K. kingae cytotoxicity. (A) Light microscopy evidence of K. kingae cytotoxicity for Chang cells. The top panel shows an intact monolayer after incubation for 10 min with E. coli DH5α, and the bottom panel shows a destroyed monolayer after incubation for 10 min with K. kingae strain 269-492. Bars = 100 μM. (B and C) LDH release assays with K. kingae strains 269-492, 23330, 23332, 97-982, and 05-001-1818 and E. coli DH5α with respiratory epithelial cells (B) and synovial and macrophage-like cells (C).