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King Agar A - Pseudomonas Agar P - Tech Agar - Pseudomonas Agar for Pyocyanin (AS-1259)
$39.00 AUD
Documentation
KING AGAR A
Catalogue No. AS-1259
www.ausamics.com.au
AS-1259 Differential Pyocyanin Detection P. aeruginosa Confirmation King, Ward & Raney Formulation
King Agar A
Pyocyanin Production Medium for Pseudomonas aeruginosa · also known as King's Medium A or Pseudomonas Agar P
King Agar A is a differential dehydrated medium formulated to enhance and demonstrate pyocyanin production by Pseudomonas aeruginosa. It remains the classical reference medium for blue-green pigment detection in clinical, environmental, water, and food microbiology confirmation workflows.
AuSaMicS manufactures King Agar A in Melbourne, Australia, to the original King, Ward & Raney (1954) formulation, giving reliable pigment expression and consistent lot-to-lot performance for confirmatory testing.
Performance Snapshot
Final pH7.2 ± 0.2
Incubation35 ± 2°C, 18–24h
ReadoutBlue-green pigment, daylight-visible
UV requiredNo
Shelf life (powder)24 months
Formulation accuracy note: King Agar A is correctly formulated with magnesium chloride (MgCl₂), not magnesium sulfate. Magnesium sulfate is used in King B medium (fluorescein detection), a different, complementary formulation. AuSaMicS documentation reflects the verified King, Ward & Raney (1954) composition, cross-checked against current BD Difco, Sigma-Aldrich, and HiMedia technical specifications.
Testing Workflow
1
Primary IsolationSelective agar (e.g. Cetrimide) if needed
2
SubcultureStreak isolate onto King Agar A
3
Incubation35 ± 2°C, 18–24h
4
Pigment ReadingDaylight; extend incubation if faint
5
ConfirmationBlue-green = pyocyanin positive
Scientific Background & Principle
Origin
King Agar A was described by King, Ward and Raney (1954) as one of two complementary media (A and B) for demonstrating the diagnostic pigments of Pseudomonas aeruginosa. King A promotes and reveals pyocyanin (blue, non-fluorescent, chloroform-soluble, diffusible pigment) while suppressing fluorescein; King B does the reverse, promoting fluorescein/pyoverdine and suppressing pyocyanin. The two media are used as a complementary pair in many confirmation schemes.
Mechanism
Gelatin peptone (pancreatic digest) is deliberately low in phosphate, since excess phosphate inhibits pyocyanin biosynthesis. Potassium sulfate and magnesium chloride act as the specific cations required to activate and enhance pyocyanin production. Glycerol, added as a 10 mL/L liquid supplement rather than autoclaved with the rest of the medium in some protocols, serves as the carbon/energy source that supports pigment expression. Because King A does not contain selective inhibitory agents, it is differential rather than selective — other organisms can grow, but only pyocyanin-producing strains (chiefly P. aeruginosa) produce the characteristic diffusible blue-green zone.
Key Applications
Clinical Microbiology
Confirmation of P. aeruginosa from wound, burn, and respiratory isolates.
Water Microbiology
Confirmation of pyocyanin-producing isolates in potable and process water testing.
Food & Beverage QC
Detection of P. aeruginosa contamination where relevant to product safety.
Environmental Microbiology
Surface monitoring and contamination-source tracing.
Formulation & Specifications
| Component | Quantity |
|---|---|
| Gelatin Peptone (pancreatic digest) | 20.0 g/L |
| Potassium Sulfate (K₂SO₄) | 10.0 g/L |
| Magnesium Chloride (MgCl₂, anhydrous) | 1.4 g/L |
| Agar | 15.0 g/L |
| Glycerol (added separately) | 10.0 mL/L |
| Total (excl. glycerol) | 46.4 g/L |
Technical Specifications
| Catalogue No. | AS-1259 |
| Medium Type | Differential pigment-production agar |
| Final pH | 7.2 ± 0.2 @ 25°C |
| Sterilisation | 121°C, 15 minutes |
| Storage (powder) | < 30°C, dry, dark |
| Storage (plates) | 2–8°C, dark, ≤ 4 weeks |
Laboratory Preparation
1
Suspend 46.4 g of dehydrated medium in 990 mL purified water.
2
Add 10 mL glycerol.
3
Heat with frequent agitation and boil for 1 minute to dissolve completely.
4
Sterilise by autoclaving at 121°C for 15 minutes.
5
Cool to 45–50°C, mix well, and pour plates.
King Agar A vs King Agar B
| Property | King Agar A | King Agar B |
|---|---|---|
| Target pigment | Pyocyanin (blue-green, non-fluorescent) | Fluorescein / pyoverdine (yellow-green, UV-fluorescent) |
| Key cation | Magnesium chloride + potassium sulfate | Magnesium sulfate + phosphate buffer |
| Phosphate level | Low (phosphate inhibits pyocyanin) | Higher (supports fluorescein pathway) |
| Reading method | Daylight — no UV needed | UV light (365 nm) enhances detection |
| Best for | Confirming P. aeruginosa via pyocyanin | Differentiating fluorescent pseudomonads generally |
Limitations & Technical Considerations
- Not strongly selective — King Agar A does not suppress non-target organisms; use a selective medium (e.g., Cetrimide Agar) for primary isolation from mixed flora before confirming on King Agar A.
