Botulism Selective Medium (BSM) is a selective and differential medium for the presumptive identification of Clostridium botulinum from food or clinical samples.
Botulism Selective Media – BSM
Product Description & Summary
BSM agar is a selective and differential media used for the presumptive identification of Clostridium botulinum from food or fecal samples. BSM contains cycloserine, sulfamethoxazole, and trimethoprim as selective inhibitory agents. A suspension of egg yolk is added for the detection of lecithinase, lipase, and proteolytic activity. The degradation of lecithin in the egg yolk results in an opaque precipitate around the colonies. Lipase destroys the fats within the egg yolk, which results in an iridescent sheen on the colony surface. Proteolytic activity is indicated by a clearing of the medium around the colonies. This medium is dispensed under oxygen-free conditions to prevent the formation of oxidized products prior to use.
Interpretation of Results & Limitations
BSM supports good growth of Clostridium botulinum from food or clinical infections. This medium supports the typical lecithinase and lipase reactions produced by some Clostridia species. Degradation of lecithin in the egg yolk, from lecithinase positive organisms, results in an opaque precipitate surrounding the colonies. Destruction of the fats within the egg yolk, from lipase positive organisms, results in an iridescent sheen on the colony surface.
BSM will not provide complete information for identification of bacterial isolates. Additional test procedures and media are required for complete identification. It is recommended that a non-selective media, such as Brucella Blood Agar (BRU, Cat. #: AS-111) also be inoculated from the same clinical specimen to assure recovery of all species present. Consult reference materials for additional information.
The following organisms are routinely used for quality assurance testing at Anaerobe Systems.
|Organism Tested||ATCC #||Results||Time||Special Reaction|
|Bacteroides fragilis||25285||No Growth|
|Fusobacterium necrophorum||25286||No Growth|
|Fusobacterium nucleatum||25586||No Growth|
|Clostridium perfringens||13124||Inhibited||Lecithinase reaction|
|Clostridium novyi||7659||No Growth|
|Clostridium sporogenes||3584||Growth||24 – 48 hours||Lipase reaction|
|Propionibacterium acnes||6919||No Growth|
|Peptostreptococcus anaerobius||28337||No Growth|
|Escherichia coli||25922||No Growth|
|Staphylococcus aureus||25923||No Growth|
Product Storage & Shelf Life
Storage: Upon receipt, store at room temperature in original package until used. Avoid overheating or freezing. Do not use media if there are signs of deterioration (shrinking, cracking, or discoloration due to oxidation of media) or contamination. The expiration date applies to the product in its original packaging and stored as directed. Do not use product past the expiration date shown on the label.
Shelf Life: 90 days from date of manufacture.