Got black swimming dots in your cell culture? Identification of Achromobacter as a novel cell culture contaminant.
Abstract
Cell culture model systems are utilized for their ease of use, relative inexpensiveness, and potentially limitless sample size. Reliable results cannot be obtained, however, when cultures contain contamination. This report discusses the observation and identification of mobile black specks observed in multiple cell lines. Cultures of the contamination were grown, and DNA was purified from isolated colonies. The 16S rDNA gene was PCR amplified using primers that will amplify the gene from many genera, and then sequenced. Sequencing results matched the members of the genus Achromobacter, bacteria common in the environment. Achromobacter species have been shown to be resistant to multiple antibiotics. Attempts to decontaminate the eukaryotic cell culture used multiple antibiotics at different concentrations. The contaminating Achromobacter was eventually eliminated, without permanently harming the eukaryotic cells, using a combination of the antibiotics ciprofloxacin and piperacillin.
2. Another possible explanation the black spot is the containmation ofMycoplasma
Good article for elimination of Mycoplasma Contamination in Cell Cultures
Abstract :
These antibiotic treatments had a high efficiency of permanent cure: MRA 64%,
ciprofloxacin 77%, BM-Cyclin 84%. Resistance to mycoplasma eradication was observed
in some cell cultures: BM-Cyclin 5%, ciprofloxacin 14%, MRA 22%. Nearly all resistant
contaminants that could be identified belonged to the species M. arginini and M. orale.
Detrimental effects of the antibiotics were seen in form of culture death caused by cytotoxicity
(in 9-13% of the cultures). Alterations of the cellular phenotypic features or selective
clonal outgrowth might represent further untoward side-effects of exposure to these
antibiotics.
Overall, antibiotic decontamination of mycoplasmas is an efficient, inexpensive, reliable,
and simple method: 269/366 (73%) chronically and heavily contaminated cultures
were cured, while 97/366 (27%) cultures could not be cleansed and were either lost or
remained infected. It is concluded that eukaryotic cell cultures containing mycoplasmas
are amenable to antibiotic treatment and that a cure rate of about three-quarters is a
reasonable expectation.
