Em. Powers, EFFICACY OF THE RYU NONSTAINING KOH TECHNIQUE FOR RAPIDLY DETERMININGGRAM REACTIONS OF FOOD-BORNE AND WATERBORNE BACTERIA AND YEASTS, Applied and environmental microbiology, 61(10), 1995, pp. 3756-3758
A simple and rapid (< 60 s) nonstaining technique with 3% potassium hy
droxide to determine Gram reactions was tested with 495 food-borne and
waterborne bacteria and yeasts. In KOH, suspensions of gram-negative
bacteria become viscous and string out. Gram-positive bacteria are not
affected. There was 100% correlation between the KOH string test resu
lts and gram-positive and gram-negative strains.