Abstract

The existing antibiotics are incapable of killing resistant pathogens including E. coli. Extended-spectrum beta-lactamases (ESBL) genes are found as one of the main causes of the resistance as it degrades the β- lactam ring of the antibiotics. This study aims at the green synthesis of silver nanocolloids from endophytic fungi Lasiodiplodia theobromae (LtNc’s), isolated from traditional medicinal plant Cinnamomum zeylanicum and biophysically characterized. Minimum susceptibility concentration, growth rate, Minimum Bactericidal Concentration and Biofilm inhibition assays were performed to evaluate the efficacy of LtNc’s against biofilm forming urinary tract infection (UTI) causing clinical strains of E. coli. The LtNc’s was found to be efficient antimicrobial agent which successfully controlled the growth and biofilm formation in E. coli. Inhibition of growth, biofilm formation, downregulation of CTX-M-15 and Amp C genes were observed when treated with LtNc’s in Urinary Tract infection (UTI) causing pathogens.

摘要

现有的抗生素无法杀死包括大肠杆菌在内的耐药病原体。广谱 β-内酰胺酶 (ESBL) 基因被发现是耐药性的主要原因之一，因为它会降解抗生素的 β-内酰胺环。本研究旨在从内生真菌Lasiodiplodia theobromae (LtNc's) 中绿色合成银纳米胶体，从传统药用植物Cinnamomum zeylanicum 中分离出来并进行生物物理表征。进行了最小易感浓度、生长速率、最小杀菌浓度和生物膜抑制试验，以评估 LtNc 对引起临床大肠杆菌菌株的生物膜形成尿路感染 (UTI) 的功效. LtNc 被发现是有效的抗菌剂，它成功地控制了大肠杆菌的生长和生物膜形成。当在引起病原体的尿路感染 (UTI) 中用 LtNc 处理时，观察到生长抑制、生物膜形成、CTX-M-15 和 Amp C 基因的下调。