Biosynthesis of silver nanoparticles and testing their antibiofilm activity against extended-spectrum beta-lactamase producer Klebsiella pneumoniae isolated from Iraqi patients

The widespread emergence and dissemination of Enterobacteriaceae strains producing extended-spectrum beta-lactamase (ESBL) enzymes pose a formidable threat to effective infection treatment. To address this critical issue, this study sought to explore the potential of nanotechnology as a solution. Specifically, the research involved the isolation and analysis of Klebsiella pneumoniae isolates obtained from 100 clinical samples. The primary objective was to detect ESBL production among these isolates. The results of this investigation unveiled that out of the 100 clinical samples, 37.83% (14 isolates) of K. pneumoniae were found to be ESBL-producing strains. Subsequently, these ESBL-producing isolates underwent testing to assess their ability to form biofilms, a crucial factor contributing to the persistence and virulence of bacterial infections. Two distinct methods, the microtiter plate assay and congo red agar, were employed to evaluate biofilm formation, and a significant proportion of the tested isolates exhibited strong biofilm-producing capabilities. Concurrently, various food samples were systematically collected from local markets with the aim of isolating Pseudomonas aeruginosa. This specific bacterial strain was chosen as a candidate for the biosynthesis of silver nanoparticles (AgNPs). The biosynthesis of AgNPs was meticulously characterized through multiple analytical techniques, including atomic force microscopy analysis, which revealed an average nanoparticle diameter of 63.02 nm. The synthesis of AgNPs was further optimized by varying crucial parameters such as temperature, incubation period, and pH. The experimental findings indicated that the most favorable conditions for biosynthesis of AgNPs using food-borne P. aeruginosa were a pH level of 5, with incubation at 37°C for a duration of 48 hours. The synthesized AgNPs were assessed for their potential anti-biofilm activity. The results of these experiments demonstrated that these nanoparticles exhibited significant activity in inhibiting the formation of biofilms by ESBL-producing K. pneumoniae strains, thereby offering a promising avenue for combatting antibiotic-resistant infections.