Aerobic Gram Negative Bacteria

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Aerobic Gram Negative Bacteria
2013-05-12 20:32:26
Haemophilis Neisseria Staphlococci Streptococci

Haemophilis, Neisseria, Staphlococci, Streptococci
Show Answers:

  1. What does the acronym HACEK stand for and why is it used?
    • Haemophilus (especially H. aphrophilus)
    • Actinobacillus actinomycetemcomitans
    • Cardiobacterium hominis
    • Eikenella corrodens
    • Kingella
    • Members of this group are fastidious and important causes of endocarditis
  2. What are the special growth requirements?
    • Hemin (X Factor) - released from hemoglobin
    • NAD (V Factor) - heat-labile compound
  3. Identify the specific growth requirements and hemolysis for each Haemophilis species
  4. Why can't Haemophilis grow on SBA but what can it do on SBA?
    • It contains NADase in the agar
    • Haemophilus species will grow around Staph aureus, causing satellitism
  5. What are the tests and results of Haemophilis?
    • Nonmotile
    • Catalase - POS
    • Oxidase - POS
  6. What are the serotypes and biotypes of Haemophilus influenzae?
    • 6 capsular serotypes - a-f
    • 8 biotypes - I-VIII
  7. What bacteria is associated with:
    Major cause of meningitis in children
    Serotypes other than b cause resipiratory tract infections, acute sinustitis, chronic bronchilits, and pneumonia
    Otitis media with effusion and sinusitis are often caused by nontypeable strains, those lacking a capsule
    Requires X and V
    ALA and Hemolysis NEG
    H. influenzae
  8. What should H. influenzae be tested for?
  9. What bacteria is associated with:
    Rarely a respiratory pathogen
    Requires V
    Hemolysis NEG
    H. parainfluenzae
  10. What bacteria is associated with:
    Pink eye (Conjunctivitis followed by invasive disease known as Brazilian purpuric fever)
    Sucrose POS
    Requires X and V
    ALA and hemolysis NEG
    Indole NEG
    Urease POS
    Ornithine decarboxylase NEG
    Haemophilus aegyptius
  11. What bacteria is associated with:
    Genital ulcers (a STD)
    Chancroids and buboes (swollen lymph nodes)
    Requires X
    ALA and Hemolysis NEG
    Haemophilus ducreyi
  12. What genera is included with the family Neisseriaceae?
    • Neisseria
    • Eikenella
    • Kingella
    • Simmonsiella
  13. What are the tests and results performed to identify the family Neisseriaceae?
    • Gram negative diplococci or coccobacilli
    • Oxidase - POS
    • Fastidious
    • Grows best in 5-10% CO2 at 37 degrees celcius
    • They cannot tolerate cold - media must be at room temp before plating
  14. Where is Neisseria gonorrhoeae found?
    • Only in humans
    • Urethra
    • Cervix
    • Anal canal
    • Oropharynx
    • Skin lesions
    • Joints
    • Blood
  15. In MALES, what are the clinical conditions associated with Neisseria gonorrhoeae?
    • Acute urethritis (pus containing urethral discharge)
    • Dysuria
    • Prostatitis
    • Epididymitis
  16. In FEMALES, what are the clinical conditions associated with Neisseria gonorrhoeae?
    • Urethral infections
    • Cervicitis
    • Infections can be asymptomatic or produce cervical discharge, fever, acute pain, and dysuria
    • Pelvic inflammatory disease (PID)
    • Gonococcal arthritis
    • Salpingitis
    • Endometritis
    • Peritonitis
  17. In NEONATES, what are the clinical conditions associated with Neiserria gonorrhoeae?
    • Gonococcal ophthalmia neonatorum (severe conjunctivitis leading to blindness)
    • To prevent conjunctivitis, antimicrobial (erythromycin) drops are given to all infants at birth
  18. What bacteria:
    Gram Stain - Intracellular in neutrophils
    Requires enriched media such as chocolate (Does NOT grow on SBA), modified Thayer-Martin, Martin-Lewis, New York City, and CG-Lect agars
