Tryptic soy broth

Tryptic soy broth or Trypticase soy broth (frequently abbreviated as TSB) is used in microbiology laboratories as a culture broth to grow aerobic and facultative anaerobic bacteria. It is a general purpose medium that is routinely used to grow bacteria which tend to have high nutritional requirements (i.e., they are fastidious).^[1]

Uses

Sterility test medium in USP and EP as well as for inocula preparation for CLSI standards.^[1]

TSB is frequently used in commercial diagnostics in conjunction with the additive sodium thioglycolate which promotes growth of anaerobes.^[2]

Preparation

To prepare 1 liter of TSB, the following ingredients are dissolved under gentle heat. Adjustments to pH should be made using 1N HCl or 1N NaOH to reach a final target pH of 7.3 ± 0.2 at 25°C. The solution is then autoclaved for 15 minutes at 121°C.^[3]

Tryptic Soy Agar contains per liter:

• 17 g pancreatic digest of casein
• 3 g peptic digest of soybean
• 5 g sodium chloride
• 2.5g dipotassium phosphate (K₂HPO₄)
• 2.5g glucose