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MICROBIOLOGY REVIEW QUESTIONS

For each question, ask yourself...
...did I answer correctly?
...what makes the incorrect answers incorrect? How can I change the 'incorrect' answer to make it 'correct'?
...do I have a good understanding about the topic asked in the question stem (e.g. if the question is about influenza medications, do i understand about other influenza issues like vaccines)
...do I have a good understanding of the topics involved in the incorrect choices (e.g. if the question is exploring clinical manifestations of botulism and a wrong answer just happens to be 'tetanus', do i also understand the clinical manifestations of tetanus)
...Am I comfortable enough on each topic raised in the question and potential answers to write several sentences describing relevant issues such as biology, structure, pathophysiology, disease manifstations, mechanisms, and epidemiolgy?
...Are any of the elements of the question a topic for which i should pull out my primary resource and refresh my memory?





1. Which of the following is typically a nosocomial pathogen?

A. VRE – vancomycin-resistant enterococci
B. Mycobacterium tuberculosis
C. Borrellia burgdorferi
D. Staphylococcus epidermidis



2. One medical student strikes another in the face during a heated argument in study group over the fermentation characteristics of E. coli., knocking out the student’s front tooth. Two days later, the hand is red, swollen, and painful at the site of contact.

Of the following, which is most likely etiology?

A. Actinobacillus actinomycetemcomitans
B. Cardiobacterium hominis
C. Pasteurella multocida
D. Capnocytophaga
E. Eikonella corrodens



3. Which toxin cleaves rRNA, blocking protein synthesis?

A. Shiga toxin
B. Pertussis toxin
C. Cholera toxin
D. E. coli LT (heat labile) toxin
E. E. coli ST (heat stabile) toxin





4. A 30 year old man presents to the emergency room with decreased level of consciousness and diffuse erythema and flushing of the skin.
Vitals: temperature of 1030F, HR of 120, RR 20, BP 90/50. He has a small area of fluctuance and erythema on his thigh where he had injured himself two days prior while cleaning brush. It is draining a tiny amount of purulent material.

A head CT is performed and is normal. Lumbar puncture reveals: protein 30, glucose 90, 3 RBCs, no WBCs, no organisms seen on gram stain. Three days later, blood cultures continue to be negative, and a culture of material expressed from the thigh lesion has grown a heavy growth of Staphylococcus aureus.

Which of the following explains this patient’s acute presentation?

A. Super-antigen production
B. Endotoxin release
C. Meningitis
D. Toxin-mediated cyclic AMP production





5. Which of the following factors would lead to enhanced ability of Staphylococcus epidermidis (coagulase-negative Staphylococcus) to adhere to an indwelling intravenous catheter?

A. Biofilm formation on the catheter
B. Conjugative pilus
C. Opa protein production
D. Type IV pilus
E. Plasmid-mediated lectin production


6. A 10 year old child living in a refugee camp develops profuse watery diarrhea with flecks of mucus “rice water stools” and dies of dehydration. Over 100 people in the same camp have developed similar symptoms within the last week.

Which of the following is true of toxin causing this illness?

A. It ribosylates G proteins, stimulating guanylate cyclase
B. It decreases cAMP levels
C. It requires infection with a lysogenic phage
D. It ADP-ribosylates elongation factor-2
E. It inactivates ribosomal RNA, blocking protein synthesis




7. Which of the following is true of bacterial genetic transfers?

A. Lysogenic conversion is mediated by bacteriophages
B. Transduction involves uptake of naked DNA
C. Transformation involves RNA
D. Conjugation is limited to very small DNA fragments
E. Meiosis occurs






8. Which of the following is true of Pseudomonas aurugenosa?

A. It produces pyocyanin
B. The sensitivities to antibiotics are consistent and predictable.
C. It is a common contaminant of nitrogen-rich soils.
D. It has a weak endotoxin that helps promote abscess formation.
E. It frequently presents as a community-acquired infection




9. What are common characteristics of HACEK organisms?

a. They are commonly associated with small vegetations on cardiac valves that require transesophageal echocardiography for accurate diagnosis
b. All are Gram-positive spore formers
c. All are serovariants of Hacekius spp.
d. They are slow growers and require extra time to grow in standard blood culture media
e. They characteristically cause pneumonia





10. Nocardia is which of the following:

A. Acid Fast
B. Gram Negative
C. acultatively Anaerobic
D. Coccoid in morphology





11. A five year old child presents with hemolytic uremic syndrome following a diarrheal illness.

Which one of the following organisms was the most likely cause of his diarrhea?

