We evaluated carboxyfluorescein diacetate succinimidyl ester (CFDA-SE) and carboxyfluorescein diacetate (CFDA) for use in fluorescence labeling and a viability test for Mycobacterium avium subsp. paratuberculosis (Map). The results showed that CFDA selectively stained live Map; however, CFDA-SE stained live and heat-killed Map. These results clearly demonstrated that CFDA can be used for a viability test of the bacilli. The staining with CFDA or CFDA/SE works well as a fluorescence probe to detect Map in milk or in cells under a fluorescent microscope. This method provided a substantial advantage in the viability check and evaluation of antibacterial drag, since it usually takes 2 to 3 months to determine the results of a viability test done by bacterial isolation.
(Paratuberculosis and Inflammatory Bowel Disease Research Team, Department of Planning and Coordination TEL +81-29-838-7781)
