What is X and V factors?
X – and V-Factor Disks are paper disks impregnated with growth factors. Each X-Factor Disk is impregnated with hemin. Each V-Factor Disk is impregnated with NAD (nicotinamide adenine dinucleotide). Each XV-Factor Disk is impregnated with a combination of hemin and NAD.
What are the X and V factors What is their role in the growth of Haemophilus species?
X factor indicates hemin and V factor indicates nicotinamide-adenine-dinucleotide, NAD. Consequently, the significant differences in growth factor requirements of Haemophilus spp. allows for their differentiation. Haemophilus spp are small, pleomorphic, gram-negative bacilli or coccobacilli with random arrangements.
Which of the following media contains the X and V factors necessary for the growth of Haemophilus influenzae?
Chocolate agar provides the factors, that is, hemin (X factor) and NAD (V factor), necessary for the growth of Haemophilus spp.
Which species of Haemophilus requires both X and V factors?
Haemophilus influenzae requires both factors X and V; accordingly, it grows on chocolate agar but not on blood agar (Fig. 30-2), although it may appear on a blood agar plate as tiny satellite colonies around the colonies of other bacteria that have lysed red blood cells.
What is the porphyrin test and how is it used to identify Haemophilus isolates?
REMEL’s Porphyrin Test Agar is a solid medium recommended for use in qualitative procedures to speciate the genus Haemophilus based on their ability to convert delta-aminolevulinic acid (ALA) to porphyrins. Porphyrin Test Agar contains hemoglobin as a source of hemin (X factor).
What is Haemophilus influenzae symptoms?
Symptoms of bloodstream infection usually include:
- Fever and chills.
- Excessive tiredness.
- Pain in the belly.
- Nausea with or without vomiting.
- Diarrhea.
- Anxiety.
- Shortness of breath or difficulty breathing.
- Altered mental status (confusion)
Where is Haemophilus found?
Haemophilus influenzae is a bacteria that is found in the nose and throat of children and adults. Some people can carry the bacteria in their bodies but do not become ill.
What routine media should be used for the isolation of Haemophilus influenzae?
For isolation of H. influenzae, chocolate agar with bacitracin can be used. Other antibiotic formulations are also available. All primary culture media should be tested for QC to ensure that the media will support the proper growth of N.
How is Hib diagnosed?
How Is Hib Diagnosed? To diagnose Hib disease, doctors do an exam and ask about symptoms. They also might take a small sample of blood, spinal fluid, or another body fluid for testing.
What is the porphyrin test in microbiology?
Porphyrin tests measure the level of porphyrins in your blood, urine, or stool. Porphyrins are chemicals that help make hemoglobin, a type of protein in your red blood cells.
How do you identify Haemophilus Parainfluenzae?
H. influenzae can be identified using Kovac’s oxidase test and determining the necessity of hemin and NAD as growth requirements. If the oxidase test is positive, hemin and NAD growth factor requirement testing should be performed. If the growth factor requirement test indicates that the isolate may be H.
How does the X and V factor test work?
In the laboratory, a lawn of the test organism is streaked onto heart infusion agar, tryptic soy agar, Haemophilus agar, or nutrient agar. The impregnated disks or strips (X, V, or XV) are placed directly on the confluent inoculation, allowing diffusion of the accessory growth factor into the medium.
How are X Factor and V factor disks impregnated?
Each X-Factor Disk is impregnated with hemin. Each V-Factor Disk is impregnated with NAD (nicotinamide adenine dinucleotide). Each XV-Factor Disk is impregnated with a combination of hemin and NAD. Using aseptic technique select isolated colonies of suspect colonies and prepare a suspension equivalent to a 0.5 McFarland standard.
Why are X and V factors needed for growth?
These are required for growth because X-dependent strains are unable to convert d-aminolaevulinic acid to protoporphyrin. They are heat stable. V factor comprises nicotinamide adenine dinucleotide (NAD) or nicotinamide adenine dinucleotide phosphate (NADP).
What does growth around the XV disk indicate?
Growth around the V disk, no growth around the X disk, and light growth around the XV disk shows a V factor requirement. Growth over the entire surface of the agar indicates no requirement for either X or V factor.