Time-kill kinetics of slowly growing mycobacteria common in XXXX .

@entity3477 @entity4581 @entity4509 @entity358 @entity3069
OBJECTIVES: This study aimed to provide basic pharmacodynamic information for key antibiotics used to treat @entity3069 and @entity3069 xenopi @entity358 . METHODS: @entity3069 hominissuis IWGMT49 and M. xenopi ATCC 19250 type strains were used; the MICs of @entity4581 , @entity4509 and @entity3477 were determined by broth microdilution. Time-kill assays were performed, exposing bacteria to 2-fold concentrations from 0.062* to 32* the MIC at 37  C for 240 h for @entity3069 or 42 days for M. xenopi. The sigmoid maximum effect (Emax) model was fitted to the time-kill curve data. RESULTS: Maximum killing of @entity3069 by @entity4509 was obtained between 24 and 120 h (0.0180 h(-1)) and was faster and higher than with @entity4581 (0.0109 h(-1)); however, regrowth and @entity4509 -resistant mutants were observed. Killing rates for M. xenopi were higher, 0.1533 h(-1) for @entity4581 and 0.1385 h(-1) for @entity3477 , yet required 42 days. There were no significant differences between the Hill's slopes determined for all of the antibiotics tested against @entity3069 or M. xenopi (P=0.9663 and P=0.0844, respectively). CONCLUSIONS: The killing effect of @entity4509 and @entity4581 on @entity3069 hominissuis was low, although @entity4509 activity was higher than that of @entity4581 , supporting its role in a combined therapy. @entity4581 and @entity3477 may have similar activity within treatment regimens for M. xenopi disease. Future studies of in vitro and in vivo pharmacokinetic/pharmacodynamic interactions are needed to improve the current regimens to treat these two important slowly growing mycobacteria in @entity358 .
