Lab 10- Hand washing/UV light

What are the normal skin biota

M luteus, S. epidermidis, S. aureus, Corynebacterium, Propionibacterium acnes

What are transient organisms

Organisms found on our skin, but do not normally grow there and are usually acquired through contact with a contaminated surface

What is the most effective way of getting transients off our skin

They are more easily removed through hand washing, which is the major way in which they are transmitted

What are the 3 components of handwashing

Friction: at least 20-30 seconds to remove the emulsified skin oils

Soap or detergent: Soap is a surfactant: surfactants insert in the lipid bilayer disrupt it & create abnormal channels that alter permeability & cause leakage both into & out of the cell. Emulsifies skin oils that have transient bacteria trapped in them

Incorporation of antiseptic into soap: kills remaining microbes without harming skin

How does a surfactant (soap) work to get rid of transients

Binds to oils in skin that contain bacteria, Emulsify oils and allow them to be scrubbed off, Can disrupt the cell membrane

What are some of the limits of surfactant like soap

Some bacteria (mycobacteria) have waxy cell walls that resist surfactants, Endospores are usually not affected

Why is it so important for clinicians to wash their hands between patients

Clinicians can have pathogenic bacteria/viruses or fungi on their hands and they can transfer this bacteria and stuff to the patients especially immunocompromised ones. Washing hands is the best way to prevent infections and protect both patients and healthcare workers

Which technique of handwashing worked best for your lab

1 minute of soap and water is the most effective way

In general what are the most difficult organisms to kill

Prions (hardest to kill), Bacterial endospores, Staphylococcus and Pseudomonas (easiest to kill out of these 3)

How does UV radiation kill bacteria

Gamma (ionizing) radiation kills by creating free radicals within the cells. UV (nonionizing) radiation kills by damaging the DNA and creating dimers between adjacent thymine or cytosine in the DNA

What does it do to the DNA of cells

damaging the DNA and creating dimers between adjacent thymine or cytosine in the DNA (nonionizing)

What are some limitations of using UV light to kill microbes

Can’t penetrate plastic and glass, Can only be used on surfaces, air, and water, Not good on living tissue

Which bacteria was more resistant to killing by UV and why

Bc. because it forms endospores

What places would UV use would work well

It would work well in a hospital setting by disinfecting the operating rooms, patient rooms, ICUs, etc… Labs

If UV light didn’t inhibit growth what could be some reasons why

Could’ve left the lid on and the UV can’t penetrate the lid,