USMLE : Microbiology Toughest Test! Trivia Quiz

25 Questions | Total Attempts: 738

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USMLE : Microbiology Toughest Test! Trivia Quiz

Microbiology is the study of organisms, those being unicellular or acellular. Microbiology involves numerous sub-disciplines, including bacteriology, virology, immunology, and physiology. It is the branch of biology that studies micro- organisms. The study of the human immune system is an example of microbiology. If you are fascinated by microbiology and want to challenge yourself, try taking this test.


Questions and Answers
  • 1. 
    A baby born at 32 weeks gestation with Apgar scores of 2 and 7 was placed in the neonatal intensive care unit. She developed a fever and leukocytosis; lumbar puncture revealed pleocytosis with increased protein, decreased glucose, and gram-positive rods. Which one of the following organisms was most likely isolated from the CSF?
    • A. 

      Escherichia coli

    • B. 

      Listeria monocytogenes

    • C. 

      Neisseria meningitidis

    • D. 

      Streptococcus agalactiae

    • E. 

      Streptococcus pneumoniae

  • 2. 
    A 27-year-old intravenous drug user presents with difficulty swallowing. Examination of the oropharynx reveals white plaques along the tongue and the oral mucosa. Which of the following best describes the microscopic appearance of the microorganism responsible for this patient's illness?
    • A. 

      Budding yeast and pseudohyphae

    • B. 

      Encapsulated yeast

    • C. 

      Mold with nonseptate hyphae

    • D. 

      Mold with septate hyphae

  • 3. 
    A 24-year-old woman in her third trimester of pregnancy presents with urinary frequency and burning for the past few days. She denies fever, nausea, vomiting, or chills. She takes no medications besides prenatal vitamins and is generally in good health. Physical examination is remarkable for mild suprapubic tenderness, and a urine dipstick is positive for white blood cells, protein, and a small amount of blood. Culture produces greater than 100,000 colonies of gram-negative bacilli. Which of the following attributes of this uropathogenic organism is most strongly associated with its virulence?
    • A. 

      Bundle-forming pili

    • B. 

      GVVPQ fimbriae

    • C. 

      Heat labile toxins

    • D. 

      Heat stable toxins

    • E. 

      P pili

    • F. 

      Type 1 pili

  • 4. 
    A febrile 23-year-old college coed presents with fatigue and difficulty swallowing. Physical exam reveals exudative tonsillitis, palatal petechiae, cervical lymphadenopathy, and tender hepatosplenomegaly. A complete blood count reveals mild anemia, lymphocytosis with about 30% of the lymphocytes exhibiting atypical features, and a mild thrombocytopenia. Coombs' test is positive. Which of the following is the most likely complication of this syndrome?
    • A. 

      Acute cholecystitis

    • B. 

      Ascending cholangitis

    • C. 

      Diarrhea

    • D. 

      Immune complex vasculitis

    • E. 

      Splenic rupture

  • 5. 
    A 37-year-old newly married man presents with multiple blister-like lesions on the glans of his penis, appearing over the past 2 days. On questioning, he recalls similar episodes over the past 2 years. Examination is remarkable for tender, 3-4 mm vesicular lesions on the shaft of his penis with no apparent crusting, drainage, or bleeding. There is also slight bilateral inguinal adenopathy. During the asymptomatic period between outbreaks, where would the causative agent likely have been found?
    • A. 

      Fibroblasts

    • B. 

      Lymphocytes

    • C. 

      Macrophages

    • D. 

      Mucoepithelial cells

    • E. 

      Neurons of the sacral ganglia

    • F. 

      Neurons of the trigeminal ganglia

  • 6. 
    A 67-year-old woman in a skilled nursing facility complains of flu-like symptoms. After several days, she develops high fever, dyspnea, and a productive cough. The nurses also notice mental status changes, and she is transported to the nearby community hospital. A chest x-ray shows a cavitary lesion in her left lung. Which of the following organisms would most likely be identified from examination of her sputum?
    • A. 

      Candida albicans

    • B. 

      Klebsiella pneumoniae

    • C. 

      Pneumocystis carinii

    • D. 

      Staphylococcus aureus

    • E. 

      Streptococcus pneumoniae

  • 7. 
    A man presents to a dermatologist because of a severe mucocutaneous rash that involves most of his body, including his palms and soles. Questioning reveals that he is a merchant marine who several months previously had an encounter with a prostitute in Southeast Asia. Which of the following is the most likely causative agent of this rash?
    • A. 

      Herpes simplex I

    • B. 

      Herpes simplex II

    • C. 

      HIV

    • D. 

      Neisseria gonorrhoeae

    • E. 

