(a) S. aureus cells (~109) that were treated with ϕNM1γ6 phage and survived infection through the targeting of an early-expressed gene (gp14) by the type III-A CRISPR-Cas system, were seeded on plates with or without gentamicin to calculate their mutation frequency. (b) Same as (a) but seeding on plates with vancomycin. (c) Same as (a) but seeding on plates with levofloxacin. (d) Same as (a) but mixing surviving staphylococci with top agar with or without ϕStaph1N phage to calculate their resistance frequency. (a-d) Box limits, interquartile range; whiskers, minimum to maximum; centre line, median; dots, individual data points; n=8 biologically independent experiments; p-values obtained with two-sided Mann-Whitney test.