IV-35. Which of the following antibiotics has the weakest association with the development of Clostridium difficileľassociated disease?
IV-36. All of the following are common causes of urethritis in men EXCEPT:
A. Gardnerella vaginalis
B. Mycoplasma genitalium
C. Neisseria gonorrhoeae
D. Trichomonas vaginalis
E. Ureaplasma urealyticum
IV-37. A 25-year-old woman presents with 2 days of urinary frequency, urgency, and pelvic discomfort. She has no pain in her vulva on urination. She has no other medical problems and does not have fevers. She is sexually active. A microscopic examination of her urine shows pyuria but no pathogens. After 24 hours, her urine culture does not grow any pathogens. Which of the following tests will likely confirm her diagnosis?
A. Cervical culture
B. Clue cells on microscopy of vaginal secretions
C. Nucleic acid amplification test of urine for C. trachomatis
D. Physical examination of the vulva and vagina
E. Vaginal pH ≥5.0
IV-38. Which of the following diagnostic features characterizes bacterial vaginosis?
A. Scant vaginal secretions, erythema of vaginal epithelium, and clue cells
B. Vaginal fluid pH >4.5, clue cells, and profuse mixed microbiota on microscopic examination
C. Vaginal fluid pH ≥5.0, motile trichomonads on microscopic exam, and fishy odor with 10% KOH
D. Vaginal fluid pH <4.5, lactobacilli predominate on microscopic examination, and scant clear secretions
E. Vaginal fluid pH <4.5, clue cells, and profuse mixed microbiota on microscopic examination
IV-39. Which of the following is most likely to be identified in a woman seen at a sexually transmitted disease clinic with mucopurulent cervicitis?
A. Chlamydia trachomatis
B. Herpes simplex virus
C. Neisseria gonorrhoeae
D. Trichomonas vaginalis
E. No organism identified
IV-40. A 19-year-old woman is seen in the emergency department for pelvic pain. She reports 1 week of pain but has developed more severe pain on the right side of her lower abdomen over the past day with accompanying fever. Additionally, she reports pain in her right upper abdomen for the past day that is worsened by deep breathing. She is sexually active with multiple partners and only reports a past medical history of asthma. Examination is notable for fever, normal breath sounds, mild tachycardia, and a tender right upper quadrant without rebound, guarding, or masses. Pelvic examination shows a normal cervical appearance, but cervical motion tenderness and adnexal tenderness are present. No masses are palpated. A urine pregnancy test result is negative and leukocytosis is present, but otherwise renal and liver function laboratory study results are normal. Which of the following is true regarding her right upper quadrant tenderness?
A. Acute cholecystitis is likely present; a tech HIDA scan should be ordered to confirm the diagnosis.
B. If a liver biopsy were performed, herpes simplex virus could be cultured from the liver tissue.
C. Laproscopic examination would show inflammation of her liver capsule.
D. Plasma PCR is indicated for diagnosis of acute hepatitis C virus (HCV) infection as the etiology of her hepatitis.
E. CT scan of the chest would confirm the presence of septic pulmonary emboli.
IV-41. A 23-year-old college student is seen in the student health clinic for evaluation of multiple genital ulcers that he noted developing over the past week. They started as pustules and after suppuration are now ulcers. The ulcers are extremely tender and occasionally bleed. Examination shows multiple bilateral deep ulcers with purulent bases that bleed easily. They are exquisitely tender but are soft to palpation. Which of the following organisms are likely to be found on culture of the lesions?
A. Haemophilus ducreyi
B. Herpes simplex virus
C. Human immunodeficiency virus
D. Neisseria gonorrhoeae
E. Treponema pallidum
IV-42. All of the following infections associated with sexual activity correlate with increased acquisition of HIV infection in women EXCEPT:
A. Bacterial vaginosis
D. Herpes simplex virus-2
E. Trichomonas vaginalis
F. All of the above are associated with increased acquisition
IV-43. After leaving which of the following patientĺs room would the use of alcohol-based hand rub be inadequate?
A. A 54-year-old man with quadriplegia admitted with a urinary tract infection caused by extended- spectrum β-lactamaseľproducing bacteria
B. A 78-year-old nursing home resident with recent antibiotic use and Clostridium difficile infection
C. A 35-year-old woman with advanced HIV and cavitary pulmonary tuberculosis
D. A 20-year-old renal transplant recipient with varicella pneumonia
E. A 40-year-old man with MRSA furunculosis
IV-44. During the first 2 weeks after solid organ transplantation, which family of infection is most common?
