KSM inhibition growth of E. coli ATM809 derivatives. A ksgA mutant of E. coli (i.e. ATM809) harboring a chromosomal copy of ksgA from E. coli (ATM810), C. trachomatis L2 (ATM811, ATM812) or the KSM resistant C. trachomatis L2ksgAE9 (ATM815) were tested for resistance to KSM as described in , with some modifications. The A600 of cultures after 24 hrs of growth in the presence of the indicated amounts of KSM was normalized to the value obtained for ATM809 under the same conditions. Data points represent the mean ± s.d. of three experiments. The parent MC4100 behaved like ATM810 and was not included for clarity.