A growing number of studies have been looking into the significance and role of the microbiome in human health and disease, and new research suggests the results of some of those studies might be unreliable and flawed, tainted by laboratory contamination.
The study — carried out by researchers at the Trust Sanger Institute and published this week in the journal BMC Biology — suggests microbes already inhabiting the DNA extracting testing kits may have a corrupting influence on the microbiotic test samples and their subsequent analysis.
"This can critically impact study results, and we're now advising caution to researchers studying microbiota," lead study author Alan Walker, a microbiologist who now conducts research at the University of Aberdeen, explained in a released statement.
The risk of contamination is heightened when DNA samples have relatively few microbial markers to begin with, making it more likely for latent microbes to skew results. Blood and lung samples, for example, have few microbes. Contamination is less likely, on the other hand, when dealing with microbiome data extracted from feces, which is teeming with microbes.
Researchers say a way to prevent false positives is to test negative control samples. In others, scientists would test an unused DNA extraction kit — one without an actual extracted DNA sample. The results could be compared alongside the used DNA extraction kit. If similar microbes were present in each, researchers would know that some level of contamination was tainting results.
More generally, researchers say their work is proof that microbiome researchers should be cautious, and avoid jumping to conclusions about links between microbes and disease.
