Small Pleomorphic Gram Negative Bacilli II Flashcards

1
Q

Gram – Negative Bacilli:
Related to the Respiratory System

A

Haemophilus spp.
Legionella spp.
Bordetella spp.

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2
Q

o Group of small, gram-negative, pleomorphic bacteria
o Normal microbiota of mucous membranes

A

Haemophilus spp.

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3
Q

Haemophilus spp. Growth requirements:

A

Hematin – from blood
NAD – from yeast extract or Staphylococcus aureus

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4
Q

Pfeiffer’s Bacillus
Infects only humans
Transmission:
- via respiratory route

A

Haemophilus spp.

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5
Q

Haemophilus spp.
Virulence factors

A

o Capsule – 6 types type B – most virulent
polyribitol ribose phosphate (PRP)
o IgA1 protease
o Fimbriae
o Membrane CHONS

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6
Q
  1. Meningitis – 95% by type B
    – most common meningitis in aged < 2 y.o.
    (5 months to 5 years in the US)
  2. Acute epiglotitis
  3. Pneumonia
  4. Septic arthritis in infants
  5. Sepsis (usually in aspleenic px)
  6. Others: otitis media, sinusitis
A

Haemophilus influenzae

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7
Q
  1. Gram stain
    gram – negative short rods or coccobacilli
A

Haemophilus influenzae

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8
Q
  1. Culture
    - Requires both X and V factors
    i. Chocolate agar Plate
    ii. Blood Agar Plate next to a streak of beta-hemolytic Staph (Staphylococcus aureus )
    iii. Mueller-Hinton Agar that has been
    fortified with both X- factor and V-factor
A

Haemophilus influenzae

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9
Q
  1. Quellung reaction
  2. Biochemical tests:
    Catalase positiveNon - hemolytic Ferments glucose
  3. Serologic tests – detect capsular PLS
    – type – polyribitol phosphate
    ex. FAT, ELISA, LPAT
A

Haemophilus influenzae

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10
Q

Sexually transmitted o Clinical Presentation
Chancroid/Soft chancre
- painful genital ulcer coexisting inguinal lymphadenopat

A

Haemophilus ducreyi

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11
Q

Laboratory diagnosis
1. Gram stain – small pleomorphic gram negative bacilli in clusters - “school of fish”

A

Haemophilus ducreyi

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12
Q

Culture
Fresh Clotted Rabbit Blood - preferred
20 – 30% Defibrinated Rabbit Blood agar
Sheep or Horse Blood
Chocolate Agar with 1% IsoVataliX and Vancomycinl

A

Haemophilus ducreyi

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13
Q

Haemophilus ducreyi
Prevention
– 1 gram oral Azithromyxin
Treatment
◼ Ceftriazone Intramuscular
◼ Oral Ciprofloxacine
◼ Oral Erythromycin

A

Note

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14
Q

Kock-Week’s Bacillus

A

Haemophilus aegyptius

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15
Q

Clinical Presentation
- Pink eye conjunctivitis
- Resembles H. influenzae biotype III

A

Haemophilus aegyptius

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16
Q

Formerly Haemophilus vaginalis
• Clinical Presentation
- Causes Bacterial vaginosis
(foul smelling vaginal discharge –fishy odor, pruritus and dysuria)

A

Gardnerella vaginalis

17
Q

Laboratory Diagnosis
1. Stains
i. Papanicolaou’s stain
“clue cells”
ii. Gram stain –gram variable or gram negative small coccobacilli

A

Gardnerella vaginalis

18
Q

Laboratory Diagnosis
3. Culture: Human Blood Tween Agar at 48 hours in 5 – 10% CO2 – Beta hemolysis
V (vaginalis) Agar
4. Whiff Test or Sniff Tests – vaginal discharge + 10% KOH
Positive test – Fishy- amine like odor

A

Gardnerella vaginalis

19
Q

Gram – negative aerobic bacilli
Associated with environmental water sources systems

A

Legionella spp.

20
Q

Legionella spp.
Important species

A
  1. Legionella pneumophila.
    -Legionnaire’s Pneumonia
    -Pontiac Fever
  2. Legionella micdadei
    Pittsburg pneumonia
21
Q

• Transmission
– Respiratory system
• Laboratory Diagnosis

  1. Stains
    i. Gram stain – stains faintly
    – noted be intracellular organisms
A

Legionella pneumophila

22
Q

Legionella pneumophila stain

A

Immunofluoresacence
Dieterle Silver Stain

23
Q
  • Does not grow on ordinary media
  • Requires high concentration of Iron and Cysteine
A

Legionella pneumophila

24
Q

Legionella pneumophila
Culture media

A

i. Buffered Charcoal Yeast Extract Agar (BCYE)
- supplemented with L – cyteine, ferric salt and alpha ketoglutarate
ii. Chocolate agar
iii. Feeley-Gorman Medium (brown pigment)

25
Q

• Strictly aerobic
• Non–fermentative
• Smallgram–negativecoccobacilli

A

Bordetella spp.

26
Q

Growth requirements: Bordetella spp.

A

Growth requirements: - Nitotinic acid
- Cysteine
- usually methionine
• Also added to the medium – remove excess fatty acids
– blood, charcoal, starch or ion exchange resins

27
Q

Bordetella spp.
Clinically important species

A
  1. Bordetella pertussis – Whooping cough
  2. Bordetella parapertussis
  3. Bordetella bronchiseptica – Kennel cough in dogs
28
Q
  • patient is highly infective
  • susceptible to antibiotic
A

Phases: 1. Catarrhal phase (1-2 weeks

29
Q

antibiotic not effective

A

Paroxysmal phase (2 -10 weeks)

30
Q

Bordetella pertussis
Virulence factors

A
  1. Capsule
  2. Beta – lactamase producing
  3. Pili (Filamentous hemagglutinin)
  4. Toxins
    - Pertussis toxin
    - Tracheal cytotoxin
31
Q

With associated lymphocytosis

A

Bordetella pertussis

32
Q

Bordetella pertussis
Direct examination of smears stained with

A

fourescein conjugated monoclonal or polyclonal antibodies

33
Q

should be incubated in a humid environment at 350C without CO2

A

Bordetella pertussis

34
Q

slow grower; should be held for 7 to 12 days

A

Bordetella pertussis

35
Q

Bordetella pertussis
Culture Media:

A

i. Regan – Lowe
ii. Bordet – Gengou
Composed of: Potato
20 – 30 % blood
Glycerol

36
Q
  • Small round and shiny
  • may give the appearance of
    “drop of mercury”
A

Bordetella pertussis