BAIRD-PARKER Agar Base

EMD Cat. No. 1.05406.0500/5007
500 g, 5 kg


For the isolation and enumeration of Staphylococcus aureus in foods and pharmaceutical materials according to BAIRD-PARKER (1962).

This culture medium complies with the recommendations of the United States Pharmacopeia XXIII (1995), the European Pharmacopeia II, the International Organization for Standardization (ISO) (1977, 1984), the International Dairy Federation (Internationaler Milchwirtschaftsverband) (1978) and the DIN Norms 10163 and 10178.



Mode of Action Preparation
Experimental Procedure and Evaluation Quality Control
Typical Composition (g/liter) Literature
Picture/Image  


Mode of Action
 This medium contains lithium chloride and tellurite to inhibit the growth of accompanying microbial flora, whereas pyruvate and glycine selectively stimulate the growth of staphylococci.
 Staphylococcus colonies show two characteristic features when grown in this opaque medium (opaque, because of its egg-yolk content)
 a) characteristic zones and rings are formed as a result of lipolysis and proteolysis,
 b) reduction of tellurite to tellurium produces a black coloration.
 The egg-yolk reaction and tellurite reduction are usually found to occur together with a positive coagulase reaction and can thus serve as an index for the latter.
 STADHOUDERS et al. (1976) recommend that egg-yolk should be replaced with blood plasma, if coagulase-positive staphylococci are to be detected directly.
 SMITH and BAIRD-PARKER (1964) recommend the addition of sulfamethazine to suppress the growth and swarming of Proteus species.


Typical Composition (g/liter)
 Peptone from casein 10.0; meat extract 5.0; yeast extract 1.0; sodium pyruvate 10.0; glycine 12.0; lithium chloride 5.0; agar-agar 15.0.
 Also to be added:
 Egg-yolk tellurite emulsion 50 ml; if required, sulphamethazine 0.05 g/l.

Preparation
 Suspend 58 g in 0.95 liter, autoclave (15 min at 121°C). Cool to 45-50°C, mix in 50 ml Egg-yolk Tellurite Emulsion and, if required, 50 mg sulfamethazine/liter. Pour plates.
 pH: 6.8 ± 0.2 at 25°C.

The plates are opalescent and yellowish-brown in color.

The ready-to-use culture medium can be stored in the refrigerator (approx. 4°C) for up to 1 month.

Experimental Procedure and Evaluation
 Dilute the sample material and spread thinly on the surface of the culture medium.
 Incubation: 24-48 hours at 35°C aerobically.
Appearance of Colonies
 		Microorganisms
Black, shiny, convex colonies 1-5 mm in diameter with a narrow, white edge surrounded by a clear zone 2-5 mm wide. Opaque rings within the clear zones only appear after 48 hous of incubation
 		Staphylococcus aureus
Black, shiny, irregular shape. Opaque zone develop around the colonies after 24 hours.
 		Staphylococcus epidermis
Growth sometimes:
 Very small, brown to black, nor clear zones.
Micrococci
Dark brown, dull, clear zones sometimes appear after 48 hours.
 		Bacillus species
White, no clear zones
 		Yeasts


Quality control (spiral plating method)

Test strains
 Inoculum
 (cfu/ml)
 		Recovery rate (%)
 		Black colonies
 		Clear zones round the colonies
Staphylococcus aureus ATCC 25923
 		10³-105
 		>= 70
 		+
 		+
Staphylococcus aureus ATCC 6538-P
 		10³-105
 		>= 70
 		+
Staphylococcus aureus ATCC 6538
 		10³-105
 		>= 70
 		+
 		+
Staphylococcus epidermidis NCTC 11047
 		10³-105
 		Not limited!
 		black-grey
 		-
Enterococcus hirae ATCC 8043
 		10³-105
 		Not limited!
 		black-grey
 		-
Bacillus subtilis ATCC 6051
 		> 105
 		<= 0.01

Escherichia coli ATCC 8739
 		> 105
 		<= 0.01

Proteus mirabilis ATCC 29906
 		10³-105
 		Not limited!
 		brown-black
 		-
Pseudomonas aeruginosa ATCC 9027
 		> 105
 		<= 0.01

Salmonella typhimurium ATCC 14028
 		> 105
 		<= 0.01



Additives

EMD Cat. No. Product Pack Size
1.03785.0001 Egg-yolk Tellurite Emulsion 10 x 50 ml
1.11351.0001 Bactident® Catalase 1 x 30 ml
Manufacturer
 		Product
e.g. International Chemical Industries Ltd., U.K.
 		Sulfamethazine

Literature

BAIRD-PARKER, A.C.: An improved diagnostic and selective medium for isolating coagulase positive Staphylococci. - J. Appl. Bact., 25; 12-19 (1962).
 DIN Deutsches Institut für Normung e.V.: Nachweis Koagulase-positiver Staphylokokken. Referenzverfahren für Milchpulver. - DIN 10178.
 DIN Deutsches Institut für Normung e.V.: Nachweis Koagulase-positiver Staphylokokken. Referenzverfahren für Milchpulver. - DIN 10163.
 European Pharmacopeia II, Chapter VII, 10.
 Internationaler Milchwirtschaftsverband; Nachweis Koagulase-positiver Staphylokokken (Referenzmethode). - Internationaler Standard 60 A (1978).
 ISO International Organization for Standardization: Dried milk. Enumeration of Staphylococcus aureus. Colony count technique. - Draft Proposal ISO/PP 8869 (1984).
 ISO International Organization for Standardization: Meat and meat products - Detection and enumeration of Staphylococcus aureus (Reference methods). - Draft Interantional Standard ISO/DIS 5551 (1977).
 NISKANEN, A., a. AALTO, M.: Comparison of selective media for coagulase-positive enterotoxigenic Staphylococcus aureus.- Appl. Envir. Microbiol., 35; 1233-1236 (1978).
 SMITH, B.A., a. BAIRD-PARKER, A.C.: The use of sulfamethazine for inhibiting Proteus spp. on Baird-Parker's isolation medium for Staphylococcus aureus. - J. Appl. Bact., 27; 78-82 (1964).
 STADHOUDERS, J., HASSINGS, F., a. VAN AALSTEN-VAN MAREN, N.O.: A pour-plate method for the detection and enumeration of coagulase-positive Staphylococcus aureus in the BAIRD-PARKER Medium without egg-yolk. - Netz. Milk Diary J., 30; 222-229 (1976).
 United States Pharmacopeia XXIII, Chapter "Microbial limit Tests", 1995.
 ISO/FDIS: Microbiology of food and animal feeding stuffs - Horizontal method for the enumeration of coagulase-positive staphylococci (Staphylococcus aureus and other species) - Part 1: Technique using Baird-Parker agar medium. Final Draft ISO/FDIS 6888-1 (1998).


Staphylosoccus aureus



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