MICROBIOLOGY Bacteria Questions and Answers

MICROBIOLOGY Bacteria Questions and Answers The ability of an unseen pathogen to cause disease can be profound. As a nurse you will not be aware that you are carrying a disease causing organism unless it's symptomatic. The relevance of microbiology to nursing practice Before the discovery of organisms people believed superstitious beliefs were the cause of disease. Microscopy allowed the identification of 2 distinct types of cells. Brief history of microbiology? Fundamental to establishing a link between bacteria and disease. Koch took anthrax from a diseased animal and grew this in a pure culture. Koch then injected the culture material into a healthy animal which was isolated which then died of from anthrax. Koch then identified this bacteria. Germ Theory of Disease Microbiology The study of microorganisms Immunology The study of the immune system Infection Control The interventions to reduce harm caused by pathogens Nomenclature Bacterial Classification Genus and Species Classification includes 2 names Strains Species can be subdivided into Bacteria Unicellular living organisms which lack organelles and a nucleus. Genetic material is not confined to a membrane. Gram Positive Thick layer of peptidoglycan wall. Teichoic acids. Resist decolorisation by ethanol. Gram Negative Presence of lipopolysaccharides which can be removed by alcohol/acetone meaning cell wall is de-colourised by ethanol. Bacteria have an outer membrane above the peptidoglycan layer. Penicillin inhibits the formation of cross linking amino acids during the synthesis of peptidoglycan cell walls. Gram positive bacteria do not have an outer membrane layer protecting the cell wall meaning Gram positive bacteria would be more susceptible. Would gram negative or gram positive bacteria be more susceptible to Penicillin bacterial cell membrane -Phospholipid Bi-layer -Embedded proteins 1. Primary stain (crystal violet) 2. Mordant (Helper solution) 3. De-colouriser (95% ethanol) 4. Counter stain (Safranin) Gram Staining Process Coccus Diplocci Staphlococci Streptoococci Sarcina Tetrad Coccobacillus short round rod Bacillus Rod shaped bacteria Spirillum spiral shaped bacteria Spirochaete Vibrio curved rod Bacterial Cytoplasm Consists of 80% water and 20% salts-protein. This is important for osmotic shock. Osmotic Shock A sudden increase in osmotic pressure within a cell that is moved rapidly into a hypotonic environment. Capsule or Slime Layer An external layer found on some, but not all, bacteria. This layer is found outside the cell wall and offers additional protection to the organism. Normal Flora Microorganisms that reside in or on the body that have homeostatic functions. Pathogen An organism that causes disease Flagella A long, whip-like filament that helps in cell motility. Many bacteria are flagellated, and sperm are flagellated. Pili Short, hairlike protein structures on the surface of some bacteria. They are involved in cell to cell attachment during bacterial conjugation. Fimbriae Thinner and shorter than pili. Involved in cell surface attachment of bacteria. Bacterial Conjugation The direct transfer of genetic material (DNA) from one bacterial cell to another (Bacterial Sex)