Introduction Nutrient agar is a general purpose medium for the cultivation of organisms that are not demanding in their nutritional requirements e.g. organisms that can be isolated from air, water, dust etc.It is the most popular media that are generally available in all laboratories for enumeration of different bacteria and their maintenance.Nutrient is made up of: Principle … Read more
By Prof Jeremiah Seni Introduction Blood agar is actually a couple of related media, all of which are rich formulations containing peptones, yeast extracts, liver or heart extracts (depending on the medium), and blood. The blood is usually sheep’s red blood cells (RBC), though horse and other species may be used. Blood agar is used … Read more
Overview Cobalt is a hard ferromagnetic, silver-white, hard, lustrous, brittle element. It is a member of group VIII of the periodic table and is located between iron and nickel and shares many chemical and physical properties with these two elements. Cobalt is found in the Earth’s crust only in a chemically combined form. Cobalt … Read more
By Prof Walter Jaoko Introduction What Is Mannitol Salt Agar? Mannitol salt agar or MSA is a commonly used selective and differential growth medium in microbiology. It encourages the growth of a group of certain bacteria while inhibiting the growth of others. This medium is important in medical laboratories as one method of distinguishing pathogenic microbes in a short period of time. It contains a … Read more
By Prof Walter Jaoko Introduction What Is XLD Agar? Xylose Lysine Deoxycholate agar (XLD agar) is a selective growth medium used for the isolation and differentiation of Enterobacter, especially Salmonella and Shigella species from food, environmental samples and clinical specimens.The agar was developed by Welton Taylor in 1965. It has a pH of approximately 7.4, leaving it with a bright pink or red appearance due to the indicator phenol red. Sugar fermentation lowers … Read more
By Prof Jeremiah Seni Introduction Pour plate method is usually the method of choice for counting the number of colony-forming bacteria present in a liquid specimen. In this method, fixed amount of inoculum (generally 1 ml) from a broth/sample is placed in the center of sterile Petri dish using a sterile pipette. Molten cooled agar … Read more
By Prof Mariam M Mirambo Introduction In microbiology, streaking is a technique used to isolate a pure strain from a single species of microorganism, often bacteria. Samples can then be taken from the resulting colonies and a microbiological culture can be grown on a new plate so that the organism can be identified, studied, or tested.The Aim of this method is to obtain … Read more
By Prof Mariam M Mirambo Introduction Endospore Staining is a technique used in bacteriology to identify the presence of endospores in a bacterial sample, which can be useful for classifying bacteria.Within bacteria, endospores are protective structures used to survive extreme conditions, but this protective nature makes them difficult to stain using normal techniques such as simple staining and Gram staining. Special techniques for endospore … Read more
By Prof Walter Jaoko Introduction Motility is one characteristic used in the identification of bacteria.The mobility in bacteria is largely credited to presence of large hair-like appendages over the body called as “flagella.” These are the locomotor organ of bacteria, though some move using axial filaments.Bacteria are classified into two: motile and non-motile. A motile … Read more