Question 1 - Single Best Answer
What is unusual about the pathogenesis of Staphylococcus aureus endocarditis relative to other bacterial causes of endocarditis?
It can occur with no previous valve damage. It does not usually cause bacteremia. It does not usually cause fever. It is not preceded by bacteremia. None of the above Ð pathogenesis of S. aureus endocarditis has no unusual characteristics.
Question 2 - Single Best Answer
The single best way to diagnose upper tract urinary tract infection is:
presence of costovertebral angle pain presence of fever positive blood culture dysuria suprapubic pain
Question 3 - Single Best Answer
A reticulate body is:
a person suffering from tetanus. the intracellular form of Borrelia. a symptom of secondary syphilis. the replicative form of Chlamydia. a brain inclusion body found in rabies.
Question 4 - Single Best Answer
The reason that the microbial profiles of organisms (kinds of organisms) causing sinusitis and otitis media are so similar is that:
both need to avoid phagocytosis to spread hematogenously after being acquired from another person. both are caused primarily by a person's normal flora. both replicate intracellularly in the ciliated cells present in both sites. both require head trauma to occur. both occur more frequently in children due to their lack of normal flora.
Question 5 - Single Best Answer
The pathogenesis of bacterial endocarditis includes which of the following?
endotoxin damage to the heart muscle intracellular bacteria growing in the heart cells bacteria growing extracellularly on a heart valve bacteria occluding coronary arteries an immunological reaction to heart muscle cells
Question 6 - Single Best Answer
What two conditions must occur together for most cases of subacute bacterial endocarditis to occur? Line NBTE and bacteremia
Question 7 - Single Best Answer
Which of the following sexual transmitted diseases have symptoms that sometimes mimic those of cystitis?
syphilis Herpes simplex papilloma virus chancroid gonorrhea
Question 8 - Single Best Answer
Most likely diagnosis in a paraplegic patient with a fever of unknown origin is: Line urinary tract infection
Question 9 - Single Best Answer
An 18-year old girl is brought to the College Infirmary by her roommate in late September. The roommate claimed the patient had been feeling fine the night before but this morning had a high fever and was difficult to arouse. A dorm-mate of the two girls had been similarly sick several days before and was still hospitalized. On physical exam the patient was found to have a temperature of 102F, to be lethargic, and to have a petechial rash. Examination of the CSF revealed numerous neutrophils. What other finding is MOST LIKELY?
high glucose level in the CSF Negri bodies in the brain Gram negative cocci in the CSF but not the blood Gram positive cocci in the CSF and also in the blood Gram negative cocci in the CSF and also in the blood
Question 10 - Single Best Answer
Disseminated gonococcal infection manifests itself primarily as:
arthritis of small to medium joints and a maculopapular rash pneumonia and upper respiratory tract infection pharyngitis upper urinary tract infection dysentery
Question 11 - Single Best Answer
In community acquired bacterial meningitis, the most common route to the central nervous system is via the:
blood. cribiform plate. middle ear. intestinal tract. sinuses.
Question 12 - Single Best Answer
A 28 year old man has been receiving antibiotic therapy during a hospitalization for nearly two weeks. He recently started to experience diarrhea. The attending physician decided to discontinue the antibiotics to see if the diarrhea would resolve. The causative agent of this man's diarrhea is MOST LIKELY:
Staphylococcus aureus Clostridium perfringens Clostridium difficile Candida albicans Enterotoxinogenic E. coli
Question 13 - Single Best Answer
The bacteria found in most cases of subacute bacterial endocarditis are: Line viridans Streptococci
Question 14 - Single Best Answer
In terms of pathogenesis, what is a major difference between bacteria that cause inflammatory diarrhea and those that cause watery diarrhea?
Only those that cause watery diarrhea produce exotoxins. Only those that cause inflammation produce endotoxin. Only those that produce watery diarrhea have adhesins. Inflammatory diarrhea is caused by invasive bacteria while watery diarrhea is usually caused by toxin-mediated secretion of water. None of the above - the bacteria are the same, it is merely the extent of pathology that is different.
Question 15 - Single Best Answer
A 55 year old man employed by an Ocala horse farm is brought to the ER in August with a high fever, stiff neck, severe headache, and lethargy. There have been three cases of fatal Eastern Equine Encephalitis (EEE) in horses reported during the summer and one other case in a human, the patient's neighbor. He is hospitalized and 10 days later a rise in serum antibodies to EEE is observed. The man contracted the disease from
another person via respiratory droplets a horse via respiratory droplets a horse via a mosquito who had bitten the horse a bird via respiratory droplets a bird via a mosquito that had bitten the bird
Question 16 - Single Best Answer
The reason old men are much more likely to have urinary tract infections than young men is because:
the length of their urethras decreases with age. they develop benign prostatic hypertrophy. they have more E. coli in their GI tract. they develop antibodies to the E. coli adhesins. they have casts in their urine which the bacteria can adhere to.