    Superoxol - POS
    Catalase - POS
    Oxidase - POS
    Glucose - POS
    Maltose, Lactose, Sucrose - NEG
    DNase - NEG
    Nitrate - NEG
    Many strains are positive for beta-lactamase production
    Neisseria gonorrhoeae
  19. What clinical conditions are associated with Neisseria meningitidis?
    • Meningococcal meningitis
    • Meningococcemia, leading to disseminated intravascular coagulation
    • Waterhouse-Friderichsen syndrome
  20. What specimens is Neisseria meningitidis found in?
    • CSF
    • Sputum
    • Blood
    • Nasopharyngeal swab
  21. What bacteria is:
    Catalase - POS
    Oxidase - POS
    Glucose and Maltose - POS
    DNase - NEG
    Nitrate - NEG
    Neisseria meningitidis
  22. What clinical conditions are Kingella associated with?
    • K. kingae - infections of bones and joints in children (immunocompromised)
    • K. dentifricans - endocarditis
  23. What is a key test to differentiate Kingella dentrificans from Neisseria gonorrhoeae?
    K. dentrificans will reduce nitrates
  24. What bacteria:
    Associated with Otitis media, Sinusitis, Respiratory tract infections
    Catalase - POS
    Oxidase - POS
    DNase - POS
    Nitrate - POS
    Butyrate esterase - POS
    Asaccharolytic (unable to breakdown carbs for energy) - all carb tests are NEG
    Moraxella catarrhalis
  25. How many toxins does staph aureus produce and name one
    • 6 different types of enterotoxin
    • Toxic Shock Syndrome Toxin-1 (TSST-1)
  26. What bacteria: 
    Associated with Food poisoning (via enterotoxin), Pneumonia, Osteomyelitis, Endocarditis, Wounds, scalded skin syndrome
    Gram positive cocci in clusters
    Beta hemolytic
    Catalase and Coagulase positive
    PYR (pyrrolidonyl-alpha-naphthylamide) and ornithine NEG
    Can tolerate high salt concentration (7.5%) of mannitol salt agar (MSA)
    Ferments mannitol, producing yellow colonies on MSA
    Staph aureus
  27. What makes Staph aureus penicillin resistant?
    Beta-lactamase production
  28. What makes Staph aureus resistant to Methicillin?
    Resistant to Beta-lactam antibiotics because of production of altered penicillin-binding proteins
  29. What makes Staph aureus resistant to Vancomycin?
    • Resistance due to VanA operon that alters the target of vancomycin in the cell wall
    • VISA (Vancomycin Intermediate Staph aureus) occurs following overproduction of the target
  30. What bacteria:
    Mostly skin flora and being nonpathogenic, Can cause disease in immunosuppressed and neutropenic patients with UTIs from catheters and shunts
    Gram positive  cocci in clusters
    Catalase positive
    Coagulase negative
    Coagulase-negative staph
  31. What bacteria:
    Most common species of coagulase negative staph
    Novobiocin susceptible
    Staph epidermidis
  32. What bacteria:
    Significant only in UTI's in women
    Novobiocin resistant
    Staph saprophyticus
  33. What bacteria:
    Frequent cause of endocarditis
    Ferments mannitol
    PYR positive
    Staph lugdunensis
  34. Describe Micrococcus
    • Considered normal flora of skin and mucous membrane - rarely cause infections
    • Modified oxidase test Positive
  35. Describe the general characteristics of Streptococcaceae
    • Catalase negative
    • Gram positive cocci in pairs or chains
    • Alpha, beta, or nonhemolytic (gamma)
