Loss of cytotoxicity of K. kingae mutants 60HllT1, 69A6T1, and 97G1T1. (A) LDH release assays with K. kingae strain 269-492 and mutants 60H11T1, 69A6T1, and 97G1T1 using Chang epithelial cells. E. coli DH5α was used as a negative control. (B) LDH release assays with E. coli strains DH5α, RTXAC, WAM716, and RTXAC/WAM716 using Chang epithelial cells.