Basic Microbiology and Immunology Practical Course 2016

Lab #1: Microbes everywhere plus contamination sources Basic Microbiology and Immunology

Microbiology… what is it???  Microbiology is the science dealing with microorganisms.  We are going to study microorganisms: 1. Microscopically 2. Macroscopically 3 Basic Microbiology and Immunology 2016

Lab #1: Introduction to Basic Microbiology  What is meant by culture media?  What is aseptic technique?  Microbes… are they found everywhere around us??? 4 Basic Microbiology and Immunology 2016

Microorganisms… How to see them?  To see and study microorganisms, that are invisible to the human eye, you need to either: 1. Magnify them (by using a microscope) OR 2. Multiply them in number (by growing them on culture media) 3. Detect their genetic material Basic Microbiology and Immunology

What is a culture medium?  Definition: It is a material used for growing microorganisms.  It exists in different forms:  Liquid  Solid  Semi solid 6 Basic Microbiology and Immunology 2016

What are the essential components of any culture medium???  Any culture medium must contain:  A source of energy  Sources of carbon, nitrogen, sulfur, phosphorus  Minerals (Example:Ca 2+,Mg 2+, Na + )  Vitamins and growth factors  Water 7 Basic Microbiology and Immunology 2016

What is a basic medium composed of??? 8 Basic Medium Nutrient Broth (liquid form) Nutrients + Water Nutrient Agar (solid form) Nutrient Broth + 2% Agar Agar* *Agar agar It is an un- branched polysaccharide obtained from the cell membranes of some species of red algae or seaweed Solidifying agent Melts at 98°C and solidifies at 42°C Not digested by microorganism Basic Microbiology and Immunology 2016

Examples of different forms of solid culture media 9 Basic Microbiology and Immunology 2016 Solid medium in a slant Solid medium inoculated by deep inoculation Solid medium in a petri dish

Microbes are found everywhere around us… How can we deal with that??? Basic Microbiology and Immunology Aseptic technique  Definition: The procedure used by microbiologists to prevent infection or to avoid self contamination

How can we make sure that we are working in an aseptic area??? Basic Microbiology and Immunology An aseptic area has the following format and rules: 1.Work in a 20 cm diameter around a blue flame 2. Never leave a culture dish open, even for a short time 3.When it is necessary to open a dish, keep the lid close to the dish and keep the lid between your face and the agar surface

Rules that must be followed to maintain an aseptic zone Basic Microbiology and Immunology For most bacterial cultures, you will use a sterile loop to inoculate or to obtain an inoculum. Flame the loop to red-hot prior to use to sterilize it. Cool the loop prior to touching the culture.

Rules that must be followed to maintain an aseptic zone (cont’d) Basic Microbiology and Immunology Pass the neck of a culture tube or any container with a culture or sterile contents through a flame before taking culture from it Use sterile glassware Use sterile culture media

Experiment #1: Microbes all around us… How to see them? You are provided with:  One sterile Petri-dish  One molten nutrient agar tube You are required to: 1. Pour the nutrient agar tube at the suitable temperature aseptically into the provided plate. 2. Leave the nutrient agar plate to solidify. Basic Microbiology and Immunology

Experiment #1: Microbes all around us… How to see them? You are required to: 3. Expose the agar plate to one of the following sources of contamination:  Air (outside the aseptic area)  Forced air (inside the aseptic area)  Skin touch (inside the aseptic area)  Cough (inside the aseptic area)  A piece of hair or cloth (inside the aseptic area)  A drop of water (inside the aseptic area) Basic Microbiology and Immunology

Experiment #1: Microbes all around us… How to see them? You are required to: 4. Designate a student (per bench) to do a control plate (not exposed to any source of contamination) 5. Label the cover of your plate with your name, number and source of contamination. 6. Incubate all your plates in the drawer beneath you in an inverted position except for the one contaminated with water (leave it upright). 7. Incubation of the plates at 37°C for 24 – 36 h allows the microorganism to reproduce. Basic Microbiology and Immunology

Incubation  At the end of the incubation period, there should be enough microorganism to form visible colonies. Basic Microbiology and Immunology Each bacterium multiplies to give a visible mass called a colony.

See you next lab to learn how to make a stain Basic Microbiology and Immunology