Week One TA Review Questions

1. Week One TA Review Questions

2. A 24 year old female presents to your office with burning urination, urgency and frequency. She is sexually active. Urine cultures show catalase positive, gram-positive cocci. The organism responsible for this patient’s symptoms is most likely to be: Coagulase positive Hemolytic Novobiocin resistant Dnasepostive Yellow pigment producer

3. A 24 year old female presents to your office with burning urination, urgency and frequency. She is sexually active. Urine cultures show catalase positive, gram-positive cocci. The organism responsible for this patient’s symptoms is most likely to be: Coagulase positive Hemolytic Novobiocin resistant Dnasepostive Yellow pigment producer

4. A 24 year old female presents to your office with burning urination, urgency and frequency. She is sexually active. Urine cultures show catalase positive, gram-positive cocci. The organism responsible for this patient’s symptoms is most likely to be: Coagulase positive Hemolytic Novobiocin resistant Dnasepostive Yellow pigment producer

5. A 24 year old female presents to your office with burning urination, urgency and frequency. She is sexually active. Urine cultures show catalase positive, gram-positive cocci. The organism responsible for this patient’s symptoms is most likely to be: Coagulase positive Hemolytic Novobiocin resistant Dnasepostive Yellow pigment producer

6. A 24 year old female presents to your office with burning urination, urgency and frequency. She is sexually active. Urine cultures show catalase positive, gram-positive cocci. The organism responsible for this patient’s symptoms is most likely to be: Coagulase positive (S. aureus) Hemolytic (S. aureus, GAS, GBS) Novobiocin resistant Dnasepostive(GAS) Yellow pigment producer (S. aureus)

7. A 17 year-old girl presents to your office with dark urine and facial puffiness. She had a minor skin infection several weeks ago that resolved spontaneously. Microscopic examination of the urine sediment shows red blood cell casts. The organisms responsible for this patient’s symptoms would most likely demonstrate: Catalase positivity Optochin resistance Bacitracin sensitivity Optochin sensitivity

8. A 17 year-old girl presents to your office with dark urine and facial puffiness. She had a minor skin infection several weeks ago that resolved spontaneously. Microscopic examination of the urine sediment shows red blood cell casts. The organisms responsible for this patient’s symptoms would most likely demonstrate: Catalase positivity Optochin resistance Bacitracin sensitivity Optochin sensitivity

9. A 17 year-old girl presents to your office with dark urine and facial puffiness. She had a minor skin infection several weeks ago that resolved spontaneously. Microscopic examination of the urine sediment shows red blood cell casts. The organisms responsible for this patient’s symptoms would most likely demonstrate: Catalase positivity Optochin resistance Bacitracin sensitivity Optochin sensitivity

10. A 17 year-old girl presents to your office with dark urine and facial puffiness. She had a minor skin infection several weeks ago that resolved spontaneously. Microscopic examination of the urine sediment shows red blood cell casts. The organisms responsible for this patient’s symptoms would most likely demonstrate: Catalase positivity (Staph) Optochin resistance (Strep viridans) Bacitracin sensitivity Optochin sensitivity (Strep pneumo)

11. BONUS QUESTION: What best describes the molecular mechanism behind the last patient’s complaints? Molecular mimicry Immune complex deposition Elaboration of erythrogenic exotoxin Inappropriate release of cytokines

12. BONUS QUESTION: What best describes the molecular mechanism behind the last patient’s complaints? Molecular mimicry Immune complex deposition Elaboration of erythrogenic exotoxin Inappropriate release of cytokines

13. A 17 year-old girl presents to your office with a two day history of fever and sorejoints. Her right knee became sore and swollen and then improved, but now her left elbow hurts. She had a sore throat three weeks ago, but never saw a doctor. What molecular mechanism best describes thispatient’s complaints? Molecular mimicry Immune complex deposition Elaboration of erythrogenic exotoxin Inappropriate release of cytokines

14. A 17 year-old girl presents to your office with a two day history of fever and sorejoints. Her right knee became sore and swollen and then improved, but now her left elbow hurts. She had a sore throat three weeks ago, but never saw a doctor. What molecular mechanism best describes this patient’s complaints? Molecular mimicry Immune complex deposition Elaboration of erythrogenic exotoxin Inappropriate release of cytokines

