Evaluation of the Inhibitory Activity of Syzygium aromaticum Extract -Chitosan Nanoparticles Against Biofilm Formation of Klebsiella pneumonia

The increasing resistance of Klebsiella pneumoniae to antibiotics has led to difficulties in treating infections due to its virulence factors. As one of its major pathogenic factors, this opportunistic pathogen may develop a thick biofilm coating, allowing the bacteria to attach to living or nonliving surfaces and promote drug resistance. Searching for therapeutic alternatives from a plant source that was safe and effective in treating this multi-drug-resistant bacteria was necessary. In this concept, Syzygium aromaticum extract (SAE) is used to combat K. pneumonia. The extract was confirmed by GC-MS and loaded onto chitosan nanoparticles (SACSNPs). The SACSNPs were prepared by the ionic gelation method with tripolyphosphate (TPP). And then characterized using UVvis, FTIR, AFM, SEM, and XRD techniques. The K. pneumonia isolates were obtained and identified using the VITEK-2 system. The MIC of SAE and SACSNPs were confirmed using a 96-well resazurin-aided microdilution method, which was 6.25 μg/ml for SACSNPs and 75.5 μg/ml for SAE. The inhibitory activity using sub-MIC of analytical substances was determined by measuring the optical density using a microplate reader with a 96-well plate and 0.1% crystal violet dye. The results show that the S. aromaticum extract loaded with chitosan nanoparticles has higher inhibitory activity against the biofilm formation of K. pneumonia than the S. aromaticum extract. Keywords: Chitosan nanoparticles, S. aromaticum, K. pneumonia, Biofilm, GCMS, resazurin, XRD.