Tryptone soya agar

Test Procedure. The test organisms were subcultured onto Tryptone Soya Agar (TSA) slopes and incubated at 37 °C for 24 hours. After incubation for each inoculum, 6 ml sterile distilled water (SDW) was added to each slope in turn, the organisms washed off and the resultant suspension homogenised. A 1 ml aliquot of the suspension was added to 100 mis SDW and homogenised to form the inoculum. 

Inoculate the surface of tryptone soya agar slant for bacteria and Sabouraud dextrose agar slant for fungi from recently revived stock culture of each of the test microorganisms. 

Promptly pour into each petri dish about 15 to 20 ml of sterile melted tryptone soya agar medium previously melted and cooled to approximately 45°C. 

Note TSA = tryptone soya agar SDA = Sabouraud dextrose agar. 

Erwinia herbicola NCIMB 12126 was obtained from the National Collection of Industrial and Marine Bacteria (Aberdeen, UK), HEPES buffer sachets and magnesium acetate were obtained from Sigma (Poole, UK), adenylate kinase assay kits were obtained from Acolyte Biomedica (Salisbury, UK), sterile tissue culture grade distilled water was obtained from Gibco (Paisley, UK), L-broth and tryptone soya agar plates were obtained from Oxoid (Basingstoke, UK). 

The plate counts at To were estimated by diluting the neat broth culture 1 in 10 with Neutralised Peptone Water (NPW) containing per L 1.0 g Bacteriological Peptone (Oxoid, L37), 8.8 g Sodium Chloride (May Baker), 3.0 g Amisol 910 (Degussa) and 30.0 g Tween 80 (BDH, 560234H) and then decimally with Phosphate Buffered Saline (Oxoid). For biocide treated samples 1 mL was diluted in 9 mL of NPW, mixed and allowed to stand for 5 min (for neutralisation of the biocide). The solution in NPW was diluted decimally (0.1 mL in 0.9 mL) in PBS. Appropriate dilutions (0.1 mL) were plated out on Tryptone Soya Agar Plates (bioMerieux) and incubated at 37 °C for 24 h. 

Coded and dated, sterile, tryptone soya agar plates should be exposed for two hours at all test sites within the isolator. These should be incubated in accordance with a written SOP at the appropriate temperature for up to five days, or as otherwise chosen by the microbiologist... 

Both organisms were grown in TSB medium, consisting of Tryptone Soya Broth (Oxoid Ltd. 3%, w/v) supplemented with inorganic ions and vitamins as described by Abbas-Ali and Coleman (1977). Batches of medium (50ml), contained in 250 ml conical flasks, were inoculated with bacteria from Tryptone Soya Agar (Oxoid Ltd.) slopes by means of a platinum loop. The cultures were incubated in a "Gyratory" incubator-shaker (model G25, New Brunswick Scientific Co., New Brunswick, N.J., U.S.A.) at 37 C in the case of S. aureus and 25 C for A. salmonicida. 

Fig. 2. Thermal survival characteristics of S. senftenberg 755W at 60 °C in O, the centre of 3-cm cubes of beef , ground beef A, phosphate buffer (0067 M), pH 70), All menstrua were pre-equilibrated to 60 C and held in 10 g quantities in sterile, polyethylene stomacher bags. Aliquots of washed cell suspensions (previously grown at 37 °C in tryptone soya broth) were added by sterile syringe. Survivors were enumerated on tryptone soya agar.

Two strains were isolated which, unlike the normal expectation of nutritionally fastidious renibacteria, could grow on tryptone soya agar (TSA) and brain heart infusion agar, and were non-pathogenic in Atlantic salmon (Daly et al., 2001). When evaluated as live vaccines, the culture which grew on TSA (= Rs TSAI) led to an RPS of 50 and 74% at 74 and 60 days after challenge, respectively (Daly et al., 2001). 

Inoculate a sample of the bacterium from an agar slope into a medium of 9 mL Tryptone Soya Broth or Nutrient Broth and incubate overnight in an orbital shaker at 37°C. 

Media are prepared to defined formulations using requisite amounts of appropriate chemicals. Many of the more commonly used media, such as nutrient broth, tryptone soya broth, malt agar, and potato dextrose agar, are available in pre-mixed dehydrated form from various specialist suppliers. Any components of media that are heat-sensitive must be added to the remainder of the medium after it has been heat-sterilized by autoclaving this is normally done by syringing in these particular components as concentrated aqueous solutions through disposable sterile filter units available from various specialist suppliers. 

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