- Not all pseudomonads produce pyocyanin — a negative result does not exclude other Pseudomonas species; complementary tests (oxidase, King B for fluorescein) are recommended.
- Pigment intensity varies with time — some strains show weak pigment at 18–24h; extending incubation or reincubating at 25–30°C for 24–48h can improve detection of weak producers.
- Presumptive, not definitive — pyocyanin production supports identification but should be interpreted alongside oxidase reaction and other confirmatory tests per your laboratory's validated scheme.
Cross-Reference / Equivalent Products
| Brand | Equivalent Product | Catalogue No. |
|---|---|---|
| BD Difco | King Medium A (Pseudomonas Agar P) | DF0449-17-0 |
| Sigma-Aldrich (Merck) | King Agar A | 60788 |
| HiMedia | King's Medium A Base | M1543 |
| Oxoid (Thermo Scientific) | Pseudomonas Agar Base (related, selective variant — requires added supplement, not an exact King A equivalent) | CM0559 |
| AuSaMicS | King Agar A | AS-1259 |
Ordering Information
| Catalogue No. | Pack Size | Format |
|---|---|---|
| AS-1259-500 | 500 g | Dehydrated powder, bottle (glycerol added separately by user) |
| AS-1259-2K5 | 2.5 kg | Dehydrated powder, bottle |
Frequently Asked Questions
What is King Agar A used for?
It confirms Pseudomonas aeruginosa by demonstrating pyocyanin, a diffusible blue-green pigment visible in daylight without UV illumination.
Does King Agar A contain magnesium sulfate or magnesium chloride?
Magnesium chloride (MgCl₂) at 1.4 g/L — not magnesium sulfate. Magnesium sulfate belongs to King B medium, formulated for fluorescein/pyoverdine production instead.
What is the difference between King Agar A and King Agar B?
King A promotes and reveals pyocyanin (blue-green, non-fluorescent) and suppresses fluorescein. King B promotes fluorescein/pyoverdine (yellow-green, UV-fluorescent) and suppresses pyocyanin. See the comparison table above.
How do you prepare King Agar A?
Suspend 46.4 g dehydrated medium in 990 mL purified water, add 10 mL glycerol, heat with agitation to boiling, autoclave at 121°C for 15 minutes, cool to 45–50°C, then pour plates.
Is King Agar A selective for Pseudomonas aeruginosa?
No — it is differential, not strongly selective. Other organisms can grow; primary selective isolation (e.g., on Cetrimide Agar) is often used before confirming pyocyanin production on King Agar A.
Common Search Queries This Product Answers
Researchers and procurement teams typically find this page searching for:
- "King Agar A composition" / "King's Medium A formula"
- "pyocyanin detection medium Pseudomonas aeruginosa"
- "King A vs King B agar difference"
- "Pseudomonas Agar P equivalent Australia"
- "BD Difco DF0449 alternative" / "Sigma 60788 equivalent"
- "buy King Agar A Australia Melbourne"
Technical Data Sheet
| Product Name | King Agar A |
| Synonyms | King's Medium A; Pseudomonas Agar P |
| Catalogue Number | AS-1259 |
| Format | Dehydrated powder (glycerol added separately) |
| Manufacturer | AuSaMicS Pty Ltd, Melbourne, Australia |
Intended Use
Differential medium for confirmation of Pseudomonas aeruginosa by demonstration of pyocyanin (blue-green, non-fluorescent, diffusible pigment) in clinical, water, food, and environmental microbiology.
Mode of Action
Gelatin peptone supplies nitrogen, carbon, sulfur, and trace elements while being deliberately low in phosphate, since excess phosphate inhibits pyocyanin biosynthesis. Potassium sulfate and magnesium chloride are the specific activating cations required for pyocyanin production. Glycerol serves as the carbon source supporting pigment expression. The medium is differential rather than selective: essentially any organism able to grow will do so, but only pyocyanin producers (chiefly P. aeruginosa) generate the diagnostic diffusible blue-green zone.
Formulation (per litre)
| Ingredient | Quantity | Function |
|---|---|---|
| Gelatin Peptone (pancreatic digest) | 20.0 g | Nitrogen/carbon source, low phosphate |
| Potassium Sulfate (K₂SO₄) | 10.0 g | Pyocyanin-activating cation |
| Magnesium Chloride (MgCl₂, anhydrous) | 1.4 g | Pyocyanin-activating cation |
| Agar | 15.0 g | Solidifying agent |
| Glycerol (added separately) | 10.0 mL | Carbon/energy source for pigment expression |
Final pH: 7.2 ± 0.2 at 25°C. Total dehydrated components: 46.4 g/L (excluding glycerol).
