Download haemophilus

HAEMOPHILUS
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HISTORY
 Hib was found in a group
of patients during an
influenza outbreak in
1892
 Haemophilus influenzae
was first isolated in 1890
by Richard Pfeiffer
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HISTORY
• Robert Koch – 1883 – conjunctivitis
• Pfeiffer – 1889–92 – influenza pandemic
• Smith, Andrews and Laidlaw – virus
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Medically important spp
•
•
•
•
•
H. Influenzae
H.ducreyi
H. haemolyticus.
H. aphrophilus
H.segnis
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• H.aegyptius (Koch.
Weeks)
• H.Para Influenzae
• H.Para haemolyticus
• H.araphrophitus
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HAEMOPHILUS
• H. influenza – meningitis, epiglotitis,
pneumonia
• H. aegypticus – epidemic conjunctivitis
• H. ducreyi – chancroid
• H. parainfluenza }
• H. aphrophilus}
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infective Endocarditis
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Morphology
Haemophilus influenzae is :
 a pleomorphic gram-negative coccobacillus.
 H.influenzae may be either encapsulated
(typeable) or unencapsulated (nontypeable).
 There are six encapsulated serotypes
(designated a–f) that have distinct capsular
polysaccharides.
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MORPHOLOGY
• Sputum – coccobacillary forms
• CSF – long bacillary filaments
• Young cultures – coccobacillary
• Older cultures – pleomorphic
• Acute infection – capsulated
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CULTURAL CHARACTERS
 Extracellular pathogen, does not invade into
cells
 Fastidious
 Haemophilus = blood loving
 However, this organism can not grow on
blood agar alone!
• Requires X factor
• Requires V factor
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CULTURAL CHARACTERS
• Aerobic, 10% CO2
• X factor – heat stable hemin/porphyrins
• V factor – heat labile – RBC
– Staphylococci/fungi
Co-enzyme – NAD or NADP
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X and V factor:
 X factor is used by H. influenzae to produce
essential respiratory enzyme such as
cytochrome – catalase and peroxidase.
 V Factor is used as electron carriers in the
organism oxidation reduction system
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Species
Growth Factor Required
--------------------------------H.
H.
H.
H.
influenzae
parainfluenzae
aphrophilus
ducreyi
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X+V
V
X
X
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SATELLITISM
 H influenzae inoculated on blood agar plate
 S aureus streaked across on same plate
 Incubate at 37C for 18-24 hrs
 Colonies of H influenzae near the S aureus
streak are large and well developed than those
farther away from S aureus streak
 V factor is available in high concentrations near
S aureus streak
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SATELLITISM
H.influenzae on blood agar showing satellitism
around S.aureus streaks
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BIOCHEMICAL REACTIONS
• Catalase-positive, oxidase-positive
• Eight biotypes
• Biotype I – meningitis
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ANTIGENIC PROPERTIES
• Three main surface antigens
• Capsular polysaccharide – 6 capsular types
a–f
• Type b – polyribosyl ribitol phosphate
(PRP) antigen
• Non-typeable – lacking capsule
• Outer membrane protein antigen or OMP
Ags Hib – 13 subtypes
• Lipooligosaccharides (LOS) – antigenically
complex
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PATHOGENICITY
• Capsular polysaccharide PRP -antiphagocytic
• Membrane Lipopolysacchride – bacterial
attachment, invasiveness, paralysis-ciliated
respiratory epithelium
• IgA protease – inactivates secretory
antibodies
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PATHOGENESIS
 Spread via respiratory droplets
 Enters upper respiratory tract and throat and
attaches to cells using fimbriae
 Endotoxin stops respiratory tract cilia from
beating and clearing the bacterial cells
 Local spread (ears, sinuses, lungs)
 Systemic spread (blood and brain)
 Endotoxin and inflammation do the damage
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PATHOGENESIS
• Clinical syndrome – invasive, non-invasive
• Invasive – meningitis, laryngoepiglottitis,
pneumonia, suppurative lesions, bronchitis
• Non-invasive – otitis media, sinusitis
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CLINICAL SYNDROMES
 Pyogenic (purulent) meningitis in young
children (2 month to 3 years) olds
 Acute epiglotitis (Croup) (2 – 7 years old)
 Cellulitis – pyogenic arthritis, osteitis
conjunctivitis, middle ear infections, and
pneumonia.
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CLINICAL SYNDROMES
 Non Capsulated H. Influenzae strains are
associated with less severe but often
persistent infections such as
I.
purulent exacerbations of chronic
bronchitis (Mainly in adult),
II. Conjunctivitis, middle ear infection
III. paranasal sinusitis
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LABORATORY DIAGNOSIS
• CSF, pus, sputum, blood culture
• NEVER REFRIGERATE SPECIMEN
• Microscopy – Gram-negative bacteria
• Culture isolation – chocolate agar, blood agar,
Levinthal’s medium, Field’s agar
• SATELLITISM
• Serology – CSF, body fluids – type ‘b’
polysaccharide – CIEP, Latex Agglutination,
coagglutination,
• PCR
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PROPHYLAXIS
• Immunoprophylaxis – purified PRP
• Conjugate vaccines
• Purified PRP – Hib PRP
• Conjugate – TT, DPT
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HAEMOPHILUS AEGYPTICUS
• Koch Week’s bacillus
• Brazil – 1984 – conjunctivitis – septicemia,
Brazilian purpuric fever
• Koch – 1883 – Egypt, Week – cultivated1887
– New York
• It requires X and V factor.
• H. aegypticus – pink eye
• Brazilian purpuric fever
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CLINICAL SYMPTOMS
• Pink eye
• Endemic – South America
• Rx – Chloramphenicol + Ampicillin
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HAEMOPHILUS DUCREYI
• Short ovoid bacilli
• End to end pairing in
short chains
• Morphology – bipolar
staining, school of fish
‘railroad track’
• Chancroid – soft sore
• Ducrey – 1890 – chancroid lesion
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Chancroid
• STD transmission
• Chancroid – soft sore
• papule, non Indurated painful ulcer,
enlarged lymph nodes (bubos)
• Lab diagnosis
• Smear: Gram negative bacilli (school of fish)
bipolar staining.
• Isolation – rabbit fresh clotted blood, CAM,
CA- isovitalex and fetal calf serum – 2–8
days – 35°C, 10% CO2 only X factor
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OTHER HAEMOPHILUS
• H. parainfluenza; only V
• Commensal – URT
• SABE – urethritis – acute pharyngitis
• H. haemolyticus – X and V – non-pathogenic
• H. aphrophilus – X, high CO2 – endocarditis, brain
abscess, sinusitis
• H. paraphrophilus – V
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HACEK
Fastidious – commensal – mouth
H – H. parainfluenza, aphrophilus,
paraphrophilus
A – Actinobacillus
C – Cardiobacterium hominis
E – Eikenella corrodens
K – Kingella kingae
Endocarditis – blood cultures – 7–30 days
Drug resistance common
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