    • Lancefield grouping is based on a cell wall antigen
  36. What is another name for Group A Strep?
    Strep pyogenes
  37. What bacteria:
    Associated with: Strep throat (pharyngitis), Impetigo, Cellulitis, Scarlet fever, Pneumonia, Otitis media (middle ear infections), Necrotizing faciitis
    Secondary effects of Rheumatic fever and Post-Streptococcal Glomerulonephritis
    Bacitracin (A disk) susceptible
    PYR positive
    Often use latex agglutination
    Group A Strep (Strep pyogenes)
  38. Name some of the virulence factors of Group A Strep (Strep pyogenes)
    • Cell wall M protein inhibits phagocytosis
    • Streptococcal pyrogenic extoxin (Spe A, B, C, F), formerly known as erythrogenic toxin, causes the rash seen in scarlet fever and act as superantigens to interact with macrophages and T helper cells to stimulate massive release of cytokines, and are associated is toxic schock syndrome (STSS)
    • Streptokinase dissolves clots
    • Hyaluronic acid capsule inhibits phagocytosis
    • Streptolysin O and streptolysin S lyse erythrocytes, platelets, and neutrophils
    • Hyaluronidase hydrolyzes hyaluronic acid, and interstitial barrier, facilitating spread of infection (strains that produce a hyaluronic acid capsule will not produce hyaluronidase)
  39. What Lancefield groups do Streptococcus dysgalactiae - subspecies equismilis express
    Lancefield group C or G antigens
  40. What clinical spectrum of diseases do Streptococcus dysgalactiae - subspecies equismilis resemble?
    • Pharyngitis
    • Skin infections
    • Necrotizing fasciitis
    • STSS
    • Endocarditis
    • Glomerulonephritis
    • Acute rheumatic fever
  41. What bacteria:
    Neonates - sepsis and meningitis
    Mothers - postpartum fever, osteomyelitis, wound infections, endocarditis, pneumonia, pyelonephritis (in immunocompromised patients)
    Can show beta hemolysis or gamma (nonhemolytic)
    CAMP test - POS
    Hippurate Hydrolysis - POS
    PYR - NEG
    Resistant to bacitracin
    Group B Streptococcus (Strep agalactiae)
  42. What bacteria:
    Associated with Wound infections, UTIs, Abdominal abcesses, Isolation of Group D, Strep in blood cultures are an indicator of colon cancer
    Bile-esculin positive
    Negative for growth in 6.5% NaCL
    PYR negative
    Group D Streptococcus
  43. What bacteria:
    Bacterial endocarditis in people with damaged heart valves
    Wound infections
    Brain abcesses
    May enter the blood after dental procedures
    Optochin (P disc) resistant
    Insoluble in bile
    Does not grow on bile-esculin medium
    Viridans streptococci
  44. What bacteria:
    Associated with Lobar pneumonia (in elderly and alcoholics), Otitis media (infants and children), Meningitis (vaccine has reduced this from occurring), Community-acquired bacterial pneumonia (sputum are often rust colored)
    Gram positive diplococci that are lancet or bullet shaped
    Alpha hemolytic
    Optochin (O or P disc) Sensitive
    Bile (10% sodium deoxycholate) soluble
    Streptococcus pneumoniae
  45. What are the most commonly encountered species of Enterococcus?
    • E. faecalis
    • E. faecium
  46. What are the tests and results to identify Enterococcus?
    • Bile esculin - POS
    • Positive for growth in 6.5% NaCl
    • PYR - POS
    • Express Lancefield group D antigen
    • Can be alpha, beta, or gamma hemolytic
  47. What causes Enterococcus to be vancomycin resistant (VRE)
    Resistance is due to altered peptidoglycan cross-link target:  D-Ala-D-Ala to D-Ala-D-Lac or D-Ala-D-Ser
  48. What is the species that are the majority of VRE (Vancymycin resistant Enterococcus)?
    E. faecium
  49. What bacteria:
    Associated with Endocarditis, Meningitis, Brain abcesses, Lung abcesses, Osteomyelitis
    PYR - POS
    LAP (leucine aminopeptidase) - POS
    Bile esculin - NEG
  50. What bacteria:
    Associatd with Osteomyelitis, Ventriculitis, Postsurgical endophthalmitis, Bacteremia in neonates
    Vancomycin resistant
    PYR - NEG
    LAP - NEG
    Catalase -NEG
  51. What was formerly known as nutritionally variant streptococci?
    • Abiotrophia
    • Granulicatella
  52. What bacteria:
    Requires Vitamin B6 (pyridoxal or pyridoxamine) for growth
    Associated with Endocarditis, Ophthalmic infections, Infections of the central nervous system (CNS)
    • Abiotrophia and Granulicatella
    • (Formerly known as nutritionally variant streptococci)