HAEMOPHILUS Flashcards
Gram-negative, small, pleomorphic coccobacilli
or rods
HAEMOPHILUS
H. influenza, H. ducreyi, H.
parainfluenzae, H. paraphorobilus, H.
parahaemolyticus, H. pittmaniae, H. aegypticus
and H. segnis
HAEMOPHILUS SPECIES
- Greek word: Haima and philos means “blood
lover”. - Obligate parasite on the mucous membrane of
humans
HAEMOPHILUS SP
- Fastidious, non-motile, caphnophilic and
facultatively anaerobic bacteria. - Clinical specimen very susceptible to dying and
extreme temperature. - Most specie cannot grow on pure BAP
HAEMOPHILUS SP
(+) catalase; Oxidase (+);
except
H. segnis
X (hemin) and V (nicotinamide
adenine dinucleotide)
Growth factors of HAEMOPHILUS SP
- Main cause of meningitis in children
- As early as less than 12 months, you can
receive the vaccine for H. influenzae
HAEMOPHILUS INFLUENZAE
Spread of H influenzae
nasopharynx → lymph nodes →meninges
- Very fastidious and rapidly killed by phagocytes
- Only member of the genus that produces IgA
protease - Does not produce endotoxin
HAEMOPHILUS INFLUENZAE
person to person (respiratory droplets)
MOT of HAEMOPHILUS INFLUENZAE
translucent, convex, tan-colored&
mucoid with “mousy” or “bleach-like odor”
Culture: CAP HAEMOPHILUS INFLUENZAE
Polysaccharide
capsule (serotypes A to F)
Principal Virulence factor of HAEMOPHILUS INFLUENZAE
: IgA protease, fimbriae
and lipopolysaccharide
Other Virulence factor of HAEMOPHILUS INFLUENZAE
(-) porphyrin (necessary for
the production of heme and later on for the
production of hemoglobin)
Biochemical test of HAEMOPHILUS INFLUENZAE
- Based on capsular characteristic. of H. influenza
- Encapsulated form: types A, B, C, D, E and F
(capsular types)
TYPABLEFORM
Most commonly known
type of H. influenzae. It can cause of serious
infections in human and the leading cause of
meningitis in unvaccinated children
H. influenza type B (Hib):
- Does not produce capsule (non-capsulated
strains) - Indigenous microbiota of URT and adheres to
human EC
NON-TYPABLE FORM
- Second prevalent etiologic agent for otitis media.
- Other: Conjunctivitis and sinusitis
NON-TYPABLE FORM
- Agent of chancroid or “soft chancre
HAEMOPHILUS DUCREYI
- Infects the mucosal epithelium, genital and nongenital skin, and regional lymph nodes.
- Painful and tender genital lesions that advance
to ulcer with satellite lesion
HAEMOPHILUS DUCREYI
Buboes or suppurative,
enlarged, draining, inguinal lymph nodes
Hallmark of chancroid:
Commonly found indigenous microbiota of the
URT of adults.
HAEMOPHILUS PARAINFLUENZAE
- Distinguishing characteristics
o Mousy/bleach-like odor; non-haemolytic - Growth Factor
o X, V - Associated Infection/disease
o Meningitis, epiglottitis, arthritis
H. INFLUENZAE (PFEIFFER’S BACILLUS)
- Distinguishing characteristics
o Genetically related to H. influenzae - Growth Factor
o X, V - Associated Infection/disease
o Pink eye conjunctivitis
H. AEGYPTICUS (KOCH-WEEKS BACILLUS)
- Distinguishing characteristics
o Non-typable (they don’t have capsule) - Growth Factor
o X, V - Associated Infection/disease
o Brazilian purpuric fever
H. INFLUENZAE BIOGROUP AEGYPTICUS
- Distinguishing characteristics
o School of fish - Growth Factor
o X - Associated Infection/disease
o Chancroid or Soft chancer
H. DUCREYI
- Distinguishing characteristics
o Tan and dry colonies; Beta-haemolytic - Growth Factor
o V - Associated Infection/disease
o Pharyngitis
H. PARAHAEMOLYTICUS
- Distinguishing characteristics
o Fructose and maltose fermentation - Growth Factor
o V - Associated Infection/disease
o Endocarditis
H. PARAINFLUENZAE
Cleansed with sterile gauze that is
pre-moistened with sterile phosphate-buffer
saline
H. ducreyi
resemble an
“amorphous serous material” because of their
pleomorphic appearance.
Gram-stain
detects the presence of enzymes that
converts delta-aminolevulenic acid into
porphyrins.
Porphyrin Test:
Kovac’s reagent (other name: pdimethylaminobenzaldehyde)
- Identifying the heme-producing species of
Haemophilus. - Reagent
red color
Porphobilinogen
– reddish-orange color
(UVL 300 nm)
Porphyrins
(+) Exhibits a red color
(H. parainfluenzae,
H. parahaemolyticus, H. paraphrobilus
and H. aphrophilus)
(-) Result
H. influenza, H. haemolyticus, H.
aegypticus and H.ducreyi.
Haemophilus species that need the X
factor are unable
to synthesize
porphyrin from delta-ALA
(aminolevulinic acid)
preferred medium for
Haemophilus because it contains the X
and V factor
CAP
grows best at 35C to
37C (except H. ducreyiat 33C) and 5 to
10 CO2
Haemophilus
H.
influenzae, grows as “satellites” on BAP
and produce NAD
V-factor dependent Haemophilus
nly NAD
required
Grown anaerobically
4 days incubation
H. aegypticus
–7 days incubation
H. ducreyi
: horse’s blood-bacitracin
agar for respiratory secretion of patient
with cystic fibrosis
H. influenzae
CAP with 1%
IsoVItaleXor Vitox
H. aegypticus
Nairobi biplate medium
(combination of gonococcal agar and
MHA with horse’s blood and
vancomycin)
H. ducreyi
rapid direct
identification of capsular antigen of H.
influenzae
Neufeld quelling test