15. A 17 year-old girl presents to your office with a two day history of fever and sorejoints. Her right knee became sore and swollen and then improved, but now her left elbow hurts. She had a sore throat three weeks ago, but never saw a doctor. The organisms responsible for this patient’s symptoms would most likely demonstrate: • Molecular mimicry • Immune complex deposition (PSGN) • Elaboration of erythrogenicexotoxin (scarlet fever) • Inappropriate release of cytokines (toxic shock syndrome)

16. Group A Strep demonstrate significant resistance to phagoctytic killing when placed in fresh human blood. This resistance can be most effectively overcome by adding antibodies to which of the following? Protein M Stretolysin O Dnase Streptokinase Teichoic acid

17. Group A Strep demonstrate significant resistance to phagoctytic killing when placed in fresh human blood. This resistance can be most effectively overcome by adding antibodies to which of the following? Protein M Stretolysin O Dnase Streptokinase Teichoic acid

18. Compared to gram-positive bacteria, gram-negative bacteria have: • Thinner peptidoglycan wall and no outer membrane • Thicker peptidoglycan wall and outer membrane • Thinner peptidoglycan wall and outer membrane • Thicker membrane and no peptidoglycan wall • Thinner membrane and no peptidoglycan wall

19. Compared to gram-positive bacteria, gram-negative bacteria have: • Thinner peptidoglycan wall and no outer membrane • Thicker peptidoglycan wall and outer membrane • Thinner peptidoglycan wall and outer membrane • Thicker membrane and no peptidoglycan wall • Thinner membrane and no peptidoglycan wall

20. Recently, a nursing home has discovered a strain of MRSA among the residents. By what mechanism does MSSA become MRSA? • Alterations in the beta-lactamase • Alteration in the penicillin binding protein • Development of a pump to get the antibiotic out of the cell • Amino acid substitution at peptidoglycan binding site • Development of enzymes to inactivate drug • Alteration of ribosomal proteins

21. Recently, a nursing home has discovered a strain of MRSA among the residents. By what mechanism does MSSA become MRSA? • Alterations in the beta-lactamase • Alteration in the penicillin binding protein • Development of a pump to get the antibiotic out of the cell • Amino acid substitution at peptidoglycan binding site • Development of enzymes to inactivate drug • Alteration of ribosomal proteins

22. a. Establishes an extracellular protein matrix called a biofilm, which protects it from antibiotics and the host’s immune system. b. Often no bacterial invasion, but still at risk for multi-system organ failure. c. Release endotoxin when killed, resulting in potent inflammation. d. Secretes protein A, which binds to the Fc terminal of IgG and inhibits complement fixation and phagocytosis. e. Has a thick peptidoglycan layer along with teichoic and lipoteichoic acids. 2 1 3 Catalase + Coagulase - 4 5

23. All of the following may be found in both gram-positive and gram-negative bacteria EXCEPT: • Peptidoglycan layer • Pili • Teichoic acid • Cell membrane • Capsule

24. All of the following may be found in both gram-positive and gram-negative bacteria EXCEPT: • Peptidoglycan layer • Pili • Teichoic acid • Cell membrane • Capsule

25. Which of the following antibiotic classes DOES NOT work by inhibiting ribosomal subunits? • Aminoglycosides • Tetracyclines • Fluoroquinolones • Macrolides • None of the above

26. Which of the following antibiotic classes DOES NOT work by inhibiting ribosomal subunits? • Aminoglycosides • Tetracyclines • Fluoroquinolones • Macrolides • None of the above

27. A 6 year old boy comes in to your clinic with otitis media. How could you confirm the most likely organism? Quellung reaction ASO titer Ask a TA PCR Serology

28. A 6 year old boy comes in to your clinic with otitis media. How could you confirm the most likely organism? Quellung reaction ASO titer Ask a TA PCR Serology

29. Which of the following complications of S. aureusinfection is NOT caused by a toxin? • Toxic shock syndrome • Impetigo • Scalded skin syndrome • Gastroenteritis • None of the above

30. Which of the following complications of S. aureusinfection is NOT caused by a toxin? • Toxic shock syndrome • Impetigo • Scalded skin syndrome • Gastroenteritis • None of the above

