Anaerobic Bacteria

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  1. Where are Anaerobic cocci generally found?
    Normal flora of the intestines, female genital tract, oral cavity, and respiratory tract
  2. What clinical conditions are associated with Anaerobic cocci?
    • Polymicrobial liver and brain abscesses
    • Wound infections
  3. What species has the tests and results:
    Catalase POS
    Produces olive-green colonies that become black
    Peptococcus niger
  4. What are the species names of Peptostreptococcus?
    • P. anaerobius
    • Finegoldia magna
    • Peptoniphilus asaccharolytica
  5. What bacteria is IDed with the test:
    Inhibited by sodium polyanethol sulfonate (SPS)
    Peptostreptococcus anaerobius
  6. What species has the tests and results:
    Small, gram-negative cocci
    Reduces nitrate to nitrite
    Does not ferment any carbohydrates
    Sensitive to kanamycin and colistin
    Resistant to vancomycin
  7. What species in general has the identifying characteristics:
    Clinical conditions: Abdomen infections, Chest infections, Pelvic actinomycosis in women with intrauterine devices (most common)
    Exudate contains sulfur granules - dense clumps of bacteria
    Gram Positive bacilli with beaded appearance, often filamentous (Branching gram positive bacilli)
    Colony morphology - smooth to molar toothlike morphology
  8. What species are included in Propionibacterium?
    • Propionibacterium acnes
    • Propionibacterium propionicus
  9. What are species are often called anaerobic diphtheroids?
  10. What species has the tests and results:
    Catalase POS
    Indole POS
    Usually Normal flora of the skin, mouth, and GI tract, Rarely pathogenic
  11. What species has the tests and results:
    Clinical conditions: BV (Bacterial vaginosis), PID (Pelvic inflammatory disease), Abdominal infections
    Curved bacilli
    Catalase NEG
    Indole NEG
    Inhibited by vancomycin
  12. Is Lactobacillus pathogenic or normal flora?
    • Normal flora of the GI and female gential tract
    • Organism helps maintain and acidic environment in the vagina
    • If the population of lactobacilli decreases, the risk of BV (bacterial vaginosis) increases
    • Rarely pathogenic
  13. What species has the tests and results:
    Clinical conditions: If the population of this organism decreases, the risk of BV (bacterial vaginosis) increases but rarely pathogenic
    Catalase NEG
    Nonmotile bacilli
    Generally aerotolerant anaerobes and will form small alph-hemolytic on SBA
  14. What are some other nonpathogenic normal oral and intestinal flora?
    • Bifidobacterium
    • Eubacterium
  15. Are most Clostridium species motile or nonmotile?
    • Motile
    • Except C. perfringens, C. ramosum, and C. inocuum
  16. What patients are more prone to infections with Clostridium perfringens?
    • Diabetics
    • Patients with circulatory disorders
  17. What does Clostridium perfringens secrete?
    Enzymes and exotoxins that cause severe tissue damage
  18. How is the Clostridium perfringens divided?
    • 5 different types
    • A-E
    • Based on the quantities and types of exotoxins produced
  19. What bacteria has the tests and results:
    Clinical conditions: Gas Gangrene (myonecrosis), Post-abortion sepsisAbdominal infections, Enterocolitis, Food poisoning (mild-moderate diarrhea)
    Produces a double zone of beta-hemolysis on SBA when incubated anaerobically
    Exhibits a positive (enhanced hemolysis) reverse CAMP test (Strep agalactiae - Group B - is substituted for Staph aureus in the standard CAMP test)
