Thermo Scientific™ MUG Disk

Description

• Presumptively identify Escherichia coli by fluorogenic assay procedure using Thermo Scientific™ Remel™ MUG Disk
• In 1976, Kilian and Bulow reported the enzyme β-glucuronidase is present in most strains of E
• coli (97%) 1
• The substrate, 4-methylumbelliferyl- β-D-glucuronide (MUG), is found to be both sensitive and selective for detection of β-glucuronidase activity
• Trepeta and Edberg used the MUG test in conjunction with oxidase, indole, and lactose fermentation for rapid, cost effective identification of E
• coli 2
• Godsey et al
• supported their findings in an evaluation of methods based on microbial enzyme activity profiles 3
• Most strains of E
• coli produce an enzyme β-D-glucuronidase
• In the indole test, the enzyme tryptophanase attacks tryptophan molecule on its side chain, leaving the aromatic ring in the form of indole
• The indole is then detected by addition of ρ-dimethylamino-benzaldehyde (Kavocs’ Reagent) which produces a red color
• β-D-glucuronidase is an enzyme that cleaves the substrate 4-methylumbelliferyl-β-D-glucuronide (MUG) and thereby produces a fluorescent product called methylumbelliferone 4
• This compound is detectable using a long wave ultraviolet light (360 nm)
• Ready to use - 4-methylumbelliferyl- β-D-glucuronide-impregnated disk Easy to store - No special storage required Easy to interpret - With visual inspection In MUG Disk test, examine the disk for fluorescence using a longwave ultraviolet light (360nm) in a darkened room
• Blue fluorescence is interpreted as positive test
• In Indole test, add one drop of Kovacs‘ Indole Reagent to the disk and immediately observe for red color development
• Interpretation: MUG Disk Test (Direct or Tube Test): Positive test - Blue fluorescence observed under 360 nm UV light Negative test - No fluorescence observed under 360 nm UV light Indole Test: Positive test - Red color development on the disk or in the tube Negative test - No red color development on the disk or in the tube