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Haemophilus species
N/a
26
Microbiology
Undergraduate 3
04/20/2015

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Term
General characteristics of Haemophilus spp
Definition
Gram negative pleomorphic bacillus.
Normal flora of respiratory tract in humans and animals.
Non-motile
Require Co2
Must be kept moist
Term
Colonies of Haemophilus spp
Definition
Very small and very clear (look like dew)
Often satellite around STA
Term
How are Haemophilus spp identified?
Definition
Based on requirements for X and V factor. Indole urease and ornithine can be used to subdivide H. influenzae and H. parainfluenzae into biotypes
Term
X Factor
Definition
Heme
Heat stable
Used in biosynthesis of respiratory cytochromes. Present in BAP and CHOC
Term
V Factor
Definition
NAD (satelliting factor)
Heat labile
Involved in oxidation-reduction process
Available in CHOC
Term
Haemophilus Quad Plate
Definition
Used for the identification of Haemophilus spp. Contains 4 quadrants. Each with a different combination of X and V factors.
Term
Satellite growth around the feeder organism inicates the need for what factor?
Definition
V factor
Term
How to perform X and V factor studies
Definition
Prepare a McFarland suspension of the organism and make a lawn of the organism on a Mueller-Hinton plate (no Heme, no NAD) Supply the factors via discs X, V and X&V.
Term
X and V factor studies interpretation
Definition
Growth around both X and X&V the organism needs X factor
Growth around V and X&V the organism needs V factor
Growth around only X&V the organism needs both factors.
Term
ALA test: Porphyrin test
Definition
If an organism is satelliting on the BAP STAX, we know it needs V (NAD) and we then need to determine if it needs X (heme) in order to ID it. Test for the ability of the organism to synthesize heme from precursors (which means it wouldn't require heme in the media)
Term
How do you perform the ALA test
Definition
ALA substrate in solution
Add organism and incubate at 35 degrees Celsius for 4 hours
Expose the tube to UV light. Red fluorescence indicates a positive test which means the organism has made porphyrins and therefore is INDEPENDENT of the X factor. Alternatively, add Kovac's reagent, shake and look for color in the lower phase.
Term
Most Haemophilus infections including osteomyelitis, cellulitis, pericarditis and pneumonia are caused by what? Also most pediatric diseases are caused by this organism.
Definition
Haemophilus influenzae type B (HIB)
Term
Infections by non-influenzae Hemophilus species include
Definition
Bacteremia/septicemia/endocarditis
Brain abscess, sinutis, empyema
Brazilian purpuric fever (BPF)
Term
Haemophilus ducreyi
Definition
Sexually transmitted disease (chancroid)
Term
Haemophilus influenzae biogroup aegypticus
Definition
Causes a severe conjunctivitis in tropical countries
Term
Haemophilus haemoglobinophilus
Definition
Normal flora of canines
Term
Haemophilus parahemolyticus
Definition
Found in human dental plaque
Term
Haemophilus aphrophilus
Definition
Doesn't require X or V factor. It can be upper respiratory flora
Term
Haemophilus parainfluenzae
Definition
Can be URF, can cause endocarditis, bacteremia
Term
Haemophilus parapphrophilus
Definition
Can be URF, can cause endocarditis, bactermia.
Term
Most strains of Haemophilus are susceptible to what?
Definition
Penicillin, chloro, sulfonamides and tetracyclines
Term
Haemophilus ampicillin resistance
Definition
Resistance is conveyed by a plasmid mediated Beta-lactamase. Testing for resistance is demonstrated by tests including the acidometic method or the chromogenic test
Term
Haemophilus ducreyi specimen collection
Definition
Clean ulcer with sterile gauze and saline
Collect exudate on a pre-moistened swab or in sterile syringe
Swab is then placed in transport media
Transport to laboratory within 1 hour of collection
Specimen should be processed ASAP
Term
Gram stain of Haemophilus ducreyi will show
Definition
School of fish clumping of organisms occurs when organism is grown in broth culture.
Term
Media for Haemophilus ducreyi must contain what?
Definition
Heme
Term
Characteristics of Haemophilus ducreyi
Definition
Adherent colonies
Gram neg bacilli
Oxidase Pos
Catalse Neg
SPS (sodium polyanephol sulfate) disc susceptible
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