Key Code: B

A 70-year-old woman was bitten on her right hand by her cat at 9:00 am. She rinsed the bite with water, and at around 5:30 she noticed swelling and pain at the site of the bite. This pain then spread to the axilla, and red streaking developed up her forearm. She also began to suffer with chills. Upon examination, two small puncture marks were found on the dorsum of her right hand-along with swelling, erythema, warmth, and tenderness. Erythema was also evident over the extensor surface of the forearm. She was found to have an elevate WBC count (with a left shift). Aspiration from an abscess on her hand was sent for culture. Gram stain showed small, gram-negative bacilli. Upon culture, this organism was found to grow on Blood Agar and Chocolate Agar, but not on MacConkey Agar. Its colonial morphology appeared as smooth, gray, non-hemolytic colonies and a slight musty odor was detected. What organism is most likely causing this infection?

A) Streptococcus pyogenes
B) Spirillum minus
C) Escherichia coli
D) Staphylococcus aureus
E) Pasteurella multocida

Answer: E

 

(Year Posted:UI  701)

 

Key Code: B

A 21-year-old man presents one afternoon with an infection on the knuckle of his right hand. Upon examination, he is found to have redness and swelling of his hand, as well as several small abrasions on the knuckle. When asked how this wound occurred, the man stated that he had been at a local bar the night before and had gotten into an argument with one of the other patrons there. The argument turned into a fistfight, and he had punched the other man in the mouth. A swab of the wound was sent to the laboratory for culture. The organism isolated had several distinct characteristics: it was a very small colony on Blood agar and appeared to pit or corrode the agar, the growth had an unmistakable smell of bleach, and it did not grow on MacConkey agar. Gram staining revealed that this was a Gram-negative, medium-length rod. What is the most likely cause of this infection?

A) Pseudomonas aeruginosa
B) Eikenella corrodens
C) Proteus vulgaris
D) Escherichia coli
E) Pasteurella multocida

Answer: B

 

(Year Posted:UI  702)

 

Key Code: B

An 18 year old woman awoke to find her left knee was hot, swollen, and very painful. A friend offered her a ride to the clinic. While she was completing her paperwork, she realized that her right hand was becoming very stiff, and she had difficulty gripping the pen. The history taken of the woman by a medical student revealed she had 3 male sexual partners during the last month. She never had a swollen joint before, but often experienced a slight burning sensation upon urination. Physical examination revealed a tender knee joint, which yielded purulent synovial fluid on aspiration. The fluid had 80,000 leukocytes/mm3. She was found to have a cervical discharge that, on Gram staining, revealed small intracellular Gram-negative diplococci. Blood culture and synovial fluid were negative for the presence of bacteria, but the discharge grew out small, translucent colonies on both Chocolate Agar and Thayer Martin Agar. The Blood Agar plate streaked with the discharge showed no growth. What is the most likely organism causing this infection

A) Neisseria meningitidis
B) Chlamydia trachomatis
C) Treponema pallidum
D) Neisseria gonorrhoeae
E) Staphylococcus aureus

Answer: D

 

(Year Posted: 2002 UI  703)

 

Key Code: B

A 58-year-old man with chronic heart disease presents with a history of fever for 18 hours, shortness of breath, left-sided chest pain & a cough. Physical examination reveals a temperature of 39.20C, respiratory rate of 44 and decreased breath sounds in the left lower lung field (posterior). WBC is 27,899 with 82% polys, 10% bands, and 8% lymphocytes. Chest x-ray reveals consolidation of left lower lobe. A culture was obtained by transtracheal aspiration and grew out alpha-hemolytic, convex colonies, which upon Gram stain, revealed Gram-postive cocci in chains. Upon further testing, this organism was shown to be sensitive to optochin. What is the most likely cause of this man's infection?

A) Streptococcus viridans
B) Streptococcus pneumoniae
C) Staphylococcus aureus
D) Streptococcus pyogenes
E) Streptococcus agalactiae

Answer: B

 

(Year Posted:UI  704)

 

Key Code: M

A 91-year-old white female with no chronic medical problems sustained a mild laceration to the anterior lower leg. Over the next 48 hours, an increasingly large area of erythema developed, which was warm to the touch, tender, and indurated. The attending physician unroofed the lesion and obtained a small amount of purulent discharge for culture. The culture was incubated aerobically, and grew out small, translucent, beta-hemolytic colonies on Blood Agar. A catalase test was negative. What should be the next step in the identification process?

A) Optochin Testing
B) Coagulase Testing
C) Bacitracin Testing
D) Bile Esculin Hydrolysis Testing
E) A battery of biochemical testing

Answer: C

 

(Year Posted: UI  705)

 

Key Code: B

A 40-year-old woman complained to her urologist about having low-grade fever with general malaise and weight loss for approximately three months. Pyuria and bacteriuria are key findings. She also has proteinuria and a reduced ability to concentrate the urine. At this office visit, she had shaking chills, severe flank pain, and appeared to have some toxicity. She was admitted to the hospital. A consultation with a cardiologist she had previously visited indicated that she may also have endocarditis. The initial impression of the urologist based on her urinary symptoms is that she has pyelonephritis-possibly chronic, although at this time she had acute symptoms. Her urine culture revealed large, round, very mucoid colonies growing on both Blood Agar (cream-colored colonies) and MacConkey Agar (pink colonies). Gram staining revealed an abundance of Gram-negative rods, and motility testing suggested this organism was Non-motile. What organism do these findings suggest?