A. Pseudomonas auruginosa
B. Enterotoxigenic E. coli
C. Salmonella typhi
D. Bacteroides fragilis
E. Enterohemorrhagic E. coli




12. Which of the following diseases is NOT caused by actual INFECTION with the etiologic agent?

A. Oroyo Fever / Carrion’s Disease
B. Cat Scratch Fever
C. Trench Fever
D. Pontiac Fever
E. Legionnaire’s Disease




13. The disease “diphtheria” is

A. Caused by Endotoxin release
B. Caused by Blockade of Elongation-factor 2
C. Due to infection with Corynebacterium jeikeum that have been lysogenically converted
D. Typically seen with yellow pseudomembranes found on colonic epithelium
E. Preventable with a vaccine targeted to attachment proteins on
the organism’s cell wall




14. A patient presents with diplopia and eye drooping, followed by progressive descending paralysis. You obtain a history of eating home-canned tomatoes.

What is the likely explanation for his symptoms?


A. Superantigen-related release of inflammatory mediators
B. Inhibition of acetylcholine release
C. Blockade of inhibitory neurotransmitters
D. Cytolytic effect on enterocytes





15. Four months after extraction of an impacted wisdom tooth, a 23 year old woman presents with a draining sinus from the angle of the jaw. Cultures are obtained of the purulent material. Two weeks later, the culture that was incubated in anaerobic conditions grows a filamentous organism that is gram positive.

What else would characterize this organism?

A. Rapid growth on chocolate agar incubated under aerobic conditions
B. Response to penicillin therapy
C. Weakly acid fast
D. Forms a potent neurotoxin
E. Causes disease in the setting of broad spectrum antibiotic use





16. Which of the following antibiotics inhibits peptidoglycan synthesis?

A. Ciprofloxacin
B. Rifampin
C. Meropenum
D. Tetracycline
E. Erythromycin




17. A 20 year old sexually active man is treated for acute purulent urethritis with intramuscular ceftriaxone. One week later he returns complaining of a thin, watery urethral discharge.

Which of the following is true?

A. It will respond to treatment with clindamycin
B. It has an extensive peptidoglycan layer that protects it from osmotic stresses.
C. Azithromycin should be administered.
D. It has elementary bodies that undergo binary fission within cellular vacuoles.
E. He was likely re-infected with the same organism from his sexual partner who was untreated.




18. Disease from which of the following organisms is characterized by an eschar AND is transmitted by a mite?

A. R. akari
B. R. rickettsia
C. R. africae
D. R. typhi
E. O. tsutsumagushi






19. Which of the following parasitizes polymorphonuclear leukocytes AND is transmitted by the Lone Star tick?

A. Ehrlichia chaffeensis
B. Ehrlichia ewingii
C. Anaplasma phagocytophilum
D. Rickettsia ricketsii





20. A 30 year old woman from Haddam, CT, presents in April with fever, myalgias and a rash on the mid thigh that is 7 cm in diameter with central clearing.

Which is most true of the infecting agent?

A. It responds to oral doxycycline
B. It can cause birth defects if she is pregnant
C. It was transmitted by dermacentor variablis (dog tick)
D. It is likely to cause chronic fatigue and disability
E. The treatment of choice is intravenous ceftriaxone





21. A 65 year old man has been in the ICU after a neurosurgical procedure to remove a meningioma. During his post-surgical course, he develops fever, increasing peripheral WBC counts (20,000, nl 5-11K) with 50% immature forms (bands), and a new pulmonary infiltrate in the left lower lobe. Sputum gram stain shows many polymorphonuclear leukocytes, no epithelial cells, and large numbers of gram-negative rod bacteria.

