Simmons Citrate Agar - BioReagent

Cat. No.: S1528357

QUALITÀ & PUREZZA BioReagent

Storage

Room temperature

Shipped In

Normal

Panoramica

For bacterial citrate utilization test

Specifiche

Specifiche e purezza

BioReagent

Condizioni di conservazione di stoccaggio

Room temperature

Spedito in

Normal

Grado

BioReagent

Product Line

Prodotti biologici

Application Protocols

The following protocol is provided as general, literature-based guidance. For this specific item, consult the CoA/Spec Sheet and your laboratory SOPs.

A. Preparation of Simmons Citrate Agar slants (literature):

• Weigh the dehydrated medium according to the supplier’s grams-per-liter specification. Not specified for this item; refer to CoA/Spec Sheet.
• Add to purified water; mix and heat to dissolve completely.
• Dispense into screw-cap tubes (e.g., 8–10 mL per 16×150 mm tube) or flasks for plates.
• Autoclave at 121 °C for 15 minutes.
• For slants: Immediately after sterilization, place tubes at an angle to create long slanted surfaces; allow to solidify.
• For plates: Cool sterile medium to ~50–55 °C, then pour into sterile Petri dishes; allow to solidify and dry.

B. Citrate utilization test (slant method, literature):

• Inoculum: Use a light inoculum from a fresh (18–24 h) culture grown on a non-selective medium to minimize nutrient carryover.
• Technique: Streak the slant surface in a zigzag; do not stab the butt.
• Incubation: 35–37 °C for 24–48 h; extend up to 7 days for slow utilizers.
• Interpretation: Growth with blue coloration indicates alkaline reaction consistent with citrate utilization (positive). No growth and no color change remain negative.
• Quality controls (examples, literature): Positive control—Klebsiella (Enterobacter) aerogenes; Negative control—Escherichia coli. Select strains per your QC program.

C. Storage of prepared media (general):

• Store sealed slants/plates at 2–8 °C, protected from light to preserve indicator color. Use within the shelf-life defined by your SOP.

Biological Roles

This product is not a biomolecule with intrinsic physiological roles; it is a formulated culture medium used in microbiology.

Functional role in laboratory biology (general/literature):

• Selective/differential function: Provides a defined carbon source (citrate) and nitrogen source (ammonium) to probe metabolic pathways in microorganisms, particularly within Enterobacteriaceae.
• Metabolic readout: Organisms expressing citrate uptake and utilization pathways convert citrate and ammonium to alkaline metabolites (e.g., ammonia), increasing pH and triggering a color change in the pH indicator (commonly bromothymol blue, literature). This readout is a proxy for the presence/absence of specific transporters/enzymes (e.g., citrate permease and downstream TCA-cycle-linked enzymes).
• Role in identification workflows: Forms part of classical biochemical panels (alongside tests like TSI, urease, indole, etc.) for phenotypic differentiation in research microbiology.

Limitations (general):

• Some strains exhibit slow citrate utilization; extended incubation may be needed to avoid false negatives.
• Heavy inocula or nutrient carryover from rich media can yield false positives. Employ a light inoculum sourced from non-selective, low-nutrient media and avoid picking excess agar or nutrients during transfer.

Note: These are general, literature-based roles. For this specific item, consult the CoA for performance data and your lab’s SOPs for QC organisms and acceptance criteria.

Buffer Applications

Not typically used as a buffer system. While Simmons Citrate Agar formulations often include phosphate salts that confer some buffering around neutrality (literature), the medium is intended for selective/differential microbiological testing rather than pH buffering of biochemical reactions.

For buffer needs, select defined buffer systems (e.g., phosphate, HEPES, Tris) tailored to your pH and ionic strength requirements.

Green Alternatives

Although Simmons Citrate Agar itself is a water-based, agar-gelled microbiological medium with generally low environmental impact during use, there are still opportunities to improve sustainability around its preparation and disposal.

