Week 10: Bacterial Aerotolerance

Respiration

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 anaerobes

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 aeroginosa

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)