OXYGEN REQUIREMENTS OF MICROORGANISMS Flashcards
What is the term called when bacteria cannot exist without the presence of oxygen?
Obligate aerobes
What is the type of bacteria that cannot grow in the presence of oxygen?
obligate anaerobes
A type of organism that will grow in the presence OR absence of oxygen
Facultative organisms
What are facultatives?
They are bacterias that can use oxygen or some alternative oxygen source
What is the facultative anaerobes?
they will grow in either the presence or absence of oxygen, but show better growth when oxygen is available
What are Microaerophiles?
organisms that require oxygen but only in limited amounts
What is the group called when they show no preference for either condition growing equally well in aerobic and anaerobic conditions?
Indifferents (aerotolerant anaerobe)
What compounds lowers the oxidation-redution potential to favour the growth of anaerobic bacteria
cysteine and sodium thioglycollate
What type of agar medium helps to localize growth and favours anaerobiosis in the bottom of the tube?
Fluid thioglycollate medium
In the presence of oxygen, what colour does it turn into? What is the name of the dye?
Pink, dye resazurin
What are the 4 broth cultures used in the oxygen requirements of microorganisms?
- Escherichia coli
- Staphylococcus aureus (lvl 2, incinerator used)
- Clostridium sporogenes
- Lactobacillus plantarum
What are the ingredients of fluid thioglycollate medium?
- agar
- resazurin
- yeast extract
- protein
What are the results for each species?
in oxygen requirements of microorganisms?
- E.coli - Facultative anaerobe
- Clostridium sporogenes - obligate anaerobe
- S. aureus - Facultative anaerobe
- L. plantarum - microaerophile
Differentiate between a microaerophile and an aerotolerant organisms.
Microaerophile : require low O2 for metabolism
Aerotolerant : can grow in O2 but not used in metabolism
Why is fluid thioglycollate a usefulmedia for the study of anaerobes?
Because it permits growth
