1. 25 yrl old woman admitted to boston hospital with fever that did not respond to
amoxicillin or ibuprofen. She is from the Phillipines and has traveled to teh states
for the previous 11 days. On examination she was febrile had an enlarged liver,
abdominal pain, abnormal urine analysis. Blood cultures were collected and were positive
for Salmonela typhi. She is diagnosed with Typhoid, the chronic carrier
state as seen in typhoid patients is due to colonization of salmonella typhi in
a) Small Intestine
b) Large Intestine
c) oral cavity
d) gall bladder
e) stomach
f) nasal cavity
Answer: D --> Gall bladder
2. 26 yr old, previously of good health came to the emergency room, for evaluation
for bloody diarrhea and diffuse abdominal pain for the last 24 hrs. She has no
history of inflammatory bowel disease, previous diarrhea or contact with other ppl.
Symptoms began 24 hrs after she had eaten undercooked hamburger at a local fast food
restaurant. Rectal exam reveal watery stool, with gross blood. What virulence factor
causes the above condition in the woman?
a) Cholera Toxin
b) heat labile toxin (LT-1)
c) Heat stable toxin (ST-a)
d) Exotoxin A
e) Exotoxin B
f) Shiga toxin (Stx-1)
Answer: Shinga Toxin
3. Shigella a gram negative pathogen associated with shigellosis. Salmonella typhi also
also a gram negative pathogen of the enterobacteriaceae family is associated with enteric
fever. Physicians need to differentiate tehse two diseases based on certain key properties
of the causative agents. The two pathogens salmonella typhi and shigella could be best
differentiated based on the property of?
a) Lactose fermentation on MacConkey Agar
b) Vaccine as a preventive measure for disease
c) reservoir for diseaes
d) catalase test
e) oxidative test
f) Invasion of blood stream
Answer: F
4. 25 yr old man sexually active, from the caribbean islands, has been working in New York
hospital for the past 3 months visited his physician with a complaint of penile ulcer.
The physician suspexts the sexually transmitted disease granuloma inguinale. The causitive
agent for this disease is?
A) Neisseria gonorrhea
B) Klebsiella granulomatis
C) Hemophillus ducreyi
D) Streptococcus pyogenes
E) staphylococcus saprophyticus
Answer: B
5. In experimental pathogenesis research project at Johns Hopkins University. Group A
Strep were added to fresh human blood. The Group A strep bacteria showed significant
resistance to phagocytic killing and can be effectively overcome by adding antibiotics
to which of the following
a) Techoic acid
b) endotoxin
c) streptolysin O
d) streptolysin S
e) DNAase
f) Protein M
Answer: F
6. 39 yr old paraplegic man with indwelling bladder catheter presents to ER complaining
of 24 hr rigors, nausea and vomiting. His temp is 38.9 C. Urineanalysis shows 3 plus
leukocyte esterase and numerous white blood cells. Urine and blood cultures grow
non lactose fermenting gram negative bacilli-pseudomonas. What is the lickely mechanism
of pathogensis in colonization of this pathogen?
a) Enterotoxin formation
b) Biofilm formation
c) Antigenic Variation
d) coagulase production
e) immune complex mediated
Answer B
7. A group of investigators is trying to develop an anti-gonococcal vaccine
(against gonorrhea bacterium). One of the approaches being used for development of
vaccine is to use chemical components of pilus to induce long lasting immunity.
This approach would most likely fail because of
a) Antigenic mimicry
b) exotoxin production
c) immune complex formation
d) antigenic variation
e) siderophone production
Answer: D
8. A 55 year old male is having low grade fever after recent replacement of his aortic
valve. Repeated blood cultures show growth of gram positive cocci. Which of the
following characteristics is most consistent with staphylococcus epidermidis as the cause
of the symptoms?
a) coagulase positive
b) coagulase negative
c) catalase negative
d) novobiocin resistance
e) bacitracin resistance
Answer B
9. A 5yr old boy is brought to the pediatrican with runny nose, low grade fever, myalgias
and headache. Has a distinctive high pitched inspiratory whistle with severe paroxysmal
coughing fits. He has numerous conjunctival hemorrhages due to his severe cough.
