LO3 Flashcards
order of inoculation
most enriched medium/media first, then to
the least selective and then progressively on to the most selective
to prevent carry over
Liquid media are always inoculated
last
culture protocol pages
There are four environmental
factors that are critically important for ensuring the growth of healthy organisms:
temperature, atmospheric gases, pH and moisture
temp
Most bacteria at 35-37°C (near human body temperature)
fungi 28-30°C (near body surface temperature).
meso thermo psycho review
atmospheric gasses review from LO1
pH ideal also review
6.5-7.5
moisture reveiw
agar and broth as wells as incubators with humidifiers
ideal temps for bac, yest, and stool pathogens like Campy
35-37
28-30
42 for stool cmapy sp
how are humidifying incubators for moisuture created
automatic water resviours that are re-filled or buckets of water is put in place
dialy checks for QA progrmas
Aerobic Conditions what type of air do these conditions have, specific name and what does that require from us
ambient air: has oxygen
O2-21%, CO2-0.03%
loose lids on culture plates and porous cotton on tubes
Capnophilic type of incubators how are levels checked
-increased CO2 conditions
-use of CO2 incubators candle jars
-attached tanks of CO2
-5-10% volume adjustment
-checked by FYRITE gas analyzer
-candle jars are simple alternative
-non toxic jar you put plates in and then when it burn the O2 is used up and you are left with 3% CO2 which is good enough, the entire jar is placed in just ambient air
-mostly used for transport when there are fastidious capnophilic organisms
microaerophilic atmosphere
5 types of available incubation
O2 is reduced and CO2 is increased
1.Campy Pak II System or Gas Generating Kit
Systems BR56 (Oxoid): water added to gas and then into a jar containing plates
2.Evacuation Replacement Systems: O2 removed, CO2, H2, N2 is replaced
3.Biobag Type Cfj (Becton Dickinson): single plate is placed into a bag that has an ampule that is then crushed which makes 5-10% O2 and 8-10%
CO2.
4.Poly Bag System: Polyethylene bags, filled with plates, are inflated with a gas mixture (5% O2, 10% CO2 and 85% N2).
5.Bacti-Gas Station: Plates are placed in sealable bags which are filled by a Campy gas cylinder (5% O2, 10% CO2, 85% N2).
anaerobic incubation
2 ways to do it
-samples aspirated surgically
-held in a holding chamber w/ no oxygen until incubation
- anaerobic jars/ pouches
- anaerobic chamber or glove box
anaerobic jars / pouches the difference btw the 2 and the 2 methods for jars
pouches/bag: resealable bag that can create an O2 free environment, good for small labs and for 1-2 plates
jars: clear plastic jar with a tight lid, the plates are put inside and there is an O2 indicator strip, the O2 is then removed either by:
gas pack: in the presents of O2 will reduce ascorbic acid to water and CO2, jar will feel warm and loos misty, the indicator strip will be blue in O2 and which with no O2 if the strip is methylene blue
evacuation replacement: strip is still used, the jar is fitted with tubes on the lids that will remove O2 and pump in other gas mixtures
