Penicillium chrysogenum-Derived Silver Nanoparticles: Explorationof Their Antibacterial
and Biofilm Inhibitory Activity Againstthe Standard and Pathogenic Acinetobacter
baumannii Compared to Tetracycline
Abstract: This study was aimed to evaluate the antibacterial and biofilm inhibitory activity of
Penicillium chrysogenum-derivedsilver nanoparticles (AgNPs) against the standard and
pathogenic Acinetobacter baumannii using a 96-well microtiterplate-based method. The AgNPs
were characterized by using UV–Vis, TEM, AFM, XRD, DLS, Zeta potential, and FT-IR.The
nanoparticles (NPs) were fabricated with a spherical shape and an average hydrodynamic diameter
of 48.2 nm. Theminimum inhibitory concentration (MIC) and minimum bactericidal concentration
(MBC) of AgNPs were found to be 4and 32 lg/mL respectively, whereas the MIC and MBC of
tetracycline were found to be 1024 and 8192 lg/mL against A.baumannii (ATCC 19606). The
AgNPs and tetracycline represented considerable biofilm inhibitory activity against boththe
standard and pathogenic A. baumannii at the studied concentrations. However, the AgNPs depicted
higher potency toinhibit the process of biofilm formation of some pathogenic A. baumannii species
compared to tetracycline. The AgNPs atthe concentration of 0.5*MIC (2 lg/mL) inhibited above
90% biofilm inhibition, whereas tetracycline reached 90% biofilminhibition at the concentration
of 4*MIC (4096 lg/mL) against A. baumannii (ATCC 19606). However, further studies
arerequired to evaluate the biofilm inhibitory efficacy of biogenic AgNPs in vivo.
Keywords: Silver nanoparticles, Biosynthesis, Antibacterial activity, Biofilm inhibitory activit
