Question 1

Repeated Neisseria meningitidis septicemias in an individual should raise physician awareness of what underlying condition?

Accepted Answer

A) C5 to C8 deficiencies 
B) Chronic hepatitis B infection 
C) Ketosis-prone diabetes 
D) Multiple myeloma 
E) Severe neutropenia

Question 2

A 45-year-old man had mental degeneration after a prolonged but inapparent infection. At autopsy, a subacute spongiform encephalopathy is found. What is the nature of the most likely causative agent?

Accepted Answer

A)  Acid-fast organism 
B) Dimorphic fungus 
C) DNA virus 
D) Viroid 
E) Prion

Question 3

A patient presents with explosive, watery, noninflammatory diarrhea along with headache, abdominal cramps, nausea, vomiting, and fever. Symptoms began the day after eating raw oysters in August. What is the most likely causative agent?

Accepted Answer

A)  Giardia lamblia 
B) Norwalk agent 
C) Rotavirus 
D) Salmonella enteritidis 
E) Staphylococcus aureus
F)Vibrio parahaemolyticus

Question 4

Anti-A isohemagglutinins are present in persons with which one of the following blood types?

Accepted Answer

A)  Type A 
B) Type B 
C) Type AB

Question 5

An autoimmune state characterized by a triad of thrombocytopenia, eczema, and recurrent infections is

Accepted Answer

A)  Myasthenia gravis 
B) Severe combined immunodeficiency disease (SCI
D)  
C) Pernicious anemia 
D) Congenital agammaglobulinemia 
E) Wiskott-Aldrich syndrome

Question 6

A mother brings her 8-year-old son to your office and reports that about 10 days ago he had a flu-like disease with a minor fever. Three days ago he had a very red face which turned normal color when touched, and now he has a red rash on his arms and legs which also blanches to touch. She states he had all the normal childhood shots. The most likely infectious cause of his symptoms is

Accepted Answer

A) Candida albicans 
B) Coxsackie A virus 
C) Parvovirus B19 
D) Staph. epidermidis

Question 7

A 59-year-old man presents at the emergency department with labored breathing and a sharp stabbing pain behind the breast bone. He complains of being weak and tired. He has a low-grade fever and an electrocardiogram shows elevated ST segments. The most likely infectious cause of these symptoms is

Accepted Answer

A) BK virus 
B) Coxsackie B virus 
C) Moraxella catarrhalis 
D) Nocardia asteroides 
E) Rotavirus

Question 8

A neonate is suspected to have combined immunodeficiency disease (SCID). (One previous sibling died of this.) Which of the following would confirm the diagnosis?

Accepted Answer

A) Presence of the thymus but absence of the bursal equivalent 
B) Deficiency in the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase system 
C) Deficiency in adenosine deaminase, and loss of this enzyme activity 
D) An absence of neutrophils

Question 9

Which complement component is most closely related to anaphylatoxin?

Accepted Answer

A)  C1qrs 
B) C2b 
C) C4b2a 
D) C5a 
E) C5b

Question 10

The Pap smear of a 19-year-old female college soccer player contains koilocytotic cells. The disease associated with the appearance of the cells could most likely have been prevented by previous administration of a(n)

Accepted Answer

A)  Inactivated virus vaccine 
B)  Inactivated whole cell vaccine 
C)  Live attenuated virus vaccine 
D)  Recombinant vaccine containing viruslike particles 
E)  Toxoid vaccine

Question 11

Mobile genetic elements that code for antibiotic resistance genes in bacteria but are incapable of self-replication are

Accepted Answer

A) Mesosomes 
B) R factor 
C) Temperate RNA phages 
D) Transposons 
E) Virulent DNA phages

Question 12

A 40-year-old man presents to the ED with a painful and swollen jaw. Two days ago he had a tooth extraction where the gums and jaw were swollen and painful. "Nodules" are felt below the surface of the tissues which are not lymph nodes. Which member of the gingival normal flora will grow contiguously into the damaged tissues, producing tissue swelling and ultimately, if untreated, will develop sinus tracts that will erupt to the surface, liberating the "nodules"?

