EN
Contaminations of in vitro cell cultures constitute a serious threat to research. Infected cell lines may negatively influence the results of experiments, as well as expose the researchers to problems associated with the termination of the culture and decontamination of the laboratory. This paper presents the most common types of contaminations in experiments based on animal cell cultures. The key sign that may indicate infection is a decreased viability of the cell line and, in many cases, destruction of the cells. Depending on the type of infection, specific signs can be observed, and different methods for the detection of the infectious agent can be applied. Typical contaminations include bacterial and viral infections, sprouting fungal and yeasts cultures, or the presence of mycoplasma, endotoxin, protozoa, and invertebrates. In some cases, cross-contamination may occur, in which a cell culture is infected by another cell line. The main source of contaminations is an inappropriate implementation of good laboratory practices by laboratory personnel, as well as the use of nonsterile reagents, plasticware and CO₂ incubators. The most common method of fighting cell line infections is the elimination of the infected cell culture and decontamination of the laboratory. In working with cell cultures, it is necessary to observe the rules of sterile work and to know the sources and signs of infection to effectively mitigate the threat.