A) Escherichia coli
B) Klebsiella pneumoniae
C) Proteus mirabilis
D) Pseudomonas aeruginosa

Answer: B

 

(Year Posted: 2002 UI  706)

 

Key Code: B

A 22-year-old newlywed female presents with symptoms of dysuria,(discomfort, pain, burning, stinging on urination), urgency and frequency. The proximal end of the urethra is inflamed. She also has suprapubic pain and tenderness. She appears to have classic manifestations of lower urinary tract infection: urethrocystitis. Her urine culture grows smooth, round, white colonies on Blood agar and smooth, round, pink colonies on MacConkey Agar. Gram-staining showed Gram-negative rods, and further testing revealed that this organism is motile, Indole positive, and negative for Citrate utilization. What is the most likely cause of this infection?

A) Escherichia coli
B) Klebsiella pneumoniae
C) Proteus mirabilis
D) Pseudomonas aeruginosa

Answer: A

 

(Year Posted:UI  707)

 

Key Code: M

When a zone of clear hemolysis is present around an isolated bacterial colony on a blood agar plate, it is a useful characteristic for identification of which of the following?

A) Streptococcus pneumoniae
B) Staphylococcus epidermidis
C) Enterococcus faecalis
D) Streptococcus pyogenes
E) Neisseria gonorrhoeae

Answer: D

 

(Year Posted:UI  708)

 

Key Code: B

Which of the following statements is true of the laboratory differentiation of Salmonella from Shigella?

A) Salmonella is motile and usually produces H2S; Shigella is non-motile and usually produces H2S
B) Salmonella is non-motile and usually produces H2S; Shigella is non-motile and usually produces H2S
C) Salmonella is motile and usually produces H2S; Shigella is non-motile and usually does not produce H2S
D) Both are motile; only Salmonella produces H2S

Answer: C

 

(Year Posted:UI  709)

 

Key Code: I

To confirm that a patient has an immunodeficiency of humoral immunity, which of the following tests should be performed:

A) T-cell quantitation
B) Immunoglobulin quantitation
C) C3 levels in serum
D) Liver biopsy
E) Cytotoxicity assays for NK cell function

Answer: B

 

(Year Posted: UI  710)

 

Key Code: I

Complement C3 and C4 levels are decreased in which of these autoimmune diseases?

A) thyroiditis
B) primary biliary cirrhosis
C) diabetes
D) systemic lupus erythematosis
E) agammaglobulinemia

Answer: D

 

(Year Posted:UI  711)

 

Key Code: I

A protein is isolated from a patient with multiple myeloma. Which of the following ratios would be most consistent with an IgG lambda myeloma protein?

A) 60:40
B) 50:50
C) 95:5
D) 5:95

Answer: D

 

(Year Posted:UI  712)

 

Key Code: I

In the majority of T cells found in peripheral blood, the TCR is encoded by

A) gamma and delta chain genes
B) alpha and gamma chain genes
C) beta and delta chain genes
D) alpha and beta chain genes

Answer: D

 

(Year Posted: UI  713)

 

Key Code: I

The approximate chance that two siblings with the same biological parents will inherit the same HLA haplotypes is:

A) 5%
B) 10%
C) 25%
D) 40%
E) 50%

Answer: C

 

(Year Posted:UI  714)

 

Key Code: I

Which of the following substances would be the best immunogen:

A) A peptide 9 amino acids in size
B) A hapten conjugated to bovine serum albumen which is then injected into a cow
C) Human IgG injected into a rabbit
D) DNA
E) Oil of Olay

Answer: C

 

(Year Posted:UI  715)

 

Key Code: I

To determine if a patient has been newly infected with Hepatitis A virus, which class of antibody to this pathogen should be assayed?

A) IgE
B) IgG
C) IgM
D) IgA

Answer: C

 

(Year Posted: UI  716)

 

Key Code: I

Which part of an IgG molecule binds specifically with the epitope of a hapten?

A) Fc fragment
B) CH2/CH3 domains
C) Hypervariable regions
D) Framework regions
E) Gm allotypic regions

Answer: C

 

(Year Posted: UI  717)

 

Key Code: I

Which of the following primary immunodeficiencies is due to a mutation in CD40L CD154

A) Bruton's agammaglobulinemia
B) Hyper-IgM syndrome
C) Wiskott -Aldrich syndrome
D) Systemic lupus erythematosis
E) DiGeorge syndrome

Answer: B

 

(Year Posted:UI  718)

 

Key Code: I

A patient is found to have a genetic defect and unable to make J chains. As a result of this defect which of the following immunoglobulins would be undetectable in serum from this patient?

A) IgM
B) IgG
C) IgA
D) IgE
E) IgD

Answer: A

 

(Year Posted:UI  719)

 

Key Code: B

Neisseria meningitidis, Haemophilus influenzae type b, and Streptococcus pneumoniae have many features in common. Of the choices below, which is FALSE?