    Lecithinase POS
    Glucose, Lactose, maltose, and fructose POS
    Spores subterminal but difficult to induce
    Nagler test - prevents the opaque zone from forming - not performed much today
    Clostridium perfringens
  20. How is Clostridium tetani treated and prevented?
    Antitoxin and vaccine (DPT: diptheria, pertussis, and tetanus trivalent vaccine) booster every 5 years
  21. What bacteria has the tests and results:
    Clinical condition: Tatanospasmin, Neurotoxin that affects the anterior horn cells of the spinal cord, resulting in involuntary muscle contractions, Contractions begin with the neck and jaw (lock jaw) and progress to a backward arching  of the back muscles
    Gram positive bacilli with round/terminal spores that resembles drumsticks
    Gelatinase POS
    Indole POS
    Lecinthinase NEG
    Lipase NEG
    Generally not cultured
    Diagnosis made by signs, symptoms, and toxin detection
    Clostridium tetani
  22. What does Clostridium botulinum produce?
    Botulism toxin
  23. What bacteria has the tests and results:
    Clinical conditions: Botulism, Infant botulism, Neurotoxin binds to the synapse of nerve fibers, resulting in acute (flaccid) paralysis and death
    Lipase POS
    Lecithinase POS
    Glucose POS
    Spores are oval, subterminal and resemble tennis rackets
    Clostridium botulinum
  24. What does Clostridium difficile produce?
    Enterotoxin A and/or cytotoxin B
  25. How is Clostridium difficile diagnosed?
    Detecting toxin in the stool
  26. What bacteria has the tests and results:
    Clinical condition: Antibiotic associated pseudomembranous colitis and Diarrhea
    Cultures should only be perfomed on watery or unformed stools
    Cycloserin-cefoxitin-fructose agar (CCFA) is used to isolate C. difficile
    Weakly fructose POS
    In anaerobic conditions, the pH indicator will turn yellow at 5.3
    Fluoresce yellow-green
    Lecinthinase NEG
    Lipase NEG
    Indole NEG
    Glucose and fructose POS
    Spores are oval and subterminal
    Clostridium difficile
  27. What clinical conditions are associated with Clostridium septicum?
    Occasionally linked to gas gangrene
  28. Describe the most common anaerobe responsible for anaerobic infections and why it is resistant
    • Bacteroides fragilis group
    • A polysaccharide capsule is an important virulence mechanism
  29. What bacteria the tests and results:
    Nonmotile gram negative bacilli with rounded ends and may be pleomorphic
    Nonhemolytic on anaerobic blood agar
    Growth in 20% bile
    Catalase POS
    Lipase NEG
    Bile esculin POS
    Lecithinase NEG
    Gelatinase NEG
    Produces brown to black colonies on BBE agar
    Resistant to penicillin, kanamycin, vancomycin
    Susceptible to rifampin
    Bacteroides fragilis group
  30. What bacteria the tests and results:
    Clinical conditions: Head, neck, and lower respiratory tract infections
    Gram negative bacilli
    Young colonies appear tan and exhibit brick-red fluorescence under ultraviolet (UV) light
    Older colonies are brown to black (may take up to 3 weeks to see brown to black pigment)
    Ferments glucose and many other carbs
    Inhibited by 20% bile
    Susceptible to rifampin
    Resistant to kanamycin
    Prevotella melaninogenica
  31. What bacteria has the tests and results:
    Clinical conditions: Head, neck, oral cavity, and urogenital tract infections
    Asaccharolytic or weak fermenters
    Pigmented colonies
    Gram negative colonies
    Brick red fluorescence under UV light
    Will NOT grow on KVLB
    Inhibited by bile
    Sensitive by Vancomycin, penicillin, and rifampin
    Resistant to kanamycin
  32. What bacteria is identified by:
    Clinical conditions: Infections of pulmonary, blood, sinus, and dental cavity, Brain abcesses, Many infections are associated with metastatic conditions
    Asaccharolytic or weak fermenters
    Nonpigmented colonies
    Long, thin, filamentous gram negative bacilli with tapered ends arranged end-to-end