31. A 37-year-old female presents to the emergency room with a fever. Chest x-ray shows multiple patchy infiltrates in both lungs. Echocardiography and blood cultures suggest a diagnosis of acute bacterial endocarditis limited to the tricuspid valve. Which of the following is the most probable predisposing condition?                  A. Congenital heart disease                  B. Illicit drug use                  C. Rheumatic fever                  D. Rheumatoid arthritis                  E. Systemic lupus erythematosus

32. A 37-year-old female presents to the emergency room with a fever. Chest x-ray shows multiple patchy infiltrates in both lungs. Echocardiography and blood cultures suggest a diagnosis of acute bacterial endocarditislimited to the tricuspid valve. Which of the following is the most probable predisposing condition?                  A. Congenital heart disease   B. Illicit drug use                  C. Rheumatic fever                  D. Rheumatoid arthritis                  E. Systemic lupus erythematosus

33. A 45-year-old male goes to the dentist for a routine cleaning. He subsequently developed a subacute bacterial endocarditis. Which of the following is true regarding the most likely causative organism? A. Catalase Positive B. Optochin Sensitive C. M-Protein virulence Factor D. Part of the normal flora of the oropharynx E. Also a major cause of pneumonia

34. A 45-year-old male goes to the dentist for a routine cleaning. He subsequently developed a subacute bacterial endocarditis. Which of the following is true regarding the most likely causative organism? A. Catalase Positive B. Optochin Sensitive C. M-Protein virulence Factor D. Part of the normal flora of the oropharynx E. Also a major cause of pneumonia

35. An 8 year old child is brought to the ED because his mother has noticed that his urine has had an orange color for the past week that has been getting darker. On physical exam, the child's blood pressure is 160/100 and you notice some edema of the lower extremities. Labs reveal a creatinine of 4.3 mg/dL (normal 0.6-1.2 mg/dL). You also learn that a few weeks ago, the child had a fever and sore throat. What is the most appropriate next step? a) Throat culture b) Urine culture c) ASO titer d) Empiric treatment with amoxicillin e) Referral to a kidney transplant surgeon

36. An 8 year old child is brought to the ED because his mother has noticed that his urine has had an orange color for the past week that has been getting darker. On physical exam, the child's blood pressure is 160/100 and you notice some edema of the lower extremities. Labs reveal a creatinine of 4.3 mg/dL(normal 0.6-1.2 mg/dL). You also learn that a few weeks ago, the child had a fever and sore throat. What is the most appropriate next step? a) Throat culture b) Urine culture c) ASO titer d) Empiric treatment with amoxicillin e) Referral to a kidney transplant surgeon

37. One of three blood culture bottles drawn from a patient with unexplained fevers reveals gram-positive cocci growing in clusters. Which of the following tests would be most useful in determining whether this organism is a part of the normal skin flora?                 A. Bacitracin resistance                 B. Catalase                 C. Coagulase                 D. Novobiocin resistance                 E. Optochin resistance

38. One of three blood culture bottles drawn from a patient with unexplained fevers reveals gram-positive cocci growing in clusters. Which of the following tests would be most useful in determining whether this organism is a part of the normal skin flora?                 A. Bacitracin resistance                 B. Catalase C. Coagulase                 D. Novobiocin resistance                 E. Optochin resistance

39. In molecular biology research, it is not uncommon to take advantage of bacteria's ability to take up DNA from the environment by combining bacteria with purified DNA and then growing the bacteria to amplify DNA copy number. This is termed: • a) Transduction • b) Conjugation • c) Incubation • d) Transformation • e) Transposition

40. In molecular biology research, it is not uncommon to take advantage of bacteria's ability to take up DNA from the environment by combining bacteria with purified DNA and then growing the bacteria to amplify DNA copy number. This is termed: • a) Transduction • b) Conjugation • c) Incubation • d) Transformation • e) Transposition

41. Which of the following best characterizes the predominant normal flora of the skin, which is commonly seen as a blood culture contaminant? • Gram-positive, alpha hemolytic cocci • Gram-positive, beta hemolytic cocci • Gram-positive, gamma hemolytic cocci • Gram-positive, catalase-positive, coagulase-positive cocci • Gram-positive, catalase-positive, coagulase-negative cocci

