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DAMB 711 Microbiology Exam 2A 100 points September 27, 2011

Your name:

______

Exam # ______

Seat # ______

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I. Multiple Choice: Choose the ONE BEST answer. Mark the correct answer in Part 1 of your answer sheet.

1. Which of the following conveys the highest risk of nosocomial infection to a hospitalized patient?

A. the hospital environment (rooms, floors, fomites) B. invasive medical devices (catheters, respirators, etc.) C. hospital personnel, including physicians D. mechanical vectors

2. The clonality of pathogenic refers to:

A. the environmental regulation of genes encoding virulence factors B. the acquisition of virulence determinants encoded on extra-chromosomal elements C. the infective dose of a specific species of bacteria D. opportunistic pathogens E. only a few strains in a species will be the etiologic agent of a disease

3. Diseases caused by this genus of bacteria are never transmitted through contaminated food.

A. B. Staphylococcus C. Mycobacteria D. Corynebacteria

4. When Vibrio cholera is moved from a high salt, basic environment to isotonic conditions, with neutral pH a sensor kinase in the bacterium phosphorylates a response regulator that initiates transcription. This is an example of:

A. the environmental regulation of genes encoding virulence factors B. the acquisition of virulence determinants encoded on extra-chromosomal elements C. the infective dose of a specific species of bacteria D. opportunistic pathogens E. only a few strains in a species will be the etiologic agent of a disease

5. In which form of tuberculosis is a patient coughing up infectious material?

A. miliary B. active C. latent/dormant D. primary E. disseminated

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6. The life threatening manifestation of diphtheria that is most frequently the cause of death is:

A. the pseudo-membrane B. heart failure caused by toxemia C. transient paralysis caused by toxemia D. bull neck

7. What are Molecular Koch's Postulates trying to determine?

A. the bacterium or other microorganism that is the etiologic (causative) agent of a disease B. the virulence determinant (gene) that encodes the major virulence factor of a pathogenic microorganism C. an appropriate animal model for a disease D. both A and B E. both B and C

8. What are Koch's Postulates trying to determine?

A. the bacterium or other microorganism that is the etiologic (causative) agent of a disease B. the virulence determinant (gene) that encodes the major virulence factor of a pathogenic microorganism C. an appropriate animal model for a disease D. both A and B E. both B and C

9. A bacterium found in that may actually kill other bacteria through metabolic synthesis of hydrogen peroxide and raise the pH of plaque through metabolic synthesis of ammonia is:

A. mutans B. S. gordonii C. S. salivarius D. S. sanguinis E. S. mitis

10. Injection of PPD (purified derivative) sub-dermally with resulting induration and inflammation in 48 to 72 hours without an X-ray showing a tubercle indicates a patient:

A. has been infected with M. tuberculosis B. has been infected with M. tuberculosis or an atypical mycobacterium C. should have his or her sputum cultured for mycobacteria D. B and C E. A, B and C

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11. A bacterium is swallowed and adheres to the mucous membranes of the host gastrointestinal tract; it begins to metabolize and replicate in the area of infection: it releases LPS which stimulates the release of massive quantities of inflammatory mediators. The bacterium avoids destruction by the host immune system by preventing complement activation.

A. This bacterium will cause disease.

B. This bacterium could do all of these things and still not be able to cause disease.

Many bacteria are intracellular parasites with specialized mechanisms for survival in the macrophage. In questions 12 and 13, below, use the following choices to identify the mechanism the bacterium used to survive the macrophage.

A. Escapes the endosome. B. Prevents fusion of the phagosome and lysosome. C. Activates transcription of an acid tolerance response gene.

A12. B13. Mycobacterium tuberculosis

14. Subacute bacterial endocarditis (SBE) differs from acute endocarditis in that:

A. is the etiological agent B. patients with mitral valve condition are predisposed to SBE and not acute endocarditis C. patients run low grade fevers and symptoms persist for months D. and faecalis are frequent causes E. C and D are true.