A. Cytomegalovirus and Epstein-Barr virus reactivation
B. Humoral immunodeficiencyľassociated infections (e.g., meningococcemia, invasive Streptococcus pneumoniae infection)
C. Neutropenia-associated infection (e.g., aspergillosis, candidemia)
D. T-cell deficiencyľassociated infections (e.g., Pneumocystis jiroveci, nocardiosis, cryptococcosis)
E. Typical hospital-acquired infections (e.g., central line infection, hospital-acquired pneumonia, urinary tract infection)
IV-45. A 22-year-old woman underwent cadaveric renal transplantation 3 months ago for congenital obstructive uropathy. After a demanding college examination schedule during which she forgot to take some of her medications, she is admitted to the hospital with a temperature of 102░F, arthralgias, lymphopenia, and a rise in creatinine from her baseline of 1.2 mg/dL to 2.4 mg/dL. Which of the following medications did she most likely forget?
IV-46. Which of the following pathogens are cardiac transplant patients at unique risk for acquiring from the donor heart early after transplant when compared to other solid organ transplant patients?
A. Cryptococcus neoformans
C. Pneumocystis jiroveci
D. Staphylococcus aureus
E. Toxoplasma gondii
IV-47. A 43-year-old woman undergoes allogeneic stem cell transplantation for acute myelogenous leukemia. Two weeks after the date of her transplantation, she is admitted to the hospital with a temperature of 101.1░F, pulse of 115 beats/min, blood pressure of 110/83 mmHg, and oxygen saturation of 89% on room air. Her white blood cell count is 500/μL, and 20% are polymorphonuclear cells. Because of hypoxia and infiltrates on plain chest radiograph, a CT scan is ordered. She is found to have
diffuse nodules and masses, some with a halo sign. Which of the following tests is most likely to be diagnostic of her disease?
A. Microscopic examination of buffy coat
B. Plasma CMV viral load
C. Serum galactomannan antigen test
D. Sputum culture
E. Urine Legionella assay
IV-48. Which of the following antibiotics inhibit cell wall synthesis?
A. Ciprofloxacin, metronidazole, and quinupristin/dalfopristin
B. Rifampin, sulfamycin, and clindamycin
C. Tetracycline, daptomycin, and azithromycin
D. Tobramycin, chloramphenicol, and linezolid
E. Vancomycin, bacitracin, and penicillin
IV-49. A 23-year-old college student is admitted to the hospital with a fever and painful, erythematous purulent nodules on his forearm. He is an avid weightlifter and other than depression treated with citalopram has been otherwise healthy. These lesions have been present for approximately 1 week, and his primary care physician attempted to treat him with clindamycin as an outpatient. After admission, he develops hypotension and evidence of systemic inflammatory response syndrome, prompting transfer to the medical intensive care unit. There, dopamine is started, linezolid is administered, and hydrocortisone and fludrocortisone are given for possible adrenal insufficiency in the context of septic shock. After 6 hours, he develops an agitated delirium with diaphoresis, tachycardia, a temperature of 103.4░F, and diarrhea. His examination is notable for tremor; muscular rigidity; hyperreflexia; and clonus, especially in the lower extremities. Which of the following drugľdrug interactions is most likely the culprit of this clinical syndrome?
IV-50. All of the following statements regarding pneumococcus are true EXCEPT:
A. Asymptomatic colonization does not occur.
B. Infants (younger than 2 years old) and elderly adults are at greatest risk of invasive disease.
C. Pneumococcal vaccination has impacted the epidemiology of disease.
D. The likelihood of death within 24 hours of hospitalization for patients with invasive pneumococcal pneumonia has not changed since the introduction of antibiotics.
