| Summary |
Rising nosocomial infections, also called hospital-acquired infections (HAIs), are of imminent public health concern as common antibiotics, such as ampicillin and kanamycin, are becoming less effective against bacterial infections. Nosocomial infections are caused by multidrug-resistant organisms (MDROs), specifically gram-negative bacteria, of the Enterobacteriaceae family, and are associated with significant mortality and morbidity and economic burdens to hospitals and patients. Patients admitted to intensive care unit (ICU) are most likely to develop infections due to prolonged exposure to hospital environments (where selection of resistant strains occur due, in part, to excessive use of ineffective disinfectants), declining immune response, and exposure to invasive medical devices harboring bacterial biofilms. Hence, innovative antibacterial treatments are needed to control the growing issue of nosocomial infections. In this study, amino-functionalized silver nanoparticles (NH2-AgNPs) were synthesized and employed as a novel antimicrobial agent against Escherichia coli K12 and Pseudomonas aeruginosa PAO1. To test the hypothesis that synergistic effects will occur when NH2-AgNPs are combined with common antibiotics (ampicillin and kanamycin), Kirby-Bauer Disk Diffusion test, LB broth growth assay, and electron microscopy analysis were used. Disk Diffusion test results revealed that NH2-AgNPs were significantly more toxic to E. coli when combined with ampicillin or kanamycin rather than when applied alone. Moreover, a potentiation effect was observed with NH2-AgNPs when combined with kanamycin against E. coli, while an antagonist effect was observed when each antibiotic was combined with NH2-AgNPs against P. aeruginosa. However, LB broth growth assay and electron microscopy results demonstrated that NH2-AgNPs, kanamycin and ampicillin were bactericidal via cell wall damage against both tested gram-negative bacteria. Taken together, our findings suggest bactericidal potential of NH2-AgNPs and may serve as a novel treatment modality against MDROs associated HAIs. |
