Microorganisms growing as collective communities called 'biofilms' are widely recognised today. Biofilms impact almost all aspects of human life: personal, medical and industrial. Escherichia coli are model organisms for the study of biofi lms. In this work, eight enteropathogenic E. coli (EPEe) and three Shigella sonnei strains (a bacterium that is very similar to E. coli and is often implicated in diseases that are similar to those caused by EPEe) were investigated for their biofilm fonning abilities in relation to a number of factors. These included nutrient availabi lity, pH, temperature, time, sodium chloride concentration and iron avai lability. E. coli were able to form biofilms under all conditions tested; however, S. sonne; was not able to form any biofi lms under any of the tested settings and therefore studies on this microorganism were discontinued. The results of the investigations into biofilm-fonning abilities directed the subsequent research. These included est imation of antibiotic resistance, examination of structural development of biofilrns and the inspection of biofi lm behaviour at genetic and proteomic levels. A modification of Calgary Biofilrn Device was employed to estimate resistance to nine antibiotics in biofi lm form. A Stovall Flow Cell was employed to study the structure of biofilms formed by one (selected) strain E. coli NCiMB 555 which was transformed to express gfp in order to visualize the biotilm morphology. E. coli NelMB 555 (un-transformed) biofilms were also grown to study proteins expression and gene regulation of six targeted genes. Of these four genes were up-regulated, one was down-regulated and onc was expressed at a similar level to planktonic forms. This study contributes to the existing knowledge of the biofilm formation by E. co/; under a number of conditions, their antibiotic resistance and gene- and protein-expression associated. The findings of the work have highlighted the need for more work especially in the field of antibiotic resistance. 4
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:595305 |
| Date | January 2013 |
| Creators | Kaur, Sumeet |
| Publisher | London Metropolitan University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
Page generated in 0.0106 seconds