ABSTRACT
Altered cut-off MICs after addition of test drug at a sub-MIC effective concentration with bacterial emulsion fluid has been noted for combination effect study by VITEK for a new drug with all commonly used drugs. A shifting from R to S range can be considered as synergism indicator. Thus tests with several resistant strains bacteria may give interaction results for all drugs. Wide range nonspecific synergism of silver nanoparticles (AgNPs) with different antibiotics were demonstrated by conventional microbroth dilution method. For all practical purpose, an indicative break point synergism with sub-MIC AgNPs and batteries of antibiotics against different multi drug -resistant strain bacteria or yeast can be performed more reliably, using automated susceptibility testing device than manually performed checkerboard method.
