HSS 1100 Lecture 3: Week 3 - General Principles of Diagnostic Microbiology.docx

• School: University of Ottawa
• Department: Health Sciences
• Course: HSS 1100
• Professor: William Yan

Document Summary

Microorganisms in nature exist as mixed cultures and are therefore difficult to study. In order to characterize microorganisms, one must isolate the different species from a clinical specimen. Nutrient material called culture media used to grow and isolate microorganisms. The type of media used based on many factors to be considered: i. ii. iii. Small portion of sample (inoculum) is used to inoculate different media to isolate microorganisms. Methods of inoculation include: i. ii. iii. Inoculated media must then be incubated at the appropriate temperature (normally 37 c) to allow microorganisms to grow and multiply. When enough cells have divided (approx. a few million), colonies are formed which are visible to the naked eye. Each colony is derived from a single cell and all cells within a colony are identical to each other. Different species have different colonial morphologies therefore can be used as mean of distinguishing different species in a mix culture.