Further history reveals he has missed several of his vaccinations. The pediatrician is
concerned for whooping cough and prepares a sputum culture. Which is the growth medium for
the lab to culture the sample on?
A) Chocolate agar
B) mannitol salt agar
C) Thayer martin media
D) Bordet Gengou Media
E) Lowenstien Jensens Medium
Answer: D
10. A 30 yr old man returns from a weekend in cape cod. He now has abdominal pain and
watery diarrhea. He visited a roadside oyster shack with several of his college buddies
and all report similar symptoms. He is asked to a stool sample for culture, which may
demonstrate which of the following organisms.
a) Campylobacter Jejuni
b) shigella dysenteriae
c) staphylococcus aureas
d) vibrio parahemolyticus
e) salmonella typhimurium
Answer D
11. A 3 yr old boy presents to pediatrician with honey crusted rash around his mouth.
His mother says that the child had a low grade fever. On exam, the child appears well.
A culture is taken on the lesion and titers for antistreptolysin O (ASO) are sent.
The culture returns with gram positive cocci in chains and his ASO titers are negative.
The patient is placed on antibiotics. His lesions are most consistent with which of the
following skin conditions?
a) scalded skin syndrome
b) furuncles
c) toxic shock syndrome
d) Impetigo
e) scarlet fever
Answer: D
12. A 25 yr old pregnant woman begins to experience contractions at 38 weeks gestation.
She is brough to the hospital for delivery. She experiences a complicated prolonged
delivery but ultimately delivers. Her newborn is transferred to teh neonatal intensive
care unit and is found to have meningitis. Reveiw of the records suggests that the
mother was colonized with Strep agalactiae. Culture of the infants cerebrospinal fluid
is consistent with S.Agalactiae meningitis. Which of the following describes the staining
characteristics of the organism?
a) Gramp + cocci in clusters
b) gram + rods
c) gram - cocci
d) gram + cocci in chians
e) gram - rods
Answer D
13.While on medical mission to Angola, a 4th year medical student is assigned to work
in the makeshift hospital of a refugee camp. He sees numerous cases of severly
dehydrated children. He learns that the children had copious rice water stools and
cannot tolerate oral hydration as it causes further diarrhea. He is asked to start
IV fluids in these children. Stool cultures return positive for vibrio cholera which
causes life threatening diarrhea through the elaboration of a toxin with which of the
following actions?
a) blocks the release of gylcine
b) blocks the release of Ach
c) degrades tissue
d) stimulates adenylate cyclase
e) inactivates protein synthesis
Answer D
14. A 5yr old boy develops cough and a sore throat. His mother decides to soothe the
infants throat by providing him with spoonfuls of unprocessed raw honey. Within a few
days, she notes he has become progressively weak and lethargic appearing and he is
brought to the emergency room for treatment. Given the history, the ER physician
presumes the symptoms are due to which of the following toxins.
a) tetnus toxin
b) botulinum toxin
c) diptheria toxin
d) pertussis toxin
e) cholera toxin
Answer B
15. A 25 yr old IV drug user presents w/h high fever with chills, malaise a productive
cough, hemoptysis and right sided pleuritic chest pain. he also reports multiple skin
infections at injection sites. The physical examination shows thrombosed peripheral
veins, splenomegaly, hepatosplenomgealy, ejection systolic murmur increasing with
inspiration heard in the tricuspid area. Imaging techniques show presence of vegetations
on tricuspid valve and tricuspid incompetence. A diagnosis of acute bacterial endocarditis
is made and blood cultures is done. The blood culture shows growth of gram positive
cocci as cultured on mannitol salt agar. The bacterial causative agent for this
condition of bacterial endocarditis is?
