Mahsa Khosravi Bache Mir - M.Sc, Department of Biology, Central Tehran Branch, Islamic Azad University, Tehran, Iran
Solmaz Shahla - Assistant Professor, Department of Biology, Central Tehran Branch, Islamic Azad University, Tehran, Iran
Behin Omidi - Assistant Professor, Department of Biology, Central Tehran Branch, Islamic Azad University, Tehran, Iran

Klebsiella pneumoniae is one of the major effects of hospital acquired infections that is resistant to many antibiotics because of producing extended spectrum β-lactamases. Today using plant extracts and nanoparticles is one of the modern attitudes in microbial infection treatments. The aim of this study is to evaluate the synergistic effect of Rheum ribes extract and copper nanoparticles on ESBL- producing isolates of K. pneumoniae. In this study, ۱۰۰ isolates of Klebsiella were collected from urinary infections. After confirmation, the ESBL- producing isolates were identified with primary screening and phenotypic confirmatory tests. After preparation of R. ribes extract and Cu nanoparticles, different concentrations were prepared and the antimicrobial effects were studied with disk diffusion method and MIC and MBC were identified. From ۱۰۰ isolates of Klebsiella, ۸۶ isolates were K. pneumoniae that after confirmatory tests, ۲۳ samples (۲۶.۷۴%) represented ESBLs. According to the results, the antimicrobial effect of extract and the synergistic effect of extract and nanoparticles were dependent to concentration in disk diffusion method. Minimum inhibitory concentration of R. ribes extract was ۱۵۰±۱ mg/ml. Cu NPS had no inhibitory effect at used concentration (۱۰ mg/ml). Using R. ribes extract and Cu NPs together reduced MIC to ۵۰±۱ mg/ml. Overall, results showed that R. ribes extract had inhibitory effect on ESBL- producing K. pneumoniae but this isolate is resistant to increasing concentration of Cu NPs. On the other hand, simultaneous use of R. ribes extract and Cu NPs had synergistic effect and intensified their effects

antibiotic resistant bacteria, extended spectrum beta-lactamase, synergism