Med Micro 2, Exam 1

8. The vaccine for the above agent has the following components:

A. Hemagglutinin and neuraminidase of influenza A and B

52. A 64 year old man has a history of chronic neurological symptoms over the preceding eight months, memory, cognition, and motor control are all affected. If this is Creutzfeldt-Jacob disease, what would you expect to observe in a brain biopsy?

B. Aggregates of bovine protein

34. A child is immunized against Polio with the killed-virus (Salk) vaccine. This vaccine produces immunity to Polio by stimulating production of neutralizing antibody. What is the locating of the epitopes bound by these neutralizing antibodies?

B. Envelope glycoproteins

6. Legionnaire's Disease is unusual from most other pneumonias in that it:

B. Is not transmitted from person to person

35. A young man who had traveled extensively in Britain developed neurological disease and at autopsy Bovine spongiform encephalopathy (also known as 'Mad cow disease' and 'New-variant Creutzfeldt-Jakob disease') was

C. Enveloped virions with RNA genomes

57. Which route of infection is most common for Acanthamoeba

C. Inhalation

55. Your patient is a young woman who wishes to become pregnant. Because of the risk to the fetus in a primary infection of a non-immune mother, for what parasitic protozoan should you check her immune status?

C. Toxoplasma gondii

28. What is the diagnosis and its subsequent cause?

B. Aspergillosis due to neutropenia

13. The most contagious period for whooping cough is:

B. The catarrhal phase

45. What if... for instance... the CSF samples showed decreased glucose and increased WBC's (95% PMN) with Gram (-) diplococci on gram stain, and the organism was recovered from blood, what would the etiologic agent?

C. Neisseria meningitides

44. What are the most important samples you should obtain?

D. BothAandB A. Blood B. CSF

53. Prion diseases infect nervous tissue and cause vacuolations in the tissue by:

A. Forcing the conformational change of normal PrPc to Prp sc

46. Identify the definitive host for Toxoplasma gondii:

B. Domesticated cats

30. Hantavirus diseases such as Hantavirus Pulmonary Syndrome and Korean Hemorrhagic Fever with renal syndrome are spread by biting insects?

B. False NOTE: Hantaviruses are carried by rats.

25. This organism is endemic to which of the following geographical regions:

C. The Mississippi and Ohio River Valleys in the United States

20. How can you differentiate between bacterial vs. viral sore throat from history, physical, and laboratory data?

Can't differentiate

5. The ideal sputum specimen to detect lower respiratory tract infections should contain:

A. > 25 neutrophils and < 10 squamous cells / low power field

17. Antigenic shift of Orthomyxoviruses is best characterized as:

A. A major change in the neuraminidase or hemagglutinin proteins

4. You are conducting an epidemiologic survey for the detection of upper respiratory carriers of Streptococcus Group A. The optimal type of specimen to be obtained for culture is:

A. A throat swab

A 37 year old male admitted to the hospital with increased white blood cell count and peripheral smear that "looks like leukemia". Bone marrow biopsy found 70 to 80% blast forms diagnostic of AML. The patient underwent a primary round of chemotherapy without succes. A second round left him extremely neutropenic and he developed a fever of unknown origin. A chest x-ray revealed bilateral infiltrates. Bronchoscopy with biopsy was performed, due to a negative bronchial lavage on the first attempt to isolate an origin, and demonstrated septate hyphae with branching.

A. Aspergillus due to invasive Aspergillosis

62. A cyanotic, listless, infant with extremely poor muscle tone is brought to the Emergency Room. Which condition is most likely?

A. Botulism

32. Which vector is associated with the disease caused by Loa Loa?

A. Deer Fly (Chrysops)

31. A family from New Jersey spent their summer vacation in southern Colorado, where they stayed in a small cabin in the mountains. A few days after they returned to New Jersey one of them developed Influenza-like symptoms. One day later he becomes very ill and is hospitalized; on his his third hospital day he died of respiratory failure. The patient had no significant history of previous illness or infections. Which of the viruses listed is most likely to have caused his illness?

A. Hantavirus

59. The patient is given a tuberculin test. Three days later, there is induration and erythema, 32 mm in diameter, at the site of injection, a positive test result. All of the following could describe this person EXCEPT:

A. He may have an active infection B. He may be highly infectious (contagious) these two bold C. He definitely will definitely develop active TB disease within a year

19. Choose the mechanism by which Mycobacteria tuberculosis survives for extended periods in a patient?

A. Inhibition of phago-lysosomal fusion

61. Which of the following is the mechanism of action of Pertussis toxin?

A. It increases levels of cyclic AMP in the respiratory epithelium leading to increase in mucous production

21. A major difference between Legionnaire's disease and Pontiac Fever:

A. Legionnaire's disease is life threatening and strikes debilitated hosts, while Pontiac Fever is a flu like disease of even healthy people.