A) Each of the diseases they cause can be prevented by a vaccine
B) They all possess peptidoglycan
C) They all rely on a capsule for virulence
D) They are all causes of meningitis
E) They are all gram-negative cocci

Answer: E

 

(Year Posted: UI  720)

 

Key Code: B

You diagnose your patient as having classical pertussis and start her on a course of erythromycin. After two weeks of antibiotic therapy, the child still feels ill with continued bouts of severe coughing. Which of the choices below would best explain this slow recovery from disease?

A) Although the patient is no longer infected, the systemic bacterial toxins continue to cause symptoms of the disease.
B) Bordetella pertussis is resistant to erythromycin.
C) The Bordetella pertussis cells have been lysogenized with a bacteriophage carrying the pertussis toxin gene.
D) The patient has lung irritation by "second hand" cigarette smoke from her smoking parents.
E) Coughing is a common side effect of erythromycin

Answer: A

 

(Year Posted:UI  721)

 

Key Code: B

Which of the following symptoms/characteristics is typical of infection with Salmonella typhi or Salmonella choleraesuis but NOT with other enteric pathogens?

A) Mild to severe watery diarrhea
B) Dehydration and electrolyte imbalance
C) Frequent passage of bloody stools
D) Invasion of the intestinal epithelial cells
E) Bacteremia

Answer: E

 

(Year Posted:UI  722)

 

Key Code: F

Fungi which reveal brown or black colored hyphae in a microscopic preparation are described as

A) saprophytic fungi
B) dematiaceous fungi
C) thermally dimorphic fungi
D) aseptate fungi
E) dermatophytes

Answer: B

 

(Year Posted:UI  723)

 

Key Code: F

Which one of the following infections can be transmitted from animal to human?

A) dermatomycosis
B) blastomycosis
C) histoplasmosis
D) sporotrichosis
E) coccidioidomycosis

Answer: A

 

(Year Posted:UI  724)

 

Key Code: P

In Chagas Disease:

A) the infectious agent is Trypanosoma gambiense
B) the vector is the tsetse fly
C) the stage found in the tissue of the human heart is the trypomastigote
D) chronic infection can cause megaesophagus and megacolon
E) the infection is diagnosed by ova and parasite exam of the stools

Answer: D

 

(Year Posted:UI  725)

Key Code: P

Which of the following is true of infections with Echinococcus granulosus:

A) The main pathology in human beings occurs in the small intestine
B) In human beings, the infection is diagnosed mainly by ova and parasite examination
C) It is extremely easy to remove the hydatid cysts surgically
D) The dog is the natural host for the adult stage of the parasite

Answer: D

 

(Year Posted:UI  726)

 

Key Code: M

What is one mechanism used by bacteria to obtain iron in the human host?

A) production of membrane channels for diffusion of hemoglobin
B) excretion of lactoferrin to obtain intracellular iron
C) production of transferrin for iron removal from host cells
D) excretion of cytolysins which lyse host cells, making iron available
E) production of a polysaccharide matrix to entrap serum iron

Answer: D

 

(Year Posted: UI  727)

 

Key Code: M

Which of the following is  NOT generally thought of as a common mechanism of antibiotic resistance?

A) Bacteria bypass the specific reaction blocked by drugs which are metabolic inhibitors
B) Bacteria decrease cell permeability to the drug
C) Bacteria destroy the antibiotic activity by enzymatic modification of the drug
D) Bacteria modify the target of antibiotic action
E) Bacteria stimulate the transfer of plasmid genes

Answer: E

 

(Year Posted: UI  728)

 

Key Code: M

The outer membrane is a complex structure of gram-negative bacteria. Which of the following is  NOT an important aspect or feature of the outer membrane?

A) Porin proteins allow passage of some small molecules
B) The barrier effect prevents some antibiotics from being useful against gram-negative bacteria
C) LPS is found only in the outer leaflet of the Outer Membrane lipid-protein bilayer
D) Some outer membrane proteins may make good candidates for vaccines
E) Lipid A helps anchor the outer membrane to the cytoplasmic membrane

Answer: E

 

(Year Posted:UI  729)

 

Key Code: M

Which of the statements below is true?

A) Obligate intracellular pathogens cannot grow outside of a host cell
B) Obligate intracellular pathogens can live as extracellular pathogens but are also able to penetrate and grow within host cells
C) During infection, obligate intracellular pathogens are exposed to the humoral and cellular arms of the host immune system
D) Extracellular pathogens are capable of penetrating and growing within host cells
E) All obligate intracellular pathogens produce ADP-ribosylating exotoxins for entry into host cells

Answer: A

 

(Year Posted:  UI  730)

 

Key Code: M

Which one of the bacterial products listed below is  NOT involved in resistance to phagocytosis?

A) polysaccharide capsule
B) lipopolysaccharide O side chains
C) M protein of Streptococcus pyogenes
D) lipoprotein
E) glutamic acid capsule

Answer: D

 

(Year Posted: UI  731)

 

Key Code: B

Toxic shock syndrome toxin-1 (TSST-1) is produced by:

A) "viridans" streptococci
B) Staphylococcus aureus
C) Staphylococcus epidermidis
D) lipopolysaccharide-containing organisms
E) Streptococcus pneumoniae

Answer: B

 

(Year Posted: UI  732)

 

Key Code: B

A 70 year old woman recently underwent hip replacement surgery. About two days after her operation she began experiencing fever and pain at the site of the surgery. A blood culture, as well as fluid aspirated from her hip, grew the same bacterium: a gram-positive, catalase positive, coagulase negative coccus. What other characteristic would you expect this organism to possess?