E. There is a clear association between prior viral upper respiratory infection and secondary pneumococcal pneumonia.
IV-51. A 75-year-old man who resides at a nursing home is brought to the hospital for altered mental
status over 1 day. He has a history of Parkinsonĺs disease and COPD. Staff noticed that he was somnolent and confused on the day of admission. In the emergency department, his temperature is 38.5░C, blood pressure is 95/65 mmHg, heart rate is 105 beats/min, respiratory rate is 24 breaths/min, and room air oxygen saturation is 85%. He has egophony over the right posterior lung field. His chest radiograph is shown in Figure IV-51. All of the statements regarding this patient are true EXCEPT:
A. Blood cultures are unlikely (<30%) to be positive.
B. His radiograph demonstrates lobar consolidation.
C. Meningitis is the most common focal complication.
D. Penicillin may be appropriate therapy.
E. Urinary antigen testing could be diagnostic.
IV-52. A 19-year-old college student is brought to the emergency department by friends from his dormitory for confusion and altered mental status. They state that many students have upper respiratory tract infections. He does not use alcohol or illicit drugs. His physical examination is notable for confusion, fever, and a rigid neck. Cerebro-spinal fluid (CSF) examination reveals a white blood cell count of 1800 cells/μL with 98% neutrophils, glucose of 1.9 mmol/L (35 mg/dL), and protein of 1.0 g/L (100 mg/dL). Which of the following antibiotic regimens is most appropriate as initial therapy?
A. Ampicillin plus vancomycin
B. Ampicillin plus gentamicin
C. Cefazolin plus doxycycline
D. Cefotaxime plus doxycycline
E. Cefotaxime plus vancomycin
IV-53. In addition to antibiotics, which of the following adjunctive therapies should be administered to
improve the chance of a favorable neurologic outcome in the patient in question IV-52?
E. Parenteral nutrition
IV-54. Which of the following biochemical tests distinguishes S. aureus from S. epidermidis?
C. Lactose fermentation
IV-55. A 30-year-old woman with end-stage renal disease who receives her dialysis through a tunneled catheter in her shoulder presents with fever and severe low back pain. On examination, she is uncomfortable and diaphoretic but hemodynamically stable. She has a soft 2/6 early systolic flow murmur. Her line site is red and warm with no pustular exudates. She is very tender over her lower back. Neurologically, she is completely intact. There is no evidence of Janeway lesions, Osler nodes, or Roth spots. Her white count is 16,700/μL with 12% bands. Immediate evaluation should include all of the following EXCEPT:
A. Admission to the hospital
B. MRI of the lumbar spine
C. Removal of her dialysis catheter
D. Transthoracic echocardiogram
E. Two sets of blood cultures followed by empiric therapy with vancomycin plus cefepime
IV-56. A 30-year-old healthy woman presents to the hospital with severe dyspnea, confusion, productive cough, and fevers. She had been ill 1 week earlier with a flulike illness characterized by fever, myalgias, headache, and malaise. Her illness almost entirely improved without medical intervention until 36 hours ago, when she developed new rigors followed by progression of the respiratory symptoms. On initial examination, her temperature is 39.6░C, pulse is 130 beats/min, blood pressure is 95/60 mmHg, respiratory rate is 40 breaths/min, and oxygen saturation is 88% on 100% face mask. On examination, she is clammy, confused, and very dyspneic. Lung examination reveals amphoric breath sounds over her left lower lung fields. She is intubated and resuscitated with fluid and antibiotics. Chest CT scan reveals necrosis of her left lower lobe. Blood and sputum cultures grow Staphylococcus aureus. This isolate is likely to be resistant to which of the following antibiotics?
D. Trimethoprimľsulfamethoxazole (TMP/SMX)
IV-57. In the patient described above, all of the following may be efficacious therapy EXCEPT:
IV-58. Which of the following organisms is most likely to cause infection of a shunt implanted for the treatment of hydrocephalus?
A. Bacteroides fragilis
B. Corynebacterium diphtheriae
C. Escherichia coli
D. Staphylococcus aureus
E. Staphylococcus epidermidis
IV-59. A 42-year-old man with poorly controlled diabetes (HbA1c, 13.3%) presents with thigh pain and fever over several weeks. Physical examination reveals erythema and warmth over the thigh with notable woody, nonpitting edema. There are no cutaneous ulcers. CT of the thigh reveals several abscesses located between the muscle fibers of the thigh. Orthopedics is consulted to drain and culture the abscesses. Which of the following is the most likely pathogen?