      Treponema pallidum

  • 8. 
    A child is brought to the pediatrician because of perianal itching, which has been disturbing the child's sleep. Physical examination reveals scaly skin in the perianal region. The physician instructs the parents to place transparent tape on the perianal region the next morning, and then return to the office. In the office, the tape is transferred to a microscope slide, and low-power examination of the tape reveals oval eggs that are flattened along one side. The microorganism most likely responsible for the child's symptoms is
    • A. 

      Ancylostoma duodenale

    • B. 

      Ascaris lumbricoides

    • C. 

      Enterobius vermicularis

    • D. 

      Necator americanus

    • E. 

      Trichuris trichiura

  • 9. 
    One week following a visit to the woods along an Eastern seaboard beach, a 50-year-old woman develops fever, headache, chills, and fatigue. A blood smear demonstrates protozoa within erythrocytes. Which of the following is the most likely pathogen?
    • A. 

      Babesia microti

    • B. 

      Leishmania donovania

    • C. 

      Plasmodium falciparum

    • D. 

      Plasmodium vivax

    • E. 

      Trypanosoma cruzi

  • 10. 
    A patient is referred to a neurologist because of ataxia. The neurologist diagnoses degeneration of the dorsal columns and dorsal roots of the spinal cord, which has caused impaired proprioception and locomotor ataxia. Which of the following organisms most likely caused this pattern of damage?
    • A. 

      Haemophilus influenzae

    • B. 

      Herpes simplex I

    • C. 

      Neisseria gonorrhoeae

    • D. 

      Neisseria meningitidis

    • E. 

      Treponema pallidum

  • 11. 
    Which of the following organisms would be most likely to cause an outbreak of enteritis in a day care center in the United States?
    • A. 

      Helicobacter jejuni

    • B. 

      Salmonella typhi

    • C. 

      Shigella species

    • D. 

      Vibrio cholerae

    • E. 

      Yersinia enterocolitica

  • 12. 
    A 60-year-old woman has been hospitalized for three weeks with widely metastatic ovarian adenocarcinoma, and she becomes septic with vancomycin-resistant enterococcus. What is the mechanism of vancomycin resistance in this organism?
    • A. 

      Acetylation of antibiotic

    • B. 

      Altered drug-binding protein

    • C. 

      β-lactamase production

    • D. 

      Decreased ribosomal binding of antibiotic

    • E. 

      Formation of novel cell wall peptide bridges

  • 13. 
    A 2-year-old boy has surgery to correct a urinary tract obstruction. Post-operatively, with an indwelling urinary catheter in place, he develops a urinary tract infection. Urine culture grows out a lactose-negative, oxidase-positive, gram-negative rod. Which of the following agents is the most likely cause of this boy's urinary tract infection?
    • A. 

      Candida albicans

    • B. 

      Enterococcus faecalis

    • C. 

      Escherichia coli

    • D. 

      Klebsiella pneumoniae

    • E. 

      Proteus mirabilis

    • F. 

      Pseudomonas aeruginosa

    • G. 

      Staphylococcus saprophyticus

  • 14. 
    A 65-year-old Laotian immigrant has developed thick, erythematous nodules on her ears and nose with significant associated sensory loss. The nodules have grown slowly over the course of many years. Biopsy of the lesions shows dermal granulomas with giant cells but no acid-fast bacteria. Culture on blood agar and Lowenstein-Jensen medium shows no growth. These findings are most consistent with which of the following diagnoses?
    • A. 

      Cutaneous leishmaniasis

    • B. 

      Onchocerciasis

    • C. 

      Rhinoscleroma

    • D. 

      Smallpox

    • E. 

      Tuberculoid leprosy

  • 15. 
    Which of the following organisms would most likely be isolated from the vagina of a normal 5 year-old girl?
    • A. 

      Candida

    • B. 

      Lactobacillus

    • C. 

      Neisseria

    • D. 

      Staphylococcus

    • E. 

      Streptococcus

  • 16. 
    A 58-year-old homeless man is brought in to the emergency room by police. His temperature is 101.8°F rectally, and he smells of cheap wine. Physical examination is remarkable for dullness to percussion, increased vocal fremitus, and decreased breath sounds and wet crackles on the right. Chest x-ray reveals consolidation of the right upper lobe. One of the nurses notes the production of thick, bloody sputum when the man coughs. The most likely causative organism is
    • A. 

      Haemophilus influenzae

    • B. 

      Klebsiella pneumoniae

    • C. 

      Pseudomonas aeruginosa

    • D. 

      Staphylococcus aureus

    • E. 

      Streptococcus pneumoniae

  • 17. 
    An archaeologist who has been excavating a very old Middle Eastern site develops a pustule on his hand. The pustule then ruptures to form a black eschar surrounded by expanding brawny edema. Which of the following organisms is the most likely cause of this condition?
    • A. 

      Bacillus anthracis

    • B. 

      Borrelia burgdorferi

    • C. 

      Francisella tularensis

    • D. 

      Spirillium minus

    • E. 

