Contaminations and what to do about them
Good microbiological techniques
Contaminations can happen, but the best way to deal with them is to avoid them. Always use good microbiological techniques:
aseptical techniques
- work with sterilized materials. This includes all consumables, media, pipettes, supplements, etc.
- work in a
Preventing contaminations
When performing less sterile methods, such as cell sorting using FACS antibiotics can be added preventively to avoid bacterial contaminations. We have experienced that the cell sorters are not sterile, and will cause bacterial growth.
Penicillin-Streptomycin
The most commonly used broad spectrum antibiotic for cell culture is Penicillin-Streptomycin. This antibiotic does not greatly affect yeast growth or reproduction.
For use, add the antibiotic in 1:100 dilution from the stock solution (Thermofisher 10.000 units/ml Penicillin & 10.000 µg/ml Streptomycin) to the medium (when using agar, assure it has cooled down to below 60°C). Aliquots are available in the top drawer of freezer 7.
Ampicillin
You can use ampicillin, however there is more natural resistance in bacteria present, so this might not work that well.
For use, add the antibiotic in 1:1000 dilution from the stock solution (100 mg/mL) to the medium (when using agar, assure it has cooled down to below 60°C). Aliquots are available in the top drawer of freezer 7.
Kanamycin
The story for kanamycin is similar to that for ampicillin.
For use, add the antibiotic in 1:1000 dilution from the stock solution (100 mg/mL) to the medium (when using agar, assure it has cooled down to below 60°C). Aliquots are available in the top drawer of freezer 7.
Contaminations in strains
If you have strains that are essential and cannot be recreated, you need to figure out a way to get rid of the contamination.
bacterial contaminations.
When contaminated with bacteria (check under the microscope).row
