Clinical Microbiology Stage Session #05

  1. Normal Flora includes?
    • Coagulase-negative Staphylococcus species
    • Diphtheroids
    • Propionibacterium acnes (anaerobe)
    • Streptococcus viridans
  2. What are the pathogens?
    • Superficial:
    • Staphylococcus aureus
    • B-hemolytic Streptococcus
    • Pseudomonas aeruginosa
    • ?Enteric?

    • Surgical:
    • Include anaerobes
  3. What are the media(s) used to innoculate wound specimens and their incubation conditions?
    • BAP
    • MacConkey
    • Chocolate
    • BAP (an)
    • Thio broth (Brewers Meat)
  4. What is an API biotype number?
    Numeric representative of a series of phenotypic characteristics expressed by and unique to a particular bacterial species.

    The number itself represents a pattern of positive and negative biochemical reactions.
  5. True or False?
    Corynebacterium is a Gram+ diphtheroid (Chinese letters, palisade), catalase +, and motile?
    • False.
    • Corynebacterium is non-motile.
  6. True or False?
    Corynebacterium urealyticum is responsible for UTIs and is urea -

    • False.
    • C. urealyticum is urea +
  7. True or False?
    Corynebacterium are faculative anaerobes
  8. Name a very resistance specie of Corynebacterium commonly found in prosthetic device implants infection and that is pyrazidamidase hydrolysis +
    C. jeikeium
  9. Arcanobacterium
    • Beta-hemolytic
    • GNR
    • Catalase -
    • Camp inhibition + (A.haemolyticum)
    • Camp inhibition - (A. pyogenes)
  10. True or False.
    Erysipelothrix rhusiopathiae
    is transmitted by handling infected animal or fish.
  11. True or False
    Erysipelothrix rhusiopathiae requires increased carbon dioxide on BAP to grow.
  12. True or False
    Erysipelothrix rhusiopathiae
    is a rare animal or fish pathogen that causes cellulitis or endocarditis.
  13. True or False
    Erysipelothrix rhusiopathiae
    is a GPR, catalase +, motile, and demonstrate alpha hemolysis on BAP.
    • False
    • Erysipelothrix rhusiopathiae is catalase - and non motile.

    Note: It could be either alpha or non hemolytic on BAP.
  14. **Pasturella multicida** is transmitted by bites or contact with animal (eg. dogs, cats).
    It causes cellulitis and respiratory infections (if you kiss your pets).
    • gncb
    • catalase +
    • spot indole +
    • oxidase +
    • DOES NOT grow on MacConkey!
  15. True or False
    Chromobacterium violaceum are gram negative rods (non fermenters) that are found in water. Colonies exhibit a violoet pigment on nutrient agar.
  16. True or false
    Pasturella multicida is GNR, catalase -
    • False
    • Pasturella multicida is GNCB, catalase +
  17. Out of the following pathogens, which is most rarely isolated from a patient wound specimen?

    B) Erysipelothrix rhusiopathiae
  18. True or False
    The toxic effect of oxygen to anaerobes is due to production of superoxide by flavoenzymes.
  19. True or False
    Q. The superoxide is produced by superoxide dismutase.
    • A. False
    • The superoxide is DESTROYED by superoxide dismutase.
  20. True or False
    Q. Most anaerobes are pathogens of the mucous membranes of the intestine.
    • A. False
    • Anaerobes are normal flora of mucous membranes and are the most abundant organisms in the intestine.
  21. True or False
    Q. Anaerobes are more difficult to decolorize on gram stains due to the increased lipid proteins in their cell membrane.
    • A. False
    • Anaerobes decolorize very easily!
  22. Because anaerobes decolorize readily on the gram stain, alternative tests can be used to determine the gram such as 3% KOH string test, and the vancomycin susceptibility test.

    Q. What are the expected results for gram positive and gram negative organisms?
    GP: 3% KOH - , Vancomycin S

    GN: 3% KOH + (except some Bacillus spp.) , Vancomycin R
  23. Q. Which of these spemicen is an acceptable specimen for anaerobic culture?

    B) Fluid aspirates (abscess)
  24. Q. Which of the follow specimen is unacceptable for anaerobic culture?