a) E coli
b) strep mutans
c) strep agalactiae
d) staph saprophyticus
e) staph Aureus
Answer E
16. A 26 yr old woman visits her family physician because of marked burning pain while
urinating (dysuria), increasing frequency of urination with small amounts of urine
(poilakiuria) and passage of few drops of blood stained debris at the end of urination
(hematuria). She got married 2 weeks ago and has just returned from her honeymoon. Her
physical exam showed no fever, normal blood pressure, no edema, moderate suprapubic
tenderness with urgency. Urine was collected in two urine containers, the second
container was turbid and blood stained, urine sedment revealed red blood cells and
white blood cells, no casts were seen. Gram stain of the urine sedment reveals gram
negative bacilli and with significant colony count of MacConkey Agar ( > 100000CFU/ml)
and lactose fermenting colonies. The causative agent responsible for the urinary tract
infection is:
a) Staph saprophyticus
b) enterococcus
c) pseudomonas aeruginosa
d) proteus
e) E coli
Answer E
17.A 35 yr old woman complains of fever and pain in the face and upper teeth (maxillary
sinus) especially while leaning forward. She has had a chronic cough, nasal congestion
and discharge for the past few months. Her physical examination shows fever, halitosis,
greenish yellow postnasal discharge, cloudiness of sinuses by transilumination. A
diagnosis of sinusitis was made. Nasal cultures showed alpha hemolyitc organism on blood
agar. The gram staining showed gram positive cocci. The causative agent involved in this
clinical case of sinusitis is:
a) staph aureus
b) strep pneumoniae
c) moraxella
d) hemophilus influenza
Answer B
18.a 30 year old man goes to the emergency room because of dyspnea, cyanosis, hemoptysis
and chest pain. He has had a fever, malaise and non productive cough for 1 week. The
patient is a sheep farmer who remembers having been treated for dark black skin
lesions in the past. Complete blood count is normal, negative blood and sputum cultures. The
vaccine involved in the prevention of this deases seen in the above farmer is based on?
a) edema factor
b) lethal factor
c) protective antigen
d) polypeptide capsule
Answer C
19. A 20 year old man from pakistan presents to ER with severea nausea and vomiting.
Careful history reveals that 2 hours ago he ate some unrefrigerated fried rice that his
wife had cooked the night before. He does not complain of any fever or diarrhea. Mild
dehydration, diffuse mild abdominal tenderness is observed. Facial staining reveals
no RBC, WBC or parasites a gram positive rod is isolated from vomitus and stool and
shown toproduce the emetic entertotoxin. The toxin responsible for the above clinical
condition has a mode of action similar to?
A) stap aureus TSST 1
B) diptherial exotoxin
C) Botulism exotoxin
D) tetanus exotoxin- tetanospasmin
E) E coli
20.54 yr old woman who underwent a left mastectomy with axillary lymph node dissection a
year ago presents with pain together with rapidly spreading redness and swelling of the left
arm. SHe shows sign and symptoms of cellulitis. Needle aspiration from the advancing
border of the skin lesion when stained and cultured show isolated beta hemolytic group
A strep. The bacterial causative agent responsible for cellulitis in the woman is?
a) strep agalactaie
b) strep pneumoniae
c) strep bovis
d) viridans strep
e) strep pyogens
answer: E
21. A 30 yr old man has severe profuse (several liters) per day watery diarrhea, vomiting
and abdominal pain. He is resident of a refugee camp in rural bangladesh near the delta
region. He also shows severe dehydration, low urine output, generalized mild abdominal
tenderness with no signs of peritoneal irritation. Stools have a characteristic rice
watery appearance (gray, slightly cloudy fluid with flecks of mucus with no blood).