A. Clostridium perfringens
B. Group A streptococcus
C. Polymicrobial flora
D. Staphylococcus aureus
E. Streptococcus milleri
IV-60. A 19-year-old woman from Guatemala presents to your office for a routine screening physical examination. At age 4 years, she was diagnosed with acute rheumatic fever. She does not recall the specifics of her illness and remembers only that she was required to be on bed rest for 6 months. She has remained on penicillin V orally at a dose of 250 mg bid since that time. She asks if she can safely discontinue this medication. She has had only one other flare of her disease, at age 8 years, when she stopped taking penicillin at the time of her emigration to the United States. She is currently working as a day care provider. Her physical examination is notable for normal point of maximal impulse (PMI) with a grade III/VI holosystolic murmur that is heard best at the apex of the heart and radiates to the axilla. What do you advise the patient to do?
A. An echocardiogram should be performed to determine the extent of valvular damage before deciding if penicillin can be discontinued.
B. Penicillin prophylaxis can be discontinued because she has had no flares in 5 years.
C. She should change her dosing regimen to IM benzathine penicillin every 8 weeks.
D. She should continue on penicillin indefinitely because she had a previous recurrence, has presumed rheumatic heart disease, and is working in a field with high occupational exposure to group A streptococcus.
E. She should replace penicillin prophylaxis with polyvalent pneumococcal vaccine every 5 years.
IV-61. A 36-year-old man is brought to the hospital by his wife because of a rapidly worsening skin infection. The patient has a history of type 1 diabetes, and his last documented HbA1c was 5.5%. His wife reports that he had a small insect bite on his calf a few days ago with some redness. Over the course of today, he has developed severe thigh pain initially with no redness, but over the past hour, he has had worsening pain and swelling with some mottling of the skin. He also reports that he feels like his thigh and calf are numb. He is febrile and tachycardic. Physical examination reveals marked tenderness and tenseness of the right leg from the thigh down. There is some redness and mottling. A femoral and posterior tibial pulse are present. CT scan of the leg shows extensive inflammation of the fascial planes but no evidence of muscle inflammation. Which of the following organisms is most likely responsible for his infection?
A. Clostridium difficile
B. Staphylococcus aureus
C. Staphylococcus epidermidis
D. Streptococcus pneumonia
E. Streptococcus pyogenes
IV-62. A 24-year-old woman is brought to the hospital by her husband with fever and severe abdominal pain. She lives in rural Pennsylvania and home delivered a child 2 days ago. She did not receive routine prenatal care. Her labor was difficult with delivery over 18 hours after membrane rupture. Her baby has been feeding well over the past 48 hours and has had no fever. The patient noticed she had low-grade fever 24 hours after birth, and her abdominal pain has developed over the past 12 hours. She is febrile to 39░C and is tachycardic. Abdominal examination is notable for marked tenderness in the lower abdomen. A pelvic examination shows a purulent material emanating from her cervix with marked adnexal tenderness. A Gram stain shows extensive neutrophils and gram-positive cocci in chains. Which of the following organisms is the most likely cause of her disease?
A. Chlamydia trachomatis
B. Gardnerella vaginalis
C. Neisseria gonorrhea
D. Streptococcus agalactiae
E. Trichomonas vaginalis
IV-63. All of the following statements regarding enterococci are true EXCEPT:
A. Enterococci are the second most common cause of hospital-acquired infections.
B. Infection with vancomycin-resistant strains of enterococci (VRE) does not increase the patientĺs risk of death compared with infection with vancomycin-sensitive strains of enterococci.
C. Patients with GI colonization by VRE are more likely to develop bacteremia than patients with GI colonization by vancomycin-sensitive strains of enterococci.
D. Physical proximity to a room colonized with VRE is a risk factor for patients developing gut colonization with VRE.
E. Strains of E. faecium are more likely to be resistant to vancomycin than strains of E. faecalis.
IV-64. A 74-year-old man with a recent history of diver-ticulitis is admitted to the hospital with 1 week of fever, malaise, and generalized weakness. His physical examination is notable for a temperature of 38.5░C, a new mitral heart murmur, and splinter hemorrhages. Three blood cultures grow Enterococcus faecalis, and an echocardiogram shows a small vegetation on the mitral valve. The organism is reported as being sensitive to ampicillin with no high-level resistance to aminoglycosides. Based on this information, which of the following is recommended therapy?
