Gram-negative Antimicrobial spectrum of Ulmus pumila

Abstract

Purpose: This study explores the antimicrobial spectrum of Ulmus pumila by screening commonly infectious gram-negative bacteria for susceptibility. Currently, many gram-negative bacteria are developing resistance to recommended antibiotic therapies used in clinical practice. It is imperative that we continue to explore new antimicrobial compounds in order to help combat the global health issue of antibiotic resistance. Method: 3g of freshly harvested leaves and flower samples of Ulmus pumila were extracted in 15 ml of 95% ethanol. The mixture was filtered to remove the debris and sterile blank discs were soaked in the clear filtrate (samples) or the extraction solvent (as background controls) for 20 minutes. Glycerol stocks of bacteria were scaled in LB broth and Muller Hinton agar was prepared with 38g of agar in a liter of water. A 100-microliter suspension of the scaled bacteria was diluted with 9 ml of 1% saline solution and 100 microliters of this saline dilution was plated. Sterile paper discs that were infused with extracts (samples) or vehicle control (95% ethanol) were placed on the freshly plated bacterial plates and incubated at 37 degree Celsius overnight. Zones of inhibition were recorded as a measure of antibacterial activity. Results: Ulmus pumila demonstrated antimicrobial activity against the following gram-negative bacteria: E. coli (16 mm mean zone of clearing), P. vulgaris (15 mm mean zone of clearing), E. cloacae (20.5 mm mean zone of clearing), and K. pneumoniae (16 mm mean zone of clearing). Conclusion: Ulmus pumila displayed antimicrobial activity against various species of gram-negative bacteria including E. coli, P. vulgaris, K. pneumonaie, and E. cloacae. Ulmus pumila has also previously demonstrated activity against some species of gram-positive bacteria. By this discovery, Ulmus pumila has the potential to serve as a broad-spectrum antimicrobial agent with activity against both gram-positive and gram-negative bacteria.