15. Bacteria that are acid fast:

A. will not retain a primary stain if acid is used as a decolorizing agent. B. will retain a primary stain even if acid is used as a decolorizing agent. C. have very low percentages of lipid in their cell walls. D. do not have mycolic acids in their cell walls.

16. A mycolic acid that can cause wasting disease when injected into mice is:

A. Wax D. B. sulfolipid C. cord factor D. Actin A E. A and B

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17. Patients that are compromised in cell mediated immunity:

A. are more susceptible to Listeria monocytogenes B. are more susceptible to Mycobacterium tuberculosis. C. are more susceptible to . D. Both A and B. E. Both B and C.

18. Infections caused by bacteria that develop resistance to this anti-microbic are untreatable unless new anti-microbics can be developed to take its place.

A. B. cephalosporin C. sulfonamide D. vancomycin

19. The anti-microbic action of the sulfonamides is due to their molecular:

A. resemblance to acyl-d-alanylalanine B. resemblance to penicillin binding (PBPs) C. resemblance to para-aminobenzoic acid (PABA) D. resemblance to trimethoprim

20. Characteristics of the Staphylococcus aureus enterotoxin that make it a dangerous cause of food poisoning:

A. It resists heat. B. Staphylococcus aureus grows in high salt environments. C. It resists proteases such as trypsin. D. A and C. E. A, B and C.

21. The exfoliative toxin is produced by ______and it causes the symptoms of ______.

A. ; scalded skin syndrome B. Streptococcus pyogenes; C. Staphylococcus aureus; scalded skin syndrome D. E. Staphylococcus aureus; impetigo

22. Mannitol salt agar is selective and differential for ______. The selective component is ______; the differential component is ______.

A. Enterococcus faecalis; 7.5% sodium chloride; mannitol B. Staphylococcus aureus; 7.5% sodium chloride; mannitol C. Corynebacterium diphtheria; tellurite; mannitol D. Staphylococcus aureus; mannitol; 7.5% sodium chloride E. Streptococcus pneumoniae; optochin; -hemolytic response 5

23. Protein A is:

A. Useful for serotyping strains of Streptococcus pyogenes.

B. A protein that is a virulence determinant for Staphylococcus aureus and can activate fibrinogen to cause clot formation around the bacterial cell.

C. A unique cell surface protein of Staphylococcus aureus that contributes to the virulence of the bacterium by binding the Fc region of immunoglobulins

D. Toxic for white blood cells.

E. Carried on a temperate bacteriophage

24. The best explanation for the influence of iron on expression of the diphtheria toxin is:

A. The gene for the diphtheria toxin is encoded by a prophage. The prophage controls expression of the toxin protein through a repressor protein that is inactive in the presence of iron.

B. The gene for the diphtheria toxin is encoded by a prophage. A repressor protein encoded on the host chromosome regulates expression of the toxin gene. Iron is a co-repressor. In conditions of plentiful iron, it binds the repressor protein, DtxR; the iron/DtxR complex then binds the tox gene promoter to prevent transcription.

C. The gene for the diphtheria toxin is encoded by a prophage. A second prophage controls expression of the toxin protein through a repressor protein. Iron is a co- repressor; in high iron concentrations it dissociates from the DtxR repressor resulting in expression of the toxin gene.

D. The gene for the diphtheria toxin is encoded by a prophage. A repressor protein encoded on the host chromosome regulates expression of the toxin gene. Iron is a co-repressor. In low iron concentrations iron dissociates from the repressor protein (DtxR) resulting in expression of the toxin gene.

E. Both B and D are correct.

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25. A method used by epidemiologists to determine the source of nosocomial infections caused by S. aureus is:

A. serotyping B. pyocin typing C. phage (bacteriophage) typing D. cell wall composition

For the bacteria that cause caries, below, answer:

A. If it is a human strain. B. If it is an animal strain. C. If it is not cariogenic

A26. Streptococcus sobrinus B27. Streptococcus maccaccae B28. Streptococcus cricetus A29. B30. Streptococcus ferus B31. Streptococcus rattus C32.

