(AB) Lauryl Sulfate Broth With Mug 500G

Lauryl Sulfate Broth was formulated by Mallmann and Darby for detection of coliform bacteria in water. This is a selective medium because it contains sodium lauryl sulfate which inhibits Gram positive microorganisms. Lactose is added to detect rapid lactose fermentation by coliforms. The addition of 4- methylumbelliferyl-B-D-glucuronide (MUG) to Lauryl Sulfate Broth allows for the rapid detection (4-24 hours) of E. coli-When the incubated medium is observed for fluorescence using a long-wave UV light (365 nm) source. It can also detect anaerogenic E-coli strains. Most strains of E. coli produce B-glucuronidase which hydrolyzes MUG to the fluorogenic compound 4- methyl-umbelliferone. Studies by Feng and Hartman noted that most E coli strains (96%) and all enterotoxigenic E coli strains (100%) and a moderate number of Salmonella (17%) and Shigella (40%) stains produce B-glucuronidase. False positives can also be caused by Streptococcus sp. Selective broth medium used to detect the presence of Escherichia coli in water and food samples by a fluorogenic procedure. (Alpha Biosciences # L12-107-500gm)

Use: Selective broth medium used to detect the presence of Escherichia coli in water and food samples by a fluorogenic procedure.

Description: Lauryl Sulfate Broth was formulated by Mallmann and Darby for detection of coliform bacteria in water. This is a selective medium because it contains sodium lauryl sulfate which inhibits Gram positive microorganisms. Lactose is added to detect rapid lactose fermentation by coliforms. The addition of 4- methylumbelliferyl-B-D-glucuronide (MUG) to Lauryl Sulfate Broth allows for the rapid detection (4-24 hours) of E. coli-When the incubated medium is observed for fluorescence using a long-wave UV light (365 nm) source. It can also detect anaerogenic E-coli strains. Most strains of E. coli produce B-glucuronidase which hydrolyzes MUG to the fluorogenic compound 4- methyl-umbelliferone. Studies by Feng and Hartman noted that most E coli strains (96%) and all enterotoxigenic E coli strains (100%) and a moderate number of Salmonella (17%) and Shigella (40%) stains produce B-glucuronidase. False positives can also be caused by Streptococcus sp.

Formula* per Liter:

• Casein Digest Peptone ............. 20.0g
• Potassium Phosphate, Monobasic. 2.75g
• Lactose .......................................... 5.0g
• Potassium Phosphate, Dibasic....... 2.75g
• Sodium Chloride ............................5.0g
• Sodium Lauryl Sulfate ........................ 0.1g
• MUG ............................................. 0.05g.

Final pH: 6.8 ± 0.2 at 25.0°C

* Grams per liter may be adj. or formula supplemented to obtain desired performance

Preparation: Mix 35.7 grams of the medium in one Liter of purified water until evenly dispersed. Prepare double strength broth for evaluating 10 mL samples. Distribute into test tubes containing inverted Durham tubes and autoclave at 121.0°C for 15 minutes.

Quality Control Specifications:

• The powder is homogeneous, free flowing and light beige.
• Visually the prepared medium is yellow to gold and clear to trace hazy.
• Expected cultural response after 18-24 hours at 35.0°C.

Organism                                                                    Result

Escherichia coli ATCC 25922                    Growth, Gas +, Fluorescence +

Proteus mirabilis ATCC 12453                   Growth, Gas -, Fluorescence -

Staphylococcus aureus ATCC 25923                         No Growth

Storage: Store the sealed bottle containing the dehydrated medium at 2 to 30.0°C. Once opened and recapped, place the container in a low humidity environment at the same storage temperature. Protect it from moisture and light. The dehydrated medium should be discarded if it is not free flowing or if the color has changed from the original light beige color.