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Assessment of altered binding specificity of bacteriophage for ciprofloxacin-induced antibiotic-resistant Salmonella Typhimurium

Kim, Jeongjin, Jo, Ara, Ding, Tian, Lee, Hyeon-Yong, Ahn, Juhee
Archives of microbiology 2016 v.198 no.6 pp. 521-529
Salmonella Typhimurium, adsorption, ampicillin, antibiotic resistance, bacteria, bacterial motility, bacteriophages, beta-lactamase, chloramphenicol, gene expression, gene expression regulation, genes, minimum inhibitory concentration, multiple drug resistance, norfloxacin, pathogens, tetracycline, transporters
This study describes a new effort toward understanding the interaction mechanisms between antibiotic-resistant Salmonella Typhimurium and phages. The antibiotic susceptibility, β-lactamase activity, bacterial motility, gene expression, and lytic activity were evaluated in ciprofloxacin-induced antibiotic-sensitive Salmonella Typhimurium (ASSTCᴵᴾ) and ciprofloxacin-induced antibiotic-resistant S. Typhimurium (ARSTCᴵᴾ), which were compared to the wild-type strains (ASSTᵂᵀ and ARSTᵂᵀ). The MIC values of ampicillin, norfloxacin, chloramphenicol, and tetracycline were significantly increased to > 512, 16, 16, and 256 μg/ml, respectively, in the ARSTCᴵᴾ. The lowest and highest extracellular lactamase activities were observed in ASSTᵂᵀ (6.85 μmol/min/ml) and ARSTCᴵᴾ (48.83 μmol/min/ml), respectively. The acrA, lpfE, and hilA genes were significantly upregulated by more than tenfold in both ASSTCᴵᴾ and ARSTCᴵᴾ. The induction of multiple antibiotic resistance resulted from the increased efflux pump activity (AcrAB-TolC). The highest phage adsorption rates were more than 95 % for ASSTᵂᵀ, ASSTCᴵᴾ, and ARSTᵂᵀ, while the lowest adsorption rate was 52 % for ARSTCᴵᴾ at 15 min of infection. The least lytic activity of phage was 20 % against the ARSTCᴵᴾ, followed by ASSTCᴵᴾ (30 %). The adsorption rate of phage against ARSTCᴵᴾ was 52 % at 15 min of infection, which resulted in the decrease in lytic activity (12 %). Understanding the interaction of phage and bacteria is essential for the practical application of phage to control and detect antibiotic-resistant bacteria. The results provide useful information for understanding the binding specificity of phages for multiple antibiotic-resistant pathogens.