Stool cultures show gram negative curved rods and motility of bacterium is tested with
dark field microscopy. The causative agent responsible for the diarrheal condition.
a) Enterotoxigenic E coli
b) enteroinvasive E coli
c) campylobacter
d) Vibrio Cholerae
e) salmonella
f) Bascillus cereus
Answer D
22. E coli strains isolated from a 5 year old caucasian female with bloody diarrhea
produces a toxin that inhibits protein synthesis in human cells. Antibiotic treatment
with ciprofloxacin increases the chances of hemolytic uremic syndrome due to release
of the toxin. The toxin shares many properties with the toxin produced by?
a) Shigella dysenteriae
b) pseudomonasa aeruginosa
c) vibrio cholrea
d) proteus mirabilis
e) clostridium difficile
Answer A
23.15 yr old female presents to your office with burning sensations, urgency and
frequency of urination. She is sexually active and seeing a new boyfriend. Urine
cultures hsow gram possitive cocci which are also catalase positive. THe organism
most likely responsible for the symptoms is
a) coagulase positve
b) alpha hemolyitc on blood agar
c) novobiocin resistant
d) lactose fermenter
e) hydrogen sulphide/gas producer on TST medium
f) showing swarminig growth on MacConkey agar
Answer C
24. clustered gram positive bacilli are isolated from tonsillar exudates of a 6 year old
boy. On microscopic exam, the bacteria have polar granules and stain deeply with alberts stain.
The pathogenicity of organism is the result of:
a) widespread T cell activation
b) blockade of NT relase
c) activation of electrolyte transport
d) impairment of protein synthesis
e) cellular membrane disruption
answer D
25. E coli isolated from patient with diarrhea. It does not ferment sorbitol on sorbitol
containing MacConkey agar medium. The toxin produced by these bacteria would most likely?
a) activate adenylate cyclase
b) inactivate guanylate cyclase
c) inactivate ribosomal subunit
d) inactivate elongation factor 2
answer C
26. Helicobacter pylori has the ability to establish lifelong colnization in stomach of
untreated humans. It is associated with chroic gastritis, gastric ulcer, and duodenal
ulcer. The machanism of pathogenesis with colonization of H pylori in the stomach
is related to a virulence factor which interferes with gastric acid secretion.
Identify the virulence factor
a) capsule
b) toxin regulated pilus
c) vacuolating cytotxin
d) urease activity
e) mutase
answer D
27. 86 yr old man saw doctor for care of a splinter wound in his right hand (acquired
3 days earlier) recieved while gardening. 7 days later he had pharyngitis and after
3 more days he went to the hospital with difficulty talking , swallowing, breathing
with chest pain and disorientation. He was admitted to the hospital with diagnosis of
stroke. On his 4 hospital day, he developed neck rigidity and respiratory failure requiring
tracheostomy and mechanical ventilation. He was transferred tomedical ICU, where the
clinical diagnosis of tetanus was made. The patient needs to be treated with?
a) surgical debridment
b) DPT vaccine
c) tetanus toxoid administration
d) tetanus Immunoglobulin
e) Tetanus toxoid and tetanus Ig
Answer E
28. Outbreak of pertussis among hospital workers was reported in USA city. Patients
presented with acute cough, paroxysms, followed by vomiting and apneic epsidoes that led to loss of
consciousness. Patients cultured with PCR testing, the serology obtained from patients
with resp symptoms. twelve health care workers and 0 patients had clinical pertusis.
The lack of disease in patients was attributed to mask use, cough etiquette and limited
face to face contact. Infection with B pertussis and development of pertussis requires
exposure to the organism, bacterial attachment to the ciliated epithelial cells of
respirator tract, proliferation of bacteria and production of localized tissue damage
and systemic toxicity. The mechanism of pathogensis attributed with attachment of
organisms to ciliated epithelial cells is due to a virulence factor known as
a) pertusis toxin
b) hemolysin
c) tracheal cytotoxin
d) lipopolysaccharide
e) filamentous hemagglutinin
answer E
29. a 74 yr old woman was admitted to the hospital with symptoms of enteritis. A stool
culture was done and gram negative bacteria with sea gull appearance were seen in gram
stain and were grown on campy aagar at 42C. After 1 week of fever, watery diarrhea,
nausea, abdominal pain, weakness and fatigue, the patients speech was noted to be
severely slurred. She was taken to the hospital where it was noted she was unable
to speak, although she was oriented and able to write coherently. She had peioral numbness
bilateral ptosis, and facial weakness were noted and her pupils were nonreactive.