Question 17 - Single Best Answer
Condyloma lata are grayish-white lesions on the female genitalia that are indicative of
chancroid. primary syphilis. secondary syphilis. gonorrhea. papilloma virus infection.
Question 18 - Single Best Answer
What are the three principal items indicative of a normal vaginal wet prep that are looked for before the examination for specific causes of vaginitis or vaginosis? Line epithelial cells, WBCs, normal vaginal flora
Question 19 - Single Best Answer
Why must bactericidal antibiotics be used to treat endocarditis? Line neutrophils cannot penetrate the vegetation
Question 20 - Single Best Answer
A high urine specific gravity would MOST LIKELY be found in a case of:
gonorrhea. syphilis. brucellosis. Helicobacter pylori gastritis. cholera.
Question 21 - Single Best Answer
To identify physical defects in heart valves to diagnose endocarditis, which of the following is most appropriate?
CT scan, if negative followed by MRI Chest X-ray, if negative followed by CT scan Use of radioactive tracers Transthoracic echocardiogram, if negative followed by transesophogeal echocardiogram None of the above, visualization of valvular damage is not required.
Question 22 - Single Best Answer
Which of the following is the LEAST LIKELY outcome of Listeria infection?
meningitis septicemia stillbirth bloody diarrhea intrauterine infection
Question 23 - Single Best Answer
What are the two most common causes of community acquired bacterial meningitis in adults in the United States at the present time? Line Streptococcus pneumoniae Neisseria meningitidis
Question 24 - Single Best Answer
How and why have the causative agents of bacterial meningitis among infants changed over the last 20 years? Line Haemophilus influenzae meningitis has dropped due to the vaccine
Question 25 - Single Best Answer
What is the pathogenesis of splinter hemorrhages in endocarditis?
emboli lodging in distal capillaries a toxin that kills endothelial cells bacteria growing in and blocking capillaries deposition of immune complexes
Question 26 - Single Best Answer
A common virulence factor for the two major causes of community acquired bacterial meningitis is:
fimbria. superantigen toxin. intracellular growth. endotoxin. capsule.
Question 27 - Single Best Answer
In rabies, analysis of the CSF would reveal:
elevated protein and normal glucose. elevated protein and elevated glucose. lowered protein and normal glucose. lowered protein and elevated glucose. normal levels of both protein and glucose.
Question 28 - Single Best Answer
A cruise ship had to return to port because 80% of the passengers were suffering from watery diarrhea accompanied by nausea and some vomiting. Most recovered with only supportive care. The ship was disinfected, and on its next cruise the same thing happened. The likely cause of this disease is:
rotavirus spread by direct contact. Norwalk virus spread by fomites. an asymptomatic carrier of Campylobacter among the crew of the ship. Vibrio cholera contaminating the chicken that was not cooked well enough. A passenger carrying Salmonella in their gall bladder.
Question 29 - Single Best Answer
Adding KOH to a wet prep is useful in visualizing:
Candida. Trichomonas. Neisseria gonorrhoeae. Mobiluncus. None of the above Ð KOH is only used for the whiff/sniff test.
Question 30 - Single Best Answer
Name 3 causes of genital ulcer disease. Line syphilis, herpes, chancroid, LGV
Question 31 - Single Best Answer
Three hours after returning from an after-church picnic at which potato salad, fried chicken, hot dogs, corn, and coconut cream pie had been served, more than half of the attendees became ill with severe vomiting and some diarrhea. Most missed work on Monday but returned on Tuesday. They likely suffered from:
Salmonella infection from the fried chicken. E. coli (ETEC) infection from the hot dogs. Clostridium perfringens food intoxication from the corn. Staphylococcus aureus food intoxication from the potato salad. Bacillus cereus food intoxication from the cream pie.
