A study of 2 rapid tests to differentiate Gram positive and Gram negative aerobic bacteria

293 aerobic bacterial pathogens were isolated from various clinical samples. All the isolates were subjected to Gram stain (GS), potassium hydroxide (KOH) string test, and Vancomycin susceptibility test. All Gram negative bacilli i.e. 100%, showed resistance to Vancomycin and KOH string test positivity (p=0.000). 97.8% of gram positive bacteria were sensitive to Vancomycin and 100% were KOH string test negative (p=0.000). As KOH string test and Vancomycin tests are simple and inexpensive, these can be used in addition to Gram staining, for rapid identification of bacterial isolates.