Development of phage-based assay to differentiate ciprofloxacin resistant and sensitive Salmonella Typhimurium

Abstract

This study was designed to evaluate the possibility of using phage-amplification assay for discriminating between antibiotic-sensitive and antibiotic-resistant Salmonella Typhimurium. The characteristics of Salmonella phage PBST32 were determined by adsorption rate, one-step growth curve, and lytic activity. The ability of phage-based method to detect S. Typhimurium ATCC 19585 (ST CIP ) was determined in single culture and bacterial mixtures of S . Typhimurium ATCC 19585 (ST WT ), Klebsiella pneumoniae , and Staphylococcus aureus . The adsorption rates of PBST32 were 95% and 93% against ST WT and ST CIP after 20\xa0min, respectively. The PBST32 showed latent period of 20\xa0min and average burst size of 90 against ST WT and ST CIP . The ST CIP was selectively detected in mixtures of S . aureus , K . pneumoniae , and ST WT by phage amplification assay. These results provide useful information for designing phage amplification method that can differentially detect antibiotic-resistant pathogens.