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Medical Microbiology — MCQ ও উত্তর

মেডিকেল ভর্তি · । এই অধ্যায়ে মোট 120টি প্রশ্ন আছে। নিচে প্রথম 10টি প্রশ্ন ও সঠিক উত্তর দেওয়া হলো।

এই অধ্যায়ে সব প্রশ্নে অনুশীলন করুন

  1. What is the minimum temperature required for effective autoclaving?

    1. 100°C
    2. 140°C
    3. 90°C
    4. 121°C

    সঠিক উত্তর: 121°C

    ব্যাখ্যা: সমাধান সঠিক উত্তর: Option D The minimum temperature required for effective autoclaving is 121°C because at this temperature, under saturated steam pressure (usually 15 psi), the autoclave can achieve reliable sterilization by destroying all forms of microbial life, including spores. Lower temperatures like 100°C are insufficient to kill resistant bacterial spores within a reasonable time frame. The standard cycle at 121°C for 15-20 minutes ensures complete sterilization of surgical instruments and materials, making it the gold standard in infection control protocols. This prevents postoperative infections and ensures patient safety in surgical settings.Reference: Surgical Infection, Neil H. Woodward, 2nd Edition.

  2. Which organism is used as a biological indicator for autoclave efficacy?

    1. Escherichia coli
    2. Staphylococcus aureus
    3. Pseudomonas aeruginosa
    4. Bacillus stearothermophilus

    সঠিক উত্তর: Bacillus stearothermophilus

    ব্যাখ্যা: সমাধান সঠিক উত্তর: Option D Bacillus stearothermophilus spores are used as a biological indicator for autoclave efficacy because they are highly resistant to heat and steam sterilization. Their spores can survive harsh conditions, making them an ideal marker to confirm that the autoclave cycle has effectively destroyed all microbial life. If these spores are killed during the process, it ensures the sterilization was successful, guaranteeing patient safety by preventing surgical site infections. Other organisms listed lack the necessary heat resistance to serve as reliable indicators in steam sterilization validation.Reference: Medical Microbiology, Jawetz, Melnick & Adelberg, 27th Edition.

  3. Which virus is most commonly associated with cervical cancer?

    1. Hepatitis B virus
    2. Human papillomavirus (HPV)
    3. Epstein-Barr virus
    4. Herpes simplex virus

    সঠিক উত্তর: Human papillomavirus (HPV)

    ব্যাখ্যা: সমাধান সঠিক উত্তর: Option B Human papillomavirus (HPV) is the most common viral cause of cervical cancer due to its ability to integrate into the host genome and produce oncoproteins E6 and E7. These oncoproteins inactivate tumor suppressor genes p53 and Rb, leading to uncontrolled cellular proliferation and malignant transformation. Persistent infection with high-risk HPV types (especially HPV 16 and 18) is strongly linked to the development of cervical intraepithelial neoplasia and invasive carcinoma. HPV detection and vaccination are key in cervical cancer prevention and management. Reference: Robbins Basic Pathology, Kumar, Abbas, Aster, 10th Edition.

  4. Which virus is the causative agent of AIDS?

    1. Hepatitis C virus
    2. Human immunodeficiency virus (HIV)
    3. Epstein-Barr virus
    4. Cytomegalovirus

    সঠিক উত্তর: Human immunodeficiency virus (HIV)

    ব্যাখ্যা: সমাধান সঠিক উত্তর: Option B The causative agent of AIDS is the Human immunodeficiency virus (HIV), which specifically targets and destroys CD4+ T lymphocytes, leading to progressive immune system failure. This immunodeficiency makes patients vulnerable to opportunistic infections and certain cancers that define AIDS. Unlike the other viruses listed, HIV directly impairs immune function by integrating into host DNA and causing chronic infection. Understanding HIV’s role is crucial for diagnosis, treatment, and prevention of AIDS. Reference: Harrison's Principles of Internal Medicine, J. Larry Jameson, 20th Edition.

  5. Rice-water stools are characteristic of infection with:

    1. Salmonella typhi
    2. Escherichia coli
    3. Vibrio cholerae
    4. Shigella dysenteriae

    সঠিক উত্তর: Vibrio cholerae

    ব্যাখ্যা: সমাধান সঠিক উত্তর: Option C Rice-water stools are characteristic of infection with Vibrio cholerae due to its production of cholera toxin. This toxin causes massive secretion of electrolytes and water into the intestinal lumen, leading to profuse, watery diarrhea that resembles rice water. The stool is typically pale, watery, and flecked with mucus, but without blood or pus. This massive fluid loss can rapidly cause severe dehydration and hypovolemic shock if untreated. The pathophysiology and clinical presentation of rice-water stools are distinctive features used to diagnose cholera. Reference: Harrison's Principles of Internal Medicine, Kasper et al., 20th Edition.