Formulation verified against BD Difco (DF0449-17-0), Sigma-Aldrich (60788), and HiMedia (M1543) current technical documentation. Uses magnesium chloride, consistent with the original King, Ward & Raney (1954) formula — not magnesium sulfate, which is specific to King B medium.
Preparation
Suspend 46.4 g dehydrated medium in 990 mL purified water. Add 10 mL glycerol. Heat with frequent agitation and boil for 1 minute to dissolve completely. Autoclave at 121°C for 15 minutes. Cool to 45–50°C, mix well, and pour plates.
Incubation Conditions
| Parameter | Condition |
|---|---|
| Temperature | 35 ± 2°C |
| Time | 18–24 hours (routine); reincubate at 25–30°C for 24–48h if pigment is weak |
| Atmosphere | Aerobic |
| Reading | Daylight; no UV required |
Quality Control — Cultural Response
| Organism | ATCC No. | Inoculum (CFU/plate) | Expected Result |
|---|---|---|---|
| Pseudomonas aeruginosa | 27853 | ≤ 100 | Good growth; strong diffusible blue-green pyocyanin pigment |
| Pseudomonas fluorescens | 13525 | ≤ 100 | Growth without pyocyanin (differential control) |
| Escherichia coli | 25922 | ≤ 100 | Growth may occur without characteristic pigment (negative control) |
Storage & Shelf Life
| Dehydrated medium | Below 30°C, tightly closed, protected from moisture/light — 24 months |
| Prepared plates | 2–8°C, protected from light — use within 4 weeks |
Literature & References
- King, E.O., Ward, M.K., Raney, D.E. (1954). Two simple media for the demonstration of pyocyanin and fluorescin. Journal of Laboratory and Clinical Medicine, 44(2), 301–307.
- Murray, P.R., Baron, E.J., Jorgensen, J.H., Pfaller, M.A., Yolken, R.H. (Eds.) (2003). Manual of Clinical Microbiology, 8th Ed. ASM Press, Washington DC.
- MacFaddin, J.F. (1985). Media for Isolation-Cultivation-Identification-Maintenance of Medical Bacteria, Vol. 1. Williams & Wilkins, Baltimore.
For laboratory, clinical, food, environmental, and water microbiology use only. Not intended for in vivo diagnostic use. AuSaMicS Pty Ltd accepts no liability for results obtained outside the stated preparation and storage conditions.
Safety Data Sheet — Summary
This is a summary view. The full 16-section GHS-compliant Safety Data Sheet (Australian format) is provided as a downloadable Word document alongside this page.
| Product Name | King Agar A, AS-1259 |
| Recommended Use | Laboratory culture medium (dehydrated) |
| Manufacturer | AuSaMicS Pty Ltd, Melbourne, Victoria, Australia |
| GHS Classification | Not classified as hazardous per Safe Work Australia criteria |
| Signal Word | None allocated |
Hazard Summary
Not classified as a hazardous chemical or dangerous good under Safe Work Australia / GHS criteria in its dehydrated form. May cause mechanical irritation to eyes and respiratory tract as a fine powder. Glycerol supplement (added separately by the user) is a low-hazard liquid; refer to its own SDS if supplied separately.
First Aid
| Route | Response |
|---|---|
| Inhalation | Move to fresh air. Seek medical attention if irritation persists. |
| Skin Contact | Wash with soap and water. |
| Eye Contact | Rinse thoroughly with water for several minutes. Seek medical advice if irritation persists. |
| Ingestion | Rinse mouth. Seek medical advice if unwell. |
Full SDS (16 GHS sections, handling, disposal, transport and regulatory information) is provided as a separate Word document — see downloads.
Certificate of Analysis — Sample Format
Each batch is supplied with a lot-specific Certificate of Analysis. A representative COA is provided as a downloadable Word document; the batch-specific COA accompanies your shipment.
| Product Name | King Agar A |
| Catalogue Number | AS-1259 |
| Batch/Lot Number | Assigned per production batch |
| Manufacture Date | Assigned per production batch |
| Retest / Expiry Date | 24 months from manufacture |
Quality Control Results (Representative)
| Test | Specification | Result |
|---|---|---|
| Appearance (powder) | Straw-coloured, homogeneous, free-flowing | Conforms |
| Final pH (25°C) | 7.2 ± 0.2 | Conforms |
| Gel firmness | Firm, clear gel | Conforms |
| P. aeruginosa ATCC 27853 pigment | Strong blue-green pyocyanin, ≤100 CFU inoculum | Conforms |
| P. fluorescens ATCC 13525 | Growth without pyocyanin | Conforms |
| Sterility (uninoculated control) | No growth | Conforms |
This tab shows a representative format. The lot-specific Certificate of Analysis issued with your order carries the actual batch number, manufacture/expiry dates, and signed QC results.
The information provided is accurate to the best of AuSaMicS Pty Ltd's knowledge at the time of publication. Product specifications may be updated without notice. For laboratory, clinical, food, environmental, and water microbiology use only. Users should verify suitability for their specific application prior to use.