FIG 6.

PA14-1 isolates RSCV-12 and RSCV-38 are resistant to infection by phage isolated from B23-2. (A) The 60-bp insertion sequence in the CRISPR array of RSCV-12 and RSCV-38. Prophages were isolated from B23-2, and plaque assays were performed to determine the level of phage infection for representative RSCV isolates (B) and the ancestor P. aeruginosa strains (C). RSCV-6 and RSCV-12 both have the same driver wspA mutation, while RSCV-36 and RSCV-38 have the same driver wspF mutation. The presence (+) or absence (−) of the CRISPR insertion is indicated. The driver mutation for each RSCV is labeled. Data are presented as mean plus SD (n = 4). Significance was determined using a Student’s t test: *, P value of <0.05.