What is Satellitism in microbiology?
: the growth of bacteria of one type in culture about colonies of another type that supply needed micronutrients or growth factors.
How do you perform Satellitism?
Procedure of Satellitism test
Mix a loopful of suspected colonies of Haemophilus colonies in about 2 ml of sterile physiological saline (or sterile peptone water). Make sure none of the chocolate agar media is transferred. Incubate both plates in a carbon dioxide-enriched atmosphere at 35 to 37°C for 18-24 hours.
Which bacteria can be determined by satellite method?
Background — Haemophilus influenzae can grow on blood agar media with Staphylococcus aureus which can provide factor V as it is called “Satellite phenomenon”.
Which organism exhibits Satellitism with Staphylococcus aureus?
ovis, is known to exhibit satellitism around S. aureus, as well as pyridoxal dependence, in a manner similar to that of so-called nutritionally variant streptococci (23).
Why does Haemophilus not grow on blood agar?
Haemophilus influenzae requires hemin (factor X) and NAD+ (factor V) for growth. Other Haemophilus species require only NAD+ and therefore grow on blood agar.
What tests can be used to differentiate members of the Enterobacteriaceae family from Pseudomonas?
Oxidase Test
It is commonly used to distinguish between oxidase negative Enterobacteriaceae and oxidase positive Pseudomadaceae.
What is the satellite phenomenon quizlet?
What is the satellite phenomenon? Most strains of Haemophilus species do not grow on 5% sheep agar blood which contains factor X (hemin) but lacks factor V (NAD). When Staphylococcus aureus is grown in a culture media containing blood, it will produce NAD as a metabolic byproduct.
What are satellite colonies of bacteria?
What are Satellite Colonies? During antibiotic selection, you may notice a few small colonies growing around a large colony on the plate. These small colonies are satellite colonies and the large colony is the colony of interest, containing both the antibiotic resistance gene (selectable marker) and gene insert.
What do satellite colonies mean?
The definition of satellite colonies is: “Satellite colonies are very small colonies that have not taken up the plasmid and that form around a large colony that has taken up plasmid.” (from the link provided by Michael).
How do you identify Haemophilus?
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.
Is Haemophilus aerobic or anaerobic?
Haemophilus spp. are small, pleomorphic, nonmotile, nonsporing Gram-negative rods or coccobacilli. They are aerobic and facultatively anaerobic. Growth is often enhanced by the addition of 5–10% carbon dioxide to the incubation atmosphere.
What are 3 general characteristics of the Enterobacteriaceae?
The Enterobacteriaceae are facultative anaerobes or aerobes, ferment a wide range of carbohydrates, possess a complex antigenic structure, and produce a variety of toxins and other virulence factors.
What two tests do all Enterobacteriaceae have in common?
Commonly used biochemical tests are; Citrate utilization Test. Indole Test.
Which of the following bacteria are most prevalent in the human gut?
The four dominant bacterial phyla in the human gut are Bacillota, Bacteroidota, Actinomycetota, and Pseudomonadota. Most bacteria belong to the genera Bacteroides, Clostridium, Faecalibacterium, Eubacterium, Ruminococcus, Peptococcus, Peptostreptococcus, and Bifidobacterium.
How do salmonella enter the body from what sources quizlet?
Salmonella is usually transmitted to humans by eating foods contaminated with animal feces.
Why are satellite colonies formed?
Satellite colonies appear since beta-lactamase is secreted by the transformed bacteria with the vector harbouring this gene selection marker and the non-transformed cells take advantage of this fact to grow up in the selection media.
What causes satellite colonies to form?
On agar plates, ampicillin degradation can lead to the formation of satellite colonies. These are very small colonies of cells that have not taken up the plasmid that form around a large colony that has taken up the bla-containing plasmid.
Why do satellite colonies grow?
The large colony secretes β-lactamase enzyme to degrade ampicillin. The degradation of ampicillin around the large colony causes the reduction of ampicillin level in that area. Satellite colonies begin to appear and grow around this area.
What disease is caused by Haemophilus influenzae?
Haemophilus influenzae (Invasive Disease)
Hib causes a variety of diseases including meningitis (inflammation of the coverings of the spinal column and brain), bacteremia (infection of the blood), and pneumonia (infection of the lungs). Fact sheets about Haemophilus influenzae and Hib.
What antibiotics treat Haemophilus influenzae?
The important antibiotics applied in the treatment of less severe H. influenzae infections include amoxicillin, cephalosporin, azithromycin, doxycycline, and fluoroquinolone. However, serious infections are managed by broad-spectrum cephalosporins and carbapenems (1,2).
What are the characteristics of Haemophilus?
H. influenzae are small, pleomorphic, gram-negative bacilli or coccobacilli with random arrangements. H. influenzae is a fastidious organism which grows best at 35-37°C with ~5% CO2 (or in a candle-jar) and requires hemin (X factor) and nicotinamide-adenine-dinucleotide (NAD, also known as V factor) for growth.
Where does Haemophilus grow?
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.
Which test is used for identification of Enterobacteriaceae?
After the growth of the isolates on the culture media, Gram staining is also used to aid identification. Biochemical tests, for example Beta-glucoronidase test, citrate utilization test, urease test, indole test, are the basic tests used for Enterobacteriaceae identification in Nigerian hospitals (Cheesebrough, 2000).
What causes Enterobacteriaceae?
Enterobacter UTI can present with dysuria, frequency, urgency, and positive leukocyte esterase or nitrites on urinalysis. Risk factors that predispose to infection include the following: Prolonged recent use of antimicrobial treatment. Immunocompromised states, particularly malignancy and diabetes.