A) Streptolysin O
B) Endotoxin
C) M protein
D) Slime
E) Lipopolysaccharide

Answer: D

 

(Year Posted: UI  733)

 

Key Code: B

Both Streptococcus pneumoniae and Neisseria meningitidis are capable of causing meningitis and are both diplococci. Which, of the choices below, is another feature they share?

A) exotoxin production
B) Braun's lipoprotein
C) capsule production
D) flagellar motility
E) fibrinogen masking molecules

Answer: C

 

(Year Posted: UI  734)

 

Key Code: M

The acid-fast cell envelope is very complex. Which of the following molecules is  NOT a component of the acid-fast cell envelope?

A) peptidoglycan
B) mycolic acid
C) wax D
D) pilin
E) cord factor

Answer: D

 

(Year Posted:  UI  735)

 

Key Code: M

By plating bacteria on medium containing rifampin, one can easily obtain spontaneous rifampin-resistant mutants which will survive and grow on the medium. The gene which is most likely mutated in these mutants encodes:

A) DNA gyrase alpha subunit
B) ribosomal 50S subunit
C) the lipid carrier undecaprenyl
D) ribosomal 30S subunit
E) RNA polymerase beta subunit

Answer: E

 

(Year Posted: UI  736)

 

Key Code: M

The process of phase and antigenic variation involves:

A) lysogeny by a bacteriophage
B) plasmid transfer
C) genetic recombination
D) sex pili
E) transduction

Answer: C

 

(Year Posted:UI  737)

 

Key Code: B

Many microbial exotoxins can be classified as having the A-B model of domain structure. The cholera toxin B domain consists of five identical polypeptides. What is the function of this B domain?

A) It ADP-ribosylates host proteins
B) It covalently links the toxin to the bacterial peptidoglycan
C) It is the enzymatically active portion of the toxin
D) It is the domain which polyclonally activates host T cells
E) It binds the toxin to the host target cell

Answer: E

 

(Year Posted:UI  738)

 

Key Code: M

Coagulase is an enzyme which:

A) breaks down hydrogen peroxide
B) has enterotoxigenic activity
C) differentiates Staphylococci from Streptococci
D) catalyzes the formation of a fibrin clot
E) degrades fibrin clots

Answer: D

 

(Year Posted:UI  739)

 

Key Code: B

A female patient presents with swollen inguinal lymph nodes and painful lesions on the genitalia and perianal region. Which of the organisms below is the most likely causative agent for this infection?

A) Group B streptococci
B) Neisseria gonorrhoeae
C) Haemophilus ducreyi
D) Moraxella (Branhamella) catarrhalis
E) Haemophilus aegypticus

Answer: C

 

(Year Posted:UI  740)

 

Key Code: M

Endotoxin is responsible for many of the effects often seen during an infection by gram-negative bacteria. Which one of the following is  NOT caused by Endotoxin?

A) stimulation of cytokine production
B) hypotension and shock
C) watery diarrhea
D) fever
E) activation of complement cascade

Answer: C

 

(Year Posted: UI  741)

 

Key Code: M

Capsules are cell surface structures external to the cell envelope. Which of the following statements is true?

A) Polysaccharide capsules are rigid and help maintain the shape of the cell
B) Capsules do not help protect the bacterium against phagocytosis
C) In adults, vaccines produced against capsules are not very effective
D) In the "test tube" capsules are dispensable but in the host they are often required to cause an infection
E) None of the statements above is true

Answer: D

 

(Year Posted: UI  742)

 

Key Code: B

Which of the following characteristics is  NOT typical of the Enterobacteriaceae?

A) They can grow either aerobically or anaerobically
B) Produce cytochrome C oxidase which gives a positive oxidase reaction
C) Can grow in the presence of bile salts
D) Have relatively simple growth requirements and can grow on simple defined media
E) Ferment glucose which results in the production of acid end-products

Answer: B

 

(Year Posted: UI  743)

 

Key Code: M

In the Limulus Assay, horseshoe crab amoebocyte lysates clot in the presence of small amounts of which compound?


B) cord factor
C) lipopolysaccharide
D) peptidoglycan
E) ß-lactamase

Answer: C

 

(Year Posted: UI  744)

 

Key Code: B

Which of the following symptoms/characteristics is typical of infection with Salmonella typhi and Salmonella choleraesuis but  NOT with other enteric pathogens?

A) Bacteremia
B) Mild to severe watery diarrhea
C) Dehydration and electrolyte imbalance
D) Frequent passage of bloody stools
E) Invasion of the intestinal epithelial cells

Answer: A

 

(Year Posted: UI  745)

 

Key Code: M

An anaerobic, thermophilic bacterium growing on a mineral salts medium with glucose as the sole carbon and energy source would be able to do which of the following?

