1.
One of three blood culture bottles drawn from a patient with unexplained fevers reveals gram-positive cocci
growing in clusters. Which of the following tests would be most useful in determining whether this organism is a
part of the normal skin flora?
A. 
B. 
C. 
D. 
E. 
2.
A 4-month-old infant presents with failure to thrive, progressive muscular weakness, and poor head control. On
questioning, the mother states that she typically feeds the baby soy-based formula sweetened with honey. Which
of the following organisms is most likely to be responsible for the child's presentation?
A. 
B. 
C. 
D. 
E. 
Corynebacterium diphtheriae
3.
A. 
B. 
C. 
D. 
E. 
4.
A 37-year-old woman presents with 3 days of progressive joint pain in her ankles, knees, and wrists. She recalls
three similar episodes over the past several years. On examination, she has a temperature of 38.7 C, her blood
pressure is 110/70 mm Hg, and her heart rate is 90/min. She has a diffuse petechial rash over her trunk and
extensor surfaces. Her ankles and knees are swollen, red, and tender with decreased range of motion, and there
is tenderness over the tendon sheaths of her hands and forearms. Blood cultures are negative. Aspiration of joint
fluid reveals a white cell count of 22,000/mm3 with no visible organisms, but culture on chocolate agar is positive.
Which of the following is an attribute of the causative organism that allows it to produce recurrent infections?
A. 
It is an intracellular pathogen
B. 
It is resistant to ceftriaxone
C. 
It is resistant to complement-mediated lysis
D. 
Its capsule is not immunogenic
E. 
Its pili undergo antigenic and phase variation
5.
A. 
B. 
C. 
D. 
E. 
6.
A patient with colorectal cancer develops septicemia complicated by endocarditis. You would expect the blood
cultures to grow
A. 
B. 
C. 
D. 
E. 
7.
A 54-year-old woman suffering from influenza deteriorates and develops shaking chills and a high fever. Physical
examination is remarkable for dullness to percussion at the left base and decreased breath sounds on the left.
Chest x-ray confirms the diagnosis of lobar pneumonia, presumed to be caused by Streptococcus pneumoniae.
The patient has no known drug allergies. Which of the following antibiotics would be most appropriate to treat the
patient's condition?
A. 
B. 
C. 
D. 
E. 
8.
An otherwise healthy 3-year-old child is brought to the pediatrician with umbilicated, flesh-colored papules on his
trunk. This condition is related to infection with which of the following viruses?
A. 
B. 
C. 
D. 
E. 
9.
A 39-year-old black man presents with complaints of anorexia, malaise, fatigue, dark urine, and upper abdominal
discomfort. He admits to homosexuality, but denies blood transfusions, alcohol intake, or intravenous drug
abuse. On physical examination, the patient has a temperature of 100.2 degrees F, scleral icterus, and jaundice.
His liver is palpable below the right costal margin, and there is moderate right upper quadrant tenderness. Liver
function test results are as follows: total bilirubin 12.4%, SGOT 980 units, SGPT 1200 units. Serologic findings
are as follows: anti-hepatitis A IgM negative, HBsAg positive, anti-HBc IgM positive, HBeAg positive, anti-HBsAb
negative, hepatitis C negative. When this patient enters the window period, what would likely be the first change
in his serologic findings?
A. 
He will become HBcAg positive
B. 
He will become HBc IgG positive
C. 
He will become HBeAg negative
D. 
He will become HBsAb positive
E. 
He will become HBsAg negative
10.
A 15-year-old girl in a rural community has swollen, painful lymph nodes in her right axilla. Physical examination
reveals multiple scratches on her right arm with a papule associated with one of the scratch marks. She states
that the scratches occurred about 5 days ago. What type of animal is the most likely source of the infection?
A. 
B. 
C. 
D. 
E. 
11.
A 73-year-old woman with a history of diabetes presents with left ear pain and drainage of pus from the ear
canal. She has swelling and tenderness over the left mastoid bone. Which of the following microorganisms is the
most likely causative agent?
