingly recognized in recently developed countries, such as India, mainly in patients with uncontrolled diabetes or trauma…… Journal-Clin Infect Dis.
Question 78. Morphological appearance of Pneumocystis jirovecii infection of the lung is best characterized by:
- Hemorrhagic and necrotizing pneumonia
- ARDS with wide-spread hyaline membrane formation
- Interstitial pneumonitis with foamy intra-alveolar exudates
- Bronchopulmonary abscess formation
Answer. (3) (Interstitial pneumonitis with foamy intra-alveolar exudates)
- Pneumocystis pneumonia (Pathology): Alveoli are filled with a typical foamy, vacuolated exudate.
- Severe disease may include interstitial edema, fibrosis, hyaline membrane formation (but not ARDS) and malnourished infants develop plasma cell infiltrate hence called interstitial plasma cell pneumonia.
Question 79. Select the false statement about P. jirovecii:
- It is seen in only immunocompromised individuals
- Frequently associated with CMV
- May be associated with pneumatocele
- Diagnosed with sputum microscopy
Answer. (2) (Frequently associated with CMV)
- P.jirovecii infection and CMV (Cytomegalovirus) infection is common in patients with renal transplant recipients, but the association with CMV infection is not documented.
About other options:
- Option a: Correct- It is an opportunistic pathogen
- Option c: Correct- The common radiographic finding in P.jirovecii pneumonia is the presence of ground-glass opacity in both lungs and atypical radiographic manifestations include cystic spaces (pneumatocele) and bullae, adenopathy, pleural effusions, and pneumothorax. BMC Infectious Diseases 2009;9:171
- Option d: Correct- Lab diagnosis is established based on visualization of P.jirovecii in expectorated sputum or BAL (Ideal sample).
Question 80. Which of the following is a fungus?
- Klebsiella
- Clostridia
- Pneumocystis jirovecii
- Listeria
Answer. (3) (Pneumocystis jirovecii)
Pneumocystis jerovecii is considered to be a fungus based on the following points:
- It takes fungal stains like Gomori’s methenamine silver stain
- It possesses chitin at all stages of development (a component of the fungal cell wall)
- Based on molecular study of 5S –rRNA.
Question 81. A young man aged 30 years, presents with difficulty in vision in the left eye for the last 10 days. He is immunocompetent, a farmer by occupation, comes from a rural community, and has a history of trauma to his left eye with vegetative matter 10–15 days back. On examinations, there is an ulcerative lesion in the cornea, whose base has raised soft creamy infiltratUlcer margin is feathery and hyphaBranching aseptate hyphae were noting there are a few satellite lesions also. Corneal scrapping shows sickle-shaped macroconidia. What should be the probable diagnosis?
- Fusarium
- Aspergillus
- Mucormycosis
- Dermatophytes
Answer. (1) (Fusarium)
- Fusarium is a hyaline filamentous fungi, that may cause a range of opportunistic infections in humans.
- In humans with normal immune systems, fusarium infections may occur in the nails (onychomycosis) and the cornea (keratomycosis or mycotic keratitis)
- Diagnosed by the presence of sickle-shaped macroconidia.
Question 82. DOC of Pneumocystis jirovecii:
- Cotrimoxazole
- Penicillin
- Amphotericin B
- Clotrimazole
Answer. (1) (Cotrimoxazole)
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