Greener practice considerations (general):

• Energy efficiency: Consolidate autoclave runs and use validated liquid cycles to minimize energy and water consumption while maintaining sterility assurance.
• Right-sizing: Prepare only the volumes required for your testing window to reduce expired waste.
• Reusable glassware: Use reusable tubes and plates when compatible with your SOPs to reduce single-use plastics.
• Safer cleaning: Prefer aqueous detergents over solvent-based cleaners for glassware where feasible.
• Waste minimization: Decontaminate spent media biologically (e.g., validated autoclave cycles) before disposal. Avoid chemical disinfectants that generate hazardous waste unless required by biosafety protocols.

Comparison of options (literature):

• Slants vs poured plates: Slants typically use less medium and packaging per test and may reduce waste for routine citrate testing.
• Dehydrated medium vs ready-to-use: Dehydrated formats lower shipping weight/volume and reduce cold-chain requirements, but require in-house sterilization energy; ready-to-use formats increase packaging and shipping impact but may reduce on-site resource use. Choose based on your lab’s capabilities and throughput.

No chemical substitute is relevant here; the choice is about format and workflow to reduce environmental footprint.

Pharmaceutical Uses

This product is intended For research use only (per Product Data) and is not designed or qualified for clinical diagnostics or therapeutic applications.

Relevance to pharmaceutical laboratories (general):

• Utility in research QC: In R&D microbiology labs, Simmons Citrate Agar can be used as part of phenotypic characterization of environmental or process isolates, aiding strain discrimination during method development or contamination investigations.
• Not an excipient: The medium is a complex mixture for culture testing and is not used as a formulation excipient.
• Compendial status: Some microbiological media have compendial analogs or references; however, specific pharmacopeial alignment for this item is not provided. Not specified for this item; refer to CoA/Spec Sheet.

No medical or clinical claims are made or implied. Use is restricted to research laboratory settings under appropriate quality systems.

Physical Properties

Because Simmons Citrate Agar is a complex dehydrated medium, single-compound physical constants are not applicable.

Item-specific data:

• Appearance: Not specified for this item; refer to CoA/Spec Sheet.
• Storage conditions: Room temperature (per Product Data).
• Shipping: Normal (per Product Data).

General/literature properties of Simmons Citrate Agar (dehydrated medium):

• Physical form: Free-flowing powder containing salts, dye indicator, and agar (literature).
• Solubility: Dispersible in water; upon heating and autoclaving, agar forms a firm gel on cooling (literature).
• Prepared medium color: Green at neutral pH; shifts to blue under alkaline conditions when citrate is utilized (literature).
• Typical preparation concentration: commonly formulated at a defined grams-per-liter dosage as per manufacturer; exact value varies by supplier. Not specified for this item; refer to CoA/Spec Sheet.
• Typical final pH (at 25 °C): approximately neutral to slightly alkaline depending on formulation; specific value varies by supplier. Not specified for this item; refer to CoA/Spec Sheet.

Not applicable to this product:

• Boiling/melting points, density, refractive index, logP, pKa: not meaningful for a heterogeneous dehydrated blend. For performance-defining parameters (e.g., pH of reconstituted medium), consult the lot-specific CoA.

Quality and Grades

• Item-specific grade: BioReagent (per Product Data).

What BioReagent typically implies (general):

• Suitable for biological and microbiological research workflows, with controlled raw materials and manufacturing to support consistent performance.
• Focus on functional/biological performance metrics (e.g., growth and differentiation of specified QC organisms) rather than ultra-trace chemical purity metrics used for analytical solvents.

Medium-specific quality considerations (general/literature):

• Performance testing: Each lot of Simmons Citrate Agar is commonly evaluated using control strains that should yield positive (growth/alkalinization with blue color) and negative (no growth/no color shift) reactions. The exact organisms and acceptance criteria are supplier-defined. Not specified for this item; refer to CoA/Spec Sheet.
• Indicator quality: The dye component must provide clear color discrimination at the designated pH window.
• Gel strength: Agar quality controls ensure appropriate firmness of slants/plates at the recommended preparation concentration.

What is not provided in Product Data:

• Stabilizers, peroxide/metal limits, UV cutoff, and other analytical-grade solvent specifications are not applicable or not specified for this item; refer to CoA/Spec Sheet for any available parameters.