Neurologic exam revealed bilateral muscle weakness in her arms and chest. On the second
hospital day, the muscle weakness extended to her upper legs. On the 3rd day the patients
mental status remained normal, bt she could only move her thumb minimally and could not
lift her legs. Sensations of light touch was normal, but deep tendon reflexes were absent.
The clinical complication after the bacterial infection as seen in this old woman will be
diagnosesd by physician as
a) acute rheumatic fever
b) acute glomerulonephritis
c) Guillian Barre Syndrome
d) meningitis
e) meningoencephalitis
Answer C --> campylobacter 42C + neural issues = GBS
30.The CDC reported an outbreak of foodborne botulism associated with contaminated
carrot juice. On sept 8 2009, three patients went to hospital in washingotn
county, georgia, with crainal nerve palsies and progressive descending
flaccid paralyiss resulting in resp failure. Patients shared meals on the previous
day. THe patients had no progression of their neurologic symptoms but they
remained hospitalized and on ventilators. Investigation determined that the patients
had consumed contaminated carrot juice produced by a commercial vendor. An
additional patient in florida was also hospitalized with resp failure ad
descending paralysis after drinking carrot juice sold in florida. Because
carrot juice has low acid content (ph = 6.0) spores of bacterial organisms can
germinate and produce toxin if contaminated juice is left at room temp.
Botulinum toxin type A was detected in serum and stool and all three patients
and in leftover carrot juice. the mechanism of action of the bacteria based
on this is
a) toxin acting as superantigen
b) toxin acting as a lecithinase
c) toxin blocks release of Ach
d) toxin affects GABA
e) toxin affects protein synthesis
Answer C
31.Septicemia and wound infections are well known complication following exposure to V
Vulnificus. A 38 yr old man with history of alcoholism and insulin dependent diabetes
developed fever, chills, nausea and myalgia 3 days after eating raw oysters. He was
admitted to the local hospital the next day with high fevers and two necrotic lesions on
his left leg. The clincial diagnosis of sepsis was made and the patient was transferred
to the ICU. Antibiotic therapy was initiated, and on the second hospital day V vulnificus
was isolated from blood specimens collected at the time of admission. Despite aggressive
medical management the patient continuedto deteriorate and died on the third day of
hospitalization. The above patient could have had one of the following professions?
a) postal worker
b) slaughterhouse worker
c) farmer
d) veterinary doctor
e) fisherman
answer E
32. The first case of inhalation of anthrax in 2001 bioterrorism attack in the united states
was a 63 year old man living in florida who had a 4 day hisotry of fever, myalgias and
malaise without localizing symptoms. His wife brought him to the regional hospital because
he awoke from sleep with fevere, emesis, and confusion. On physical exam, he had a temp
of 39C, blood pressure of 150/80Hg, pulse was 110 and respirations were 18. No resp
distress was noted. Treatment was initiated for presumed bacterial meningitis. Basilar
infiltrates and a widened mediastinum was noted on the initial chest radiograph. Gram stain
of CSF revealed many neutrophils and large gram positive rods. Anthrax was suspected and
penicillen treatment was initiated. Within 24hrs of admission, CSF and blood cultures
were positive for bacillus anthracis. During the first day of hospitilization the patient
had a dral mal seizure and was intubated. On the second day hypotention, azotemia developed
with subsequent renal failure. On the 3rd day refractory hpyotension developed, and the
aptient had a fatal cardiac arrest. This patient illustrates the rapidity with which
patients with inhalation anthrax can deteriorate despite a rapid diagnosis and appropriate
antimicrobial therapy. Although the resp tract is the route of exposure patients do not develop
pneumonia rather the abnormal chest radiograph is caused by hemorrhagic mediastinitis.
