Table of Contents
What is Fraser broth?
Fraser Broth is a selective medium used for the secondary enrichment of Listeria monocytogenes and Listeria spp., as described in ISO 11290-1:2017. Fraser Broth is not intended for use in the diagnosis of disease or other conditions in humans.
How to prepare Fraser broth?
Suspend 28.7g in 500ml of distilled water and mix well to dissolve completely. Sterilise by autoclaving at 121°C for 15 minutes. Cool to below 50°C, and aseptically add the contents of one vial of Fraser Selective Supplement (SR0156) reconstituted as directed in the product insert.
How to prepare Half Fraser Broth?
Dehydrated base Dissolve 129.2 g of powder (code 356-4604) in 2.25 l of distilled water, mix until a homogenous suspension is obtained. Heat gently, swirling frequently, then bring to soiling point until completely dissolved. Dispense 225 ml per bottle. Sterilize 15 minutes in autoclave at 121°C.
What is half Fraser broth?
Half Fraser Broth is a modification of Fraser Broth which contains half of the concentration of nalidixic acid and acriflavine hydrochloride to aid in the recovery of stressed cells. Half Fraser Broth is used as the primary enrichment broth in the ISO methodology for the detection of Listeria.
How do you make Palcam Agar?
Suspend 69 g in 1000 ml distilled water. Heat to boiling to dissolve the medium completely. Sterilize by autoclaving at 15 lbs pressure (121°C) for 15 minutes. Cool to around 50°C and aseptically add the dissolved contents of 2 vials of PALCAM Listeria Selective Supplement according to Van Netten et al.
What is Palcam agar used for?
Palcam Agar Base is used with supplements as a selective and differential medium for the detection and isolation of Listeria monocytogenes from food and environmental samples. Palcam Agar Base is not intended for use in the diagnosis of disease or other conditions in humans.
Why Palcam is used for Listeria?
PALCAM Medium is highly selective due to the presence of lithium chloride, ceftazidime, polymyxin B and acriflavine hydrochloride. It allows the easy differential diagnosis of Listeria monocytogenes by utilising the double indicator system.
Which antibiotic is used in the Palcam Agar?
The addition of lithium chloride and antibiotics like polymyxin-B-sulfate, ceftazidim and acriflavine suppress the growth of the gram-negative bacteria and most gram-positive bacteria.
What Agar is used for Listeria?
BD PALCAM Listeria Agar is a selective differential medium for the isolation and detection of Listeria monocytogenes and other Listeria species from foods and clinical specimens. In BD PALCAM Listeria Agar, Columbia Blood Agar Base provides the nutrients and cofactors required for growth of Listeria.
What grows Palcam Agar?
As it has been corectly pointed by all the colleagues, enterococci and staphylococci can indeed grow on PALCAM agar but these bacteria can easily be differentiated since they ferment mannitol contained in the medium, changing the color of the medium from red to yellow. L.
Can Listeria grow on MacConkey Agar?
Grow at/on: pH 5.5-9.6 (pH 7.2-7.6 optimum). Temperature range 0-45 ºC. Grow on 40% bile agar. Weak growth on MacConkey agar.
What agar does Listeria grow on?
Meuller-Hinton agar
Once in the lab, Listeria species grows on a special type of agar called Meuller-Hinton agar. Culture will reveal gram-positive rods with colonies that are beta-hemolytic.
Is listeriosis gram-positive or negative?
Listeria monocytogenes is a facultative, intracellular, gram-positive rod that is responsible for causing the infection listeriosis. Listeria causes severe infection in the elderly, neonates and the immunocompromised with only a self-limited gastrointestinal infection in the immunocompetent.
What media is used for Listeria?
Brain Heart Infusion (BHI) is the most commonly used non-selective media for cultivation of Listeria species.
What antibiotics treat Listeria?
Ampicillin is the drug of choice. It interferes with bacterial cell wall synthesis during active multiplication, causing bactericidal activity against susceptible organisms.
Can I use Fraser broth as a secondary enrichment medium?
All Fraser Broth enrichment cultures should be subcultured to plating medium. The medium is intended for the isolation of Listeria spp. from food and environmental samples when used as the secondary enrichment medium in the USDA-FSIS methodology for Listeria isolation.
What is half Fraser broth used for?
Half Fraser Broth is a modification of Fraser Broth which contains half of the concentration of nalidixic acid and acriflavine hydrochloride to aid in the recovery of stressed cells. Half Fraser Broth is used as the primary enrichment broth in the ISO methodology 5 for the detection of Listeria. 1.
How accurate is Fraser broth in detecting Listeria?
Fraser Broth has proven to be remarkably accurate in detecting Listeria spp. in food and environmental samples 1,2. All Listeria spp. hydrolyse aesculin to aesculetin. Aesculetin reacts with ferric ions which results in blackening.
Why is lithium chloride used in Fraser broth?
Lithium chloride is included in the medium to inhibit the growth of enterococci which can also hydrolyse aesculin. Care must be taken when using Fraser Broth with DNA probe methodology because the high salt content of the medium may have an inhibitory effect on detection 4.