B. Ampicillin plus gentamicin
IV-65. Which of the following drugs is bactericidal and approved by the FDA for some infections caused by vancomycin-resistant E. faecium?
IV-66. A 42-year-old man with HIV has been developing worsening disease because of HAART resistance and worsening viremia. Over the past 6 months, his CD4 T-cell count has fallen below 100/μL. He has not been compliant with prophylactic medication because he is tired of taking pills. He comes to clinic reporting 3 weeks of productive cough and low-grade fever. A chest radiograph shows multiple small necrotizing nodules in the bilateral lower lobes. A percutaneous needle biopsy reveals some neutrophils and small gram-positive coccobacilli that the laboratory says looks like corynebacterium. A culture grows Rhodococcus equi. All of the following are effective therapy EXCEPT:
IV-67. An 87-year-old nursing home resident is brought by ambulance to a local emergency department. He is obtunded and ill-appearing. Per nursing home staff, the patient has experienced low-grade temperatures, poor appetite, and lethargy over several days. A lumbar puncture is performed, and the Gram stain returns gram-positive rods and many white blood cells. Listeria meningitis is diagnosed and appropriate antibiotics are begun. Which of the following statements regarding Listeria meningitis distinguishes it from other causes of bacterial meningitis?
A. There is more frequent nuchal rigidity.
B. More neutrophils are present on the cerebrospinal fluid (CSF) differential.
C. Photophobia is more common.
D. Presentation is often more subacute.
E. White blood cell (WBC) count is often more elevated in the CSF.
IV-68. Several family members present to a local emergency department 2 days after a large family summer picnic at which deli meats and salads were served. They all complain of profuse diarrhea, headaches, fevers, and myalgias. Their symptoms began about 24 hours after the picnic. It appears that everyone who ate Uncle Sandyĺs Salami Surprise was affected. Routine cultures of blood and stool are negative to date. Which of the following is true regarding Listeria gastroenteritis?
A. Antibiotic treatment is not necessary for uncomplicated cases.
B. Carriers are asymptomatic but can easily spread infection via the fecalľoral route.
C. Gastrointestinal illness can result from ingestion of a single organism.
D. Illness is toxin mediated, and organisms are not present at the time of infection.
E. Person-to-person spread is a common cause of outbreaks.
IV-69. A 26-year-old woman presents late in the third trimester of her pregnancy with high fevers, myalgias, backache, and malaise. She is admitted and started on empirical broad-spectrum antibiotics. Blood cultures return positive for Listeria monocytogenes. She delivers a 5-lb infant 24 hours after admission. Which of the following statements regarding antibiotic treatment for this infection is true?
A. Clindamycin should be used in patients with penicillin allergy.
B. Neonates should receive weight-based ampicillin and gentamicin.
C. Penicillin plus gentamicin is first-line therapy for the mother.
D. Quinolones should be used for Listeria bacteremia in late-stage pregnancy.
E. Trimethoprimľsulfamethoxazole has no efficacy against Listeria spp.
IV-70. A 64-year-old man with a long history of heroin abuse is brought to the hospital because of fever and worsening muscle spasms and pain over the past day. Because of longstanding venous sclerosis, he no longer injects intravenously but ôskin pops,ö often with dirty needles. On examination, he is extremely sweaty and febrile to 101.4░F. There are widespread muscle spasms, including the face. He is unable to open his jaw because of muscle spasm and has severe back pain because of diffuse spasm. On his leg, there is a skin wound that is tender and erythematous. All of the following statements regarding this patient are true EXCEPT:
