Important Biofilms in Clinical Microbiology - Research Paper Example

Important Biofilms in Clinical Microbiology Biofilms are now present in all the environmental systems such as aquatic and industrial water systems, these biofilms were first described by Anton Von Leuwenhook but were not discovered until 1978. These biofilms are complex polymer matrix containing water channels through which the surface cells communicate among themselves. The physical structure and the characteristics of the cells were found by using the scanning electron microscope and confocal laser scanning microscope. Further studies have found that these biofilms are formed by certain genes in the micro organisms. The micro organisms growing in these biofilms have become resistant to the antimicrobial agents. These biofilms are now found on the medical devices and this creates a problem. Many diseases such as cystic fibrosis and the valve endocarditis are associated with biofilms. (Donlan and Costerton 2002, Watnick 2000). The present of these micro organisms on the surface is determined by the colony forming units. This is the traditional method of determination of the adherent cells on the surface. The disadvantage of this method is that the CFU varies for the different methods of identification such as fluorescent micro scoping and electron microscopy. This method is widely used for the identification of the low concentration of the bacteria on the sea water, sewage water and on the earth sludge. The evaluation of the samples using the scanning electron microscope is difficult because of the requirement of the high vacuum. And the three dimensional structure visualization of the structure is limited here. The determination of the biofilms thickness, density, porosity, roughness, bio-volume are required for the evaluation and the quantification of the biofilms. (Hannig et. al 2010). Biofilms are clinically important. More than 80% of the infections cause4d in our body are based on the biofilms. The major infections in our body includes infections in the soft tissues, middle ear, dental implants, urogenital tract, eye, urinary tract prostheses, infections on the peritoneal membrane and the peritoneal dialysis catheters, hemodialysis catheters , cardiac implants in our body such as pacemakers, ventricular assist devices and prosthetic heart values, internal fixation devices, tracheal and ventilator tubing and percutanoeus sutures. Though the non mucosal layer resists the entry of the pathogens into the body, the bacteria have been found to adopt numerous strategies for the action against the anti microbial. The scientists say many reasons for this antimicrobial activity such as efflux, biofilms formation and the cell wall permeability and sometimes the expression of the genes that are mediating the inactivating enzymes. Among them the bacterial biofilms are found to express different virulent properties. It was observed that the bacteria’s that are found at the bottom and at the top are found to have different actions against the host. Those bacteria’s that live on the biofilms or those that depend on these biofilms are found to have resistant to both the immunological and the non specific defense mechanisms in the body. This biofilms act as a medium for the communication between the cells. These bacteria’s are found to use quorum sensing, the cell to cell communication. These quorum sensing bacteria are found to produce certain chemical signal molecules based on the cell density. These bacteria also regulate the gene expression among them by gene transfer. The gene transfer between the avirulent commensal organism and the virulent organism, converts the avirulent bacteria in to virulent bacteria. The presence of the biofilms makes this gene transfer possible. (nidcr.nih.gov 2010). The nasocomial pathogens are associated with the infections caused due to the implanted medical devices. These pathogens cause great problems in the diagnosis and treatment of the infections. It was found that an extra cellular polysaccharide adhesion, produced by the Staphylococcus epidermidis, a key virulence determinant, was required for the biofilms formation. This adhesion production is encoded in the ica operon and is produced by the phase variable regulation (ON-> OFF mechanism) .Further research is required for the development of the novel strategies for the therapeutic intervention. The extra cellular polysaccharide called alginate was found to be widely associated with the chronic Pseudomonas aeruginosa infections in the Cystic fibrosis. Alginate is produced widely by the P.aeruginosa, which plays a key role as a virulence factor in the formation of the biofilms and form encystment process with the Azotobacter vinelandii. The alginate was isolated for the studies form the P.fluorescens , P.putida, P.Mendocina and P.syringae. The genes responsible for the production of the alginate were found to be present at least in 24 genes of the bacterial chromosome and so far have no evident for plasmid involvement. The gene coding for the alginate synthesis is algL. This gene encodes alginate lyase. The regulation of the alginate biosynthesis is a very complex process and this involves the specific gene products. The gram negative bacteria Pseudomonas aeruginosa was found to interact with the epithelial cells and the underlying mucosal layer. When the biofilm formation by the polysachharide Psl to the epithelial cell was observed, it was found that Psl was found to be associated with the initial attachment and the role of pathogenesis was not found in them. The function and role of the Psl was studied using the NF-kappa luciferase reporter system in the human epithelial cells. The studies indicated that the Psl was foud to be associated with the flagellin- mediated NF-kappa B activation. (Byrd et. al 2010). A study was conducted by Presterl group to determine the effect of the antibiotics on these biofilms that are formed on the Viridans group Streptococci (VGS) blood stream isolates. These VGS cause the bacterial endocarditis and are found to be associated with the multi