M439-10

Microbial Viability Assay Kit-WST #Unit: 500 tests

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Description:

Storage: 0-5 ºC

Shipping Condition: Ambient Temperature

Chemical Name:

CAS Number:

Features:
-Convenient 96-well microplate colorimetric assay
-Wide variety of microorganism detection
- No harvesting or washing required

Microbial Viability Assay Kit-WST is utilized for bacteria and Fungi viability determination. This kit contains WST-8 and electron mediator. WST-8 (2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium, monosodium salt) produces a water-soluble formazan dye upon bioreduction in the presense of an electron mediator (Fig. 2-12). Absorbance spectrum of WST-8 formazan dye is shown in Fig. 2-13. Since the assay solution is stable in culture medium, it can be added directly to maicrobial cell culture and incubated for 1-2 hours or overnight if necessary. The microbial cell viability can be determined as 450 nm absorbance.

Assay principle:

Antimicrobial Susceptibility Test of Staphylococcus aureus to Oxacillin:
Organisms Methicilin-resistant Staphylococcus aureus subsp. aureus ( MRSA ) Staphylococcus aureus ( SA ) Antimicrobial agent Oxacillin (beta-lactam antibiotic of the penicillin class) Procedure 1. Culture MRSA and SA with Mueller-Hinton broth containing various concentrations of Oxacilin for 6 hours at 35oC.2. Add coloring solution (Microbial Viability Assay Kit-WST) equal to 1/20 volume of the culture medium.3. Incubate for 2 hours at 35oC.4. Measure the O.D. at 450 nm to determine the MIC (Minimum Inhibitory Concentration).

The data indicates that MRSA has lower susceptibility than SA.The MICs of MRSA and SA can be determined as 32 mg/ml and 0.5 mg /ml, respectively. They are close to the MICs determined by CLSI (Clinical Laboratory Standards Insutitute) method.

Determination of the initial number of viable E. coli cells:
1. Culture E. coli with Mueller-Hinton medium.2. Add Microbial Viability Assay solution with 1/20 volume of the culture medium to the E. coli culture3. Measure the O.D. every 25 min at 450 nm.* Data indicates the correlation between the initial number of E. coli and time-dependent O. D. increase.

Influence of culture media or substances used for bacterial cell culture.

The data indicated that WST-8 is less sensitive to various culture media or substances which are used for bacterial cell culture. WST-8 is a better tetrazolium salt than XTT for bacterial cell viability assay.

Applicable organisms

This assay kit was co-developed with Biotechnology and Food Research Institute, Fukuoka Industrial Technology Center.

MSDS
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