Experimental and Monte Carlo Insights into the Biofilm Control of Klebsiella pneumoniae Using Green-Synthesized Ag/Ni(OH)2/Clove Nanocomposites

One of the most significant challenges with disease control in humans and animals is biofilm formation by Klebsiella pneumoniae (K. pneumoniae). The current study investigated the prevalence of K. pneumoniae in fecal and milk samples from cattle and humans, along with their antimicrobial susceptibility patterns and biofilm formation, using conventional methods. In addition, the efficacy of Ag/Ni(OH)2/Clove and Ag/Ni(OH)2/C nanocomposites was comparatively evaluated to combat resistance and biofilm-associated traits. K. pneumoniae was recovered from 48.0%, 38.0% and 43.3% of the fecal, milk and stool samples, respectively. Moreover, antimicrobial susceptibility testing revealed a noteworthy pattern shared between human and animal samples. Furthermore, a Congo Red (CRA) assay and molecular detection of the biofilm-associated genes iut-A and mrk-A demonstrated that the majority of K. pneumoniae isolates exhibited biofilm characteristics. Using a green chemistry approach, Ag/Ni nanoparticles displayed greater bactericidal activity in the calcined form, as evidenced by a lower MIC (20.83 ± 5.23 μg/mL), an increase in the inhibition zone diameter (20.67 ± 1.76 mm), and low cytotoxicity toward HEK293 cells that was evident only within the lower tested concentration range (7.8–62.5 µg/mL), where cell viability remained above 90.0%; viability declined markedly at higher concentrations, with IC50 values of 264.7 µg/mL for Ag/Ni(OH)2/Clove and 282.8 µg/mL for Ag/Ni(OH)2/C. Notably, compared with Ag/Ni(OH)2/Clove, Ag/Ni(OH)2/C nanocomposites exhibited stronger antibiofilm properties. Likewise, the green synthesis of Ag/Ni(OH)2/Clove and Ag/Ni(OH)2/C nanocomposites represents an efficient approach for improving safety profiles in biological applications when applied within this lower, biocompatible concentration range, particularly against microbial strains exhibiting drug resistance and biofilm formation. Monte Carlo (MC) simulations were performed to investigate the interactions of the Ag/Ni(OH)2 composite with lipopolysaccharide (LPS), ergosterol, and chitin, which represent bacterial and fungal cell wall components. The negative adsorption energies (−50.15, −23.46, and −8.08 kcal/mol) indicated strong adsorption, supporting the experimentally observed antibacterial and antifungal activities of Ag/Ni(OH)2 composite.