    A) Catherterized urine
  25. Q. What is the redox indicator used to assess anaerobic conditions?
    A. Resazurin
  26. True or False
    Cysteine is the reducing agent in the Cary/Blair medium.
  27. True or False
    The Cary/Blair medium is used as a transport media for anaerobes.
  28. True or False
    Anaerobic plates are usually incubated for 24 hrs.
    • False.
    • Plates are incubated anaerobically for at least 48 hours.
  29. Q. Vitamin K supports the growth of which organism(s)?

    D) Prevotella and Porphyromonas
  30. Hemin supports the growth of which organism(s)?

    D) Prevotella and Bacteroides
  31. What is the reducing agent in the Brewers Meat?

    B) thiglycolate
  32. Bacteroides bile esculin agar (BBE) has which of the ingredients in it?

    • C) bile salts, gentamicin, esculin
    • *note: Bacteroides fragilis hydrolyzes the esculin.
  33. CDC blood agar is enriched with?

    C) yeast extract, L-cysteine, and vitamin K
  34. CCFA (cycloserine cefoxitin fructose egg yolk agar) is selective for which organism?

    C) Clostridium difficile
  35. True or False
    Brewers Meat should be stored at room temperature and boil and cooled right before use.
  36. EYA (egg yold agar) is used to determine lecithinase and lipase production of clostridia and fusobacterium.

    An organism producing both lecithinase and lipase, respectively, would produce what kind of reaction?

    c) clear, clear
    • A) opaque, pearl sheen
    • *Note: The opaque zone is due to cleavage of lecithin relasing insoluble fats. Lipase cleaves lipids, releasing glycerol which floats to the surface giving a pearl sheen.
  37. An ideal holding jar system is composed of how many jars?

    B) 3
  38. The second jar in the system of holding jars is used for what purpose?

    A) BAP or media that is in working progress
  39. Which of the following are obligate anaerobes?

    B) Clostridium haemolytic and Bacteroides fragilis
  40. True or False
    Methylene blue is a redox indicator.
    A blue colour indicates a reduced state.
    • False.
    • Blue -> oxidized
    • colourless -> reduced
  41. Which of the following are reducing agents?

    D) all of the above
  42. To acheive anaerobic conditions, oxygen is combined with hydrogen to form molecules of water.
    2H2 + 02 ---> 2H20

    What is the catalyst used in anaerobic gas packs for this reaction to proceed forward?

    A) Palladium
  43. True or False
    Haemophilus cannot grow in anearobic conditions because it is a capnophilic organism.
    • False.
    • Haemophilus can grow pinpoint colonies in anaerobic conditions because the BAP RBC are slightly lysed releasing V factor.
  44. Spot indole testing should be performed from which media?

    • C) Columbia based BAP or egg yolk agar
    • Note: only media with tryptophan will be suitable for a spot indole test since tryptophan is the precursor molecule to indole.
  45. The following is not true of a Nagler test:

    D) none of the above
  46. Which organism is known to be Reverse Camp test + ?

    A) Clostridum perfringens
  47. True or False
    To be Reverse Camp + means that the organism produces a beta lysine.
  48. Which of the following is not a Gram positive rod organism?

    • B) Veillonella
    • It is a gram negative cocci
  49. Which of the following is indole - ?

    D) Mobiluncus
  50. Which of the following is not catalase + ?
    a) Propionibacterium
    b) Mobiluncus
    c) Peptococcus niger
    d) Lactobacillus
    d) Lactobacillus
  51. Which of the following is non motile?

    A) Clostridium perfringens
  52. Which of the following is the cause of the "floppy infant" syndrome?

    C) Clostridium botulinum
  53. Which of the following is the correct expected test results for Porphyromonas?

    C) Catalase -, Kanamycin R, Colistin S, Vancomycin S
  54. Which of the following is the appropriate series of test results for Bacteroides fragilis?
    a) Catalase -, indole -, Kanamycin R, Colistin S, Vancomycin R
    b) Catalase -, Kanamycin R, Colistin S, Vancomycin S
    c) Catalase +, Kanamycin R, Colistin R, Vancomycin R
    c) Catalase +, Kanamycin R, Colistin R, Vancomycin R
  55. Prevotella melaninogenica and Porphyromonas are both gram negative coccobacilli and are very similar in biochemical reaction. How would you differentiate the both?
    Prevotella melaninogenica --> Vancomycin R

    Porphyromonas --> Vancomycin S
  56. Which of the following is not a gram negative rod?

