Practical Microbiology Lab. 4 PDF

Assist. Prof. Dr. Ameer Mezher Hadi Al-Zahrawi University College Lab. 4 Practical Microbiology Department of Dentisy ‫ــــــــــــــــــ...

Assist. Prof. Dr. Ameer Mezher Hadi Al-Zahrawi University College Lab. 4 Practical Microbiology Department of Dentisy ‫ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ‬ 1- Differential media  allow multiple bacteria to grow but with distinguishable colonialcharacteristic.  Allow for preliminary characterization of bacteria.  Example:  Blood agar: is a type of enriched medium but give hemolyticcharacteristic of bacteria  Combination media [selective and differential media]  Mannitol salt agar selective and differentiation ofStaphylococci. 1 Assist. Prof. Dr. Ameer Mezher Hadi Al-Zahrawi University College Lab. 4 Practical Microbiology Department of Dentisy ‫ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ‬ Table : Differential Media Medium Substances That Differentiates Between Facilitate Differentiation Blood agar Intact red blood cells Types of hemolysis displayed by different species of Streptococcus Mannitol salt Mannitol, phenol red Species of Staphylococcus agar MacConkey agar Lactose, neutral red Bacteria that ferment lactose (lowering the pH) from those that do not Urea broth Urea, phenol red Bacteria that hydrolyze urea to ammonia Sulfur indole Thiosulfate, iron H2S gas producers from nonproducers motility (SIM) Triple-sugar iron Triple sugars, iron, and Fermentation of sugars, H2S production agar (TSIA) phenol red dye 2 Assist. Prof. Dr. Ameer Mezher Hadi Al-Zahrawi University College Lab. 4 Practical Microbiology Department of Dentisy ‫ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ‬ 1- Transport media:  Used when specimen cannot be processed immediately.  Preserve the viability of microorganism in specimen but not allowto growth.  Most transport media contain a salt and buffer to preventdestruction of cell by enzyme. 3 Assist. Prof. Dr. Ameer Mezher Hadi Al-Zahrawi University College Lab. 4 Practical Microbiology Department of Dentisy ‫ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ‬ 1- Enumeration media:  Used to count the numbers of organisms in milk, water, food, soil,and other samples 2- Assay media:  Used to test the effectiveness of antimicrobial drugs on the growthof microorganisms 3- Reducing medium:  Contains a substance (thioglycolic acid or cystine) that absorbsoxygen or slows the penetration of oxygen in a medium,  Important for growing anaerobic bacteria. 4