Characterization of the biosynthesized Syzygium aromaticum-mediated silver nanoparticles and its antibacterial and antibiofilm activity in combination with bacteriophage

Abstract

Contamination with bacteria and organic matters is becoming a serious challenge for governments and a central issue for public health. Biosynthesized silver nanoparticles (AgNPs) are currently gaining attention due to the additional properties provided by thier combination with natural products. Here, we employ Syzygium aromaticum (Clove) in the bioreduction of silver ions into (Sa-AgNPs) for antibacterial and antibiofilm applications. The results of zeta potential, UV–vis spectrum peak at 450 nm, along with the scanning and transmission electron micrographs (SEM, TEM) confirmed the spherical structure of Sa-AgNPs with a size ranging from 7 to 15 nm and a −28.1 mV zeta potential value. In addition, Sa-AgNPs presented potential antioxidant and photocatalytic activity with an ability to sense various ions in water samples. Furthermore, Sa-AgNPs delineated an outstanding activity against the Gram-negative Salmonella typhimurium (S. typhimurium) DT04 NCTC 13348, with minimum inhibitory and bactericidal concentrations (MIC, MBC) of 22.5 µg/ml and 45 µg/ml, respectively. Sa-AgNPs also present a high ability to prevent the biofilm formation of the Gram-positive, Staphylococcus sciuri (S. sciuri). Moreover, the dual combinatorial Sa-AgNPs and Salmonella bacteriophage ZCSE6 showed a synergistic antibacterial effect at a multiplicity of infection (MOI) of 0.1. The highest synergistic activity was recorded against S. typhimurium, as evidenced by the time-killing curves and a smaller MIC (11.25 µg/ml) & MBC (22.5 µg/ml), after the combination with phage ZCSE6 (MOI 0.1). Moreover, the cytotoxicity and blood hemolysis assays confirmed the safety of the biogenic Sa-AgNPs. Accordingly, the study's findings support the utility of the safety and efficacy of Sa-AgNPs for various antibiofilm and antibacterial applications. Furthermore, it introduces the potential of combining AgNPs with bacteriophages for a synergetic effect against the contaminating bacteria.