Chemical characterization and antibacterial activity of lipopolysaccharide extracted from the local isolate of Enterobacter cloacae

Aims:The study aims to isolate and identify Enterobacter cloacae, extracted lipopolysaccharide, and chemical assays for LPS characterization, constituent separation of LPS using high-performance liquid chromatography technique and study the antibacterial activity of lipopolysaccharide. Methodology and results:We isolated and identified the E. cloacae from clinical specimens and then the lipopolysaccharide (LPS) was extracted from E. cloacae using the methanol-chloroform method.The five isolates of E. cloacae were identified.The isolate was used to extract lipopolysaccharide.The extract was identified using biochemical tests, such as the Molisch test, to detect carbohydrate content and the Folin reagent to determine protein concentration and lipid solubility in the organic solvent.Biodrop was used to determine nucleic acid concentration.The antibacterial activity of different concentrations of LPS is studied against the Proteus mirabilis species isolated from urine samples.The extraction method showed their activity with low concentrations of protein and nucleic acids in the extract.Fourier transform infrared (FTIR) and high-performance liquid chromatography (HPLC) techniques were used to perform the chemical analysis of lipopolysaccharides. Conclusion, significance and impact of study:The results of the extract's chemical analysis using FTIR and the HPLC separation technique have shown that the obtained compound is LPS.The lipopolysaccharide demonstrated its activity in inhibiting microbial growth.In addition, the antimicrobial activity of E. cloacae LPS against the P. mirabilis isolates demonstrated its efficacy in inhibiting P. mirabilis at all concentrations 1100, 1000, 900, 800 and 700 g/mL.