A study of 25 cheeses finds that a slow-growing bacterium can outcompete its relatives with the help of fungi.
Benjamin Wolfe at Tufts University in Medford, Massachusetts, and his colleagues examined the relative abundance of Staphylococcus bacteria (three species pictured), which are common in cheese. They found that Staphylococcus equorum dominated, despite being the slowest grower in lab tests. In the presence of fungi of the genus Scopulariopsis, S. equorum lowered its expression of genes involved in iron uptake and metabolism. The fungi could be providing the bacterium with freely available iron needed for growth, saving S. equorum the effort of acquiring and processing the nutrient, and allowing it to outcompete other bacteria.
Fungi could be influencing the diversity of other bacterial communities, including those in humans, the authors say.