1. Choose the best match for the mechanism(s) controlling normal flora in the lower respiratory tract:

A. Mucociliary Action

16. Why are nosocomial versus community acquired pneumonias usually caused by different microorganisms?

A. Nosocomial patients suffer more aspiration and need to be intubated

A 68 year old woman begins to suffer from motor and cognitive difficulties and, after seven months of progressive decline, dies. On the autopsy, in sections of brain tissue, there is prominent vacuolar degeneration of tissue and amyloid deposits, but no evidence of inflammation. 39. Which of the following is most likely the cause of death?

A. Progressive multifocal leukoencephalopathy (JC Virus)

A 14 year old African American girl from rural Tennessee is referred with a history of intermittent cough and pulmonary infiltrates. She first consulted her primary care doctor 7 months earlier because of fever, malaise, and cough of 1 week duration. A chest x-ray then revealed a patch left lower lobe infiltrate, and she was treated with penicillin VK on an outpatient basis. All symptoms subsided after 10 days but she developed low-grade fever and cough three month later. Chest x-ray at the revealed a patchy middle lobe infiltrate and right hilar adenopathy. She was treated again with penicillin and her symptoms gradually subsided. Since that time her only symptoms are rare intermittent cough. Current chest film reveals a right hilar mass, felt by the radiologist to be enlarged hilar nodes and in addition patchy infiltrates in the left upper, and right lower and middle lobes. At this time the patient is hospitalized for full workup. She remains asymptomatic and afebrile throughout her hospital stay. CBC results show a possible immunodeficiency, urine and liver function all within normal limits. FH history reveals the child was born to an HIV + mother. Multiple sputum for microbiologic exam in non diagnostic. Repeated skin PPD tests are negative; mumps skin test is positive. Bronchoscopy is normal, but mediastinoscopy reveals enlarged right hilar lymph nodes. Histological exam of biopsy reveals caseating necrosis but no microorganisms are seen on appropriately stained smears.

A. Tuberculosis C. Klebsiella pneumonia

29. A 12 year old boy develops a heart murmur. To help confirm or rule out Acute Rheumatic Fever, you should order a serological test for antibodies to a specific bacterial antigen. In this test, which antigen should be used?

B. ASO (streptolysin O) of Streptococcus pyogenes

Questions 43 - 45: An 18 year old college student awakens in the middle of the night with a severe headache. During the next few hours, it gets worse and she can't think clearly. Her roommate is concerned of her worsening disposition and takes her to the acute care facility. On presentation she is in acute distress, has a stiff neck, and a conjunctival petechiae are noted bilaterally. Also have compromised memory and cognition, and seizures may occur. PML is relentlessly progressive and death usually occurs within 6 months of initial symptoms. 43. What is the diagnosis?

B. Acute bacterial meningitis

The patient is placed on therapy for TB. Three weeks after discharge, the result of fungal serology returns. Histoplasmin yeast titer is 1:64. After 5 weeks of incubation in appropriate media, both sputum and lymphatic tissue biopsy revealed no bacterial, mycobacterial or fungal growth. Repeated skin test with PPD are negative. The patient remains asymptomatic and her chest xray is unchanged. 65. Which of the following is the best diagnosis?

B. Acute primary histoplasmosis (possible dissemination)

15. Confirmatory test in case of primary atypical pneumonia would be:

B. Bacitracin susceptibility

9. Which of the following organisms causes Whooping Cough?

B. Bordetella pertussis

51. A 55 year old woman developed diplopia, one day after eating home canned fruit. (Diplopia = double vision, from inability to coordinate the direction of gaze of the eyes.) A few hours later she develops difficulty speaking, bilateral weakness of her arms, nausea, vomiting, dizziness, blurred vision, and dry mouth. However she is alert, oriented, and has no fever. Choose the best diagnosis:

B. Botulism

23. A previously healthy 64 year old ornithologist travels from New Jersey to the California desert to study birds. Three weeks after his return to New Jersey he develops fever, chest pain, and muscle aches, and an erythema multiforme rash. These persist for six weeks after which his wife finally persuades him to seek medical attention. X-ray shows several lesions in the left lung and accumulation of fluid in the left pleural cavity. A lung biopsy contains large spherule forms amind neutrophils and lymphocytes (see sketch below). Culture on Saboraud / dextrose agar at 30* C produces large colonies of hyphae. Which of the pathogens below is most likely to have cause this infection?

