Cell culture contamination

[Manos_bio]

Our lab is a hematology lab. Today we found out with the help of microbiology lab that our cultures were infected with Pseudomonas aeruginosa and Stenotrophomonas maltophilia. We work with bone marrow derived human MSCs, and as u understand it is difficult to retrieve any sample lost... So we think we should complete our medium with ciprofloxacin a fluoroquinol analogue which perturbs the bacterial DNA gyrase and mamalian topoisomerase II. What concentration should we use? Is there any better antibiotic we could use, which would have less adverse effects on our cells?

[Katleen]

I would not start an antibiotic treatment blindly, especially when working with organisms with known multi-resistance. Send some of the contaminated cultures (just some medium is enough or they can probably use the sample you sent them to determine the contamination) to your microbiology lab and aks them to do an antibiogram. Use those results to determine which antibiotic to use at what concentration.