Introduction to Lab Ex. Distribution of Microbes in the Environment

1. Introduction to Lab Ex. Distribution of Microbes in the Environment

2. Introduction to Lab 8: Ex. Distribution of Microbes in the Environment This purpose of this exercise is to look for the presence of microorganisms in the environment. Using the culture media prepared in the previous lab we will look for growth of bacterial and fungal organisms in three different environments. The 3 environments that will be tested will be: - the air - personal environment - a fomite (an inanimate object that can transmit microorganisms from person to person) Using aseptic technique these environments will be swabbed and then streaked on the surface of the agar. After allowing time for growth the plates will be examined for microbial growth.

3. Microorganisms are found in various environments. These organisms move from one environment to another due to transfer by natural or human/animal interactions and movements. Microorganisms are found in the air by transfer from soil, water, animals, and humans (coughing/sneezing, etc) Fomites carry microorganisms that are transferred to their surface from the air, or from human contact. Personal environments will carry microorganisms that are part of the normal flora (organisms that are found on/in animal/human tissues under normal conditions) Moist areas of the body will host more organisms than dry areas.

4. Normal Microbiota and Host • Transient microbiota may be present for days, weeks, or months • Normal microbiota permanently colonize the host • Symbiosis is the relationship between normal microbiota and the host • In commensalism, one organism is benefited and the other is unaffected. • In mutualism, both organisms benefit. • In parasitism, one organism is benefited at the expense of the other. • Some normal microbiota are opportunistic pathogens.

5. Locations of normal microbiota on and in the human body:

6. Reservoirs of infection are continual sources of infection. • Human — AIDS, gonorrhea • Carriers may have inapparent infections or latent diseases • Animal — Rabies, Lyme disease • Some zoonoses may be transmitted to humans • Nonliving — Botulism, tetanus • Soil

7. Transmission: ways by which infectious agents are spread from one source/host to another host. • Contact • Direct Requires close association between infected and susceptible host • Indirect Spread by fomites • Droplet Transmission via airborne droplets • Vehicle Transmission by an inanimate reservoir (food, water) • Vectors Arthropods, especially fleas, ticks, and mosquitoes • Mechanical Arthropod carries pathogen on feet • Biological Pathogen reproduces in vector