PTF1A and infection: It is noteworthy that transduction of a nontargeting cas9 phagemid leads to a 2 log lower number of E. coli and S. flexneri CFU when compared to mock infections in vitro andthe use of PEG-treated lysates prepared on the mutant pacA* lysogen could reduce such non-Cas9-mediated effects on S. flexneri by approximately tenfold.