Microbiological growth media and methods of using the same
Inventors
SHARA, Kate • SCHWEDOCK, Julie • VOGEL, Sommer
Assignees
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Publication Number
US-10793823-B2
Publication Date
2020-10-06
Expiration Date
Abstract
The present invention features general-purpose microbiological growth media capable of supporting growth of microorganisms on membranes. The media contain casein digest, soybean digest, animal tissue digest, yeast extract, dextrose, a phosphate buffer, hemin, and L-cystine. The invention features an all-purpose microbiological growth media that can support the growth of anaerobes, molds, injured spores, and general aerobic bacteria to a greater extent than other media.
Core Innovation
The invention provides an all-purpose microbiological growth medium for membrane-based sterility testing. The medium is formulated to support anaerobes, molds, injured spores, and general aerobes more effectively than conventional media, and it comprises casein digest, soybean digest, animal tissue digest, yeast extract, dextrose, a phosphate buffer, hemin, and L-cystine.
The medium excludes tris(hydroxymethyl)aminomethane and, in some embodiments, is substantially free of added sodium. At 22 C the composition is solid or is liquid or gel, with defined ranges for the digest components, dextrose, and L-cystine, and with a phosphate buffer characterized by a buffer capacity constraint.
The medium further includes optional components for sterility testing, including optional gelling agents, optional surfactant, and optional disinfectant neutralizers, with examples including histidine, thiosulfate, polysorbate 80, and lecithin. The medium may also include sheep blood, including lysed forms, and documented embodiments include solid powder or liquid/gel forms, kit embodiments, and a preparation workflow that includes mixture preparation, optional cooling, optional pH adjustment to a stated range, and adding sheep blood.
Comparative example outcomes show improved growth and recovery across multiple stressed organisms and molds versus USP-referenced media, including TSA, FTM, and Schaedler broth/chocolate agar. The document describes the use of the medium on permeable membranes for culturing and sterility testing.
Claims Coverage
The document provides two independent composition claims that cover solid and liquid or gel embodiments. Each independent claim includes the core ingredient set, exclusion of tris(hydroxymethyl)aminomethane, and 22 C physical state, while adding defined quantitative ranges for multiple components. Additional dependent claims refine functional constraints, hemin amount, and optional formulation components such as surfactant and neutralizers.
Solid all-purpose growth medium without tris(hydroxymethyl)aminomethane
A solid composition at 22 C comprising casein digest, soybean digest, animal tissue digest, yeast extract, dextrose, a phosphate buffer, hemin, and L-cystine, wherein the composition does not comprise tris(hydroxymethyl)aminomethane and excludes the phosphate buffer from total mass of the composition while defining ingredient mass ranges for casein digest, soybean digest, animal tissue digest, yeast extract, dextrose, and L-cystine.
Liquid or gel all-purpose growth medium without tris(hydroxymethyl)aminomethane
A liquid or gel composition at 22 C comprising casein digest, soybean digest, animal tissue digest, yeast extract, dextrose, a phosphate buffer, hemin, and L-cystine, wherein the composition does not comprise tris(hydroxymethyl)aminomethane and wherein specified concentration ranges are defined for casein digest, soybean digest, animal tissue digest, yeast extract, dextrose, and L-cystine.
Phosphate buffer with defined buffer capacity
A composition in which the phosphate buffer provides a buffer capacity between 0.1 mmol per (pH unit) and 100 mmol per (pH unit) upon dissolution in an aqueous medium.
Hemin content within a defined range
A composition in which hemin is present between about 0.2 g/kg and about 1 g/kg.
Exclusion of added sodium
A composition in which the composition does not contain added sodium.
Disinfectant neutralizer selection
A composition further including a neutralizer selected from histidine, thiosulfate, polysorbate 80, and/or lecithin.
Polysorbate surfactant
A composition in which the surfactant is a polysorbate.
Across the independent composition claims, the core formulation is an all-purpose microbiological growth medium at 22 C that excludes tris(hydroxymethyl)aminomethane and includes a defined set of digest-derived components plus dextrose, a phosphate buffer, hemin, and L-cystine, with different quantitative ranges for solid and for liquid or gel. Dependent claim refinements define phosphate buffer buffer capacity, hemin content, optional exclusion of added sodium, and optional inclusion of disinfectant neutralizers and a polysorbate surfactant.
Stated Advantages
Improved growth and recovery of stressed organisms and molds compared with conventional media, including TSA, FTM, and Schaedler broth/chocolate agar.
Supports anaerobes, molds, injured spores, and general aerobes more effectively than conventional media.
Documented Applications
Membrane-based sterility testing using permeable membranes, including culturing and sterility testing with the described medium.
Kit embodiments for sterility testing contexts, including Growth Direct Sterility cassette.
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