Farrell's medium is a selective bacteriological
medium
Medium may refer to:
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Aviation
*Medium bomber, a class of war plane
*Tecma Medium, a French hang glider design
Communication
* Media (communication), tools used to store and deliver information or data
* Medium of ...
for ''
Brucella
''Brucella'' is a genus of Gram-negative bacteria, named after David Bruce (1855–1931). They are small (0.5 to 0.7 by 0.6 to 1.5 µm), non encapsulated, non motile, facultatively intracellular coccobacilli.
''Brucella'' spp. are the caus ...
'' species which is prepared by the addition of six antibiotics to a basal bacteriological medium such as
serum dextrose agar. In order to prepare 1 liter of the Farrell's medium, the following quantities are added to 1 liter of serum dextrose agar:
polymyxin B sulfate (5000 units =5 mg),
bacitracin (25,000 units = 25 mg),
natamycin
Natamycin, also known as pimaricin, is an antifungal medication used to treat fungal infections around the eye. This includes infections of the eyelids, conjunctiva, and cornea. It is used as eyedrops. Natamycin is also used in the food indust ...
(50 mg),
nalidixic acid
Nalidixic acid (tradenames Nevigramon, NegGram, Wintomylon and WIN 18,320) is the first of the synthetic quinolone antibiotics.
In a technical sense, it is a naphthyridone, not a quinolone: its ring structure is a 1,8-naphthyridine nucleus that ...
(5 mg),
nystatin
Nystatin, sold under the brandname Mycostatin among others, is an antifungal medication. It is used to treat '' Candida'' infections of the skin including diaper rash, thrush, esophageal candidiasis, and vaginal yeast infections. It may also be ...
(100,000 units), and
vancomycin
Vancomycin is a glycopeptide antibiotic medication used to treat a number of bacterial infections. It is recommended intravenously as a treatment for complicated skin infections, bloodstream infections, endocarditis, bone and joint infections, ...
(20 mg). Vancomycin inhibits the growth of
gram-positive bacteria on this medium, while nystatin inhibits the growth of
fungi
A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from ...
. Other antibiotics inhibit the growth of
gram-negative bacteria
Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wall ...
other than ''Brucella'' species, thus favoring the exclusive growth of the latter in this medium.
References
External links
The Nutrient Requirements of Cells
{{Authority control
Cell culture media
Microbiological media