Question 32 - Single Best Answer
A woman is hospitalized for a breast biopsy to determine if she has breast cancer. She is kept in the hospital because of an idiosyncratic (unusual) reaction to the anesthetic. On the second day of hospitalization she developed a fever and was somewhat nauseated. Later, her blood pressure began to drop. The resident who examined her did not remove the dressing covering her biopsy wound and indicated that he thought her symptoms were due to a bad reaction to the hospital food. The next day, however, she went into shock, and during the ensuing treatment to stabilize her, the bandage came off her incision. It was red and swollen and exuding pus. A Gram stain of the pus showed gram-positive cocci in clusters. They were grown on blood agar and found to be beta hemolytic. They were catalase-positive and coagulase-positive. The relationship between her wound and the drop in blood pressure was:
the Enterococci in her wound got into her bloodstream and caused endotoxic shock. the Streptococcus from her wound spread along the fascia and into the capillaries, causing fluid to leak. The Staphylococcus epidermidis in her wound released peptidoglycan into the bloodstream, which stimulated a cytokine cascade. the Staphylococcus aureus in her wound produced a superantigen.
Question 33 - Single Best Answer
Which of the following best explains how timely diagnosis and treatment of Chlamydia trachomatis infection of the genital tract can reduce the number of deaths that occur in pregnant women?
Pregnant women are more prone to systemic infection by this organism. It will reduce ectopic pregnancy. It will prevent lethal autoimmune reactions that occur during pregnancy. Pregnant women are more likely to experience upper urinary tract infection. Chlamydia infection reduces fertility.
Question 34 - Single Best Answer
Which of the following is NOT a virulence factor for Staphylococcus aureus?
production of hydrogen peroxide Protein A (an Fc binding protein) Fibronectin binding protein Coagulase Enterotoxin
Question 35 - Single Best Answer
The most effective treatment for a case of clinical tetanus would be respiratory support plus:
penicillin penicillin plus tetanus toxoid penicillin plus tetanus antitoxin Polymyxin None of the above Ð tetanus cannot be cured.
Question 36 - Single Best Answer
Decubitous ulcers (bed sores) are most likely to cause death by which of the following mechanisms?
The bacteria causing the ulcers spread to the brain. The exotoxins produced in the wound cause a precipitous drop in blood pressure. The exotoxins produced in the wound cause a flaccid paralysis. The endotoxin of bacteria in the wound lead to systemic organ failure. Hemorrhage and blood loss.
Question 37 - Single Best Answer
The difference between botulism food intoxication and infant botulism can best be described by which of the following statements?
In the food intoxication the toxin acts in the spinal chord while in infant botulism the toxin acts at the neuro-muscular junction. In infant botulism the bacteria colonize the intestine and produce toxin there while in food intoxication the preformed toxin is ingested. In food intoxication spores are ingested while in infant botulism they are not. In infant botulism a wound is involved while in food intoxication there is no wound. None of the above Ð there are no differences between infant botulism and the food intoxication.
Question 38 - Single Best Answer
Sexually active young women are more prone to urinary tract infections because:
hormones change the sugar composition of the glycoproteins on the bladder epithelial cells and allow the bacteria to stick better. UTI's are sexually transmitted. having urethritis makes it more likely that a woman will get cystitis. the physical act of intercourse introduces periurethrally colonizing bacteria into the urethra. the bladder muscle is temporarily denervated during sexual intercourse causing urine to pool in the bladder.
Question 39 - Single Best Answer
Question 40 - Single Best Answer
What is one virulence MECHANISM shared by almost all organisms causing STD's?
production of exotoxins intracellular growth secretion of IgA proteases sometimes causing inapparent infections ability to stimulate sexual activity in their hosts, causing the remarkable correlation between sexual activity and STD's
Question 41 - Single Best Answer
A VDRL test measures:
anti-syphilis IgM. anti-syphilis IgG. anti-gonococcal pilus IgA. anti-cardiolipin antibodies. anti-Herpes antibodies.
Question 42 - Single Best Answer
Factors that are associated with E. coli causing upper urinary tract disease are:
mannose-sensitive fimbria and urease. mannose-resistant fimbria and hemolysin. Shiga-like toxin and attaching/effacing adherence. invasion of host cells and cytotoxicity. resistance to macrophages and production of a capsule.
Question 43 - Single Best Answer
Which of the following organisms are major causes of inpatient urinary tract infection (10% or more) but are NOT major causes of community acquired urinary tract infection (less than 10%)?
Enterococci Pseudomonas Enterobacter Klebsiella All of the above ARE major causes of inpatient but are NOT principal causes of community acquired urinary tract infections.
Question 44 - Single Best Answer
In a vaginal wet prep Leptothrix can best be described as:
gram-variable coccobacilli that adhere to epithelial cells. spiral-shaped, highly motile bacteria. branched, pseudohyphae-forming rods. long, hair-like bacilli. ovoid, highly motile protozoans.
Question 45 - Single Best Answer
What is the maximum acceptable time from arrival of a patient suspected of having bacterial meningitis until antibiotics are initiated?
