Week 10: Bacterial Aerotolerance

Respiration

involves oxidation of substrates for energy necessary for life

Oxidation

when a substance LOSES a hydrogen ion and electron

Reduction

when a substance GAINS a hydrogen ion and electron

Oxidation Reduction Potential

measure of the tendency of a chemical substance to gain or lose electrons

obligate aerobes

an organism that REQUIRES oxygen to grow

* uses **cellular respiration**

Obligate **an**aerobes

microorganisms **killed** by normal atmospheric concentrations of oxygen

* uses **anaerobic respiration/fermentation**

Facultative anaerobes

does not require oxygen for growth, BUT grows better in its presence

* oxygen present = ATP by aerobic respiration


* no oxygen present = fermentation/anaerobic respiration

Aerotolerant anaerobes

ignores oxygen and grows equally well whether it’s present or not

Microaerophiles

requires **lower levels** of oxygen within an environment

Capnophiles

thrives in presence of high concentration of **carbon dioxide**

Biofilm

* when cells stick to e/o and also to surface
* more resistant to antibiotics

Dental caries

cavities

* breakdown of teeth due to acids made by bacteria

What type of aerobe or anaerobe is this? (extra points if u can name the bacteria used)

Obligate anaerobe

* \*clostridium sporogenes

What type of aerobe or anaerobe is this? (extra points if u can name the bacteria used)

Obligate aerobe

* \*psuedomonas **aero**ginosa

What type of aerobe or anaerobe is this? (extra points if u can name the bacteria used)

Facultative anaerobe

\*staphylococcus aureus

What type of aerobe or anaerobe is this? (extra points if u can name the bacteria used)

Microaerophile

* \*steptococcus pyogenes

What type of aerobe or anaerobe is this?

Aerotolerant anaerobe

Pellicle

Protein film

What step of **biofilm formation in the mouth** is this?

Pellicle formation

What step of **biofilm formation in the mouth** is this?

Initial adhesion

What step of **biofilm formation in the mouth** is this?

Maturation

What step of **biofilm formation in the mouth** is this?

Dispersion

What two things protect bacteria from harming the mouth?

* Saliva **washes** bacteria away
* Lysozyme **kills** bacteria

Where are some niches for bacteria in the mouth

* teeth
* tongue
* pockets under gums

What are the two important bacterias within **dental carries?**

* lactobacillus acidophilus
* streptococcus mutans

What are the 2 types of sugars **sucrose (strep mutans**) creates in relation to cavities?

* Fructose
* Glucan

What does **fructose** create in relation to cavities?

Lactic acid which breaks down enamel

What does **glucan** create in relation to cavities?

Biofilms

What test do we use to detect the susceptibility to form cavities?

Snyder’s test

Characteristics of **thioglycollate tubes**

* identifies oxygen requirements of bacteria
* medium **consumes** O2 so anaerobes can grow

What percentage of **nitrogen, oxygen and trace gases** are in the atmosphere?

* 78% nitrogen
* 21% oxygen
* 1% trace gases

How much percentage of **O2** and **CO2** is contained within a candle jar?

* 8-10% O2
* 3-5% CO2

How is oxygen free environment reached in the **candle jar**?

by lighting a small candle in the sealed jar

How is the oxygen consumed?

Flame consumes most of the oxygen which elevates the CO2 levels

How much percentage of **O2** and **CO2** is contained within the anaerobe jar?

* 0% O2
* 10-15% CO2

How is oxygen free environment reached in the **anaerobe jar?**

* Sealing jar w/ gas generator packet
* chemicals within the packet reacts w/ the O2 to create water and CO2 **(CHEMICALS + O2 → WATER + CO2)**

What does the strip in the jar indicate?

It will turn white when the oxygen in the jar is consumed

* Blue strip = aerobic
* White = anaerobic

Which is a positive result of the Snyder’s test?

Right tube (yellow)