(Cell Host & Microbe 25, 233–241.e1–e5; February 13, 2019) We the editors of Cell Host & Microbe have been informed by the Lead Contact and corresponding author, Dr. Morten O.A. Sommer, about new data that relate to Figure 2B in their original Uribe et al. paper. The original paper reported that AcrIIA8 directly binds to SpCas9 in addition to directly inhibiting SpCas9 activity in a DNA cleavage assay. In follow-up experiments, the direct binding of AcrIIA8 and SpCas9 could not be reproduced. Despite multiple attempts by both the authors and a group of collaborators, additional experiments with new batches of AcrIIA8 did not show direct binding to SpCas9. Using mass spectrometry, the identity of AcrIIA8 in all samples was confirmed. However, it was found that the original batch used for generating the data in Figure 2B was contaminated with AcrIIA9. Accordingly, the binding to SpCas9 that was originally attributed to AcrIIA8 actually resulted from contamination with AcrIIA9. Although the finding that AcrIIA8 binds to SpCas9 is no longer accurate, the anti-CRISPR activity of AcrIIA8 that was originally demonstrated in the in vitro cleavage assay has been confirmed using the new samples. With this note, we and the authors would like to alert the community and direct you to additional data related to Figure 2B, which have been deposited in Mendeley Data and can be accessed here. The remaining findings in the paper are unchanged, and these new data do not alter the main conclusions of the paper. Discovery and Characterization of Cas9 Inhibitors Disseminated across Seven Bacterial PhylaUribe et al.Cell Host & MicrobeFebruary 5, 2019In BriefUribe et al. developed a high-throughput approach to screen for type II-A CRISPR-Cas inhibitors in metagenomic libraries based on their functional activity rather than sequence homology or genetic context. This approach led to the discovery of four novel anti-CRISPR proteins, homologs of which are widely distributed across seven bacterial phyla. Full-Text PDF Open Archive