Microbiology Laboratory Course Overview

Microbiology Laboratory Course - January 20-21, 2025

• Course dates are January 20-21, 2025
• The course covers microbiology practices and lab rules, glassware, microbiology tools, microscopy, handling and examining cultures and waste disposal.
• Instruments used in microbiology lab include: Analytical balance, Autoclave, Bunsen burner, Centrifuge, Colony Counter, Deep Freezer, Homogenizer, Hot plate, Hot air oven, Incubator, Laminar Air Flow/Laminar Hood, Magnetic Stirrer, Microscope, pH Meter, Spectrophotometer, Vortex Mixture/Vortexer, Water Bath, Water Distiller, Petri-dishes and culture plates, Bijoh bottles, and Durham tubes.

Analytical Balance

• An analytical balance is a type of balance commonly used to measure mass in the sub-milligram range.

Autoclave

• An autoclave is a pressurized chamber used for sterilization and disinfection using time, pressure, and steam.
• The autoclave combines three factors: time, pressure, and steam.
• Autoclaves use steam as the sterilization agent.

Bunsen Burner

• A Bunsen burner is a gas-fueled, single open flame, standard lab tool.
• It is named after Robert Bunsen.

Centrifuge

• A centrifuge is a device allowing the rotation of an object around a single axis.
• Outward force is perpendicular to the axis.
• Lab centrifuges are motor-based to rotate liquid samples.
• This leads to the separation of components of the mixture.
• Centrifuges use the principle of sedimentation.

Colony Counter

• A colony counter estimates the density of a liquid culture by counting CFUs (colony-forming units) on agar or culture plates.
• It can accommodate different plate sizes, allowing manual counting (touch pressure) or using a digital counter.

Deep Freezer

• A deep freezer preserves substances at extremely low temperatures to minimize microbial growth.
• This principle prevents change in concentrations over long periods of time.
• Useful in preserving medical equipment, food items, blood samples, medicines, and injections over extended periods.

Homogenizer

• A homogenizer is a device for mixing various liquids and materials, such as tissue, plants, food, soil, and more.
• The device works by passing large globules of substances through a narrow orifice at high pressure.

Hot Plate

• A hot plate is a standalone heater used in microbiology labs as a tabletop heating system.
• It uses electricity to produce heat via coils.
• The plates are used for heating glassware and other components.
• Hot plates are often used with water baths.

Hot Air Oven

• A hot air oven is an electrical device used for sterilizing equipment and samples using dry heat.
• The oven uses a forced-air or static-air principle to evenly distribute heat, preventing materials from overheating or catching fire.

Incubator

• An incubator is a device used in labs for the growth and maintenance of microorganisms and cultures.
• Incubators provide optimal temperature, pressure, moisture, and other conditions needed for microorganism growth.

Laminar Air Flow/Hood Chamber

• A laminar air flow/hood chamber is a closed device used for processes and instruments sensitive to microbial contamination.
• The device uses HEPA filters and UV germicidal lamps for sterilization.
• It maintains a sterile environment.

Magnetic Stirrer

• A magnetic stirrer is used in microbiology labs for mixing liquids.
• It utilizes a rotating magnetic field that rotates a stir bar to mix the liquid.
• It is noise-free, and the tiny stir bars reduce contamination.

Microscope

• A microscope is a device that allows for an extremely close view of minute particles.
• Microscopes vary in type and use, but based on magnification and position of the object from the lens or electromagnets, a clear view can be achieved.

pH Meter

• A pH meter measures the H-ion concentration in water-based solutions to determine acidity or alkalinity.
• It functions via a potentiometric method, measuring the electric potential between a reference and pH electrode.

Spectrophotometer

• A spectrophotometer is an optical instrument that measures light intensity related to wavelength.
• Quantitative analysis is possible by measuring light absorption from a colored solution.

Vortex Mixture/Vortexer

• A vortex mixer aids in mixing samples in glass tubes or flasks.
• Motorized shafts inside create turbulent flow within the sample fluids.

Water Bath

• A water bath is a standard device used for chemical reactions requiring a constant controlled temperature.
• A sensor transfers water temperature to a reference value in the system that heats the water to the desired temperature to control temperature for reactions.

Water Distiller

• A water distiller purifies water through the distillation process.

###Wire Loop on Petri Dish

• A wire loop is used to transfer cultures between Petri dishes.

BIJOH Bottles

• BIJOH Bottles are used for sugar fermentation tests.

Glasswares

• A variety of glassware is used in microbiology labs.

Durham Tubes

• Durham tubes are used to check for gas production during fermentation tests.
• They are inserted upside down inside bigger tubes to monitor gas production.

Microscopy Instructions

• Includes microscope parts, instructions for proper use, care and handling.
• Microscope care and handling instructions focus on safe operation and maintaining cleanliness.

Handling and Examining Cultures

• Microscopic examination is an important aspect of observing microorganisms, providing information on their morphology.
• Handling and examining cultures require supplying appropriate nutrients, and moisture in proper composition in a medium (broth, agar, semi-solid etc.).

Classification of Culture Media

• Classification of Culture Media based on physical nature (liquid, semi-solid, solid, biphasic) and function (supportive, enriched, selective, differential, indicator, transport, anaerobic).

Types of Culture Media

• Culture media descriptions according to their physical form: liquid, solid, semi-solid.
• Examples of culture media formats: broth, agar plates.
• Solid media is suitable for separating bacterial growth and isolating species.

Solid Media - Colony

• A colony represents a single species of bacteria, originating from a single cell.
• Colonies can be transferred to another medium to grow as a pure culture.

Pure Culture

• A pure culture contains only one type of microorganism.
• Single, separated colonies are essential in obtaining a pure culture from multiple organisms.

Evaluation

• Each colony on a plate represents one species of bacteria.
• Transferring a single colony permits the study of one species without interference from others.
• Colony morphology (appearance of the colony) is important for characterizing and identifying microorganisms.

Disposal of Laboratory Wastes and Cultures

• Treat waste to prevent transmission of diseases.
• Proper treatment is needed to prevent contamination of soil, water, and air.
• Waste materials like culture media, cotton plugs, paper, and more should be treated before disposal.