Bacterial biofilm are communities of microorganisms which are attached to a surface and its formation is critical not only for environmental survival but also for successful infection. Staphylococcus aureus, one of the most frequently occurring community and hospital associated pathogens, can cause infectious diseases including mild skin infection and endocarditis. Biofilm forming micro-organisms are antibiotic resistant as it offers an extra covering around the cells that makes them persistent against antibiotics. It causes serious problems because its widespread infections cannot be controlled with antibiotics.

There has been an increasing trend to use antimicrobial agents to cope up the antibiotic resistance cause by this microorganism. Plants of Hazara Division are known for their antimicrobial potential, but their antibiofilm potential has not been explored. In current study plants known for their antimicrobial potential will be selected, their extracts will be prepared and their antibiofilm activity will be evaluated. IntroductionStaphylococcus aureus being a gram-positive bacterium, is generally associated with implant-related and nosocomial infections (Lister and Horswill, 2014). It is involved in causing a number of infections ranging from, stye, dental caries, carbuncle, periodontitis, impetigo and to persistent tissue infections (Arciola et al. , 2012). Staphylococcus aureus is colonized in approximately 30% of human population (Antonia M et al. , 2005). It is one of the causative pathogenic agent in Diabetes Mellitus patients (National Diabetes Statistics Report, 2011).

In 2013, it was reported that 382 million people were having diabetes worldwide, and this figure is expected to rise to 592 million by 2035 (Guariguata et al, 2014). Being obese causes more sweating that raises skin colonization with Staphylococcus aureus. Staphylococcus aureus being halo-tolerant, can easily survive there. Additionally, staphylococci expresses lipases that clears antimicrobial skin lipids (Brauweiler et al, 2014). Diabetes Mellitus type II results from insulin resistance, in this the cells are unable to use insulin accurately. Recent studies have shown that bacterial products from unusual micro flora leads to the development of DMII through increased inflammation, mainly affecting dipocytes (Piya et al. , 2013). Obese people and diabetic patients have more Staphylococcus aureus colonization (Creely et al. , 2007). Bacteria, in their natural environment, typically form communities of organisms that settle and multiply on the surfaces and are surrounded by a self-produced matrix, called biofilm (Donlan and Costerton, 2002). Its made up of extracellular polymeric substances (EPS), that modify the surface properties of the bacteria to both encourage and prevent initial attachment to a surface (Tsuneda et al. , 2002) or cell aggregation (Kevin et al. , 2007).

Biofilm displays a modified phenotype with respect to growth, protein production and gene expression (Donlan and Costerton, 2002). Biofilm formation is an adaptive protected manner of growth allowing bacteria to survive in inimical environments. Biofilm assists the bacteria to scatter and colonize new positions according to their need which is facilitated by quorum sensing (Akira et al. , 2006). When antibiotics are used against bacteria, maximum planktonic cells are destroyed as well as most of the cells in biofilm. Few of the planktonic persisters that are left after the use of antibiotic, are destroyed by immune system of host, so that they do not represent clinical problem. But unlike these persisters, biofilm persisters are shielded from host immune system by polysaccharide matrix, so that a small population of persisters is responsible for increased biofilm resistance. When the concentration of antibiotics is reduced, the persisters reestablish the biofilm, so that new planktonic cells are released. This dynamics describes reverting nature of biofilm infections (Brooun, 2000). Staphylococcus aureus can form a multilayered biofilm surrounded by a glycocalyx. It consists of b-1, 6-linked N-acetyl glucosamine residues (80–85%) and an anionic fraction with a lesser content of non-N-acetylated D-glucosamine residues that has phosphate and 15–20% ester-linked succinate (Mack et al. , 1996). The risk of antibiotic resistance in Staphylococcus aureus has increased immensely for several years and the health costs have enlarged intensely. Different figures reported by some nations regarding annual deaths due to antibiotic resistance with 22,000 additional deaths in the US, and 12,500 in France, 25,000 in Europe, (Dubourg et al. , 2017).

According to National Institutes of Health U. S (NIH), 80% of bacterial infections occurring in the human body are related to biofilm (Davies, 2003). It has been reported that the incidence of nosocomial infections caused by Methicillin Resistant Staphylococcus aureus in Pakistan is constantly on the rise ranging from 5 to 61% (Qureshi et al. , 2000). Bacteria within a biofilm are 1,000 times more resistant to antibiotics and are innately insensitive to the host immune response (Musk and Hergenrother, 2006). This is mainly due to decreased bacterial growth rate, decreased drug penetration into the biofilm due to the presence of extracellular polymeric substances, active starvation response and alteration in bacterial gene expression also leads to biofilm resistance (Nguyen et al. , 2013). This natural resistance makes biofilm-associated infections very challenging to overcome.

In order to eradicate the Staphylococcus aureus biofilm, various strategies are employed including the use of various chemicals, antibiotics and plant extracts. Steven et al. (2010) has proposed that the blend of an antibiofilm agent containing a 2-aminoimidazole/triazole motif with conventional antibiotics offers an effective strategy for removing Staphylococcus aureus biofilm colonization. Biosurfactants have merited renewed focus due to their ability to inhibit or disrupt microbial biofilm (Banat et al. , 2014). Carson et al. (2009) has shown that a series of 1-alkyl-3-methylimidazolium chloride ionic liquids has antibiofilm activity against Staphylococcus aureus. The application of mupirocin by nasal irrigation is effective in eliminating Staphylococcus aureus biofilm present on the sinus mucosa of patients with CRS and may propose an extra treatment to patients with recalcitrant sinusitis (Kim and Kwon 2016). Presently, despite the long-term research, plants seem to be an inexhaustible wealth of new compounds. A number of plant extracts contain components (terpenes, phenol derivatives etc. ) having the ability to reduce or inhibit microbial cell attachment and biofilm growth (Ramim et al. , 2015).

Quercetin and tannic acid are the plant extracts that have been reported for inhibiting the formation of recalcitrant biofilm of Staphylococcus aureus (Jin at el. , 2013). Vijayyakumar et. al (2015) have reported that Pam-ZnO NPs (from leaf extracts of Plectranthus amboinicus) have effective control on Staphylococcus aureus biofilm. Antibacterial and anti-biofilm potential of Sesbania grandiflora has been proved very effective for controlling the biofilm formed by Staphylococcus aureus (Arumugam et al. , 2017). Results from a recent study have indicated the potential of dichloromethane (extract of Piper regnellii) against methicillin-resistant Staphylococcus aureus and methicillin-sensitive Staphylococcus aureus biofilm (Lara et al. , 2017). Pakistan is an agricultural country having diversity in plants. A wide number of plant extracts are currently being studied and widely used to cure different medical issues. But much of them need to be investigated further to know there antibiofilm activity.