A. 
B. 
C. 
D. 
E. 
12.
A 29-year-old female diagnosed with AIDS has been suffering from a progressive blurring of vision in her right
eye. On funduscopic examination, a small white opaque lesion is noted on the retina of her right eye. Which of
the following is the most appropriate therapy for this patient?
A. 
B. 
C. 
D. 
E. 
13.
A newborn is infected in utero with an enveloped virus containing double-stranded DNA. The child develops
petechiae, hepatosplenomegaly, and jaundice. Brain calcifications are detected on computed tomography (CT).
With which of the following viruses is the newborn most likely infected?
A. 
B. 
C. 
D. 
E. 
14.
A. 
B. 
C. 
D. 
E. 
15.
A 33-year-old woman presents with fever, vomiting, severe irritative voiding symptoms, and pronounced
costovertebral angle tenderness. Laboratory evaluation reveals leukocytosis with a left shift; blood cultures
indicate bacteremia. Urinalysis shows pyuria, mild hematuria, and gram-negative bacteria. Which of the following
drugs would best treat this patient's infection?
A. 
Ampicillin and gentamicin
B. 
C. 
Gentamicin and vancomycin
D. 
Phenazopyridine and nitrofurantoin
E. 
16.
A newborn infant has multiple, hemorrhagic, cutaneous lesions and does not respond to sound. Head CT scan
shows periventricular calcifications. Which of the following infectious agents is the most likely cause of this child's
presentation?
A. 
B. 
C. 
D. 
E. 
17.
A very ill neonate has widespread granulomas. In utero infection with which of the following organisms is
suggested by this finding?
A. 
B. 
C. 
D. 
E. 
18.
A 37-year-old female presents to the emergency room with a fever. Chest x-ray shows multiple patchy infiltrates
in both lungs. Echocardiography and blood cultures suggest a diagnosis of acute bacterial endocarditis limited to
the tricuspid valve. Which of the following is the most probable etiology?
A. 
B. 
C. 
D. 
E. 
Systemic lupus erythematosus
19.
A 4-year-old boy is brought to the emergency room in extreme respiratory distress, with a temperature of 103.8
degrees Fahrenheit. He is drooling and has difficulty swallowing, and on physical examination, inspiratory stridor
is noted. A lateral x-ray shows swelling of the epiglottis. He has had no previous vaccinations. Which of the
following agents is the most likely cause of these symptoms?
A. 
B. 
C. 
D. 
E. 
20.
A. 
Branching hyphae with rosettes of conidia
B. 
Branching, septate hyphae
C. 
D. 
Hyphae, arthroconidia, and blastoconidia
E. 
Pigmented, septate hyphal fragments
F. 
Short, curved hyphae and round yeasts
21.
A. 
B. 
C. 
D. 
E. 
22.
An African child develops massive unilateral enlargement of his lower face in the vicinity of the mandible. Biopsy
demonstrates sheets of medium-sized blast cells with admixed larger macrophages. This type of tumor has been
associated with which of the following?
A. 
Epstein-Barr virus and t(8;14)
B. 
C. 
D. 
Human immunodeficiency virus and CD4
E. 
Human papillomavirus and t(2;5)
23.
A. 
B. 
C. 
D. 
E. 
24.
A 36-year-old man with AIDS develops right-sided weakness involving the lower, but not the upper, limb. MRI
scans reveal a ring-enhancing lesion within the white matter of the left frontal lobe. A biopsy shows coagulative
necrosis of brain parenchyma with macrophage-rich chronic inflammatory infiltration admixed with microscopic
cysts that contain characteristic bradyzoites. Which of the following is the most common source of this type of
infection?
A. 
B. 
C. 
D. 
E. 
25.
A 16-year-old girl presents with a painlessly enlarged lymph node in her right axilla. Peripheral blood counts are
within normal limits. The lymph node is biopsied, and numerous granulomas filled with neutrophils and necrotic
debris are observed. Which of the following organisms could produce this disease?
A. 
B. 
C. 
D. 
E.