Evaluation of antibacterial activity of selected plant extracts against Serratia marcescens

Abstract

Abstract BACKGROUND: Serratia marcescens is a well-known Gram-negative, rod-shaped bacterium commonly found in soil, animal skin, hospital environment, and plant-based raw materials. It is an opportunistic pathogen that causes serious infections, including pneumonia, bloodstream infection, wound infection, meningitis, and respiratory and urinary tract infections. Due to multiple resistant strains of S. marcescens being identified, new and effective plant-based antimicrobial compounds/drugs against S. marcescens must be searched. The present study is focused to explore the Stem of Neem (Azadirachta indica), Seed of Nirgundi (Vitex negundo) and Clove buds (Syzygium aromaticum) for their antibacterial activity against the isolated S. marcescens. METHODS: The S. marcescens was isolated from the garden soil of CARI Jhansi and identified based on various morphological and biochemical tests. We also checked the antibiotic profile of isolated S. marcescens. The ethanolic and methanolic extracts of the selected plant parts were prepared and explored for their antibacterial activity against S. marcescens using the disc diffusion method. RESULTS: The antibiotic profile of S. marcescens showed resistance to multiple broad-spectrum antibiotics, including erythromycin, rifampicin, chloramphenicol, and narrow-spectrum antibiotic vancomycin. At the same time, it was sensitive to kanamycin, streptomycin, ciprofloxacin, and ofloxacin. We observed that both methanolic and ethanolic extracts of clove buds were effective, while only the ethanolic extract of Nirgundi seed and Neem stem were found to be effective against S. marcescens. CONCLUSION: From this study, we conclude that both methanolic and ethanolic extracts of Clove buds, while only the ethanolic extract of Nirgundi seed and Neem stem, were found effective and showed significant inhibition of growth of S. marcescens.