A) Grow optimally in air, at 65°C, on complex media
B) Grow in the absence of oxygen, at 65°C, on a minimal medium
C) Grow optimally in the absence of oxygen, at 25°C, on a complex medium
D) Grow in air, at 65°C, on a minimal medium
E) Grow optimally in air, at 25°C, on a complex medium

Answer: B

 

(Year Posted:UI  746)

 

Key Code: B

Members of the genus Mycobacterium are termed "acid-fast" because

A) in the Gram staining procedure, they stain rapidly with the acidic stain
B) they rapidly decolorize with acid alcohol in the Kinyoun staining procedure
C) they may be cultured in growth media at pH 2.0
D) they resist decolorization with acid alcohol in the Kinyoun staining procedure
E) they resemble certain acid-tolerant fungi

Answer: B

 

(Year Posted:UI  747)

 

Key Code: B

A number of biochemical tests may be used to aid in the identification of gram-positive cocci. The catalase test is used to evaluate the production of an enzyme that

A) will coagulate citrated rabbit plasma by reacting with fibrinogen
B) will catalyze the degradation of hydrogen peroxide
C) will degrade the catalase sugar found in host phagocytes
D) will confer resistance to the antibiotic catamycin
E) will react with hydrogen peroxide to produce teichoic acids

Answer: B

 

(Year Posted:UI  748)

 

Key Code: B

The O antigen, H antigen, and K antigen are cell surface antigens of the Enterobacteriaceae used in serotyping and various classification systems. In which species would the H antigen be of no possible use for distinguishing between strains?

A) Salmonella typhi
B) Shigella dysenteriae
C) Escherichia coli
D) Salmonella enteritidis
E) Enterotoxigenic E. coli

Answer: B

 

(Year Posted:UI  749)

 

Key Code: B

Which sexually transmitted disease presents with a genital discharge?

A) chancroid
B) condyloma
C) gonorrhea
D) granuloma inguinale
E) syphilis

Answer: C

 

(Year Posted:UI  750)

Key Code: B

Anaerobic bacteria such as Bacteroides, Clostridium, Eubacterium, and Bifidobacterium are most often found in / on the:

A) oral cavity
B) stomach
C) small intestine
D) large intestine
E) skin

Answer: D

 

(Year Posted:UI  751)

 

Key Code: B

Neither a pathogenic factor nor an invasive characteristic of staphylococci:

A) capsule
B) endotoxin
C) laminin receptors
D) pyrogenic toxins
E) hyaluronidase

Answer: B

 

(Year Posted: UI  752)

 

Key Code: B

Which of the following is most likely to cause acute bacterial pharyngitis in an 8 year-old boy?

A) alpha hemolytic streptococci
B) Group A, beta hemolytic streptococci
C) Staphylococcus epidermidis
D) Streptococcus mutans
D) Staphylococcus aureus

Answer: B

 

(Year Posted: UI  753)

 

Key Code: B

Most common cause of meningitis in the elderly

A) group B streptococci
B) Escherichia coli
C) Haemophilus influenzae
D) Neisseria meningitidis
E) Streptococcus pneumoniae

Answer: E

 

(Year Posted:UI  754)

 

Key Code: M

The Gram stain

A) is a simple stain
B) is a differential stain
C) is a fluorescent stain
D) stains microbial capsular material
E) stains cytoplasmic storage granules

Answer: B

 

(Year Posted: UI  755)

 

Key Code: B

Neisseria meningitidis, Haemophilus influenzae type b, and Streptococcus pneumoniae have many features in common. Of the choices below, which is FALSE? 

A) They all possess peptidoglycan
B) They are all causes of meningitis
C) They all rely on a capsule for virulence
D) They are all gram-negative cocci
E) Each of the diseases they cause can be prevented by a vaccine

Answer: B

 

(Year Posted: UI  756)

 

Key Code: B

Which is NOT a characteristic of diphtheria toxin?

A) It has the same mode of action as Pseudomonas aeruginosa exotoxin A
B) Its production and systemic spread in a host causes the symptoms of the disease known as diphtheria
C) It is encoded by a bacteriophage gene
D) It ADP-ribosylates and inactivates host elongation factor 2
E) It ADP-ribosylates host GTP binding proteins

Answer: E

 

(Year Posted:UI  757)

 

Key Code: B

Which is NOT a characteristic of Listeria monocytogenes?

A) it can grow at cold temperatures (e.g. 4°C)
B) neonates are particularly susceptible to systemic infection with the organism
C) it is found widely in nature
D) it is transmitted by respiratory aerosols from infected carriers
E) it is a facultative intracellular pathogen

Answer: D

 

(Year Posted:  UI  758)

 

Key Code: B

A pharyngeal pseudomembrane is associated with:

A) epiglottitis
B) diphtheria
C) impetigo
D) Group A streptococcal pharyngitis
E) erysipelas

Answer: B

 

(Year Posted:UI  759)

 

Key Code: B

The disease-causing bacteria cultured from a patient with a pharyngeal pseudomembrane have all of the characteristics listed below except:

A) They produce an exotoxin if lysogenized by a certain bacteriophage
B) They show a palisade "Chinese character" cell arrangement in smear
C) They produce polyphosphate storage granules
D) They are gram-positive
E) They are invasive and can infect any organ system in the body

Answer: E

 

(Year Posted: UI  760)

 

Key Code: B

Escherichia coli may be best known for the diarrheal diseases that it causes but it is also the causative agent of many other types of opportunistic infections. Which of the following is NOT generally associated with E. coli?