B. Coccidiodes immitis

2. A child develops a "cold" which progresses to severe pharyngitis. Pharyngeal exudate fo... tough 'membrane', difficult to remove without causing bleeding. Culture of a throat swab shows selective tellurite agar produces abundant black colonies. Other cultures produce only no... flora. Which organism is most likely to have cause this infection?

B. Corynebacterium diphtheriae

7. A respiratory disease spread by the droplet aerosol route during winter causing severe headache, cough, fever, malaise and congestion is most compatible with which of the following as an etiological agent?

B. Influenza A

36. What is the etiologic agent of PML - Progressive Multifocal Leukoencephalopathy?

B. JC-Virus

. A 55 year old male indigent was admitted to the hospital with complaints of chest pain and productive sticky bloody sputum. Chest x-ray revealed consolidation in the right upper lung field. Blood and sputum cultures reveal an organism that accounts for a small percentage of pneumonia cases but extensive damage produced by the organism results in high case fatality rates (up to 90% in untreated patients. Which of the following describes etiologic agent?

B. Klebsiella pneumoniae

63. Antibodies to the Influenza virus of subtype H5N1 completely fail to neutralize virus of subtype H2N2. However, CTL which kill H5N1-infected cells kill H2N2-infected cells efficiently. What is the most likely explanation for the broad effectiveness of anti-H5N1 CTL, compared to the restricted effectiveness of anti-H5N1 neutralizing antibody?

B. Matrix and nucleocapsid proteins of H2N2 and H5N1 virions have amino acid sequences in common C. In H2N2 virions hemagglutinin is found in the interior, not in the envelope

41. The organism is most likely:

B. Meningococcus

60. The sputum sample was sent for culture on Lowenstein-Jensen agar and in the BACTEC system. The probable diagnosis was readily established by x-ray, direct smear, and skin testing. What was the labor and time intensive culture procedure performed?

B. Only highly virulent mycobacteria grow on the media used for culture

12 year old boy comes to the pediatrician presenting with brassy cough, coryza, and conjunctivitis, fever, malaise, and photophobia. History of present illness reveals that a few days ago his mother found minute, whitish spots over the buccal / labial mucosa that rapidly increased in number and coalesced. Red, morbilliform, blanching rash. Labratory: Unsegmented ssRNA with a helical nucleocapsid on viral isolation in the tissue culture. 37. What is your diagnosis?

B. Rubella THIS QUESTION WAS DIFFERENT ON TEST WITH SAME ANSWERS... THE ANSWER FOR MY TEST QUESTION WAS MEASLES NOTE: Unsegmented ssRNA with a nucleocapsid is most commonly Rubella (Rubi Virus) in younger populations.

56. A missionary returning from work in Central America is at risk of being bitten by an arthropod carrying which of the following protozoa?

B. Trypanosoma cruzi

49. A 72 year old woman, a resident of Atlantic County, NJ, develops signs and symptoms of viral encephalitis. Serology confirms the pathogen as Eastern equine encephalitis virus. Which line in the table below correctly identifies the environmental reservoir and vector of this virus?

B. Wild Birds- mosquito

48. A 38 year old man came to the office with a chief complaint of jaw discomfort and inability to open his mouth fully for 3 days. He also said he had struck his right shin with a hammer 10 days earlier while attempting to fix his lawn mower. The hammer penetrated deeply through the skin, and although the wound hurt and bled, he had not sought medical attention. Seven days after the original insult, he started noticing jaw discomfort and the inability to open his mouth completely. On the 3rd day of this discomfort, his wife urged him to seek medical attention. The patient had no history of medical or surgical procedures, he had no known allergies, and was not taking medications. The diagnosis of this disease can only be made on clinical grounds. What is the diagnosis?

B. Wound tetanus

54. Being bitten by a tsetse fly (genus Glossina) would transmit which of the following disease:

C. African sleeping sickness

. The 1918 Influenza pandemic was produced by a virus of subtype H1N1. After the pandemic subsided, there was no pandemic epidemic until 1930,when one was produced by the virus subtype H0N1. After this, again there was no pandemic until 1957; this one was caused by a virus of subtype H2N2. Which of the following is chiefly responsible for producing this p... of pandemics at intervals of one or more decades?

