Reinforced Clostridial Agar (RCA)

EMD Cat. No. 1.05410.0500
500 g


Medium proposed by BARNES and INGRAM (1956) for the cultivation and enumeration of clostridia, other anaerobes and facultative microorganisms in foodstuffs and other materials.
MUNOA and PARES (1988) developed a Bifidobacterium Iodoacetate Medium (BIM-25) on the basis of Clostridial Agar for the selective cultivation and differentiation of Bifidobacterium species.
Additives

EMD Cat. No. Product Pack Size
1.10641.0007 Anaerocult® A mini 1 x 25
1.06994.0001 Polymyxin-B-sulfate
13674 Plate basket 1ea
Anaerocult® P 1 x 25
1.13829.0001 Anaerocult® A 1 x 10
14255 Anaeroclip® 1 x 25
1.13675.0001 Anaerotest® 1 x 50
1.16387.0001 Anaerobic jar 1 ea

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



Mode of Action
 This culture medium is free from inhibitors and contains cysteine as a reducing agent. According to HIRSCH and GRINSTED (1954), Polymyxin B can be added to inhibit Gram-negative bacteria.

Preparation
 Suspend 50 g/liter, if desired dispense into test tubes, autoclave (15 min at 121 °C). If required, cool to 45-50 °C and add 0.02 g Polymyxin B/liter in form of a filter-sterilized aqueous solution.
pH: 6.8 ± 0.2 at 25 °C.
 The medium in the tubes or Petri dishes is clear and yellowish-brown.

Experimental Procedure and Evaluation
 Prepare stab cultures of the sample material in test tubes or use the pour-plate technique.
Incubation: 24-48 hours at an optimal temperature (e.g. 35 °C) under anaerobic conditions (e.g. Anaerocult® A, Anaerocult® A mini, or Anaerocult® P).
Count the colonies and, if necessary, perform additional tests.
Quality control

Test strains
 Growth
Clostridium bifermentans ATCC 19299
 		good / very good
Clostridium difficile 15
 		good / very good
Clostridium histolyticum HW-6
 		good / very good
Clostridium perfringens ATCC 13124
 		good / very good
Clostridium perfringens ATCC 10543
 		good / very good
Escherichia coli ATCC 25922
 		good / very good
Bacillus cereus ATCC 11778
 		good / very good

Typical Composition (g/liter)
 Meat extract 10.0; peptone from casein 10.0; yeast extract 3.0; D(+)glucose 5.0; starch 1.0; sodium chloride 5.0; sodium acetate 3.0; L-cysteinium chloride 0.5; agar-agar 12.5.
Literature

BARNES, E.M., a. INGRAM, M.: The effect of redox potential on the grown Clostridium welchii strain isolated from horse muscle. J. Appl. Bact., 19; 177-178 (1956).
 HIRSCH, A., a. GRINSTED, E.: Methods for the growth and enumeration of anaerobic sporeformers from cheese, with observations on the effect of nisin. J. Dairy Res., 21;101-110 (1954).
 MUNOA, F.J., a. PARES, R.: Selective medium for isolation and enumeration of Bifidobacterium spp. Appl. Environm. Microbiol., 54; 1715-1718 (1988).