Rogosa SL Broth

Rogosa SL Broth is a modification of media described by Rogosa, Mitchell and Wiseman. Rogosa SL Broth is similar to Rogosa SL Agar (LC-1096), but lacks the agar and is very selective due to its high sodium acetate and ammonium citrate concentrations and its low pH, which is very advantageous for the cultivation of lactobacilli and inhibits most microorganisms including streptococci and molds and limits swarming but allows the growth of lactobacilli.

Sucrose, arabinose and dextrose are fermentable carbohydrates as carbon and energy sources. Tryptone provides nitrogen, vitamins, minerals and amino acids essential for growth. Yeast extract is a source of vitamins, particularly of the B-group. Sulfate salts provide inorganic ions; sorbitan monooleate is a surfactant and is incorporated to neutralize phenols, hexachlorophene and formalin. Monopotassium phosphate acts as a buffer system.

Typical formula in g/L, adjusted and/or supplemented as required to meet performance criteria.

Preparation

Suspend 60 grams of the medium in one liter of distilled water. Mix well and dissolve by heating with frequent agitation. Boil for one minute until complete dissolution. Add 1.32 mL of glacial acetic acid and mix well. Distribute in tubes and heat again at 90-100 °C for 2-3 minutes. DO NOT AUTOCLAVE.

Instructions for use

1. Insert a loopful or swab with the inoculum into the medium and move the loop back and forth several times.
2. Incubate the broth culture at 35 ± 2 °C for 18-48 hours.
3. Reading and interpretation of the results.

• Rogosa, M. J. A. Mitchell and R.F. Wiseman. 1951 A selective medium for the isolation and enumeration of oral and fecal lactobacilli. J. Dental Res. 30:682.
• MacFaddin, J. D. 1985. Media for isolation-cultivation-identification-maintenance of medical bacteria, vol. 1. p. 678-680. Williams & Wilkins, Baltimore, MD.