Trypticase soy agar

Trypticase soy agar (TSA) in bottles and prepoured in sterile petri dishes... 

Trypticase soy agar and Sabouraud s agar, in petri dishes, were streaked with E. coli and Aspergillus sp. and placed on top of books packed on the cart. The cart was placed in the chamber and exposed to ethylene oxide for 4 hr. These petri dish samples were used for a special part of the second series of experiments. 

At the sampling times, a sterile stainless steel cylinder (inside area = 3.56 cm ) was held firmly to the skin area to be sampled. Five milliliters of sterile stripping fluid, consisting of 0.1% Triton X-100 in 0.1 mol/L phosphate-buffered saline solution (pH 7.8), was added to the cylinder, and the skin area inside the cylinder was massaged in a circumferential manner with a sterile rubber policeman for 2 minutes. One-milliliter aliquots of this solution (10-fold dilution) were removed and plated—with 10°, 10, 10 10 and lO dilutions, as appropriate— in triplicate on trypticase soy agar containing 1.0% Tween 80 and 0.3% lecithin as neutralizers. 

Blood agar plates Adjust trypticase soy agar base to pH 6.0 and then autoclave. Cool sterilized agar in a 50 °C water bath. Add defibrinated sheep blood to 5% final concentration immediately prior to pouring plates. Store at 4 °C. 

Dilute the suspension of bacteria removed form the catheter, plate on trypticase soy agar, and incubate at 37 °C for colony counting. 

Pseudomonas aeruginosa (isolated from soil, George Mason University culture collection) was grown on Trypticase Soy Agar (Difco) slants. Incubation temperature in both cases was 26 C. 

To detect low levels of bacteria that might be missed with the quantitative technique, 5 pL of a biological fluid is inoculated into 5 mL of trypticase-soy broth and incubated overnight at 37°C. If bacterial growth is identified, the colonies are seeded onto a tryptic soy blood-MacConkey agar plate for further identification. 

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