A) community acquired urinary tract infections
B) nosocomial bacteremia
C) enteric fevers
D) abdominal abscesses and peritonitis
E) neonatal meningitis

Answer: C

 

(Year Posted:  UI  761)

 

Key Code: B

Escherichia coli strains cause a variety of enteric diseases. Enterotoxigenic (ETEC) E. coli causes one type of diarrheal disease. Which of the following is NOT characteristic of ETEC disease?

A) Heat stable (ST) and/or heat labile (LT) toxins are produced
B) Specific K-antigens or pili are required for intestinal colonization and full virulence
C) ETEC are often associated with "travelers diarrhea"
D) Intestinal epithelial cell invasion is responsible for the appearance of blood in stools
E) The toxins and K-antigens are located on large ent plasmids

Answer: D

 

(Year Posted: UI  762)

 

Key Code: B

Legionnaire's Disease is characterized by all but one of the following (identify the FALSE statement):

A) Severe pneumonia that may spread to both lungs
B) Cough that produces copious amounts of sputum
C) Rapidly rising fever and slowing of heart rate (bradycardia)
D) Mental changes (confusion, amnesia, delirium) in about 50% of patients
E) Mortality rates of 15-50% in outbreaks; even higher in immunosuppressed patients

Answer: B

 

(Year Posted:  UI  763)

 

Key Code: B

The most commonly isolated bacterial pathogen(s) associated with dog and cat bite wounds and bite wound infections is:

A) Capnocytophagia canimorsus
B) Bartonella henselae
C) Streptobacillus moniliformis
D) Ehrlichia canis
E) Pasteurella multocida

Answer: E

 

(Year Posted: UI  764)

 

Key Code: B

Which of the choices below is descriptive of the catarrhal stage of pertussis?

A) Bordetella pertussis bacteremia occurs
B) Episodes of severe coughing occur
C) Lasts from weeks to months
D) Characterized by symptoms such as rhinitis and sneezing
E) Hemorrhaging and pneumothorax can occur

Answer: D

 

(Year Posted:  UI  765)

 

Key Code: B

A 45-year-old female who smokes and is an alcoholic develops fever and cough and a 10-pound weight loss over 6 weeks. Her family has noticed that her breath is very foul smelling. Temperature is 100°F with pulse rate of 96/minute. Which sputum smear most likely matches the clinical description?

A) Sputum smear - polymorphonuclear neutrophils and acid-fast bacilli
B) Sputum smear - polymorphonuclear neutrophils and gram-positive cocci
C) Sputum smear - polymorphonuclear neutrophils and yeast forms
D) Sputum smear - polymorphonuclear neutrophils and no organisms seen
E) Sputum smear - polymorphonuclear neutrophils and mixture of gram-negative bacilli, gram-positive cocci, and coccobacilli

Answer: E

 

(Year Posted: UI  766)

 

Key Code: B

Which one of the following tests is NOT used for the diagnosis of syphilis?

A) VDRL
B) Culture
C) FTA-ABS
D) Dark field microscopy
E) Direct fluorescent antibody staining

Answer: B

 

(Year Posted: UI  767)

 

Key Code: B

Which of the following statements about syphilis is NOT true?

A) The most common manifestation of late syphilis is asymptomatic neurosyphilis
B) The lesions of secondary syphilis clear spontaneously without therapy
C) Some patients with syphilis have spontaneous cure even without therapy
D) With successful therapy the serum micro-hemagglutination test for Treponema pallidum (MHA-TP) should become negative.

Answer: D

 

(Year Posted: UI  768)

 

Key Code: B

Which of the following is the basic microscopic pathologic finding in syphilis?

A) Acute inflammation with polymorphonuclear neutrophils
B) Granulomatous inflammation of large arteries
C) Obliterative endarteritis
D) Giant cells with intranuclear inclusions

Answer: C

 

(Year Posted: UI  769)

 

Key Code: B

Which of the following statements about serologic tests for syphilis is true?

A) The rapid plasma reagin (RPR) test is a specific anti-treponemal antibody test
B) Following successful antibiotic therapy, the rapid plasma reagin (RPR) serum titer should fall
C) The rapid plasma reagin (RPR) serum test is positive in 99% of cases of primary syphilis
D) The MHA-TP (microhemagglutination) test measures IgG and IgM antibodies directed against a lipoidal antigen produced by interaction of Treponema pallidum with host tissues

Answer: B

 

(Year Posted: UI  770)

 

Key Code: B

Which of the following is the least likely clinical manifestation of Lyme disease?

A) Skin rash
B) Arthritis
C) Nausea, vomiting, diarrhea
D) Myocarditis
E) Headache

Answer: C

 

(Year Posted: UI  771)

 

Key Code: B

Coagulase negative staphylococcus is the most predominant organism found in blood stream infections in intensive care units due to its role in indwelling central intravenous catheter infections. What is the major virulence factor possessed by coagulase negative staphylococcus which makes it a significant pathogen in central venous catheter and other prosthetic device infections?


B) Bacterial membrane receptors for fibrin
C) Bacterial membrane associated adhesins
D) Production of a mucopolysaccharide rich bacterial slime layer
E) Production of a potent exotoxin

Answer: D

 

(Year Posted: UI  772)

 

Key Code: B

Which is NOT an element in the pathogenesis of Mycobacterium tuberculosis disease?