C. Appearance of a virus with a new combination of genome segments

33. An 18 year old man has fever, stiff neck, headache, and difficulty speaking; he rapidly passes into a coma. CSF shows no signs of bacterial or fungal infections by contains many lymphocytes. A brain biopsy is ordered, principally to confirm or rule out Herpes simplex virus (HSV) as the cause of illness. Why is it important to distinguish HSV encephalitis from that caused by other viruses?

C. Drugs exist for treatment of HSV encephalitis

. A 7-year-old patient presents with pain in the left ear. Pus is drained from the ear and a sample sent for culture. Gram stain reveals neutrophils and small Gram-Negative bacteria. A common pathogen in this setting is Haemophilus influenzae. However, the bacteria in the smear are so small that it is difficult to decide whether they are really rods or cocci. What information from the lab would allow identification of the organism as H. influenzae?

C. Growth on agar supplemented with hemin and NAD ( = Factors X and V )

24. A patient presents with a slowly-developing pneumonia. Several opacities are seen in a lung x-ray. On his second hospital day he develops high fever and hypotension. In a stained smear of leukocytes from the buffy coat of blood, tiny intracellular yeast forms are seen. When blood is centrifuged a thick layer of red erythrocytes collects at the bottom of the tube. Above this is a this off white layer that contains the white cells - the "buffy coat. Above the buffy coat is the clear pale-yellow plasma. What organism is this most likely to be?

C. Histoplasma capsulatum

An 8 year old boy with a slight cold and temperature of 101* F, is complaining of headache and slight pain in the neck, and was taken to the office of a man who was not a physician. Local heat and manipulation of the cervical spine produced some relief. Ten grams of aspirin reduced the temperature to 100* F over 3 hours. The child vomited once before going to bed that night. The following morning his temperature was 103* F and he was sleepy. His mother decided to permit him to stay in bed at his request. At noon, he could not be aroused, and a physician was called. He found a comatose boy with a rapid pulse, nuchal rigidity, and a positive Kernig's sign. 40. The diagnostic procedure most likely to aid in the correct diagnosis is a:

C. Lumbar Puncture

14. A 20-year-old college student with no previous history of significant illness comes to the clinic because of ten days of low fever, dry cough, and malaise. Chest x-rays show widespread diffuse inflammation of the lungs. She is given a prescription of an erythromycin-class drug, because a common bacterial cause of this type of illness in college students is resistant to all beta-lactam antibiotics. Which organism below best fits this description?

C. Mycoplasma pneumoniae

38. Which of the following could be a fatal long term consequence of the above organisms?

C. PRP

18. Which of the following fungi is associated more commonly in patients with AIDS?

C. Pneumocystis carinii

A 23 year old man is plowing a field on a hillside. The tractor strikes a large rock and tips over, pinning him underneath. The ground is muddy, and he is able to work his way free. He discovers a deep, penetrating puncture wound on his calf. He walks home and washes the soil of the wound site and puts a bandage over it. A week later the wound is healing, and the leg is not swollen, but he begins to experience generalized muscle spasms, with stiffness and pain in his shoulders and back. He has difficulty with eating and swallowing, with painful jaw and facial muscles. 42. Which of the following organisms is most like responsible for these findings?

D. Clostridium tetani

A 30 year old HIV + male has been referred to you because of hemoptysis ( Hemoptysis = coughing up blood ). A cavitary lesion in the right upper lobe of the lung is seen on chest x-ray ( Cavitary lesion = opaque lesion on x-ray with a central region of low density produced by the death of tissue. ) A sample of sputum is obtained and a smear is acid fast stained using the red dye carbol-fuchsin. 58. If this is tuberculosis, what would you expect to observe after acid fast stain of the sputum?

D. Red-staining bacilli

47. How would one acquire an infection with Trypanosoma cruzi?

D. being bitten by a kissing bug (genus Triatoma)

50. Which of the following organisms should you suspect in a case of fatal fulminant meningoencephalitis of a 7 year old boy from swimming in a pond?

N. Fowleri

10. Pseudomonas aeruginosa is most commonly seen in otitis externa (swimmer's ear)

True

22. Asplenic patients are at higher risk of fulminant infections by encapsulated organisms like Streptococcus pneumoniae

True

12. DACRYOCYSTITIS is a bacterial infection of the lacrimal sac

true