Which of the following would be most likely to be effective therapy for the infection?

A. Cefipime
B. Oxacillin
C. Daptomycin
D. Linezolid
E. Vancomycin





22. Which of the following can be seen in a patient with long-standing positive VDRL (RPR) and positive FTA tests who does not receive antibiotic therapy?

A. Aortic aneurysm
B. Chronic arthritis
C. Atrioventricular conduction delays
D. Relapsing fevers
E. Genital Ulcer





23. A five year old child presents with hemolytic uremic syndrome following a diarrheal illness.

Which one of the following organisms was the most likely cause of his diarrhea?

A. Pseudomonas auruginosa
B. Enterotoxigenic E. coli
C. Salmonella typhi
D. Bacteroides fragilis
E. Enterohemorrhagic E. coli





24. A 50 year old female nurse develops an abscess on her skin. A culture reveals MRSA. She has an allergy to penicillin and TMP/SMX (hives, difficulty breathing), so she is started on a regimen of linezolid. Other medications include Prozac (fluoxetine) for mild depression and levothyroxine . These have been controlled for many years. She presents to the ER with tachycardia, anxiety, and flushing after attending an anniversary dinner at Max Downtown. You get the history that she has eaten raw oysters, had a glass of red wine, with an appetizer of smoked meats and cheeses.

What is the likely cause of her symptoms?

A. Sepsis from Vibrio
B. Acute alcohol Intoxication
C. Exacerbation of her mental health issues (anxiety)
D. Serotonin syndrome
E. Thyrotoxicosis
F. Bacteremia from S. Aureus / MRSA





25. Link the correct drug-toxicity combination

A. Tigecycline       1.  Seizures
B. Daptomycin      2. Flushing (Red Man Syndrome)
C. Erythromycin     3. Inactivation by surfactant
D. Linezolid          4. Serotonin syndrome
E. Imipenem         5. Hyperemesis





26. Which of the following antibiotics inhibits peptidoglycan synthesis?

A. Ciprofloxacin
B. Rifampin
C. Imipenem/cilastatin
D. Tetracycline
E. Erythromycin





27. Enterococcus has endogenous resistance to which of the following:

A. Quinolones
B. Ampicillin
C. Cefazolin
D. Vancomyin
E. Linezolid





28. A child care worker presents with cramps and acute onset foul smelling greasy loose stools that float in the toilet. A stool antigen test is positive for Giardia lamblia.

Which is true of the organism?

A. It infects the large bowel epithelium
B. It can cause a pulmonary syndrome with severe infections in immunocompromized patients
C. It responds to therapy with ivermectin
D. It is acid-fast
E. The trophozoite has two nuclei





29. The Reduvid or “kissing bug” transmits which agent?

A. Trypanosoma cruzi
B. Leishmania donovani
C. Trichinella spiralis
D. Trypanosoma gambiense
E. Plasmodium ovale
F. Babesia microti





30. A patient with AIDS is admitted to an ICU with fever and hypotension that is persistent despite broad spectrum antibacterial therapy. A urinary antigen test is positive for Histoplasma capsulatum.

What statement best characterizes this organism?

A. It is a thermally dimorphic fungus
B. It is endemic in the Desert Southwest
C. It is associated epidemiologically with cattle
D. It responds to echinocandin antibiotics
E. It frequently causes meningitis





31. A 35 year old male presents with chronic dyspepsia. Antibody testing is positive for IgG antibody to Helicobacter pylori.

Which of the following is a true statement about the organism?

