Microbiology & Infection Control Overview

Microbiologists have specific conventions for naming bacteria, and it was previously assumed straightforward but requires detailed note-taking.

When typing bacterial names on a computer, one should use italicized font to denote them.
- Italicize by highlighting the text and clicking the I button at the top of the interface.
When handwriting, the bacterial names must be underlined instead of italicizing.
- Important for clarity and adherence to microbiological conventions.

There are specific terms for describing bacterial shapes:
- Coccus (plural: cocci) - spherical-shaped bacteria.
- Diplococci-Cocci in a pair (aka Cat-Eyes)
- Bacillus (plural: bacilli) - rod-shaped bacteria; informally referred to as bacilli in some dialects.

Bacteria can be divided based on gram staining results into Gram-positive and Gram-negative.
- Gram-positive cocci can form arrangements of clusters or pairs.
  - The arrangement can appear similar to cat eyes under the microscope.
- Bacilli are primarily described simply as Gram-positive rods or Gram-negative rods, without detailing spatial arrangement.
- Important distinction in identifying diplococci arrangements, especially in Gram-positive samples.

The shape of bacteria is generally hereditary but can be altered by environmental factors or antibiotic exposure.
- Some bacteria exhibit pleomorphic characteristics (varying shapes), especially among bacilli.
Gram-negative cocci exhibit a kidney bean appearance while observing their morphology.

Discussed important components such as peptidoglycan walls, glycocalyx (slime layer), and flagella variations.

The objective is to empower students to understand Gram staining for pure cultures and identify primary organisms accordingly.

Sterilization- The process of eliminating all microbial life, including resistant spores.
- Special attention is required for potential virulence factors that reside within endospores.
- Understanding that if endospores survive, then bacteria can re-emerge, leading to infections.
- Stress on the fact that once sterilization is achieved, it is considered permanent.

Disinfection- The process that does not kill all spores or viruses; rather, it reduces or inhibits bacterial growth and is used primarily on surfaces.
- Requires sufficient exposure time to be effective:
  - Recommended to keep surfaces wet with disinfectants for about three to five minutes depending on the pathogen.
- Importance of cleaning heavy spills before disinfecting.

Antisepsis: Chemical disinfection of skin or mucous membranes; includes actions such as showering but with a deeper clean like what is performed in phlebotomy.
Germicide: Rapidly kills bacteria but does not destroy spores.
Bacteriostasis: Inhibits growth without killing the organism; many antibiotics function in this manner.
- Compliance with antibiotics is stressed to prevent rebound infections.

Asepsis: Total removal of pathogens from an object.
De-germing: Mechanical cleansing of skin to remove transient microbes (e.g., washing hands).
- Antiseptic methods offer deeper cleaning than de-germing with soaps and antibiotics.

Sanitization reduces pathogens to safe levels but does not guarantee sterility, commonly practiced in food service. For example, restaurants have 3 different sinks for dishwashers: 1 to wash, 1 to rinse and 1 to soak in sanitizing solution.
- Centers on mechanical cleansing and use of sanitizing chemicals.

Moist heat - a method of killing bacteria through boiling or flowing steam. It denatures proteins to kill microorganisms typically after ten minutes of exposure, but it may not kill endospores.
Autoclaving -a method of killing bacteria that utilizes high heat and pressure, generally for fifteen minutes, and it kills endospores.
Dry heat -we can use this method to kill bacteria by 1. Direct Flaming 2. Incineration and 3. Hot-air sterilization
Direct flaming - an effective way of killing bacteria through directly exposing it to an open flame
Incineration -a dry heat method that provides efficient sterilization through completely burning it with caution
Hot Air Sterilization -a dry heat method that effectively kills bacteria at high temperatures (170°C for 2 minutes).
Pasteurization -a method that effectively kills pathogens mostly in foods like milk at 72°C for fifteen seconds to prevent spoiling. This kills all pathogens and some non-pathogens.

Filtration - a method that separates bacteria from liquids by running it through a screen or mesh filter. This is usually used in water treatment plants and household water filters.

Refrigeration: A cold bacteriostatic method that inhibits growth but does not kill.
Deep freezing -a cold method that preserves bacterial cultures, often supplemented by substances like glycerol.

Lyophilization - a cold method that Involves drying in a high vacuum and freezing at extreme temperatures (<20 deg. C) for long-term storage.
- Used for lab reagents and quality controls.
Desiccation - a method that removes water, which can inhibit microbial growth.
Radiation - a class of methods that includes gamma rays and UV light/sunlight (Non-ionizing) and Ionization, that are effective in disinfection but require careful handling.
Osmotic Pressure - a method used to filter and kill bacteria through Plasmolysis

10% Bleach (Clorox) - This disinfectant is regarded as the best and most common disinfectant for surfaces and in laboratory countertops (not on analyzers)
To make it, you use 10% of a jug of bleach, then add the rest of it with water.
Understanding the correct use of disinfectants, including knowing the correct concentrations for application, is crucial for efficacy.

70% Isopropyl Alcohol - #1 use as skin antiseptic
Chlorhexidine - it’s harsh on skin and is usually used for surgical scrubs
Povidone Iodine - Iodine and alcohol mixed together to make this antiseptic that is often used for surgical scrub

Alcohol - An antiseptic that is best used on devices like analyzers. 70% Isopropyl alcohol is good for the skin.

Silver - This metal is a really good disinfectant that has bacteriostatic properties. It’s used to prevent Neisseria gonorrhea in kids. We must be sure to read the label to know how well to use it.

Importance of washing hands often, especially when handling money and in contact with various surfaces to prevent infection.
- Hand sanitizers, especially those containing alcohol, serve as effective disinfectants when washing is not feasible.

Emphasized protocols in food safety including multiple sink use for washing dishes and sanitizing.
The impact of improper hygiene practices on foodborne disease outbreaks, especially in public settings.