R.Priyadharshini et al./ Elixir Biosciences 113 (2017) 49272-49276 49272 Introduction Bacterial adhesion Adhesion is the procès that helps bacterial attachement to any surface. Adhesion is an important and initial step for the colonization of the microbes to the host or other nonbiological environments, which can contribute to the bacterial or microbial pathogenesis and related outcome. Microbial adhesion, coadhesion and anti adhesion studies would carry significant clinical implication interms of preventive measures should be taken to avoid the initial steps involved in the pathogenesis of the microbes. The World Health Organization realized the importance of the medicinal herbs and their use in traditional medicine. Therefore, WHO actively creating strategies, guidelines and standards for the medicines of botanical source (WHO 2002). The positive qualities of the medicinal plants have been acknowledged by many authors (Kaushik et al 2002, Aliyu et al., 2007) and they are highly appriciated. Based on the different types of mechanism and their function, the organic chemicals known as plants secondary metabololities, classified as chemotherapeutic agents and antimicrobials (bacteriostatic and bactericidal agents). Therefore the scientific community at global level leads to develop new better drugs against these microbial infections, especially against the drug resistant infections (Parekh and Chana, 2007). In this situation it is felt essential to search and discover new antimicrobials which are the most effective to treat the drug resistant pathogens. The different types of medicinal properties of the C.roseus had been documented.The antibacterial (Muhammad et al., 2009) antifungal (Jaleel et al., 2007) and the antiviral (Farnsworth et al., 1968) had been already studied. Terminalia chebula (Retz.) is a south Indian medicinal plant, called the “King of Medicine” in Tibet and is always listed first in the list of Ayurvedic Materia Medica because of its extraordinary healing power . Anwesa etal (2011) found out the combination effect of T. chebula fruit extract with some selected routinely used antibiotics against multidrug-resistant uropathogenic E. coli in a view to elucidate their possible synergistic activity. The involvement and the interaction of the gram positive and the gram negative bacteria for their synergistic colonization mechanism was extensively studied (Holmes et al 1996, Jenkins on et al 1990, Hogan & Kolter 2002). Keeping all these points in view, in this present study, we included drug resistant poly pathogenic bacteria to test the antiadherence property of the T. chebula and C. roseus ethanolic extracts. Material and Method Plant extract preparation The method already we have used and published earlier (Priyadharshini et al 2016) has been used to prepare the extracts from T. chebula seed and C. roseus leaves. Each individual concentrated extracts (30 ml) were taken and mixed with sterile distilled water (30 ml) separately and used ARTICLE INFO Article history: Received: 11 November 2017; Received in revised form: 6 December 2017; Accepted: 15 December 2017; Keywords Microbial adhesion, Innovative Dual Invitro Model System. Synergistic Antiadherence Bioactiviy of Terminalia Chebula and Catharanthus Roseus Ethanol Extracts against Human Pathogenic Bacteria of Clinical Source R.Priyadharshini 1 , V. Udhaya 1 , D. Sangeetha *,1 , M.R. Suseela 2 , V. Natarajan 2 and C. Sudan Suhaa 3 Department of Microbiology, Faculty of Science, Annamalai University, Tamil Nadu, India. 2 Department of Microbiology, Faculty of Medicine, Annamalai University, Tamil Nadu, India. 3 Visva Arokya Trust, Chidambaram, Tamil nadu. ABSTRACT Microbial adhesion is a initial and essential step for the attachment of microbes to the host tissues. Adhesion is considered as one of the microbial virulence markers. In view of finding plant based solution to prevent the bacterial adhesion, the present study was undertaken. Invitro experimental study was conducted to screen the antiadherence bioactivity of T. chebula and C. roseus extracts. Both gram positive and gram negative bacterial strains were included in this study. Tube from urine collection bag was used as substratum in the invitro sudy. Innovative Dual Invitro Model System (IDIMS) was used to perform the experiments. Tested specimens were collected and screened under light microscope. Specimens were also subjected to culture and CFUs were counted. The reduced number of bacterial cells in the specimen was recorded from the light microscopic study, and from specimen culture. Decreased number of CFUs were noted. From this we conclude that the T. chebula and C. roseus extracts (singly) as well extract combination possess antiadherence property. Hence we suggest these two plant extracts, singly or their combination can be used as antimicrobial agent to prevent the adhesion of the human pathogenic bacteria to the objects. However further established research in this field is felt essential to bringout new informations and to support our study reports. © 2017 Elixir All rights reserved. Elixir Biosciences 113 (2017) 49272-49276 Biosciences Available online at www.elixirpublishers.com (Elixir International Journal)