organ failure in the patients with neutropenia disease. The formation of the endocartitis plaque was the serious outcome. The formation of the biofilm on the leaflets of the heart values is the major entity with the serious outcome. The treatment of this endocarditis was considered complex because of the choice for the antibiotics, dosages and the duration ofhte therapy. The use of the antibiotic moxifloxacin has resulted in the decrease in the thickness of the biofilm. This showed to be the most active quinolone both in the experimental and the clinical carditis. Hence further controlled studies are going on in this field to evaluate the moxifloxacin’s ability to reduce the endocarditis. The use of Tecicoplanin and moxifloxacin at higher concentrations resulted in a significant decrease in the biofilm production. Thus testing the effects of the antibiotics to identify whether the biofilm formation is involved in the biofilm formation or not. (Presterl et. al 2005). These biofilms are found to have a greater importance in the environment. The biofilms, a matrix of extra cellular polymeric substances, play an important role in the synthesis and the degradation of the organic matter, processing of the sewage, treatment of the petroleum contaminated water and in the process of nitrification. These biofilms are also found associated wit the bio-corrosion. The best example for the bio-corrosion is the bacteria Desulfovibrio vulgaris which corrodes the steel. The biofilms are of great advantage to the bacteria. The biofilms, the matrix, protects the bacteria from the UV exposure, salinity, metal toxicity, acid exposure, antibiotics, antimicrobial agents and dehydration. The study of these biofilms in the human tissue is still a question. (Dongari-Bagtzoglou 2008). The biofilms are found on the amniotic fluid sludge also. The amniotic fluid sludge was detected and retrieved by transvaginal amniotomy, when this sludge was viewed under the scanning electron microscope and fluorescence insitu hybridization technique, bacteria were identified from them. The presence of the exopolymeric matrix was identified by using the histochemistry using wheat germ agglutinin lectin method. The physical structure of the biofilm was analyzed using the laser scanning microscopy. The researchers are now in the stage of the determining the prevalence of the microbial biofilms in the intra-amniotic infection. Here the diagnosis of the presence of the biofilms and microbial invasions is extremely challenging and the current methods are not sufficient in the detection of the infections. (Romero 2008). The biofilms formed on the living cells show a vary avidity for the specific environment. Some of the bacteria form the biofilm very quickly as in the buccal and the vaginal epithelia and others are colonized only adhering to the specific ligands present in the body. As these biofilms are threatening the medical society, various measures have been taken to control the biofilm formation. The novel combinations of the physical and the chemical techniques are prepared to enhance the activity of the antibiotics. Similarly the invention of the novel antibiotics with increased antibiotic ability can be done. The research on the development of the anti-adhesive compound can be done as it will inhibit the bacteria from adhering to the surface to form the biofilms. It was proved that the bacteria exhibit different characters when they are found at the top and bottom of the biofilms. The smart surfaces created by using the smooth regions without any cracks or space for the micro organisms deposit can be used to reduce the infections. What ever may be the technique developed all have the disadvantage of small life span. Similarly the use o the probiotis for the reduction or removal of the bacteria from the infection site can be practiced. The best example is the use of the bacteria culture to prevent the yeast contamination in the artificial voice boxes. This technique is very easy to practice and can produce great results on usage. All the above said techniques and ideas have cleared the clinical tests and now provide the key for future control strategies. (Jass 2003, Costerton, Montanaro and Arciola 2005). References: Byrd, M. S., B. Pang, M. Mishra, W. E. Swords, and D. J. Wozniak 2010, The Pseudomonas aeruginosa Exopolysaccharide Psl Facilitates Surface Adherence and NF-kappaB Activation in A549 Cells, American Society for Microbiology, vol. 1, no.3, pp.140-10 Costerton, J.W., L. Montanaro and C. R. Arciola 2005, Biofilm in inplant infections: its production and regulation, The International Journal of Artificial Organs, vol.28, no.1, pp.1062-8. Dongari-Bagtzoglou, A 2008, Pathogenesis of mucosal biofilm infections: challenges and progresses, Expert Review of Anti-Infective Therapy, vol. 6, no. 2, pp. 201-8. Donlan, R. M and Costerton, J. W. 2002, Biofilms: Survival Mechanisms of Clinically Relevant Microorganisms, Clinical Microbiology Reviews, vol .15, no. 2, pp.167- 193. Hannig C., M. Follo, E. Hellwig and A. Al-Ahmad 2010, Visualization of adherent micro- organisms using different techniques, Journal of Medical Microbiology, vol. 59, pp 1-7 Jass, J., S. Surman and J. T. Walker 2003, Medical biofilms: detection, prevention, and control, John Wiley and Sons. nidcr.nih.gov 2010, National Institute of Dental and Craniofacial Research, Immunology of Biofilms, accessed on 2nd September 2010, http://www.nidcr.nih.gov/GrantsAndFunding/See_Funding_Opportunities_ Sorted_By/ConceptClearance/CurrentCC/ImmuneBiofilm.htm Presterl E., A. J. Grisold, S. Reichmann, A. M. Hirschl, A. Georgopoulos and W. Graninger 2005, Viridans streptococci in endocarditis and neutropenic sepsis: biofilm formation and effects of antibiotics, Journal of Antimicrobial Chemotherapy, vol. 55, no. 1, pp. 45-50 Romero, RM and Scaudinin, C 2008, Detection of a microbial biofilm in intra-amniotic infection, American Journal of Obstetrics & Gynecology, vol. 198, no. 1, pp. 135 Watnick, P and Kolter, R 2000, Biofilm , City of Microbes, Journal of Bacteriology, vol. 182, no. 10, pp. 2675-2679. Read More