Introduction to Lab Ex. Distribution of Microbes in the Environment

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.

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/humantissues under normal conditions) Moist areas of the body will host more organisms than dry areas.

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. Normal Microbiota and Host

Locations of normal microbiota on and in the human body:

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

Transmission: ways by which infectious agents are spread from one source/host to another host. Contact DirectRequires close association between infected and susceptible host IndirectSpread by fomites DropletTransmission via airborne droplets VehicleTransmission by an inanimate reservoir (food, water) VectorsArthropods, especially fleas, ticks, and mosquitoes MechanicalArthropod carries pathogen on feet BiologicalPathogen reproduces in vector