    Colony morphology - opalescent with speckles
    Indole POS
    Lipase POS
    Nitrate NEG
    Catalase NEG
    Relatively biochemically inactive
    Sensitive to kanamycin and colistin
    Resistant to Vancomycin
  33. What are the 2 important species of Fusobacterium?
    • Fusobacterium nucleatum
    • Fusobacterium necrophorum
  34. What are the clinical conditions associated with Fusobacterium nucleatum?
    • Serious pulmonary infections
    • More common isolate
  35. What clinical conditions are associated with Fusobacterium necrophorum?
    • Lung abcesses
    • Liver abcesses
    • Arthritis
    • Causes serious infections
  36. What is the gram stain morphology of Bacteroides and Prevotella?
    Pale, pleomorphic gram negative coccobacilli with bipolar staining
  37. What is the gram stain morphology of Clostridium?
    • Larg gram positive bacilli
    • Spore location (terminal, central, or subterminal) is important in species identification
  38. What are the most important biochemical tests performed on anaerobes?
    • Catalase
    • Nitrate
    • Urease
    • Indole
    • Antimicrobial susceptibility disks can also be used to identify anaerobes
  39. What nutrient is needed to enhance the growth of Prevotella and Porphyromonas?
    Vitamin K
  40. What nutrient is needed to enhance the growth of Bacteroides and Prevotella?
  41. What media is used for general growth of all anaerobes?
    CDC (Centers for Disease Control and Prevention anerobic blood agar)
  42. What media is selective and differential used to culture and presumpitvely identify Bacteroides fragilis?
    BBE (Bacteroides bile esculin agar)
  43. What media is an enriched selective medium for isolation of slowly growing  anaerobes such as Prevotella and Bacteroides?
    • KVLB (Kanamycin-vancomycin lakes sheep blood agar)
    • Laked blood enhances pigment formation
  44. What media is enriched and selective used to grow most anaerobes, including Clostridium and Bacteroides, also inhibits the growth of facultative, anerobic gram-negative bacilli (like Enterobacteriaceae)?
    PEA (Penylethyl alcohol agar)
  45. What media inhibits gram-negative organisms and is used to grow most gram-positive anaerobes and facultative anerobes?
    Columbia-colistin-naladixic agar with 5% sheep blood
  46. What media is used to detect proteolytic enzymes (lipase and lecithinase) produced by Clostridium?
    Egg yolk agar
  47. What does Lecithinase activity on egg yolk agar look like?
    Produces and opaque zone from the cleavage of lecithin releasing insoluble fats (diglyceride)
  48. What broths with reducing agents can be used to grow anerobic bacteria?
    • Thioglycolate and cooked (or chopped) meat
    • Resazurin can be added as an oxidation-reduction indicator
  49. When resazurin is added to thioglycolate as an indicator, how does it look and what does it indicate?
    • Pink in the presence of oxygen
    • Colorless when reduced
  50. What are commonly used systems to place solid media in anaerobic conditions for obligate anaerobes to grow?
    • Anaerobic GasPak jars and bags
    • Anaerobic hoods
  51. What are the indicators used to ensure the anaerobic conditions have been met, in anaerobic GasPak jars and bags?
    • Pallidium causes the following reaction:
    • 2H2 + O2 > 2H2O2
    • Methylene blue is the most commonly used oxidation-reduction indicator that will turn from blue to white, indicating reduction
  52. What test must be performed before attempting to identify a possible anaerobe?
    Aerotolerance test
  53. Describe the Aerotolerance test
    • Colony is inoculated to an anerobic blood agar plate (incubated aerobically) and to a chocolate agar plate (incubated with increased CO2)
    • Isolates growing only on the plate incubated anaerobically are obligate anaerobes
  54. When would you suspect anaerobic bacteria in an infection?
    • Foul odor (from gas production)
    • Necrotic tissue
    • Anaerobic body sites, wounds, abcesses
    • Surgical specimens
  55. Define and obligate anaerobe
    Bacterium that cannot use oxygen for metabolism and oxygen is lethal to the microorganism
  56. Define aerotolerant anaerobe
    Bacterium that cannot use oxygen but can grow in its presence
  57. Define facultative anaerobe
    Bacterium that will use oxygen if it is present and can grow, albeit more slowly without oxygen
  58. Define obligate anaerobe
    Bacterium that requires oxygen at concentrations found in room air, about 20%
  59. Define microaerophile
    Bacterium that requires oxygen at concentrations of 5-10%
  60. Define Capnophile
    Bacterium that requires increased concentration of CO2
Card Set:
Anaerobic Bacteria
2013-05-28 00:46:28

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