Evaluation of phage adsorption to Salmonella Typhimurium exposed to different levels of pH and antibiotic

Abstract

This study was designed to evaluate the physicochemical properties of phage P22 in different pH and antibiotic levels as measured by growth kinetics, phage adsorption, and lytic activity. P22 was susceptible to acidic pHs and stable above pH 4. The latent period of P22 was 45 min and burst size was 34 phages/cell. The adsorption ability of phage to Salmonella Typhimurium was varied depending on the multiplicity of infections (MOIs). The latent period was reduced to 6.84, 4.02, and 1.72 h, respectively, on the levels of the host at 10⁴, 10⁶, and 10⁸ CFU/ml. No significant differences in adsorption were observed between pH 4 and pH 7, but the lytic activities were significantly enhanced at the presence of ceftriaxone (CEA) and ciprofloxacin (CIP) at pH 7. Therefore, the phages combined with antibiotics can be a promising therapeutic tool to control antibiotic-resistant bacteria. This results provide a better understanding of host-phages interactions in different environmental conditions.

Keywords: Antibiotic resistance; Lytic activity; Phage adsorption; Phage therapy; Salmonella.