55. Antitussives, Expectorants and Mucolytics or Therapy of Cough
56. Drugs used in Bronchial Asthema
57. Nasal Decongestants and Cold remedies or Therapy of Allergic Rhinitis
58. Chemotherapy of Tuberculosis
59
Physiology
59. Mechanism and Mechanics of Breathing
60. Regulation of Respiration
61. Pulmonary circulation
62. Pulmonary Gas exchange
63. Gas transport and Exchange
64. Lung compliance
65. Pulmonary Function Tests
66. Spirometry
67. Applied Respiratory Physiology
68. Abnormal Breathing
69. Artificial Respiration
70. Lung Defense Mechanism
71
Microbiology
25. Haemophilus influenzae
INTRODUCTION
HISTORY
VIRULENCE FACTORS
Capsular polysaccharide
Bacterial endotoxin
Outer membrane proteins
IgA1 proteases
Pili
Other adhesion proteins
PATHOGENESIS
CLINICAL MANIFESTATION
LABORATORY DIAGNOSIS
Specimen collection
Sputum
Blood
CSF
Aspirates from joints, middle ears or sinuses
Storage
It is highly sensitive to low temperature, and thus should never be refrigerated.
Transport
It should be transported immediately.
Direct smear microscopy
Gram staining
Gram -ve coccobacilli
Pleomorphic appearance
Capsule detection (Quellung reaction)
Capsular swelling occurs when a drop of CSF is mixed with type b antiserum and methylene blue and observed under microscope.
Antigen detection
The type b capsular antigen can be detected in by
Latex agglutination test
Direct-IF test
ELISA
Culture
Culture medium
H. influenzae is highly fastidious, requires two accessory growth factors (factor X and V) in blood for their growth.
Factor X is a hemin, present freely in blood
Factor V is nicotinamide adenine dinucleotide (NAD), which is present inside RBCs. It is also produced by some bacteria, such as Staphylococcus aureus.
Basal media
On growth on Nutrient agar and Peptone water as they lack X and V factors.
Enriched media
Blood agar
Growth is scanty is because only factor X is availabe freely in blood agar and factor V is minutely availabe as it is present intracellularly.
Chocolate agar
Grows well on chocolate agar.
Blood agar with S. aureus streak line
Colonies of H. influenzae can grows adjacent to S. aureus streak line- a phenomenon called as Satellitism.
Satellitism
When S. aureus is streaked across a blood agar plate perpendicular to the H. influenzae streak line, factor V is released from S. aureus.
Therefore, it forms larger colonies adjacent to S. aureus streak line and size of the colonies decreases gradually away from the S. aureus streak line.
This phenomenon is called Satellitism, a property that is routinely employed for the isolation of H. influenzae.
Special media
Fildes agar and Levinthal's agar containing factor X and V.