42. Which of the following best characterizes the predominant normal flora of the skin, which is commonly seen as a blood culture contaminant? • Gram-positive, alpha hemolytic cocci • Gram-positive, beta hemolytic cocci • Gram-positive, gamma hemolytic cocci • Gram-positive, catalase-positive, coagulase-positive cocci • Gram-positive, catalase-positive, coagulase-negative cocci

43. A 30 year old man comes into the ER sweating profusely and has a mild fever. He says that in the last few days he has been very short of breath, has developed a cough and palpitations, and has been waking up at night with sweating. The only other significant piece of information you get from his history is that he had dental surgery about 6 weeks ago and that he only filled his prescription for pain medication and not for his antibiotics. The organism most likely responsible for these symptoms is: • a) Staphylococcus aureus • b) Streptococcus viridans group • c) Streptococcus pyogenes • d) Staphylococcus epidermidis • e) Streptococcus bovis

44. A 30 year old man comes into the ER sweating profusely and has a mild fever. He says that in the last few days he has been very short of breath, has developed a cough and palpitations, and has been waking up at night with sweating. The only other significant piece of information you get from his history is that he had dental surgery about 6 weeks ago and that he only filled his prescription for pain medication and not for his antibiotics. The organism most likely responsible for these symptoms is: • a) Staphylococcus aureus • b) Streptococcus viridans group • c) Streptococcus pyogenes • d) Staphylococcus epidermidis • e) Streptococcus bovis

45. A 2 year old child presents with a fever and a diffuse rash that resembles an extremely bad sunburn with some unroofed blisters on the face. You make a diagnosis of Staph Scalded Skin Syndrome. When you attempt to culture the blisters, nothing grows. The reason is that: • This syndrome is caused by enterotoxin produced by Staph. aureusand the organism is not actually in the skin • This syndrome is caused by TSST-1 toxin produced by Staph. epidermidis and the organism is not actually in the skin • This syndrome is caused by exfoliative toxin produced by Staph. aureusand the organism is not actually in the skin • An adequate sample was not obtained by culture and should be repeated, since this syndrome is caused by Staph. aureus invading the skin • Staph. epidermidis does not readily grow on standard media

46. A 2 year old child presents with a fever and a diffuse rash that resembles an extremely bad sunburn with some unroofed blisters on the face. You make a diagnosis of Staph Scalded Skin Syndrome. When you attempt to culture the blisters, nothing grows. The reason is that: • This syndrome is caused by enterotoxin produced by Staph. aureusand the organism is not actually in the skin • This syndrome is caused by TSST-1 toxin produced by Staph. epidermidis and the organism is not actually in the skin • This syndrome is caused by exfoliative toxin produced by Staph. aureusand the organism is not actually in the skin • An adequate sample was not obtained by culture and should be repeated, since this syndrome is caused by Staph. aureus invading the skin • Staph. epidermidis does not readily grow on standard media

47. A woman comes into your office to see you because she threw up a few hours after an office picnic. She has felt fine since but is going on vacation tomorrow and wants to make sure she won’t be sick. After you reassure her that her disease was caused by a pre-formed toxin and that she should be fine, the woman asks you about the bacteria that made the toxin. Luckily you haven’t repressed all of your memories from medical school and so you can tell her that the bug is a: • Gram positive cocci in chains &coagulase positive • Gram negative cocci in clusters &catalase negative • Gram positive cocci in chains &coagulase negative • Gram positive cocci in clusters &coagulase positive • Gram positive cocci in clusters &coagulase negative

48. A woman comes into your office to see you because she threw up a few hours after an office picnic. She has felt fine since but is going on vacation tomorrow and wants to make sure she won’t be sick. After you reassure her that her disease was caused by a pre-formed toxin and that she should be fine, the woman asks you about the bacteria that made the toxin. Luckily you haven’t repressed all of your memories from medical school and so you can tell her that the bug is a: • Gram positive cocci in chains &coagulase positive • Gram negative cocci in clusters &catalase negative • Gram positive cocci in chains &coagulase negative • Gram positive cocci in clusters &coagulase positive • Gram positive cocci in clusters &coagulase negative

49. The age group most susceptible to Group B Streptococcus infections is: • < 1 mo • 1-5 years • 12-25 years • >75 • Not age related – greatest risk is for IV drug users

50. The age group most susceptible to Group B Streptococcus infections is: • < 1 mo • 1-5 years • 12-25 years • >75 • Not age related – greatest risk is for IV drug users