Chemical Synthesis of a Polyvinylpyrrolidone-Capped Silver Nanoparticle and Its Antimicrobial Activity against Two Multidrug-ResistantAeromonas Species

This study investigated the antimicrobial activity of polyvinylpyrrolidone-capped silver nanoparticles (PVP-AgNPs) in vitro against two antibiotic-resistant isolates of Aeromonas hydrophila and A. caviae. Solid crystal silver nanoparticles were synthesized by the chemical reduction approach employing polyvinylpyrrolidone (PVP) as a neutral stabilizer, glucose as a reducing agent, and sodium hydroxide as a catalyst. The crystallinity and purity of the prepared PVP-AgNPs were investigated using the X-ray diffraction spectrometer (XRD). Transmission electron micrograph analysis demonstrated the formation of irregular spherical shapes PVP-AgNPs with average crystallite size diameters ranging from 5.07 to 9.74 nm. By phenotypic and gene sequence analysis, A. hydrophila and A. caviae isolates were identified from diseased Nile tilapia. Our findings showed that all A. hydrophila and A. caviae isolates were multidrug-resistant (MDR) and showed resistance to four antimicrobial classes. The PVP-AgNPs displayed 15 mm and 14 mm clear inhibition zones for A. hydrophila and A. caviae, respectively. In addition, the minimum inhibitory concentrations for PVP-AgNPs were estimated to be 6.25 mu g/ml and 7.5 mu g/ml for A. hydrophila and A. caviae, respectively. The chemically synthesized PVP-AgNPs were found to possess a strong antimicrobial effect against A. hydrophila and A. caviae with the possibility to be used as a commercialized antimicrobial agent in the aquaculture industry.