Accepted Answer

A) Actinomyces israelii 
B) Nocardia asteroides 
C) Mycobacterium kansasii 
D) Fusobacterium nucleatum

Question 13

A Peace Corps volunteer who recently returned from rural Africa develops symptoms of liver damage and a blocked bile duct after general anesthesia for a knee replacement. What is the nature of the most likely causative agent?

Accepted Answer

A)  Cestode 
B) Dimorphic fungus 
C) Filamentous fungus 
D) Fluke 
E) Nematode
F)Protozoa

Question 14

Which of the following childhood vaccines is most likely to prevent otitis media in young children?

Accepted Answer

A) H) influenzae 
B) Measles, mumps, and rubella 
C) Meningococcal 
D) VZV

Question 15

Latent infection of neurons occurs with

Accepted Answer

A)  Cytomegalovirus 
B) Herpes simplex virus 
C) Measles virus 
D) Poliomyelitis virus 
E) Rabies virus

Question 16

It is August. A 30-year-old man appears at your office complaining of difficulty in breathing, headache, and joint and lower back pain. He has a 101°F fever and a prominent cough. During your history taking, only one unusual activity, the thorough cleaning of an old hunting shack, was noted. The cleaning involved removal of old food containers, pots, and bedding, plus some rodent nests. He also deployed new mouse traps. Based on this history, what agent is most likely causing his symptoms?

Accepted Answer

A) Chlamydia pneumonia 
B) Influenza A virus 
C) Legionella pneumonia 
D) Pneumocystis jiroveci 
E) Sin Nombre virus

Question 17

A 15-year-old boy on antibiotics to clear up a community-acquired methicillin-resistant Staphylococcus aureus has clindamycin added to his treatment regimen to slow the production of the various toxins including Panton-Valentine leukocidin. He recovers but develops Clostridium difficile diarrhea. Why does C. difficile cause diarrhea?

Accepted Answer

A)  C. difficile multiplies and causes disease in a mechanism similar to that of Listeria 
B) 
C)  difficile multiplies, secreting Shiga toxin during cell lysis 
C) 
C)  difficile stacks itself on the colonic surface to cause malabsorption and the appearance of a pseudomembrane 
D) 
C)  difficile exotoxins damage the cells, causing a disruption in transport and attracting polymorphonuclear cells to cause the appearance of a pseudomembrane

Question 18

An RNA tumor virus associated with the neurologic disease tropical spastic paraparesis is

Accepted Answer

A)  AKR leukemia virus 
B) Human immunodeficiency virus 
C) Human T-lymphotropic virus type 1 
D) Rous sarcoma virus

Question 19

An 11-day-old neonate has been brought to his pediatrician because the infant has developed a sharp cough. Physical examination also reveals a mild conjunctivitis with some pus; a chest film confirms pneumonia. No organisms are seen on Gram stain of the pus. What is the most likely causative agent?

Accepted Answer

A) An obligate intracellular organism unable to make its own ATP 
B) A diplococcus that has a high potential vto cause blindness as well as the pneumonia 
C) An organism that has no peptidoglycan or other cell-wall polymer 
D) An obligate intracellular organism infective vascular endothelium 
E) An organism that may be demonstrated by acid-fast stain and is largely intracellular

Question 20

A 2-year-old infant's mother reported her son has had three infections in the past 6 months. Which of his serum values (mg%) would indicate he had an immunodeficiency disease?

Accepted Answer

A)  IgA $\rightarrow$ 350 
B) IgG $\rightarrow$ 650 
C) IgM $\rightarrow$ 150 
D) IgE $\rightarrow$ 0.05

Exam 11: Travelers Diarrhea: Identifying the Causative Agent