Lab 01 Microbio (BIO 28)

What are some key lab rules?

• Golden Rule: treat all microorganisms as potential pathogens

• Don’t wear contacts

• Don’t eat or drink in the lab

• Wear gloves if handling blood or human product

• No open toe shoes

• Every piece of trash has an appropriate destination

• Clear workspaces of bags, books, etc.

• Clean workspace and wash hands before and after leaving lab

• Label everything! For glass and test use labeling strips

How do you clean a chemical spill?

Cover up spills and accidents with 70% ethanol or 10% bleach and let paper towels sit over them for around 10 minutes. Discard of the materials in their appropriate containers.

What is sterile? How are things sterilized?

• Sterile is free of all forms of life, nothing can be born here.

• Things are fully sterilized through an autoclave which uses 121 (C) and extreme pressure to kill everything including endospores (resistant structures formed by some bacteria and can create new bacteria under the right conditions)

• Generally in microbio, healthcare, etc. everything has to be sterlized before use and after it is used (to ensure we are not releasing microbes into the enviroment). Thus the need for special trash that can be autoclaved before discarded.

What is contamination? What is the biggest source of contamination?

Introduction of unwanted microorganisms in a certain area. The biggest source is air.

Biohazard waste disposal

• Most biohazard materials (plastic culture, swabs, toothpicks, wipes and gloves) can go into plastic biohazard bags.

• Sharp objects always go into a hard walled sharp container instead of a plastic biohazard bag!

Define: microorganisms, pathogens

Microorganisms: organism too small to see without some sort of magnification, naked to the human eye.

Pathogen: Disease causing microorgansim including: bacteria, virus, fungi, algae, protozoa and

Helminthes. Either the organsim itself can cause disease or the products (such as Algae)

Define: Infection vs Infectious disease

Context: Humans have microbes that live with us that are beneficial. Some microbes only belong in certain areas and are blocked off by barriers. A breach of this barrier may cause an infection.

Infection: Microbes breaching these barriers and ending up in unwanted areas. Infection does not always mean disease - if it can colonize our body and interfere with our state of health a disease has happened.

Infectious Disease: A disease in which you can isolate the infectious agent or its product from a patient

• Products can be toxins or enzymes; malaria has a specific protozoa, Botulism has a specific toxin in the blood or tools

• OR can be antibodies, i.e., an antibody test for HIV antibodies

What is Nutrient Agar (NA), and how does it work?

• Definition: A general-purpose solid growth medium used to cultivate bacteria and microorganisms.

• Key Components:

  • Nutrient Sources (Beef extract & peptone): Provide the proteins, carbohydrates, and vitamins that microbes digest and convert into energy for growth.

  • Solidifying Agent (Agar): A carbohydrate derived from marine red algae that turns liquid broth into a solid surface.

• Why Agar (vs. Gelatin): Most microbes cannot digest agar, so the medium stays solid during incubation (unlike gelatin, which bacteria can liquefy).

What are biosafety levels?

BSL. All living microbes are grouped into 4 categories based off their pathogenicity (ability to spread), BSL 1 - BSL 4

What is BSL 1?

BSL 1- Non-pathogenic and not known to cause any disease

• Can cause disease in immunocompromised patients

• Practice common sense and a normal level of lab safety (i.e what we learned)

• Example: b subtilis, which is found everywhere OR E. Coli, common in the human intestine

What is BSL 2

BSL 2- Known pathogens and known to cause disease

• Picked up from the environment, sharing things but not extremely viral

• Inoculation and other percutaneous injuries, ingestion, mucous membrane
  exposure.

• Examples: Hep B, Hep C, HIV (some say this is BSL 3)- Usually no known inhalation tranmission

• Usually transmitted through ingestion, injury, mucous membrane exposure

• Precaution: Care for sharps, keep cuts covered, no eating and drinking, usually behind a Class I or II biological safety cabinet (behind a glass w/o ventilation)

What is BSL 3 and 4?

BSL 3- serious or lethal diseases transmissible vie inhalation. (ex:
M. tuberculosis, SARS)

Transmission: aerosol inhalation, inoculation and other percutaneous injuries, ingestion, mucous
membrane exposure

• Added safety precautions, ventilation, improved air flow, etc.

BSL 4- Extremely exotic agents where disease has a high fatality rate

• Morbidity leads to morality

• Ex: E bola

• Only a couple of specialized laboratories exist to deal with

What is the difference between Normal (Resident) Flora and Transient Flora?

• Normal (Resident) Flora: Microorganisms that permanently live in and on the body (skin, mouth, hair, nails, digestive/urogenital tracts). They are generally harmless or beneficial.

• Transient Flora: Temporary microbes picked up from the environment or surfaces throughout the day. Some could be pathogenic, could cross barriers and cause infection.

• Health Impact: Transient microbes can include potential pathogens. They can enter the body through breaks in the skin (open wounds) or ingestion (eating without washing hands) to cause infection.

Which body systems have normal flora, and which are considered sterile?

Open Systems (Have Normal Flora): Body systems exposed to the external environment, such as the respiratory, digestive, and urinary/reproductive tracts.

Closed Systems (Normally Sterile): Internal areas not exposed to the outside environment, including the blood, bone, muscular system, nervous system (brain/spinal cord), and internal organs.

How do handwashing experiments use Colony Forming Units (CFUs) and colony characteristics?

• Handwashing Purpose: Simple handwashing mechanically removes superficial transient flora to prevent pathogen transmission.

• CFU (Colony Forming Unit): A visible microbial colony that arises from a single viable cell or group of cells.

• Measuring Effectiveness: Comparing the number of CFUs before and after handwashing shows how effectively bacteria were removed.

• Colony Characteristics: Features such as shape, size, texture, and color are used to identify and distinguish different species of bacteria and fungi growing on agar.

Define inoculation

To introduce a microbe into a growth medium purposefully

What is environmental surveillance?

Looking for microbes in an environment to find new drugs or to ensure good public health.

Basically, to assess both the types and numbers of specific microbes present in specific environments.

Examples of environmental surveillance

Healthcare:

• Workers/agencies will often swab OR’s, rooms, and every part of the hospital to ensure people are washing their hands and that sanitation methods are effective.

Public health:

• Ensure restaurants are preparing food correctly w/ no disease risk

• Check the environment to look for new disease

New antibodies:

• Drug companies sample soil and other environments to look for microbes that could be effective anitbitoics or other drug use