~ 2114 ~ Journal of Pharmacognosy and Phytochemistry 2018; 7(3): 2114-2121 E-ISSN: 2278-4136 P-ISSN: 2349-8234 JPP 2018; 7(3): 2114-2121 Received: 03-03-2018 Accepted: 07-04-2018 Muslima Jahan Department of Biotechnology and Genetic Engineering, Islamic University, Kushtia, Bangladesh Md. Abuhena Department of Biotechnology and Genetic Engineering, Islamic University, Kushtia, Bangladesh Abul Kalam Azad Department of Biotechnology and Genetic Engineering, Islamic University, Kushtia, Bangladesh Mohammad Minnatul Karim Department of Biotechnology and Genetic Engineering, Islamic University, Kushtia, Bangladesh Correspondence Muslima Jahan Department of Biotechnology and Genetic Engineering, Islamic University, Kushtia, Bangladesh In vitro antibacterial and antibiofilm activity of selected medicinal plants and spices extracts against multidrug resistant Pseudomonas aeruginosa Muslima Jahan, Md. Abuhena, Abul Kalam Azad and Mohammad Minnatul Karim Abstract Pseudomonas aeruginosa is a human opportunistic pathogen known to build biofilm and is able to proliferate within the biofilm. Antibacterial substances are of natural origin, and it is thought that their influences on the environment are important and can be used as biological control agents. In the present study, multi-drug resistant and the high yielding biofilm Pseudomonas aeruginosa strains have been isolated from the hospital waste. Multi-drug resistance pattern was studied with disc diffusion assay using commercially available antibiotic discs. Ten isolates were multi-drug resistant among eighteen isolates. Modified crystal violet staining method was performed to know the ability of biofilm formation by isolated strains. All of the isolates were able to form biofilm except one. Antibiofilm and Antimicrobial activity of medicinal plants Centella asiatica (Thankuni), Mentha spicata (Mentha), Azadirachta indica (Neem), Psidium guajava (Guava) and spices Syzygium aromaticum (Cloves), Cinnamomum zeylanicum (Cinnamon) extracts were studied with modified crystal violet biofilm assay and Well diffusion assay respectively. Both Methanol and ethyl acetate extract of guava leaf showed lowest antibacterial activity against all selected isolates. MIC values were determined for each extracts and it was ranged from 500 μg mL -1 to 2000 μg mL -1 . Methanol and ethyl acetate extract of Cinnamon, Neem and Mentha showed high antibiofilm activity suggested that these extracts might act as a potential antibiofilm agent against Pseudomonas aeruginosa. Despite of the fact that the extracts were not pure compounds, antimicrobial activity as well as antibiofilm activity were observed. This recommends the potency of these extracts and could be a target for further research to search antibiofilm bioactive compound for therapeutic uses. Keywords: medicinal plants, spices extracts, multidrug, Pseudomonas aeruginosa 1. Introduction Pseudomonas aeruginosa is a human opportunistic pathogen and it has been emerging as a primary source of nosocomial infections [1] , including infections of artificial implants, contact lenses, urinary cathetersacheal tubes [2] . Biofilm is a community of cells attached to either a biotic or abiotic surface enclosed in a complex exopolymeric substance (EPS) [3] . Pseudomonas is known to build biofilm and is able to proliferate within the biofilm. Within the biofilm the bacteria are protected from the immune system, from antibiotics and, outside the body, from other adverse environmental factors [4] . The misuse and abuse of antibiotics are recognized to create selective pressure, resulting in the widespread development of resistant bacterial strains [5, 6] . Facing these limitations of antibiotics, there is an increasing need for the discovery and the development of antimicrobial agents that present novel or unexplored properties to efficiently control and manage bacterial infectious diseases [7] . Inhibition of bacterial virulence and/or biofilm formation by targeting nonmicrobicidal mechanisms are examples of increasingly explored antipathogenic approaches [8-11] . According to World Health Organization, to obtain a variety of drugs against many diseases, medicinal plants are one of the potential targets. Among the developed countries, about 80% people use medicinal plants derived traditional medicine. In this post antibiotic era where there is increasing multi drug resistant pathogens, research work on medicinal plants should be carried out to better understand their safety, properties and efficiency [12] . In the recent past, there has been an increased interest in the therapeutic properties of some medicinal plants and natural compounds which have demonstrated for their antibacterial and antibiofilm activities. Present study aimed to isolate multi-drug resistant biofilm forming Pseudomonas aeruginosa strains and screening of medicinal plants Centella asiatica (Thankuni), Mentha spicata (Mentha), Azadirachta indica (Neem), Psidium guajava (Guava) and spices