33. A Staphylococcus aureus that cannot produce this enzyme is avirulent.

A. B. lipase C. coagulase D. hyaluronidase E. staphylokinase

34. “Acidogenic” describes a characteristic that conveys virulence to the etiologic agents of:

A. Ludwig’s angina B. strep throat C. sub-acute bacterial endocarditis D. osteomyelitis E. caries

35. Antimicrobics that inhibit peptidoglycan synthesis attack this biosynthetic precursor:

A. acyl-d-alanylalanine B. penicillin binding proteins (PBPs) C. para-aminobenzoic acid (PABA) D. N-acetylglucosamine-N-acetylmuramic acid (NAM-NAG) E. DNA dependent RNA polymerase 7

36. The diphtheria toxin has the same effect on procarytic protein synthesis that ______has on eukaryotic protein synthesis. They both disrupt the action of the ______enzyme.

A. clindamycin: translocase B. erythromycin: peptidyl transferase C. chloramphenicol:peptidyl transferase D. streptomycin:inhibition of the initiation complex E. penicillin:inhibition of transpeptidase

37. The bacterium ______is the most frequent cause of nosocomial infections while ______is the second most frequent cause.

A. Staphylococcus aureus; Escherichia coli B. Escherichia coli; Enterococcus faecalis C. Enterococcus faecalis; Staphylococcus aureus D. Escherichia coli; Staphylococcus aureus

38. Which of the following anti-microbics disrupts membrane function by binding ergosterol in fungal membranes?

A. chloramphenicol B. streptomycin C. the polyene, amphoteracin B D. clindamycin E. polymyxin B

39. An example of a biological vector is:

A. a Staphylococcus aureus infection transmitted by an animal bite B. a medicine bottle covered with the pathogen Staph. aureus. C. transmission of a pathogen that must live in a mosquito to complete its life cycle D. a fly whose legs are covered with

40. If the portal of exit and portal of entry of a disease is on the same person:

A. this is an endogenous infection. B. this is evidence that the disease is spread by a fomite. C. this is evidence of spread by a biological vector. D. the individual must be immunocompromised.

41. A common portal of exit for diseases that are spread by contaminated food and water is:

A. Blood. B. Skin scales or flakes. C. Respiratory secretions. D. Fecal wastes. 8

42. Areas of the human body that are colonized by high levels of microorganisms (107 to 1011 per gram, cc or ml) are the:

A. skin, stomach and esophagus B. kidneys, middle ear, bladder and dental pulp C. colon, dental plaque and saliva D. skin and nasopharynx

43. The kidneys, middle ear, bladder and dental pulp are areas of the human body that:

A. have low levels of microorganisms, approximately103 per gram, cc or ml. B. are not colonized by normal flora and, therefore, are usually sterile C. have high levels of microorganisms, approximately >107 to 1011 per gram, cc or ml D. have medium levels of microorganisms, 104 to 107 per gram, cc or ml

44. Statement A: An endotoxin is likely to be protein. Statement B: An exotoxin is usually not heat stable.

A. Statement A is true. B. Statement B is true. C. Both statements are true. D. Neither statement is true.

45. Specimens for diagnosis of an infectious disease are usually collected from the:

A. portal of entry B. portal of exit C. biological vector D. mechanical vector

46. This acute phase protein will opsonize bacteria:

A. muramyl-dipeptide B. flagella C. C5a D. interleukin 1 E. C reactive protein

47. The normal flora will be distributed in various body sites that support their specific growth requirements. The specific genera that occupy each body site may have all except the following characteristics:

A. resistance to natural antibiotics, such as penicillin or colicin, that may be released by other bacteria occupying the body site B. resistance to host defense factors, such as lysozyme C. presence only when the host is suffering from disease D. adhesins specific to that body site E. pathogenesis 9

48. Statement A: Enterococcus faecalis is associated in high incidence with root canal treatment failure. Statement B: Enterococcus faecalis strains that cause nosocomial infections are dangerous pathogens, because they tend to be antimicrobic resistant.

A. Statement A is true. B. Statement B is true. C. Both statement A and B are true. D. Neither statement A nor B is true.

