STOOL MICROSCOPY AND CULTURE Objectives 1. To know the procedure of processing a clinical stool specimen. 2. To perform microscopical examination on stool. 3. To perform a culture on the stool. 4. To make presumptive identification of pathogens isolated from the stool culture. Procedure 1. Describe the appearance of the stool sample provided. 2. Using the direct saline method make a wet mount of the stool specimen provided. 3. Examine the preparation using the 10x objective, adjust the objective to 40x for a close and higher magnification. 4. Distinguish between WBC, RBC, bacteria and parasitic ova or larvae. 5. Report on your findings using the work sheet provided. 6. Culture the stool sample onto BA with ampicillin, MCA, Skirrows media and selenite broth. 7. Incubate the medias in their respective temperatures and atmospheric conditions. 8. Read cultures after 24 hours of incubation Stool culture reading 1. Describe the colonial morphology and growth on the culture plates. 2. Distinguish the significant growth from the non-significant ones. 3. Identify your pathogen(s) by performing the standard microbiological tests. 4. Make a presumptive identification of the pathogenic isolates. 5. Complete the work sheet. 6. Report the stool results on the respective request form. Questions 1. What is “occult blood”? 2. Describe the procedure for occult blood. 3. Name the other methods for detecting parasites in stool. 4. How can features of parasites, parasitic eggs, etc. be highlighted during the microscopical examination? 5. Give the synonyms of the following parasites; hookworm, pinworm and round worm. 6. What is the significance of each of the following medium used for stool cultures? 7. What does the presence of numerous WBC in stool microscopy indicate? 8. What does the presence of numerous RBC in stool microscopy indicate? 9. Name 4 bacterial stool pathogens and outline how you will identify each of them from your primary culture plates.