      Yersinia pestis

  • 18. 
    A 33-year-old woman who has recently returned from several years in the Peace Corps in Guatemala presents with severe, acute, right upper quadrant abdominal pain. She recalls that before coming back to the United States, she had several months of bloody diarrhea. CT scan of the liver demonstrates lesions that are interpreted to be abscesses. Which of the following organisms is the most likely cause of her illness?
    • A. 

      Ascaris lumbricoides

    • B. 

      Entamoeba histolytica

    • C. 

      Enterobius vermicularis

    • D. 

      Salmonella typhi

    • E. 

      Shigella species

  • 19. 
    A previously healthy 11-year-old girl develops a gastrointestinal infection with cramping and watery stools. After several days, she begins to pass blood per rectum, and is hospitalized for dehydration. In the hospital, she is noted to have decreasing urine output with rising blood urea nitrogen (BUN). Total blood count reveals anemia and thrombocytopenia, and the peripheral smear is remarkable for fragmented red cells (schistocytes). Infection with which of the following bacterial genera is most likely responsible for this syndrome?
    • A. 

      Campylobacter

    • B. 

      Clostridium

    • C. 

      Salmonella

    • D. 

      Shigella

    • E. 

      Vibrio

  • 20. 
    A 20-year-old man visiting Europe dives into a secluded natural pool. He later develops meningoencephalitis localized to the base of his brain. The causative organism is found to be the free-living amoeba, Naegleria fowleri. Which of the following structures did he probably damage during the dive?
    • A. 

      Cribriform plate

    • B. 

      Lacrimal bone

    • C. 

      Mandible

    • D. 

      Nasal bone

    • E. 

      Zygomatic bone

  • 21. 
    A 1-year-old girl presents with a 2-day history of fever, vomiting, and watery, nonbloody diarrhea. On physical exam, she appears dehydrated. Which of the following best describes the most likely infecting organism?
    • A. 

      It has a complex double-stranded DNA genome

    • B. 

      It has a partially double-stranded circular DNA genome

    • C. 

      It has a segmented, double-stranded RNA genome

    • D. 

      It has a single-stranded circular RNA genome

    • E. 

      It has a single-stranded RNA genome

  • 22. 
    A 16-year-old male with sickle cell disease is hospitalized for a severe infection. His spleen has autosplenectomized and he has suffered from other minor infections in the past. His symptoms include fever, chills, cough, and chest pain. Bacteria from the patient's sputum yield optochin-sensitive organisms with a positive Quellung reaction. The organism is
    • A. 

      Escherichia coli

    • B. 

      Haemophilus influenzae

    • C. 

      Klebsiella pneumoniae

    • D. 

      Neisseria gonorrhoeae

    • E. 

      Streptococcus pneumoniae

  • 23. 
    Which of the following is specifically associated with infection with Schistosoma haematobium?
    • A. 

      Adenocarcinoma of the bladder

    • B. 

      Adenocarcinoma of the renal pelvis

    • C. 

      Squamous cell carcinoma of the bladder

    • D. 

      Transitional cell carcinoma of the bladder

    • E. 

      Transitional cell carcinoma of the renal pelvis

  • 24. 
    An active intravenous drug abuser presents to the emergency department with fever of 5 days' duration, a cough occasionally productive of blood, and pleuritic chest pain. Petechiae are present in his mouth and conjunctivae, and splinter hemorrhages are visible under the fingernails. Which of the following test results would most likely confirm the identity of the causative agent?
    • A. 

      Antibodies to p24 capsid antigen

    • B. 

      Antibodies to Trichinella spiralis antigen

    • C. 

      Blood culture of a catalase-positive, novobiocin-sensitive, gram-positive coccus

    • D. 

      Blood culture of a coagulase-positive, catalase positive, gram-positive coccus

    • E. 

      Blood culture of a gamma-hemolytic, gram-positive coccus on bile-esculin agar

    • F. 

      Blood culture of an alpha-hemolytic, optochin-resistant, gram-positive coccus

    • G. 

      Blood culture of an alpha-hemolytic, optochin-sensitive, gram-positive coccus

  • 25. 
    A 22-year-old woman presents with a 1-week history of mild lower abdominal pain and a yellowish vaginal discharge. She describes the pain as dull in nature, relieved slightly by acetaminophen and worsened by intercourse. Pelvic examination reveals a red, swollen cervix without motion tenderness. The mucosa is friable. Potassium hydroxide (KOH) mount is negative, and wet mount does not reveal clue cells. Gram's stain of the exudate reveals gram-negative cocci. Which of the following procedures would most likely lead to the correct diagnosis?
    • A. 

      Culture the blood on Thayer-Martin agar

    • B. 

      Order DNA probe assays of endocervical exudates

    • C. 

      Order serologic tests to identify specific capsular antigens

    • D. 

      Order the germ tube test

    • E. 

      Order the rapid plasma reagin (RPR) test

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