Practical tip:

• For regulated work or method validation, retain the CoA for the lot used and document the performance of internal QC strains alongside manufacturer recommendations.

Reaction and Applications

Chemical reaction use: Not applicable. Simmons Citrate Agar is a selective/differential culture medium, not a synthetic reagent.

Microbiological applications (general/literature):

• Citrate utilization test: Detects the ability of organisms (commonly among Enterobacteriaceae) to use citrate as the sole carbon source and ammonium salts as the sole nitrogen source. Conversion of ammonium to ammonia/alkaline metabolites raises pH, and the indicator shifts color (green → blue), with/without growth depending on the organism.
• Differentiation: Helps distinguish citrate-positive taxa (e.g., Klebsiella/Enterobacter spp., literature) from citrate-negative taxa (e.g., many Escherichia coli strains, literature) as part of biochemical identification panels.
• Format flexibility: Suitable for slants (test tubes) or poured plates; slants enable long, oxygen-accessible surfaces for inoculation by streaking the slant surface.

Practical tips (literature):

• Inoculum density matters: Use a light inoculum from a young culture to avoid false positives from carryover nutrients. Do not stab the butt; streak the slant only.
• Incubation: 35–37 °C for 24–48 h is commonly used; some strains may require up to 7 days. Record both growth and color change.
• Controls: Include a known positive and negative control strain each run to validate medium performance.

Note: Exact preparation, incubation, and acceptance criteria vary by supplier and laboratory SOP. For this item, refer to CoA/Spec Sheet and your validated method.

Reaction Conditions

Chemical reaction conditions are not applicable. Instead, the relevant parameters are those for medium preparation and microbiological incubation.

Medium preparation (general/literature guidance):

• Reconstitution: Disperse the dehydrated medium in purified water at the manufacturer-recommended grams-per-liter concentration. Not specified for this item; refer to CoA/Spec Sheet.
• Dissolution: Heat with stirring to fully dissolve; avoid scorching.
• Sterilization: Autoclave at 121 °C for 15 minutes (typical). Allow to cool to ~50–55 °C before pouring plates or forming slants.
• Slant formation: Dispense into tubes before sterilization or immediately after, then cool at an angle to form slanted surfaces.

Incubation (general/literature):

• Inoculation: Lightly streak the slant surface with a fresh culture; do not stab the agar.
• Temperature/time: Commonly 35–37 °C for 24–48 h; slow growers may require up to 7 days.
• Readout: Growth accompanied by a green-to-blue color shift indicates alkaline reaction consistent with citrate utilization; absence of growth/color change indicates negative under the test conditions.

Always adapt to your SOPs and consult the item’s CoA/Spec Sheet for any supplier-specific directions.

Safety and Handling

Safety classification for this specific item has not been provided.

• GHS classification, signal word, pictograms, H-statements: Not specified for this item; refer to SDS.
• General hazards (literature/practice): Dehydrated culture media are generally regarded as low hazard chemicals but may cause irritation to eyes, skin, and respiratory tract due to dust. Avoid inhalation and contact with eyes and skin.

Personal protective equipment (general laboratory practice):

• Wear lab coat, safety glasses or goggles, and appropriate gloves (e.g., nitrile). Use a dust mask/respirator if handling generates airborne particulates; consult SDS for respirator selection.

Handling and hygiene:

• Minimize dust generation. Handle in a well-ventilated area. Wash hands thoroughly after handling.
• When preparing media, heat cautiously to avoid bumping/boil-over. Use appropriate heat-resistant glassware and autoclave-rated closures.

Storage and incompatibilities:

• Store at room temperature in a tightly closed container, protected from moisture and strong acids/bases that could alter indicator color or medium performance (general guidance). Per Product Data, standard room temperature storage and normal shipment are acceptable.

First aid (overview; defer to SDS):

• Inhalation: Move to fresh air; seek medical advice if symptoms persist.
• Skin/eye contact: Rinse with water for several minutes; remove contaminated clothing; obtain medical attention if irritation continues.
• Ingestion: Rinse mouth; do not induce vomiting; seek medical advice.