A. Culture of the wound may reveal Clostridium tetani.
B. Intrathecal antitoxin administration is recommended therapy.
C. Metronidazole is the recommended therapy.
D. Permanent muscle dysfunction is likely after recovery.
E. Strychnine poisoning and antidopaminergic drug toxicity should be ruled out.
IV-71. A 34-year-old injection drug user presents with a 2-day history of slurred speech, blurry vision that is worse with bilateral gaze deviation, dry mouth, and difficulty swallowing both liquids and solids. He states that his arms feel weak as well but denies any sensory deficits. He has had no recent illness but does describe a chronic ulcer on his left lower leg that has felt slightly warm and tender of late. He frequently injects heroin into the edges of the ulcer. On review of systems, he reports mild
shortness of breath but denies any gastrointestinal symptoms, urinary retention, or loss of bowel or bladder continence. Physical examination reveals a frustrated, nontoxic appearing man who is alert and oriented but noticeably dysarthric. He is afebrile with stable vital signs. Cranial nerve examination reveals bilateral cranial nerve VI deficits and an inability to maintain medial gaze in both eyes. He has mild bilateral ptosis, and both pupils are reactive but sluggish. His strength is 5/5 in all extremities except for his shoulder shrug, which is 4/5. Sensory examination and deep tendon reflexes are within normal limits in all four extremities. His oropharynx is dry. Cardiopulmonary and abdominal examination findings are normal. He has a 4 cm × 5 cm well-granulated lower extremity ulcer with redness, warmth, and erythema noted on the upper margin of the ulcer. What is the treatment of choice?
B. Equine antitoxin to Clostridium botulinum neurotoxin
C. Intravenous heparin
IV-72. A 19-year-old man presents to the emergency department with 4 days of watery diarrhea, nausea, vomiting, and low-grade fever. He recalls no unusual meals, sick contacts, or travel. He is hydrated with IV fluid, given antiemetics, and discharged home after feeling much better. Three days later, two of three blood cultures are positive for Clostridium perfringens. He is called at home and says that he feels fine and is back at work. What should your next instruction to the patient be?
A. Return for IV penicillin therapy.
B. Return for IV penicillin therapy plus echocardiography.
C. Return for IV penicillin therapy plus colonoscopy.
D. Return for surveillance blood culture.
IV-73. Which of the following is the most common clinical manifestation of Neisseria meningitidis infection?
A. Asymptomatic nasopharyngeal colonization
B. Chronic meningitis
D. Petechial or purpuric rash
IV-74. A 21-year-old college student is admitted to the hospital with meningitis. CSF cultures reveal N. meningitides type B. The patient lives in a dormitory suite with five other students. Which of the following is recommended for the close household contacts?
A. Culture all close contacts and offer prophylaxis to those with positive culture results
B. Immediate administration of ceftriaxone to all close contacts
C. Immediate administration of rifampin to all close contacts
D. Immediate vaccination with conjugate vaccine
E. No therapy necessary
IV-75. A 19-year-old man comes to clinic complaining of 2 days of severe dysuria and urethral discharge. Urine analysis shows pyuria. He reports unprotected sexual contact with a new partner within the past week. DNA probe is positive for N. gonorrhea. Which of the following is the most effective therapy?
A. Intravenous ceftriaxone
B. Intramuscular penicillin
C. Oral azithromycin
D. Oral cefixime
E. Oral levofloxacin
IV-76. A 44-year-old man presents to the emergency department for evaluation of a severe sore throat. His symptoms began this morning with mild irritation on swallowing and have gotten progressively severe over the course of 12 hours. He has been experiencing a fever to as high as 39░C at home and reports progressive shortness of breath. He denies antecedent rhinorrhea and tooth and jaw pain. He has had no ill contacts. On physical examination, the patient appears flushed and in respiratory distress with use of accessory muscles of respiration. Inspiratory stridor is present. He is sitting leaning forward and is drooling with his neck extended. His vital signs are as follows: temperature of 39.5░C, blood pressure of 116/60 mmHg, heart rate of 118 beats/min, respiratory rate of 24 breaths/min, and oxygen saturation of 95% on room air. Examination of his oropharynx shows erythema of the posterior oropharynx without exudates or tonsillar enlargement. The uvula is midline. There is no sinus tenderness and no cervical lymphadenopathy. His lung fields are clear to auscultation, and cardiovascular examination reveals a regular tachycardia with a II/VI systolic ejection murmur heard at the upper right sternal border. Abdominal, extremity, and neurologic examinations are normal. Laboratory studies reveal a white blood cell count of 17,000/μL with a differential of 87% neutrophils, 8% band forms, 4% lymphocytes, and 1% monocytes. Hemoglobin is 13.4 g/dL with a hematocrit of 44.2%. An arterial blood gas on room air has a pH of 7.32, a PCO2 of 48 mmHg, and a PO2 of 92 mmHg. A lateral neck radiograph shows an edematous epiglottis. What is the next most appropriate step in evaluation and treatment of this individual?