49. Tuberculosis caused by the Mycobacterium avium complex is a zoonose whose nonhuman host is::

A. cattle B. reptiles (turtles) C. primates D. birds E. raccoons

50. The disease incidence of 8 cases of Listeria monocytogenes in adult patients within a 3 month period is:

A. Endemic. B. Epidemic. C. Sporadic. D. Pandemic E. None of the above.

51. The disease incidence of acne caused by Staphylococcus aureus is:

A. Endemic. B. Epidemic. C. Sporadic. D. Pandemic E. None of the above.

52. Catalase is a virulence factor that has the following activity:

A. binds the Fc region of immunoglobulins to disrupt complement activation and opsonization. B. converts fibrin to fibrinolysin. C. chelates calcium. D. converts urea to carbon dioxide and ammonia. E. converts hydrogen peroxide to oxygen and water.

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53. Bacteria with the ability to survive, metabolize and reproduce at pH 5.5 and below are:

A. acidogenic B. glucosyl transferases C. asaccharolytic D. aciduric E. inhibitors of acid diffusion

54. Staphylococcus aureus is potentially etiologic in all except the following:

A. B. food poisoning C. scalded skin syndrome D. scarlet fever E. pyoarthrosis

55. The carbohydrate capsule of ______is a virulence determinant and is used to serotype the species.

A. Streptococcus anginosus B. Staphylococcus aureus C. Streptococcus pneumoniae D. Streptococcus pyogenes E. Corynebacterium diphtheriae

56. One of the following is not a common cause of meningitis in newborns. Which one?

A. Streptococcus sanguinis B. Listeria monocytogenes C. Streptococcus agalactiae Group B

57. An elderly patient develops meningitis 3 days after being admitted to the hospital. Upon culture of the patient’s cerebrospinal fluid, a Gram + diplococcus is isolated that is - hemolytic on blood agar and sensitive to the bile salt, optochin. This is a presumptive diagnosis for:

A. Staphylococcus aureus B. Escherichia coli C. Streptococcus pyogenes D. Streptococcus pneumoniae E. Streptococcus agalactiae

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58. A streptococcus is isolated from a patient with a suppurative pharyngitis. When grown on blood agar, it is beta hemolytic and sensitive to a bacitracin disc. This is a presumptive positive test for:

A. Streptococcus pneumoniae B. Viridans streptococci C. Streptococcus agalactiae D. Enterococcus faecalis E. Streptococcus pyogenes

59. The antigen used to subdivide S. pyogenes into serotypes is:

A. the Lancefield carbohydrate B. the hemolysin C. the M protein D. the teichoic acid E. A, C, and D.

60. These streptococci do not have the Lancefield group-specific carbohydrate:

A. Viridans streptococci and Streptococcus pneumoniae B. Most beta hemolytic streptococci C. Enterococcus faecalis and D. S. anginosus and S. milleri E. Streptococcus agalactiae and Streptococcus pyogenes

61. A child that suffers from strep throat followed by scarlet fever is predisposed to this sequelae of S. pyogenes infections.

A. toxic shock syndrome B. acute glomerulonephritis C. D. rheumatoid arthritis

62. Use of this medical device/procedure involves substantial risk of transmission of blood-borne pathogens (hepatitis and HIV) both to patients and hospital personnel.

A. urinary catheter B. hemodialysis C. respirator D. vascular catheters

63. Of the following, which conveys the lowest risk of nosocomial infection to a hospitalized patient?

A. the hospital environment (rooms, floors, fomites) B. invasive medical devices (catheters, respirators, etc.) C. hospital personnel, including physicians

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64. A microorganism that develops resistance to penicillin may also develop resistance to:

A. clindamycin B. cephalosporins C. polymyxin B D. tetracycline E. streptomycin

65. These two low virulence pathogens frequently cause opportunistic infections in burn patients.

A. Escherichia coli and Staphylococcus aureus B. Pseudomonas aeruginosa and Enterococcus faecalis C. Escherichia coli and Pseudomonas aeruginosa D. Pseudomonas aeruginosa and Serratia marcescens E. Serratia marcescens and Staphylococcus aureus

