All Free Microbiology MCQs with Answers

• A. Van Gieson's stain
• B. Periodic acid schiff stain
• C. Masson Trichrome stain
• D. Toluidine blue stain

Explanation: Periodic acid-Schiff stain highlights fungal cell-wall polysaccharides, so it stains Candida yeast cells and hyphae vividly.

• A. Noncapsulated fungus infecting man
• B. Causes meningitis
• C. Melanin production related to virulence
• D. Basidiomycetes yeast

Explanation: Cryptococcus neoformans is an encapsulated basidiomycetous yeast that can cause meningitis, and its melanin production contributes to…

• A. India ink preparation
• B. Methanamine silver stain
• C. Ziehl-Neelsen stain
• D. Pyte-ferraco stain

Explanation: India ink provides a dark background against which the unstained capsule of Cryptococcus appears as a clear halo.

• A. Zygomycetes
• B. Ascomycetes
• C. Basidiomycetes
• D. Deuteromycetes

Explanation: In the traditional medical classification used in many exam texts, most medically important fungi were placed among the Deuteromycetes or…

• A. Histoplasmosis
• B. Rhinosporodiosis
• C. Phaeohypomycosis
• D. Chromoblastomycosis

Explanation: Chromoblastomycosis is identified histologically by brown, thick-walled, multi-septate sclerotic bodies, also called copper-penny bodies.

• A. Microscopic examination of skin scrapings
• B. KOH staining
• C. Wood light examination
• D. All of the aboveOrder DNA Kits

Explanation: Superficial fungal infections can be assessed by direct microscopy of skin scrapings, often after KOH treatment, and Wood light…

• A. Dermatophyte infection are exclusively man to animal
• B. Rhinosporidium causes deep infection in man
• C. albicans is not pathogenic to lab animals
• D. Candida infection is usually endogenous

Explanation: Candida infection is commonly endogenous because Candida may be part of the normal gastrointestinal or genital flora and causes disease…

• A. Grocott Gomori Methenamine silver
• B. Hematoxylin and Eosin
• C. KOH wet mount
• D. Peri-iodic Acid Schiff

Explanation: A KOH wet mount rapidly clears keratin and other tissue debris, leaving fungal hyphae and spores visible under the microscope.

• A. Endocarditis
• B. Mycetoma
• C. Meningitis
• D. Oral thrush

Explanation: Candida albicans can cause oral thrush, endocarditis, and occasionally meningitis, particularly in immunocompromised patients.

• A. Conjunctivitis
• B. Tenea capitis
• C. Desert rheumatism
• D. Thrush

Explanation: Candida commonly causes thrush, an overgrowth infection producing creamy white lesions in the mouth or genital tract.

• A. Alternaria
• B. Aspergillus
• C. Osporium
• D. Candida albicans

Explanation: Candida albicans characteristically forms pseudohyphae along with budding yeast cells, helping distinguish it from many other yeasts.

• A. Spherules
• B. porangiospores
• C. Chlamydospores
• D. Oidia

Explanation: A sporangium is a sac that contains sporangiospores, which are released when it ruptures.

• A. Aspergillus niger
• B. Aspergillus fumigatus
• C. Aspergillus flavus
• D. All of the above

Explanation: Aspergillus flavus is the classic producer of aflatoxins, especially aflatoxin B1, in contaminated food and stored grains.

• A. Candida albicans
• B. Candida stellatoidea
• C. Candida tropicalis
• D. Candida pseudotropicalls

Explanation: Candida albicans forms germ tubes when incubated in serum, making the germ-tube test useful for its rapid identification.

• A. Mucorsis
• B. Mycosis
• C. Fungosis
• D. Micromia

Explanation: A fungal infection is termed mycosis, derived from the Greek word for fungus.

• A. Blood agar
• B. Tissue culture
• C. Sabouraud's agar
• D. Thioglycollate medium

Explanation: Sabouraud's agar is acidic and commonly contains antibiotics, which suppress many bacteria while supporting fungal growth.

• A. Giardia lambia
• B. Ascaris lumbriocoides
• C. Strongyloides
• D. Entamoeba

Explanation: Strongyloides larvae usually enter through the skin from contaminated soil, rather than being acquired by the faeco-oral route.

• A. Indirect hemagglutination
• B. ELISA
• C. Counter immune electroporesis
• D. Microscopy

Explanation: ELISA detects antibodies against Entamoeba histolytica and is useful in invasive disease, where stool microscopy may be negative.

• A. Plasmodium vivax
• B. Plasmodium falciparum
• C. Leishmania donovani
• D. Microfilaria

Explanation: Blackwater fever is severe intravascular haemolysis classically associated with Plasmodium falciparum, often after repeated infection or…

• A. Plasmodium ovaie
• B. Leishman donovani
• C. Entamoeba histolytica
• D. Toxoplasma

Explanation: Kala-azar, or visceral leishmaniasis, is caused by the Leishmania donovani complex.