Correction to: Nature Microbiology https://doi.org/10.1038/s41564-019-0537-z, published 26 August 2019.

In the version of this Article originally published, the symbols in Fig. 1e (left graph) representing samples with or without CaCl2 were mixed up and should have been switched; that is, the data should show that samples receiving CaCl2 had a higher percentage of neuraminidase activity than CaCl2-negative samples. This has now been rectified and the corrected panel is shown below.

Fig. 1e
figure 1

Original and corrected.