10 minutes 30 minutes 60 minutes It depends if the CT scan is positive for mass lesions. It depends if the CSF Gram stain is positive.
Question 46 - Single Best Answer
What are the most frequent causes of community acquired and nosocomial bacterial meningitis, respectively? Line S. pneumoniae and Gram-negative bacilli
Question 47 - Single Best Answer
Each of the following is a meningeal symptom EXCEPT:
vomiting. confusion. fever. headache. lethargy.
Question 48 - Single Best Answer
Describe the three principal characteristics of a CSF profile for bacterial meningitis. Line PMNs, low glucose, high protein
Question 49 - Single Best Answer
Which of the following are NOT MAJOR criteria for diagnosing bacterial endocarditis?
Two separate positive blood cultures with typical organisms Splinter hemorrhages and Janeway lesions Positive echocardiogram for endocardial involvement New regurgitant murmur None of the above Ð All of these ARE MAJOR criteria for diagnosing bacterial endocarditis.
Question 50 - Single Best Answer
Which of the following are most important for distinguishing necrotizing otitis externa from acute otitis externa?
hoarseness, dysphagia, facial palsy otorrhea otalgia presence of a cholesteatoma presence of bacteria
Question 51 - Single Best Answer
If a patient in the United States who had not traveled overseas experiences microangiopathic hemolytic anemia and kidney failure from toxin-mediated cytotoxicity of endothelial cells, which of the following best describes the pathogenesis?
Gram-negative rod that also invaded epithelial cells causing necrosis. The organism was likely acquired from undercooked beef. It was an ascending infection from the lower urinary tract. The disease has human to human spread only. The organisms entered the kidney by hematogenous spread.
Question 52 - Single Best Answer
What is the most important reason why lymphogranuloma venereum is not seen in the United States very much?
It is not looked for on a regular basis. Public health is better here than in other countries. We have a vaccine against it. The specific LGV serovars of Chlamydia are not prevalent here. Our sexual practices are different than other countries.
Question 53 - Single Best Answer
A 20 year old sexually active male presents with a chancre on his penis. The VDRL test is positive. This man definitely has:
syphilis chancroid Herpes Chlamydia One cannot tell from the information provided.
Question 54 - Single Best Answer
The most common etiological class of agents causing diarrhea in the United States is:
viruses. bacteria. parasites. fungi.
Question 55 - Single Best Answer
Which of the following best explains why EHEC enterohemorrhagic colitis is generally not treated with antibiotics?
It usually leads to Clostridium difficile pseudomembranous colitis. The normal flora is disrupted and yeast grow out. A phage's gene expression may be induced. An antibiotic resistance plasmid might be selected for. A spontaneous mutation leading to antibiotic resistance might be selected for.
Question 56 - Single Best Answer
Why are patients with diarrhea caused by ETEC generally treated with antibiotics?
To prevent the entry of these bacteria into the United States. The disease can progress to sepsis if untreated. The disease can progress to urinary tract infection if not treated. To help the patients enjoy their vacation. None of the above - ETEC patients are not treated because it is a self-limiting diarrhea.
Question 57 - Single Best Answer
Francisella tularensis and Salmonella enterica serovar Typhi have which of the following in common?
Both are not transmitted between humans. Both can enter via arthropod bite or inhalation. Both produce capsules yet are intracellular pathogens of phagocytes. Both are endemic to the United States. Both are zoonoses.
Question 58 - Single Best Answer
If the genetic changes that have occurred to Yersinia pestis over the past millennia were somehow undone, this bacterium would cause what type of disease?
enteritis pneumonia meningitis urinary tract infection None of the above - there would be no change in its disease.
Question 59 - Single Best Answer
Which of the following do Lyme disease and Rocky Mountain Spotted Fever have in common?
Both cause chronic diseases in which the final stage is primarily immune mediated. Both are caused by bacteria with two different intracellular replication forms. Both are transmitted by ticks. The skin rashes are similar in appearance and are frequently confused. Both are highly transmissible between humans.
Question 60 - Single Best Answer
Anthrax is initiated by contact of a human with:
a vegetative cell. a spore. a toxin. another human being. Any of the above.
Question 61 - Single Best Answer
Helicobacter pylori is associated with all of the following EXCEPT:
gastritis. peptic ulcer. adenocarcinoma. dysentery. asymptomatic carriage.
Question 62 - Single Best Answer
The diagnostic criteria for bacterial vaginosis include each of the following EXCEPT:
thin, gray vaginal discharge. vaginal pH >4.5. highly motile, ovoid protozoal cells with flagella and an undulating membrane. Clue cells. positive KOH (whiff/sniff) test.
