Two by Two

Despite a growing understanding of the importance of microbiota, microbial communities living in and around us, and how disrupting them can lead to disease, we still know little about specific relationships between bacteria, making it difficult to take action. Setting out to change this, researchers studied interactions between a bacterium commonly found in our mouths, Aggregatibacter actinomycetemcomitans (Aa, pictured), and 15 other microbes, from either the same or different environments. Genetic manipulations revealed that Aa required different sets of genes to be successful when paired with another microbe, depending on whether its partner helped or hindered. Surprisingly, Aa generally fared better with species it does not normally encounter than alongside those it naturally co-occurs with, suggesting that co-existing communities are not always supportive. In our mouths, Aa can sometimes cause periodontitis, a serious form of gum disease, and its interactions with other oral bacteria could contribute to this pathogenic switch.

Written by Emmanuelle Briolat

Emmanuelle Briolat

Writer

A researcher specialising in visual signals in Lepidoptera, camouflage and the effects of light pollution, Emmanuelle’s writing covers a range of topics, from biomedical research to children’s books about moth defences.

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• Image by Derren Ready, from the Wellcome Image collection
• Research from School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
• Image originally published under a NonCommercial-NoDerivs 3.0 Unported Creative Commons Licence
• Research published in PNAS, September 2019