practical bacteriology from scratch

practical bacteriology from scratch

your safety first   take care when working with pathogenic microorganisms wear coat  when you are in lab and remove after finish keep the lab disk for equipment only wear gloves when dealing with microorganisms clean  clean  table before and after test mask eye protect  keep your hand away from mouth and eye and nose  use mechanical pipetting report the spill and disinfect the area well  wash hands after any procedure deal well with fire smooth small one with towel large one use expenditure follow the instructions included in lab safety manual be professional in handling microscope  there are many types with many uses bright field microscope  dark field microscope phase contrast microscope fluorescent microscope electro microscope  it is essential tool practice using the microscope with low power medium power  high power and take care when use oil immersion lens sterilization the most important topic in microbiology  without keeping your environment sterile it is impossible to obtain Apure culture  sterilization methods heat sterilization  sterilization by radiation sterilization by disinfectant chemicals   use of antimicrobial bacterial culture is a  method for isolate bacteria the culture may be natural in origin or synthetic or both culture may be ordinary enriched      blood agar is enriched media They contain substances Blood ,Serum. Extract of plants or animal tissues that enhance growth of bacteria   Heated blood agar chocolate agar ▪ heated blood agar chocolate agar heating blood ▪ in water path at 75c for 10 minutes ▪ Until blood become chocolate brown in color      differential or specific  and see it in colonies which in appearance characteristic after culture we need to sea the bacterial cell clearly stain  our tool to change the background and sea bacterial morphology and enhance the contrast we sea details  differential or structural preparing the smear and fix on Bunsen flame   simple stain like methylene blue crystal violet negative staining is simplest method   differential stain differentiate the bacteria into two groups  like gram stain differentiate bacteria into gram +ve gram -ve  it is invented by hans gram he use methylene blue as basic stain iodine as   bacteria are not decolorized and remain violet after decolorization carbol fuchsine a red counter stain is used to impart a pink color to the decolorized gram negative organisms The acid fast stain is a different stain in 1882 Paul Ehrlich discovered mycobacterium tuberculosis the causative agent of tuberculosis retained the primary stain even after washing with an acid alcohol mixture most bacteria are decolorized by acid alcohol only family mycobacteriacae and nocardiacea The cell wall of acid fast contain wax like lipid called mycolic acid render the cell impermeable to most stain technique developed by franz zeil and fredrch neelsen capsule stain Some bacteria are surrounded by slimy layer called capsule some glycoprotein some polypeptide all appear water soluble heat fixed smear destroy the capsule if not fixed slide from slide combine negative and simple staining species of bacteria related to genera bacillus or clostridium produce heat resistant structure called spores resistance to chemicals and heat due to thick tough spore coat  Schaeffer- Fulton methods utilize malachite green to stain the endospores and safranin or carbol fuchsin to stain the vegetative portion of the cell green spore contained in pink vegetative bacilli

bacteria to continue its life and defend herself produce enzymes like oxidases catalase coagulase we use these enzyme in identifying every bacteria biochemical test are designed for this purpose step by step you can be bacteriologist  just keep going