A) Granuloma formation
B) Production of a mycobacterial exotoxin
C) Cell-mediated delayed type hypersensitivity
D) Host lymphokines
E) Mycobacterial cell wall components

Answer: B

 

(Year Posted: UI  773)

 

Key Code: B

Which of the following actions would NOT be recommended for the prevention or treatment of clostridial myonecrosis?

A) administration of antitoxins
B) administration of penicillin
C) hyperbaric oxygen treatment
D) rapid closure and thorough wrapping of large wounds
E) surgical debridement of necrotic tissue

Answer: D

 

(Year Posted:UI  774)

 

Key Code: B

Of the choices listed below, the bacterial species capable of forming endospore-like structures that render it resistant to drying is

A) Rickettsia akari
B) Bartonella quintana
C) Bartonella henselae
D) Coxiella burnetii
E) Rickettsia conorii

Answer: D

 

(Year Posted:UI  775)

Key Code: F

Which of the following is a site of action for amphotericin B?

A) Cell (plasma) membrane
B) Oxidative phosphorylation
C) DNA replication
D) Protein synthesis
E) Enzymes involved in folate metabolism

Answer: A

 

(Year Posted:  UI  776)

 

Key Code: F

Which of the following situations that allow microorganisms to be introduced into the host would NOT result in dermatophyte infections?

A) A child playing with the family cat
B) Two children playing together
C) Inhalation of conidia
D) Walking barefoot around the swimming pool
E) Sharing a towel in the locker room after a strenuous game of tennis

Answer: C

 

(Year Posted:UI  777)

 

Key Code: F

The presence of pigmented sclerotic bodies in material removed from a lesion is characteristic of which of the following infections?

A) Coccidioidomycosis
B) Chromoblastomycosis
C) Mycetoma
D) Nocardiosis
E) Contact dermatitis

Answer: B

 

(Year Posted: UI  778)

 

Key Code: F

An individual whose hobby is the breeding and rearing of racing pigeons is admitted to the hospital with apparent CNS impairment. Which one of the following diseases would be suspected?

A) candidiasis
B) paracoccidioidomycosis
C) a dematiaceous fungus
D) cryptococcosis
E) blastomycosis

Answer: D

 

(Year Posted: UI  779)

 

Key Code: B

Which of the following statements about the Rapid Plasma Reagin (RPR) test is true?

A) It is an agglutination test for non-gonococcal urethritis
B) It detects non-treponemal antibodies
C) It detects treponemal antigens
D) It detects non-gonococcal antibodies
E) It detects treponemal antibodies

Answer: B

 

(Year Posted: UI  780)

 

Key Code: F

Fungal conidia which are formed by fragmentation of a hyphal strand are

A) blastoconidia
B) arthroconidia
C) sporangiospores
D) chlamydoconidia
E) pseudohyphae

Answer: B

 

(Year Posted: UI  781)

 

Key Code: B

A 75-year-old man presents with the sudden onset of photophobia, stiff neck, and high fever without focal findings or autonomic involvement. Which of the following is LEAST likely to cause this illness:

A) Streptococcus pneumoniae
B) Listeria monocytogenes
C) Streptococcus pyogenes
D) Klebsiella pneumoniae
E) Escherichia coli

Answer: C

 

(Year Posted:  UI  782)

 

Key Code: P

Which one of the following statements about infection with Onchocerca volvulus is true:

A) The adults live in subcutaneous tissues
B) The larvae infect the heart
C) Chronic infections cause elephantiasis
D) The disease is transmitted to humans by the tsetse fly
E) Diagnosis is made by examination of thick and thin blood smears

Answer: A

 

(Year Posted:  UI  783)

 

Key Code: P

Which one of the following statements about infections by hookworm is true:

A) There may be pulmonary manifestations
B) The two species causing disease in humans can be distinguished by differences in their eggs
C) The adults live in the large intestine
D) Human infections occur by ingestion of the eggs
E) Autoinfection occurs and manifests itself clinically

Answer: A

 

(Year Posted: UI  784)

 

Key Code: B

Optochin (Taxos "P") selectively inhibits the growth of:

A) Enterococcus faecalis
B) Streptococcus agalactiae
C) Streptococcus pneumoniae
D) Streptococcus pyogenes
E) viridans Streptococci

Answer: C

 

(Year Posted: UI  785)

 

Key Code: B

The capsule of Bacillus anthracis is composed of

A) arabinogalactan
B) D-glutamic acid
C) lipopolysaccharide
D) polysaccharide
E) protective antigen

Answer: B

 

(Year Posted:  UI  786)

 

Key Code: B

Which of the following statements DOES NOT apply to bacterial endospores:

A) they are formed by Bacillus species
B) they are formed by Clostridium species
C) they are resistant to disinfectants
D) they are resistant to desiccation
E) they contain an incomplete genome

Answer: E

 

(Year Posted: UI  787)

 

Key Code: B

A 23 year-old man wrecks his motorcycle running into a highway embankment, suffering multiple injuries including a compound fracture of the lower leg heavily contaminated with soil and gravel. Several hours later he is discovered and transported to the trauma unit. Over the course of the day he develops more swelling and unrelenting, intense pain in the leg. Over the next several hours hemorrhagic blisters and crepitation (palpable subcutaneous gas) advance rapidly up the leg. High dosage penicillin therapy is begun. Gram-positive rods are observed in stained specimens from the lesion. Which of the following enzymatic activities is associated with the major toxin involved in the likely disease process?

