LAB WEEK 15 (Cultivation of Anaerobes)

obligate aerobes

microorganisms that will only grow in the presence of O2

facultative anaerobes

grow either aerobically or in the absence of O2, but better in oxygens presence

obligate anaerobe

grow only in the absence of O2 and are actually harmed by its presence

aerotolerant anaerobes

cannot use O2 but are not harmed by its presence

microaerophiles

require a small amount of O2 for normal growth but are inhibited by O2 at normal atmospheric tension

agar deep culture

the place in the tube that contains the proper O2 concentration

what medium did we use in class to test a bacteriums oxygen requirements?

thioglycollate broth

what is one of the most convenient plate methods to determine a bacteriums oxygen requirements?

Brewer’s anaerobic Petri plate

Brewer’s anaerobic agar contains a high concentration of ________

thioglycollic acid

GasPak anaerobic system

hydrogen and CO2 are generated by an envelope after the addition of water

how is oxygen removed from a GasPak anaerobic system chamber?

a palladium catalyst catalyzes the formation of water from hydrogen and O2, thereby removing O2

Why would GasPak pouches be used instead of the system?

for greater convenience and visibility

what is the simplest method for growing anaerobes?

adding Oxyrase for Broth to both medium and inoculate

what is a more up to date method for working with anaerobes?

anaerobic chamber

anaerobic chamber

a chamber that can be used to maintain an anaerobic environment— has an airlock port

what are the ingredients in brewers anaerobic agar that remove O2 from the medium?

Thioglycollic acid— free sulfhydryl groups in thioglycollic acid reduce any O2 present to make an anaerobic envrionment

of the methods used in this exercise to create an anerobic environment, which works best, and why?

Gas pak system— reduces O2 levels to one part per million

what is the role of the palladium catalyst in an anaerobic jar?

catalyzes the formation of water from hydrogen and oxygen, removing oxygen from the chamber

Oxyrase for broth

5 ml of broth

thioglycollate broth

can be used to test an organisms oxygen requirements

PEA isolation plates are for isolation of

gram positive organisms

what will be streaked for primary isolation?

MSA

If an MSA plate turns yellow, we can say that the colonies are likely_______

S. aureus or S. saprophyticus

why is the coagulase test an excellent definitive test for confirming S. aureus?

97% of S.aureus are coagulase positive and the other 2 species are always coagulase negative

what other organism can cause clotting?

pseudomonas

T/F- S. saprophyticus and S. epidermidis will be indistinguishable if S. saprophyticus does not ferment mannitol

True

what can be used to distinguish S. saprophyticus and S. epidermidis?

the novobiocin test

______ is known to be novobiocin resistant

S. saprophyticus