Thermo Scientific™ Remel™ BactiDrop™ Desoxycholate

Thermo Scientific™ Remel™ BactiDrop™ Desoxycholate (10%) is a ready-to-use liquid reagent designed for the detection of bile solubility to differentiate Streptococcus pneumoniae from other bile-insoluble alpha-hemolytic streptococci.

The bile solubility test is a classical confirmatory method in clinical microbiology. When 10% sodium desoxycholate is applied, S. pneumoniae cells undergo lysis due to bile-induced disruption of the cell membrane and activation of autolytic processes. Other alpha-hemolytic streptococci remain intact, enabling rapid differentiation.

This product is CE marked and intended for use in clinical microbiology laboratories.

Principle of the Method

The test is based on the susceptibility of Streptococcus pneumoniae to bile salts.

When 10% desoxycholate is applied:

• Pneumococcal cells lyse due to membrane derangement and surface tension changes at the medium–membrane interface.
• Other alpha-hemolytic streptococci and Gram-positive cocci do not lyse under the same conditions.

S. pneumoniae possesses an autolytic intracellular enzyme that causes rapid self-lysis when cultivated on artificial media. The action of bile salts facilitates this lytic response, producing a clear and interpretable reaction.

Test Formats and Interpretation

Spot Test (Colony Test on Blood Agar)

Positive Result:

Colony disintegration within 30 minutes.

Negative Result:

Colony remains intact within 30 minutes.

Tube Test (Broth Suspension Method)

Positive Result:

Clearing of the test suspension within 3 hours; control suspension remains turbid.

Negative Result:

Both test and control suspensions remain turbid within 3 hours.

Reagent Composition

Each vial contains:

• 10% w/v sodium desoxycholic acid
• Ethanol
• Sodium Merthiolate
• Demineralized water

Product Specifications

Applications

• Clinical microbiology laboratories
• Hospital diagnostic laboratories
• Identification of pneumococcal isolates
• Confirmation testing of alpha-hemolytic colonies from blood agar
• Respiratory specimen isolate differentiation

Storage and Handling

Store at 20°C to 25°C.

For professional laboratory use only.

Refer to product documentation for complete instructions.

Thermo Scientific Remel BactiDrop Desoxycholate (10%) provides a reliable, ready-to-use solution for bile solubility testing in clinical microbiology. With clear spot and tube test interpretations, it enables rapid differentiation of Streptococcus pneumoniae from other alpha-hemolytic streptococci, supporting accurate identification and patient management decisions.