Always consult the product-specific SDS for authoritative safety information.

Solvent Selection

This product is a dehydrated microbiological medium and is not used as a reaction solvent.

Practical preparation guidance (general/literature):

• Vehicle: Purified water is used to dissolve/disperse the dehydrated medium. Heat to aid dissolution before sterilization by autoclaving.
• Ionic strength and buffering: The formulation typically contains phosphate salts that contribute to ionic strength and buffering capacity around neutrality (literature). Do not adjust ionic strength unless your protocol explicitly requires it, as changes can alter selectivity.
• Alternatives: For citrate utilization testing, related media (e.g., Simmons Citrate Broth or Christensen’s citrate media, literature) may be selected when slants/plates are not required. Choice depends on workflow (slant inoculation vs turbidimetric broth assays).

If you require a true solvent for auxiliary steps (e.g., sanitization, equipment cleaning), select based on that separate use case; this medium itself is reconstituted in water only.

Storage and Reconstitution

Item-specific storage and shipping:

• Storage conditions (as sold): Room temperature (per Product Data). Protect from moisture and excessive humidity to prevent caking and degradation of performance.
• Shipped: Normal (per Product Data).

Reconstitution (general/literature guidance):

• Water quality: Use purified/deionized water (microbiological grade). Follow the supplier’s grams-per-liter concentration. Not specified for this item; refer to CoA/Spec Sheet.
• Dissolution: Heat with stirring until fully dissolved. Avoid localized overheating.
• Sterilization: Autoclave at 121 °C for 15 minutes. Do not over-sterilize as indicator dyes can degrade.
• Pouring/forming: Cool to ~50–55 °C before pouring plates or setting slants.

Storage of prepared media (general):

• Plates/slants: Store at 2–8 °C, sealed to prevent desiccation and protected from light. Allow to equilibrate to room temperature before inoculation to prevent condensation.
• Shelf-life: Follow your laboratory SOP or internal validation; indicator-containing media can lose responsiveness over time. Not specified for this item; refer to CoA/Spec Sheet.

Re-use and stability:

• Do not re-melt plates multiple times; repeated heating can degrade the indicator and agar.

For research use only (per Product Data). Always consult the lot-specific CoA and SDS for definitive instructions and safety information.

Structure and Identity

This product is a prepared microbiological culture medium (dehydrated powder) rather than a single, well-defined chemical entity. As such, discrete molecular identifiers are not applicable to the product as sold.

• Item identity (from Product Data): Simmons Citrate Agar (SKU: S1528357), BioReagent grade.
• CAS, CID, InChIKey, SMILES: Not applicable to complex media; not specified for this item; refer to CoA/Spec Sheet.
• Molecular formula and molecular weight: Not applicable to a mixture; not specified for this item; refer to CoA/Spec Sheet.

General description (literature):

• Simmons Citrate Agar is a selective/differential medium used to assess an organism’s ability to utilize citrate as the sole carbon source and ammonium as the sole nitrogen source. A pH indicator (commonly bromothymol blue, literature) reports alkaline metabolites from citrate utilization with a characteristic color change of the medium from green to blue.
• Structural features (conceptual, literature): The product is a heterogeneous blend of inorganic salts, indicator dye, and agar gelling agent. No discrete 2D/3D molecular structure is assignable to the mixture.

Implications for identity control:

• Lot-to-lot quality is assured by medium-specific performance tests (growth/response of control strains) rather than by single-compound identity metrics. Consult the CoA for the lot’s performance criteria.

Synthetic Utility

Not applicable. Simmons Citrate Agar is a culture medium and does not serve as a reagent or building block in chemical synthesis.

If your workflow requires chemical synthesis steps adjacent to microbiology, handle those reagents separately and avoid cross-contamination of culture areas with synthetic chemicals.

Target Specificity

Not applicable. This product is not an antibody, probe, or targeted binding reagent. Its selectivity arises from the culture medium’s composition (carbon/nitrogen sources and pH indicator) that differentially supports organisms capable of citrate utilization (general/literature).