A. It makes urease
B. It is associated with gastric squamous cell carcinoma
C. It will grow easily on standard blood agar
D. Gram stain will demonstrate marked gram positivity
E. Untreated disease may lead to colonic ulcerations





32. Which of the following is the mechanism of action of amphoterocin B?

A. Inhibition of Squalene Epoxidase
B. Inhibition of 14-α-demethylase
C. Inhibition of β-1,3 –D glucan synthase
D. Inhibition of protein synthesis
E. Formation of pores in cell membrane





33. Which of the following is a typical manifestation of Trypanosoma cruzi  infection?

A. Mega-colon
B. Descending paralysis
C. Diarrhea
D. Subcutaneous nodules
E. Jaundice





34. Which of the following is true of neurocystercercosis?

A. It is acquired by ingestion of infected meat.
B. It is caused by Taenia saginata (beef tapeworm)
C. Human cannibals who ingest infected human brain (uncooked) would develop intestinal worms
D. The organism characteristically forms adult worms in the porcine (pig) GI tract
E. It is epidemiologically linked to contact with contaminated fresh water





35. Which of the following is true of Asperigillus infections?

A. The portal of entry is often from breaches in skin integrity
B. 90-degree branching of hyphae is characteristic
C. Antibody testing is useful for diagnosis
D. Angioinvasion is common
E. Eosinophils are important in host defense





36. Which intestinal parasite's life cycle has a tissue and lung phase, but NOT a skin phase?

A. Stronglyoides stercoralis
B. Ascaris
C. Enterobius vermicularis - pinworm
D. Necator americanus - hookworm
E. Trichura trichuris – whipworm




37. For the malaria treatments below, match the drug to the characterisitic side effect

A. Atovaquone proguanil    1. photosensitivity
B. Tetracycline                 2. nightmares
C. Mefloquine                   3. tinnitus
D. Primaquine                 4. hemolysis
E. Quinine                      5. nausea





38. Which of the following drugs works as GABA agonist?

A. Ivermectin
B. Trimethoprim-Sulfamethoxizole
C. Tinadazole
D. Chloroquine phosphate
E. Praziquantel





39. An eight-year old boy who emigrated from Nigeria last week presents with fever and is found to have 5% parasitemia with P. falciparum. Which of the following is true of this illness?

A. It is important to treat with an agent active against the hypnozoite phase in order to prevent relapse
B. It is likely to resistant to chloroquine
C. It infects only very young RBCs
D. It infects only very old/senescent RBCs






40. Which of the following is a cause of heterophile-negative mononucleosis?

A. Toxoplasmosis
B. Anaplasmosis
C. Coccidiodomycosis
D. Babesiosis
E. Paracoccidioidomicosisproctitissarcomucosis





41. You are evaluating a 50 year old IV drug user with HIV. He has had persistently elevated liver enzymes for 1 year. You draw blood tests which show the following:

Hepatitis A IgG: +
Hepatitis A IgM: -
Hepatitis B Surface Antigen: +
Hepatitis B Surface Antibody: -
Hepatitis B IgG Core Antibody +
Hepatitis C antibody: +
Hepatitis C PCR:  not detected

Which clinical scenario explains the immunologic pattern seen?


A. Acute Hepatitis A
B. Acute Hepatitis B
C. Chronic Hepatitis B
D. Chronic Hepatitis C
E. Cytomegalovirus





42. Which virus has a segmented genome?

A. HIV-2
B. Influenza B
C. Polyoma virus
D. Hepatitis B virus





43. Which of the following inhibits viral polymerase by mimicking pyrophosphate?

A. Foscarnet
B. Valganciclovir
C. Cidofovir
D. Docasonol
E. Fomiversen





44. Maraviroc most directly interferes with the function of which component of the HIV virus?

A. GP120
B. GP41
C. P24
D. RNA-dependent DNA polymerase
E. CXCR4





45. A patient with AIDS and CD4 count of 15 presents with subacute visual loss. Retinal exam reveals hemorrhages and exudates in the periphery.

What of the following agents would be the most effective therapy for this infection?

A. Ganciclovir
B. Acyclovir
C. Zanamivir
D. Ribavirin
E. Zidovudine





46. Which of the following is true of Influenza A virus?

A. Neuraminidase is required for viral attachment.
B. Oseltamivir interferes with the M2 protein
C. It has a seven-segmented genome
D. Zanamivir interferes with Hemagglutinin
E. Yearly immunizations are required due to antigenic drift





47. Which of the following is a DNA virus?

A. Influenza B virus
B. Respiratory syncytial virus
C. Rubella (German measles)
D. Parvovirus
E. Polio virus





48. A 23 year old man presents with his fifth episode of genital ulceration. The lesions start as an itching sensation on the shaft of his penis, then painful blisters, then ulceration.

