CO2 Incubators > Control and Prevention of Contamination  »   What are the pros and cons of using antibiotics?

It is virtually impossible to discuss contamination sources and problems without including a segment on the use of antibiotics.  Although there are different schools of thought regarding the virtues of antibiotics, the author strongly suggests not using them for the majority of cell culture work.  There are several reasons why antibiotics are contraindicated.  First, they tend to give the user a false sense of confidence which leads to a relaxation of aseptic technique and frequently serves to increase the risk of contamination.  Secondly, most antibiotics are not bactericidal, that is they do not kill the organisms, but rather are bacteriostatic, thereby slowing down the metabolic processes.  Consequently, the presence of antibiotics can delay the detection of contaminating organisms.  This can be very unnerving in experiments that take place over an extended period of time because the investigator has no way if knowing when the insult occurred.  Third, certain cell types can lose or have a certain receptors masked on the plasma membrane in the presence of antibiotics.  Finally, antibiotics are toxic to cells at high concentrations and prolonged use of these drugs will alter the population of cells being cultured thereby selecting for organisms that are resistant to the drug.  There are certain instances when the use of antibiotics is indicated and they are the following.  If one is doing primary cultures of organs or tissues that are known to have normal flora associated with them, such as gastrointestinal tract or the oropharynx, one should use antibiotics to prevent the contaminants from taking over the culture.  Secondly, if one is doing large scale culturing for the purpose of purifying a product, it is best to add antibiotics to the cultures so as not to risk loss of product.  Finally, if the laboratory facilities are inadequate from the point of air handling or one is doing field studies, then antibiotics may be necessary.

In general however, investigators and cell culturists should refrain from using antibiotics and depend rather on good sterile techniques and good laboratory practices.  The purer and more defined our cell culture conditions can be the better the experiments and the more reliable the results.  Furthermore, if we really are interested in studying cell behavior we should make every attempt possible to create an environment that best mimics the in vitro situation. 

In conclusion I will leave you with two thoughts.  First, when it comes to cell culture, cleanliness is truly next to Godliness.  Second, preventing contamination through good laboratory quality control practices, is the most efficient, economical and reliable way of growing cells in culture.