A) ADP-ribosylation of elongation factor 2 (EF-2)
B) ADP-ribosylation of GTP-binding proteins
C) calmodulin-dependent adenylate cyclase
D) phospholipase C
E) ß-lactamase

Answer: D

 

(Year Posted: UI  788)

 

Key Code: B

Which of the following is NOT a characteristic of Legionella pneumophila?

A) Facultative intracellular organism
B) Found in fresh water
C) Lives in both macrophages and protozoans
D) Obligate anaerobe
E) Opportunistic pathogen

Answer: D

 

(Year Posted:UI  789)

 

Key Code: B

Rickettsia cause disease primarily by causing:

A) Allergic reaction in the host
B) Fever
C) Myositis with muscle cell death
D) Vasculitis (invasion of the vascular endothelium)
E) Pneumonia with lobar consolidation

Answer: D

 

(Year Posted: UI  790)

 

Key Code: F

Azoles such as ketoconazole and itraconazole exhibit their antifungal action by which ONE of the following mechanisms?

A) inhibition of a late step in ergosterol biosynthesis
B) inhibition of chitin synthesis
C) inhibition of peptidoglycan synthesis
D) specific binding to ergosterol-containing membranes
E) specific binding to microtubules

Answer: A

 

(Year Posted:  UI  791)

 

Key Code: P

Which of the following statements about cutaneous larval migrans is FALSE?

A) Adults are not found in human beings
B) It is caused by dog and cat hookworms
C) Diagnosis is clinical and does not require an ova and parasite exam
D) The larvae may infect distal organs such as the liver and eye
E) Infection is acquired by the larvae penetrating the skin

Answer: D

 

(Year Posted:  UI  792)

 

Key Code: P

Which of the following statements about echinococcosis (= hydatid disease) is FALSE?

A) The infection is acquired by swallowing tapeworms eggs
B) The parasite causing the disease is Taenia solium
C) The infection characteristically involves the liver
D) Symptoms are mainly due to mass effects caused by the increasing size of the cyst
E) This is an example of a "dead-end" infection

Answer: B

 

(Year Posted: UI  793)

 

Key Code: P

Which of the following statements about genitourinary schistomiasis is FALSE?

A) The causative agent is Schistosoma haematobium
B) Infection is acquired by larvae, i.e. cercariae, burrowing through the skin
C) Pathology is due directly to the presence of the adult worms
D) The infection is detected by examination of urine for eggs
E) Squamous carcinoma of the urinary bladder is a recognized complication

Answer: C

 

(Year Posted: UI  794)

 

Key Code: P

Which Plasmodium species is MOST LIKELY to cause fatal disease

A) P. vivax
B) P. malariae
C) P. falciparum
D) P. ovale

Answer: C

 

(Year Posted: UI  795)

 

Key Code: P

Humans are frequently made aware that they are infected with one of the following organisms due to passing segments in their stool. Which organism is this?

A) Echinococcus granulosus
B) Hymenolepis nana
C) Diphyllobothrium latum
D) Taenia saginata
E) Paragonimus westermani

Answer: D

 

(Year Posted:  UI  796)

 

Key Code: F

Sporothrix schenckii infection frequently presents with:

A) Lymphocutaneous lesions
B) Bone lesions
C) Pulmonary infiltrates
D) Sinus tracks draining "granules"
E) Mucosal ulcerations

Answer: A

 

(Year Posted: UI  797)

 

Key Code: F

Detection of polysaccharide antigen is most useful in the diagnosis of:

A) Candidiasis
B) Aspergillosis
C) Cryptococcosis
D) Dermatomycosis
E) Coccidioidomycosis

Answer: C

 

(Year Posted:  UI  798)

 

Key Code: B

An 80-year old woman sought treatment in the emergency room because of a stiff jaw and dysphagia. She had slightly slurred speech and difficulty opening her mouth. A wood splinter from a forsythia bush had been lodged in her left shin for approximately 1 week. During a 2-week period she was treated for tremors, muscle spasms and apnea. Aerobic cultures of the wound were negative but cultures grown under anaerobic conditions showed the presence of large gram positive rods. The toxin responsible for the clinical signs and symptoms acts by:

A) Activation of adenyl cyclase
B) Activation of glycine degradation pathways
C) Inhibiting the release of acetyl choline
D) Inhibiting the release of inhibitory neurotransmitter
E) Inhibiting the fusion of phagosomes with lysosomes

Answer: D

 

(Year Posted:UI  799)

 

Key Code: B

A 24-year old female presents to the emergency room with fever and in shock. She has desquamation on the trunk of the body and palms of the hands and soles of the feet. A gram positive coccus which is catalase positive and coagulase positive is isolated from a cervical swab. The toxin responsible for this clinical syndrome is best described as a:

A) Adenyl cyclase
B) ADP ribosylating toxin
C) Endotoxin
D) Enterotoxin
E) Super antigen

Answer: E

 

(Year Posted:UI  800)