Thermo Scientific™ Gram-Sure

Description

• Differentiate aerobic, Gram-negative and Gram-positive rods or coccobacilli with Thermo Scientific™ Remel™ Gram-Sure reagent-impregnated disks
• This is a rapid disk test performed using fluorescent technology
• The Gram stain is generally the first step in the identification of bacteria and decides subsequent identification procedures
• The tendency of some Gram-positive rods to appear Gram-variable or Gram-negative, especially members of the genera Bacillus , Erysipelothrix , Lactobacillus , and Listeria , may often result in misclassification
• Differentiate aerobic, Gram-negative and Gram-positive rods or coccobacilli with Gram-Sure Disks
• Ready to use - Reagent-impregnated disk
• No further prepartion is necessary
• Rapid test - Incubate at room temperature for 5-10 minutes
• Easy to interpret - Gram-negative organisms (blue fluorescence under longwave ultraviolet light) are easy to differentiate from Gram-positive organisms (no fluorescence under longwave ultraviolet light)
• The cell walls of Gram-negative organisms contain aminopeptidase, which is detected by hydrolysis of L-alanine-7-amido-4-methylcoumarin from a non-fluorescent substrate to a fluorescent compound
• In 1976, Cerney reported using L-alanine-4-nitroanilide to detect cell-wall aminopeptidase, which correlated with Gram negativity 1
• In 1990, Manafi and Kneifel evaluated various chromogenic and fluorogenic substrates for the ability to differentiate Gram-positive and Gram-negative bacteria 2
• They recommended using the fluorogenic substrate L-alanine-7-amido-4-methylcoumarin due to its higher test sensitivity and pronounced blue fluorescence indicating a positive reaction
• Gram-Sure disk contains the reactive ingredient L-alanine-7-amido-4-methylcoumarin which exhibits pronounced blue fluorescence and increased test sensitivity
• Aerobic, Gram-negative rods and coccobacilli show a bright blue fluorescence, whereas Gram-positive rods and coccobacilli do not display any fluorescence
• This test is used to serve as an adjunct to the traditional Gram stain method and not a replacement.