Question 63 - Single Best Answer
Ultrasound is used to examine anatomic defects of the urinary tract:
whenever there is a possible upper tract infection. if the intravenous pyelogram shows abnormalities. only in culture-positive cases. if urethritis is suspected. None of the above Ð ultrasonography has no value in diagnosing urinary tract infection.
Question 64 - Single Best Answer
Helicobacter pylori and Campylobacter jejuni have each of the following in common EXCEPT:
They are gram-negative curved rods. Their LPS mimics human antigens. They are spread by fecal-oral transmission. They are believed to cause cancer indirectly or directly. All of the above ARE common to these bacteria.
Question 65 - Single Best Answer
For which of the following is diagnosis made by assaying for a major virulence factor rather than culture?
Shigella flexneri Clostridium difficile Salmonella enterica serovar Typhi Enterohemorrhagic E. coli Campylobacter jejuni
Question 66 - Single Best Answer
A 24 Caucasian female graduate student presented with -CC: Fever and chills for 5 days -3 wks PTA she traveled to Indonesia and Singapore. While in Singapore she noted soft 2-3 bowel movements per day without fever. She noted decreased appetite and mild fatigue. - 5 days PTA, two days after returning to the US she began experiencing bed shaking chills and fevers to 102-104.6 ¡F. Fever was associated with myalgias and watery non-bloody diarrhea, approximately one bowel movement every 4 hours. -4 days PTA seen in student health where she was given intravenous fluids and sent home. -3 days PTA Her fever persisted and she continued to have myalgias and diarrhea. She also complained of nausea and vomiting. -PE: Temp 103.4¡F, BP 110/70, P 88, RR20 -Appearance: mildly toxic appearance -HENT: normal conjunctiva, throat: no exudates -Neck: supple -Lungs: good breath sounds; Heart: nl S1 and S2 without murmur -Abdomen: nontender, hyperactive bowel sounds, liver edge palpable 4 cm below the right costal margin. -No palpable nodes. Skin: no lesions noted -LAB: WBC 1,800 (45% PMN, 22% band forms) (normal 5,000-10,000 with 70% PMN) -Liver function tests: ALT 385 (nl 0-35) AST 433 (nl 0-35). BUN 10 (WNL) and S. Creat. 0.9 (WNL).10 points total - please use the letters to separate your answers. -A. (6 points) What are the most likely causes for her diarrhea? (Include at least 3 causes and explain why you picked each etiology. Finally pick which cause you favor and why. Support your diagnosis using the facts provided in the case protocol). -B. (3 points) What additional tests would be helpful in determining the cause of her illness? (Include 3 and explain why each test would be helpful) -C. (1 point) Would you treat this patient with antibiotics? Explain why or why not. Text 1. The patient has a persistent high fever over 5 days. This is distinctly unusual for a viral gastroenteritis. Furthermore the WBC demonstrates a marked increase in band forms and is abnormally low (suggests increased accumulation of acute inflammatory cells). These findings are most consistent with a bacterial etiology. The finding of abnormal liver function tests as well as myalgias suggest this is a systemic illness rather than an infection localized to the gastrointestinal tract and strongly suggesting the patient has enteric fever. Enteric fever is most commonly caused by Salmonella typhi or Salmonella paratyphi. Other causes of enteric fever are Campylobacter fetus and Yersinia enterocolitica. These diseases are most commonly contracted in underdeveloped countries and the student had visited Indonesia. Another clue is the slow heart rate in association with a high fever. Other possible causes include Shigella; however this infection is usually associated with bloody diarrhea. Enteroinvasive E. coli (EIEC), or Enterohemorrhagic E. Coli (EHEC) are also possible. EHEC in particular causes a systemic illness, however there was no evidence of renal failure or bloody stools in the patient presented, making EHEC less likely. Campylobacter jejuni is also possible, however again this disease usually is associated with bloody diarrhea and rarely causes generalized systemic complaints. -2. Diagnostic tests: Given the history of chills and high fever blood cultures should be drawn. To clarify the inflammatory response in the GI tract a methylene blue smear of the stool should be performed. A stool culture should be ordered to determine the etiology because the clinical manifestations are high likely to be due to a bacterial infection of the GI tract. -3. An antibiotic should be administered in this patient because of the systemic nature of her complaints as well as her failure to improve with iv hydration. Enteric fever can be fatal if not treated with antibiotics and warrants immediate antibiotic therapy. The drug of choice is usually third generation cephalosporin (ceftriaxone) or a fluorquinolone (ciprofloxacin).