As a physician working in the area you will prescribe one of the antibiotics as
chemoprophylaxis
a) ciprofloxacin
b) vancomycin
c) metranodazole
d) rifampin
Answer A
33. 18 yr old collage sophmore developed signs and symptoms of meningitis
and was admitted to a city hospital. The clinical samples were collected and neisseria
meninigitidis was established as a causative agent of meningitis. He was sharing
a room with two other students who were not vaccinated with the vaccine for neisserial
meningitis. As a physician you would use the following antibiotics as a chemoprophylaxis
a) penicillen
b) eryhtromycin
c) tetracycline
d) isoniazid
e) Rifampin
Answer E
34. Patient with damaged heart valve was undergoing dental surgery that is highly prone
to endocarditis caused by virdians group strep.Chemoprophylaxis used for such patients
shouldinclude
a) trimethoprim sulfa drug
b) rifampin
c) ciprofloxacin
d) ceftriaxone
e) Amoxicillen
answer E
35.Gas gangrene is a clinical condition associated with gram positive rod clostridium perfringens
A major toxin, alpha toxin is responsible for gas gangrene conditions along with several
other invasins. Alpha toxin results in destruction of membrane and widespread cell death.
The alpha toxin is basically a?
a) collagenase
b) hyaluronidase
c) DNAase
d) protease
e) lecithinase
answer E
36. a Hurrincane occured in Carribean islands in october, 2008. After 1 week of the
event a disease was spread in the islands having natural rivers passing near animals
farms. The organism causing the disease entered through the skin abrasions in all people
walking through flooded areas. the disease is?
a) cat scratch disease
b) tularemia
c) anthrax
d) leptospirosis
e) plague
answer D
37. a 55 yr old game warden in Vermont found a dead musckrat on the bank of a stream. He
picked up the animal thinking it might have been illegally trapped or shot; it was not
and the game warden buried it. Four days later he developed a 1.5cm painful ulcer on
the index finger of his right hand, a 1 cm ulcer on his right forehead and pain in his right
axilla. Physical exam also revealed right axillar lymphadenopathy. This patient is most
likely infected with?
a) herpes virus
b) bartonella
c) bacillus anthracis
d) francisella tularensis
answer D
38. A 12 yr old girl arrives in the emergency room with pains, swelling and limited
motion of her left hand; she also complains of fever and chills. The girl was bitten
by a cat yesterday while playing at a friends house. A yellowish green purulent fluid
drains from the wound.Gram negative bacteria were isolated from the fluid. The likely
organism responsible for the girls symptoms is
a) brucella
b) pasteurella
c) yersinia
d) franscisella
Answer B
39. 24 yr old woman has fever, malaise and a dry nonproductive cough.
She also complains of headache, muscle aces and leg pain. Lab values are significant
for elevated cold agglutinins. Which of the following microorganisms is responsible
for her symptoms >
a) Haemophilus influenze
b) Klebsiella pneumoniae
c) legionella pneumophila
d) mycoplasma pneumoniae
e) strep pneumoniae
Answer D
40. A 35 yr old sexually active man presents to her interist with a painless
penile vesicle. Physical examinations reveals inguinal lymphadenopathy .
THe infecting organism is definitively diagnosed and is known to exist in a
distinct extracellular and intracellular forms. Which of the following
is the most likely pathogen?
a) Calymmatobacterium granulomatis
b) chlamydia trachomatis
c) haemophilus ducreyi
d) nesisseria gonorrhoeae
e) treponema pallidum
answer B
he will also ask a question were a bunch of senior citizens are in a room
with an air conditions and they all under go symptoms of pneumonia,
chills, confusion, they key to this question is that no one dies
and the air conditions/water cooling system the answer to that is
answer Legionella
Another question that will appear where u drive passed a farm and notice
that there is water runoff coming from a farm where a lot of cows are located
what is the most likely disease to be contracted
answer is E coli