  6. The primary mode of transmission for rotavirus is:

    1. Respiratory droplets
    2. Fecal-oral route
    3. Vector-borne
    4. Sexual contact

    সঠিক উত্তর: Fecal-oral route

    ব্যাখ্যা: সমাধান সঠিক উত্তর: Option B Rotavirus is primarily transmitted via the fecal-oral route, as the virus is shed in large quantities in the stool of infected individuals. Contaminated hands, surfaces, water, and food facilitate its spread, especially in settings with poor hygiene. This mode of transmission explains the high incidence of rotavirus in young children and in areas with inadequate sanitation. Respiratory droplets, vectors, and sexual contact are not significant routes for rotavirus infection. Understanding this is crucial for implementing effective infection control measures and preventing outbreaks. Reference: Nelson Textbook of Pediatrics, Kliegman RM, 21st Edition.

  7. Which is the most common bacterial cause of gastroenteritis worldwide?

    1. Staphylococcus aureus
    2. Vibrio cholerae
    3. Campylobacter jejuni
    4. Salmonella enterica

    সঠিক উত্তর: Campylobacter jejuni

    ব্যাখ্যা: সমাধান সঠিক উত্তর: Option C Campylobacter jejuni is the most common bacterial cause of gastroenteritis worldwide due to its high prevalence in contaminated food, particularly undercooked poultry. It causes inflammatory diarrhea with symptoms such as fever, abdominal pain, and bloody stools. Unlike Staphylococcus aureus, which causes toxin-mediated food poisoning, Campylobacter leads to actual mucosal invasion. Its ability to colonize the gastrointestinal tract and produce enterotoxins is key to its pathogenicity. Effective diagnosis relies on stool culture or PCR, and treatment is mainly supportive, with antibiotics reserved for severe cases. This highlights its clinical significance in infectious diarrhea management globally.Reference: Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases, Gerald L. Mandell et al., 9th Edition.

  8. Erythema chronicum migrans is the characteristic skin lesion of:

    1. Syphilis
    2. Measles
    3. Leprosy
    4. Lyme disease

    সঠিক উত্তর: Lyme disease

    ব্যাখ্যা: সমাধান সঠিক উত্তর: Option D Erythema chronicum migrans is the pathognomonic skin lesion of Lyme disease, caused by the spirochete Borrelia burgdorferi transmitted through tick bites. It appears as a slowly expanding, erythematous, and often annular rash at the site of the tick bite, typically within 3 to 30 days. This lesion is not seen in syphilis, measles, or leprosy. Recognition of erythema chronicum migrans is critical for early diagnosis and treatment of Lyme disease to prevent systemic complications. Reference: Harrison's Principles of Internal Medicine, Fauci et al., 20th Edition.

  9. Koplik spots are pathognomonic for which disease?

    1. Mumps
    2. Measles
    3. Rubella
    4. Chickenpox

    সঠিক উত্তর: Measles

    ব্যাখ্যা: সমাধান সঠিক উত্তর: Option B Koplik spots are small, white or bluish-white lesions on an erythematous base found on the buccal mucosa opposite the molars. They are considered pathognomonic for measles and typically appear 1-2 days before the characteristic skin rash. Their presence helps in the early clinical diagnosis of measles, distinguishing it from other viral exanthems. These spots are a hallmark early sign and are not seen in mumps, rubella, or chickenpox.Reference: Harrison's Principles of Internal Medicine, J. Larry Jameson et al., 20th Edition.

  10. HIV-associated dementia is primarily mediated by:

    1. Direct neuronal infection
    2. Infected macrophages and microglial cells
    3. Astrocyte proliferation
    4. Oligodendrocyte loss

    সঠিক উত্তর: Infected macrophages and microglial cells

    ব্যাখ্যা: সমাধান সঠিক উত্তর: Option B HIV-associated dementia is primarily caused by infected macrophages and microglial cells within the central nervous system. These cells serve as reservoirs for HIV and release neurotoxic substances, such as inflammatory cytokines and viral proteins, leading to neuronal dysfunction and death. Importantly, HIV does not directly infect neurons, but the indirect effects of infected immune cells cause the cognitive and motor deficits observed in the disease. This mechanism explains the characteristic subcortical dementia seen in HIV patients. Reference: Harrison's Principles of Internal Medicine, Fauci et al., 20th Edition.

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