66. A bacterium that reduces tellurite in selective media to produce black colonies is:

A. Staphylococcus aureus and Corynebacterium diphtheria B. Corynebacterium diphtheria and Streptococcus mutans C. Staphylococcus epidermidis and Corynebacterium diphtheria D. Enterobacter aerogenes and Streptococcus pneumoniae E. Pseudomonas aeruginosa and Streptococcus mutans

67. A species of staphylococcus that cannot produce coagulase but is a cause of urinary tract infections and bacteremias, mostly in hospitalized patients.

A. Staphylococcus aureus B. Staphylococcus saprophyticus C. Staphylococcus epidermidis D. Staphylococcus lugdunensis E. All except A.

68. Bacterial virulence factor(s) that specialize(s) in obtaining sequestered iron from the host and delivering it to the bacterial cell:

A. lysozyme B. siderophores C. transferrin and lactoferrin D. bacteriocins and antibiotics

69. These anti-microbics bind to the 30S subunit of the bacterial ribosome and inhibit protein synthesis by preventing binding of amino-acid charged tRNAs:

A. chloramphenicol, erythromycin and clindamycin B. tetracycline and streptomycin C. polymyxin B and amphoteracin B

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70. This bacterium is an intracellular parasite and the virulence of the bacterium depends on actin-dependent intracellular motility and intercellular spread

A. Pseudomonas aeruginosa B. Corynebacterium diphtheria C. Listeria monocytogenes D. Staphylococcus aureus E. Streptococcus pyogenes

71. The M protein:

A. Useful for serotyping strains of Staphylococcus aureus.

B. A protein that is a virulence determinant for Staphylococcus aureus and can activate fibrinogen to cause clot formation around the bacterial cell.

C. A protein that is unique to the cell surface of Staphylococcus aureus and that contributes to the virulence of the bacterium by binding the Fc region of immunoglobulins

D. Is coiled around the pili of Streptococcus pyogenes; acts as an adhesin by binding the bacteria to keratinocytes and epithelial cells; activates fibrinogen to form a fibrin clot that protects the bacterium from opsonization and phagocytosis.

E. The unusual capsule of C. diphtheria .

72. Early onset neonatal diseases caused by Listeria monocytogenes are spread through:

A. respiratory droplets B. transplacental passage C. consumption of contaminated milk D. contact with family pets E. B and C

73. Bacteria that alter anti-microbic binding sites on enzymes such as DNA dependent RNA polymerase and DNA gyrase may develop resistance to:

A. polymyxin B B. sulfonamides C. penicillin and vancomycin D. rifampin and quinolones E. erythromycin and clindamycin

74. Mycobacteria resist malachite green and NaOH because their cell wall is 60% lipid.

A. The statement is true. B. The statement is false.

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Part II. Matching: The questions below consist of headings followed by a list of phrases. For each phrase select the ONE heading that best describes that phrase. Mark the answer in Part 2, numbers 1 through 11, of your answer sheet.

1. necrotizing fasciitis 8. Lactobacillus casei 2. hyaluronidase 9. osteomyelitis 3. puerperal fever 10. glucan (mutan) 4. cellulitis 11. viridans streptococci 5. coagulase 12. catalase 6. toxic shock syndrome 7. human carriers

41. inflammation caused by bacterial invasion of the lymphatics and connective tissues under the skin

22. “spreading factor” produced by invasive pathogens such as streptococci and staphylococci

113. etiologic in more than 80% of sub-acute bacterial endocarditis infections

74. important to the transmission of diphtheria

35. Infection of uterus after delivery

86. the bacterium closest to the pulp in carious lesions

97. a focal infection typically caused by S. aureus growing in a nearby blood vessel

48. rapid biochemical test that will distinguish streptococci from staphylococci

19. tissue necrosis caused by strains of invasive Streptococcus pyogenes

1010. water insoluble component of cariogenic plaque

611. disease symptoms are caused by pyrogenic exotoxins that cause multiple organ failure

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