Molecular Aspects of Biofilm Essay -- Biology, Cluster of Cells

Almost all bacteria are known to have certain stage of life where they live in form of biofilms. A biofilm is nothing but cluster of cells embedded within a self-produced polymeric matrix and adherent to a living or inert surface (Costerton et al, 1995). Development of biofilm begins with the attachment of planktonic bacteria to a surface, initially through weak and reversible Van der Waals forces and then anchors itself irreversibly by cell adhesion structures such as pili. The primary colonizers facilitate the arrival of other cells by producing polymeric adhesion matrix that also holds the biofilm together (Costerton et al, 1995). In course of colonization and maturation of biofilm, cells communicate via quorum sensing which also leads to phenotypic and genotypic changes in cells (Diggle et al, 2007). This development of biofilm confers bacterial cells higher antibiotic resistant and immunity to environmental insults. Enhanced antibiotic resistance due to biofilm development impo ses increasing concerns in antimicrobial therapy, especially when it comes to biomedical devices associated infections (Donlan, 2001). According to an estimate, contamination of surgical instruments by biofilm increases approximately 1.6 billion dollars in hospital expenditures annually in United States of America (Gupta et al, 2002). Biofilms not only cause nuisance in clinical aspects but they also create a number of serious problems in industrial operations like in fluid processing operations, mechanical blockages, impedance of heat transfer process, and biodeterioration of components of metallic and polymeric systems that results in loss of billions of rupees each year (Rao et al, 1993 and 2009; Fleming, 2002; Boffardi, 2005). Pseudomonas aerugi... ...s censored i.e. some part of sample may lost before the final outcome is speculated or speculation itself is incomplete (Kaplan & Meier, 1958). In KM survival plot, survival probability is measured after certain time periods and between two sampling time points survival probability is assumed to be constant so as an outcome we speculate a series of horizontals steps of survival probability over a period of time (Bland & Altman, 1998). Survival probability was calculated as P=Nt/N. Where P is survival probability, N0 is initial number of cells, Nt is number of viable cells after giving biocide doses at t time. Standard error in P was calculated as SE=√[P(1-p)/N] The upper and lower limit of 95% confidence interval were calculated as =PÂ ±1.96*SE. The upper limit of probability of survival of cells at different doses were taken into account for plotting the graph. Molecular Aspects of Biofilm Essay -- Biology, Cluster of Cells Almost all bacteria are known to have certain stage of life where they live in form of biofilms. A biofilm is nothing but cluster of cells embedded within a self-produced polymeric matrix and adherent to a living or inert surface (Costerton et al, 1995). Development of biofilm begins with the attachment of planktonic bacteria to a surface, initially through weak and reversible Van der Waals forces and then anchors itself irreversibly by cell adhesion structures such as pili. The primary colonizers facilitate the arrival of other cells by producing polymeric adhesion matrix that also holds the biofilm together (Costerton et al, 1995). In course of colonization and maturation of biofilm, cells communicate via quorum sensing which also leads to phenotypic and genotypic changes in cells (Diggle et al, 2007). This development of biofilm confers bacterial cells higher antibiotic resistant and immunity to environmental insults. Enhanced antibiotic resistance due to biofilm development impo ses increasing concerns in antimicrobial therapy, especially when it comes to biomedical devices associated infections (Donlan, 2001). According to an estimate, contamination of surgical instruments by biofilm increases approximately 1.6 billion dollars in hospital expenditures annually in United States of America (Gupta et al, 2002). Biofilms not only cause nuisance in clinical aspects but they also create a number of serious problems in industrial operations like in fluid processing operations, mechanical blockages, impedance of heat transfer process, and biodeterioration of components of metallic and polymeric systems that results in loss of billions of rupees each year (Rao et al, 1993 and 2009; Fleming, 2002; Boffardi, 2005). Pseudomonas aerugi... ...s censored i.e. some part of sample may lost before the final outcome is speculated or speculation itself is incomplete (Kaplan & Meier, 1958). In KM survival plot, survival probability is measured after certain time periods and between two sampling time points survival probability is assumed to be constant so as an outcome we speculate a series of horizontals steps of survival probability over a period of time (Bland & Altman, 1998). Survival probability was calculated as P=Nt/N. Where P is survival probability, N0 is initial number of cells, Nt is number of viable cells after giving biocide doses at t time. Standard error in P was calculated as SE=√[P(1-p)/N] The upper and lower limit of 95% confidence interval were calculated as =PÂ ±1.96*SE. The upper limit of probability of survival of cells at different doses were taken into account for plotting the graph.