Small Pleomorphic Gram Negative Bacilli II

Question 1

Gram – Negative Bacilli:
Related to the Respiratory System

Answer 1

Haemophilus spp.
Legionella spp.
Bordetella spp.

Question 2

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

Answer 2

Haemophilus spp.

Question 3

Haemophilus spp. Growth requirements:

Answer 3

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

Question 4

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

Answer 4

Haemophilus spp.

Question 5

Haemophilus spp.
Virulence factors

Answer 5

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

Question 6

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

Answer 6

Haemophilus influenzae

Question 7

1. Gram stain
   gram – negative short rods or coccobacilli

Answer 7

Haemophilus influenzae

Question 8

2. 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

Answer 8

Haemophilus influenzae

Question 9

3. Quellung reaction
4. Biochemical tests:
   Catalase positiveNon - hemolytic Ferments glucose
5. Serologic tests – detect capsular PLS
   – type – polyribitol phosphate
   ex. FAT, ELISA, LPAT

Answer 9

Haemophilus influenzae

Question 10

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

Answer 10

Haemophilus ducreyi

Question 11

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

Answer 11

Haemophilus ducreyi

Question 12

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

Answer 12

Haemophilus ducreyi

Question 13

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

Answer 13

Note

Question 14

Kock-Week’s Bacillus

Answer 14

Haemophilus aegyptius

Question 15

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

Answer 15

Haemophilus aegyptius

Question 16

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

Answer 16

Gardnerella vaginalis

Question 17

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

Answer 17

Gardnerella vaginalis

Question 18

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

Answer 18

Gardnerella vaginalis

Question 19

Gram – negative aerobic bacilli
Associated with environmental water sources systems

Answer 19

Legionella spp.

Question 20

Legionella spp.
Important species

Answer 20

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

Question 21

• Transmission
– Respiratory system
• Laboratory Diagnosis

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

Answer 21

Legionella pneumophila

Question 22

Legionella pneumophila stain

Answer 22

Immunofluoresacence
Dieterle Silver Stain

Question 23

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

Answer 23

Legionella pneumophila

Question 24

Legionella pneumophila
Culture media

Answer 24

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)

Question 25

• Strictly aerobic
• Non–fermentative
• Smallgram–negativecoccobacilli

Answer 25

Bordetella spp.

Question 26

Growth requirements: Bordetella spp.

Answer 26

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

Question 27

Bordetella spp.
Clinically important species

Answer 27

1. Bordetella pertussis – Whooping cough
2. Bordetella parapertussis
3. Bordetella bronchiseptica – Kennel cough in dogs

Question 28

• patient is highly infective
• susceptible to antibiotic

Answer 28

Phases: 1. Catarrhal phase (1-2 weeks

Question 29

antibiotic not effective

Answer 29

Paroxysmal phase (2 -10 weeks)

Question 30

Bordetella pertussis
Virulence factors

Answer 30

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

Question 31

With associated lymphocytosis

Answer 31

Bordetella pertussis

Question 32

Bordetella pertussis
Direct examination of smears stained with

Answer 32

fourescein conjugated monoclonal or polyclonal antibodies

Question 33

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

Answer 33

Bordetella pertussis

Question 34

slow grower; should be held for 7 to 12 days

Answer 34

Bordetella pertussis

Question 35

Bordetella pertussis
Culture Media:

Answer 35

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

Question 36

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

Answer 36

Bordetella pertussis