    • B) Mobiluncus
    • Note: gram variable curved bacilli.
  57. Def'n: Toxoid
    The toxic portion of the toxin is destroyed without alterring the antigenic quality of the toxin, a good antitoxin response against Diphtheria, Tetanus, Botulism
  58. Def'n: Opsonin
    Serum proteins that attach to a foreigh substance and enhance phagocytosis.
  59. Def'n: Prozone
    False negative reactions in a serological test due to antibody excess.
  60. Def'n: Exotoxin
    Produced by gram + organisms, polypeptide, heat unstable, highly antigenic, makes good toxoids, specific against certain tissue (nerve cells, muscles).
  61. Def'n: Endotoxin
    Part of the gram - cell wall, lipopolysaccharide, heat stable, not highly antigenic, does not make good toxoids, non specific toxic effects (fever).
  62. Def'n: Hapten
    A low molecular weight substance that can bind to an antibody once it is formed, but that is incapable of stimulating antibody production unless bound to a larger carrier molecule.
  63. Def'n: Acute phase reactant
    Protein that increases due to infection; C-reactive protein, complement (faciliates phagocytosis).
  64. Def'n: C-reactive protein
    is an acute phase protein indicating inflammation.
  65. Def'n: Cell mediated hypersensitivity
    Involves T-lymphocytes (delayed 48-72 hrs); PPD, tuberculin test
  66. Def'n: Antibody mediated hypersensitivity
    involves B-lymphocytes (immediate, anaphylactic); hay fever, food
  67. Def'n: Acquired (adaptive) immunity
    Specific response to eliminate pathogen (T-cells, B-cells, antibodies)

    • 1- Active immunity
    • a. Natural
    • b. Artificial (vaccine to stimulate production of one's own antibodies)

    • 2- Passive immunity
    • a. Natural (from mother to infant)
    • b. Artificial (vaccine containing antibodies already made.)
  68. Def'n: Precipitation reactions
    Soluble antigen + soluble antibody = insoluble complex
  69. Which of the following are not precipitation reactions?

    • D) Patho Dx
    • note: this is an agglutination reaction
  70. True or False
    In the Reverse passive agglutination, we are looking for the antibody.
    • False, we are looking for the antigen.
    • ie. this is an example of patho Dx
  71. True or False
    In Coagglutination, latex beads are used as carrier particle for the antibody.
    False, bacteria (staph) are the carrier particle for the antibody.
  72. True or False
    In complement fixation, RBC lysis indicates a positive reaction.
    • False, RBC lysis indicates a negative reaction.
    • Note: we are looking for the antibody in the specimen. If the latter was present, it would have bound to their respective antigen and the compliments. Indicator RBC which have already been sensitized are then added. Since no complement are available, the RBC are intact, meaning a positive result.
  73. True or False
    Direct fluorescent antibody is used to determine if an antibody is present in a patient specimen.
    False, we are looking for the antigen in the patient specimen.
  74. True or false
    Indirect fluorescent antibody is used to determine the presence of an antibody in a patient serum.
  75. True or False
    Treponema pallidum is a spirochete that is the causative agent of syphilis and does not gram stain.
  76. In which stage of a syphilis infection would you expect to find a positive blood culture?

    B) secondary
  77. True or false
    In Nontreponemal (non specific) tests, we are looking for Reagin (non specific antibody).

    Such tests include:
    VDRL (Venereal disease researach lab)
    RPR (rapid plasma reagin)
    TRUST (Toluidine red unheated serum test)
  78. True or False
    If you had syphilis 2 years ago but was treated and are now free of the disease, you would still test positive in a treponemal (specific) test.
    • True
    • Note: The treponemal (specific) test provides info wheather you were infected in the pass or any time in your life (even if previously treated). It is a permanent result.
  79. Which organism is the causative agent of Lyme disease and is transmitte dto humans by ticks?

    D) Borrelia bugdorferi
  80. Which of the following is not a spirochete?

