What are the disadvantages of the prophylactic use of antibiotics in cell culture?

The use of antibiotics creates a false sense of security and allows users to develop poor aseptic techniques. This leads to low-level contamination with partially resistant bacteria occurring but being overlooked for a time. This then leads to cells with undetected contamination being cultured for extended periods of time; increasing the risk that contamination will spread throughout the laboratory and eventually antibiotic-resistant strains of bacteria may develop. Mycoplasma infections can also occur more easily; as they are often introduced along with contaminants such as bacteria and fungi. Last but not least; antibiotics are known to have negative effects on the metabolism of eukaryotic cells - more details on this topic can be found in our blog article "Antibiotics in cell culture: friend or enemy".