The Science of Escherichia Coli essays

The Science of Escherichia Coli essays Escherichia coli (E. coli) is a member of the family Enterobacteriaceae along with Shigella, Yersenia, Klebsiella, Salmonella, and Proteus spp. These are microbes that are normally seen worldwide in soil, water, vegetation, and even as normal flora of the gastrointestinal tract (Cohen, Powderly, Opal, Berkley, Calandra, Clumeck, Finch, Hammer, Holland, Kiehn, McAdam, Maki, Norby, Holland, Solberg, and Verhoef, 2004). The commensal E. coli normally inhabits the human intestines and may even be beneficial to man by participating in digestive processes. However, commensally and pathogenic E. coli strains can cause illnesses that manifest with mild to severe symptoms such as diarrhea, meningitis, urinary tract infections (UTI), or fatal septicemia. E. coli is a gram-negative, non-spore forming short to ovoid, rod-shaped bacteria. Like other enterobacters, its cell wall has several components: an inner cytoplasmic membrane, a peptidoglycan layer, an outer membrane that consists of an inner phospholipids protein layer and an outer lipopolysaccaharide (LPS) layer, and an additional capsule. The integrity of the cell wall is necessary to keep the organism alive. The cytoplasmic membrane regulates nutrient and metabolic products coming in and out of the organism. One should be familiar with these cellular wall components because they have antigens that distinguish E. coli from others. The O-antigen is specific for E. coli's LPS. The O-antigen may possess adhesive factors that make pathogenic E. coli cause diseases such as UTI, while other O serogroups allow for colonization factors and toxins to be released for it to cause diarrhea (Cohen et al., 2004). Other identifying antigens are the capsular (K), flagellar (H), and fimbriae (F) antigens. K1 antigen of E. coli is associated with neonatal meningitis and UTI. E. coli can live without oxygen, making it a facultative anaerobe. It is capable of fermenting lactose which is the sugar found...