Which of the following is true of this virus?

A. It remains dormant in the basal ganglia
B. It is a positive-sense single stranded RNA virus
C. It is an enveloped virus
D. It will respond to ribavirin therapy
E. A scraping of the lesion showing multinucleated giant cells definitively identifies this virus





49. Which of the following viruses encodes for a viral reverse transcriptase?

A. Flavivirus
B. Hepadnavirus
C. Picornavirus
D. Paramyxovirus
E. Reovirus





50. Which of the following is an RNA virus that can cause fetal abnormalities?

A. Parvovirus B-19
B. Rubella virus
C. Cytomegalovirus
D. Toxoplasma
E. Rotavirus





51. A 45 year old previously healthy man presents with two days of increasing confusion, personality changes culminating in a grand mal seizure. MRI shows edema of the temporal lobe. What organism is the MOST LIKELY as an etiologic agent?

A. Toxoplasm gondii
B. Streptococcus pneumonia
C. Varicella Zoster virus
D. Type I Herpes virus
E. Type II Herpes virus
F. Cryptococcus neoformans






52. A 35 year old male presents with a rash that is concerning for smallpox. What factor would be most consistent with a diagnosis of smallpox?

A. Several lesions are crusted, others appear vessiculated or plaque-like
B. Lesions are concentrated over the face and trunk
C. He is a pet shop owner who specializes in exotic animals from Africa and South America
D. Palms and soles are spared
E. Lesions appeared at the same time





53. A 30 year old healthcare worker is being evaluated for pre-employment physical. She has no personal history of varicella (chickenpox) as a child. A titer for varicella antibody is negative. What should you do?

A. Administer two doses of varicella vaccine
B. Administer one dose of varicella vaccine and recheck a titer
C. Administer varicella zoster vaccine
D. Do not administer vaccine; furlough the patient with any varicella exposures






54. Which of the following is true of INFLUENZA?

A. Influenza B has a 7-segmented genome
B. The inactivated vaccine contains both Neuraminidase and Hemaglutinin
C. Live vaccine is indicated for infants and elderly populations
D. Inactivated vaccines can on rare occasions cause acute influenza





55. Which of the following is NOT currently targeted by HIV drug therapy?

A. Fusion
B. Protease
C. Integration
D. Reverse Transcription
E. CXCR4

56. An organism has been gram stained and is shown below:

What is the most important factor determining the color of this organism on gram staining?

A. Intracellular pH
B. Membrane-bound Efflux Pumps
C. Membrane-associated Glycolipids
D. K-Antigens
E. Peptidoglycan






57. A sputum specimen is stained carbol fuschin and then decolorized with acid alcohol and then counterstained with methylene blue. The following is seen:

What is true of the organism?

A. It contains a large glycolipid layer
B. It has an outer cell membrane
C. The organism lacks peptidoglycan
D. It is an obligate anaerobe
E. It grows well on blood agar

58. You obtain a gram stain of a blood culture in a patient with infective endocarditis and see the following with gram stain of the culture. Further evaluation in the lab reveals it to be Abiotrophia defectiva.

Which of the following is a true statement about the organism?

A. It has an outer membrane permeated by porins
B. Host antibody will react to this organism’s O-antigen
C. Each cell has a distinct nuclear membrane
D. Periplasmic proteins will lyse certain antibiotics
E. It has a single lipid bilayer cell membrane


59. An Iraq war veteran presents with a skin lesion. He spent the last tour in large part living in foxholes where he suffered from multiple insect bites.

What is the likely organism?


A. Penicillium marfenii
B. Leishmania donovani
C. Bacillus anthracis (anthrax)
D. Corynebacterium diphtheriae
E. Schistosoma mansoni

 
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