    • C) Pasteurella
    • Note: it is a gram negative coccobacilli
  81. True or False
    Infectious mononucleosis (Epstein-barr virus) causes the production of heterophile antibodies.
  82. After Guinea pig cell absorption and Beef RBC absorption respectively, what would be observable on sheep RBC from an infectious mononucleosis patient serum?
    Agglutination, no agglutination
  83. Which of the following is true of the Weil Felix reaction:

    A) uses Proteus antigen to detect Richattsial antibody.
  84. True or false
    For the interpretation of serology, two specimen is always required; the acute serum (frozen), and the convalescent serum (10-14 days after acute) should be run at the same time. A fourfold increase in titer from the acute to convalescent is diagnostic of an infection.
  85. True or False
    Presence of IgM antibody means a recent infection.
  86. True or False
    Agglutination testing for bacterial pathogens involves both antigen and
    antibody being at the soluble (molecular) level, while precipitation testing to confirm the presence of an infection involves both antigen and antibody being in suspension (at the particulate level).
    False. (The reverse is true.)
  87. True or False
    Pasteurella multocida is a Gram-positive bacillus which is responsible for wounds following bites from domestic animals and is catalase and
    oxidase positive.
    False. (It is a gram negative coccobacillus.)
  88. True or False
    A characteristic by which Actinomyces species differ from fungi is cell wall
  89. True or False
    Injection of the BCG vaccine results in naturally-acquired active immunity.
    False. (Artificially-acquired active immunity)
  90. True or False
    Yersinia pestis is the causative agent of plague, a zoonotic infection
    transmitted to humans by rat bites.
    False. (It is transmitted from one mammalian host to another by flea bites.)
  91. True or False
    An anaerobic jar prepared by either the evacuation-replacement
    technique or using a disposable hydrogen/carbon dioxide generator
    requires the use of palladium-coated alumina pellets as a catalyst.
  92. True or False
    In the complement fixation test, the antibody is found in the patient's
    serum, and the antigen is prepared from the infecting organism; a positive
    test is shown by hemolysis of indicator red blood cells.
    False. (A positive test is shown by no hemolysis.)
  93. True or False
    Organisms in the Bacteroides fragilis group can be identified by their
    resistance patterns to antibiotics such as kanamycin and vancomycin,
    and the presence of a characteristic brick-red fluorescent colour when observed under ultra-violet light.
    False. (The fluorescent pigment is characteristic of Porphyromonas spp. and Prevotella spp.)
  94. True or False
    Clostridium tetani is a Gram-positive anaerobic bacillus which produces
    two endotoxins, a hemolysin and a neurotoxin.
    • False. (They are exotoxins.)
    • *Note: Gram positive produce exotoxins.
    • Gram negative produce endotoxins.
  95. True or False
    The absence of hemolysis in the 1/666 dilution in an antistreptolysin-O
    titration indicates that the patient has had a recent infection with Streptococcus pyogenes; the result is expressed as 666 Todd units.
  96. True or False
    Leprosy, caused by Mycobacterium leprae, is a disease which is endemic
    in parts of the southern United States, and can only be cultured in live
  97. True or False
    Actinomyces species are Gram-positive, aerobic bacteria associated with
    wound infections of the face and head.
    False. (They are anaerobic.)
  98. True or False
    Injection of a diphtheria toxin results in artificially-acquired passive
    False. (It is a toxoid, and will result in active immunity.)
  99. True or False
    Acceptable specimens for the cultivation of anaerobes include suprapubic
    bladder aspirates, syringe aspirates of abscess fluid, and wound swabs placed in an appropriate anaerobic transport system immediately after collection.
  100. True or False
    The body's first line of immunological defense involves physical barriers,
    such as mucous membranes and cilia, as well as phagocytosis by
    False. (Phagocytosis is a second line defense mechanism.)
  101. True or False
    Nocardia asteroides is a Gram-positive organism which possesses a
    mycelial structure and may stain positive with the Ziehl-Neelsen stain.
  102. True or False
    Anaerobic Gram-positive cocci include members of the genera
    Peptostreptococcus and Veillonella.
    False. (Veillonella spp. are gram negative.)
  103. True or False
    Wound infections can be polymicrobial, resulting from infections by
    combinations of facultative bacteria.
  104. True or False
    Eikenella corrodens are Gram-negative coccobacilli which ferment
    glucose and are associated with human bite wounds.
    • False. (Eikenella corrodens is biochemically inert.)
    • *Note: Eikenella corrodens is usually gram negative bacilli but may sometimes appear gram negative coccobacilli.
  105. True or False
    Direct immunofluorescent antibody techniques involve adding fluorescein
    isothyocyanate-labelled antibody to a smear of a particular bacterium.
Card Set
Clinical Microbiology Stage Session #05
Wounds and Anaerobes Serology