TY - JOUR
T1 - High-intensity meropenem combinations with polymyxin B
T2 - new strategies to overcome carbapenem resistance in Acinetobacter baumannii
AU - Lenhard, Justin R
AU - Bulitta, Jürgen B.
AU - Connell, Terry D.
AU - King-Lyons, Natalie
AU - Landersdorfer, Cornelia
AU - Cheah, Soon-Ee
AU - Thamlikitkul, Visanu
AU - Shin, Beom Soo
AU - Rao, Gauri
AU - Holden, Patricia N
AU - Walsh, Thomas J.
AU - Forrest, Alan
AU - Nation, Roger L
AU - Li, Jian
AU - Tsuji, Brian T
PY - 2017
Y1 - 2017
N2 - Objectives: The pharmacodynamics of polymyxin/carbapenem combinations against carbapenem-resistant Acinetobacter baumannii (CRAB) are largely unknown. Our objective was to determine whether intensified meropenem regimens in combination with polymyxin B enhance killing and resistance suppression of CRAB. Methods: Time-kill experiments for meropenem and polymyxin B combinations were conducted against three polymyxin B-susceptible (MIC of polymyxin B=0.5 mg/L) CRAB strains with varying meropenem MICs (ATCC 19606, N16870 and 03-149-1; MIC of meropenem=4, 16 and 64 mg/L, respectively) at 108 cfu/mL. A hollowfibre infection model was then used to simulate humanized regimens of polymyxin B and meropenem (2, 4, 6 and 8 g prolonged infusions every 8 h) versus N16870 at 108 cfu/mL over 14 days. New mathematical mechanismbased models were developed using S-ADAPT. Results: Time-kill experiments were well described by the mathematical mechanism-based models, with the presence of polymyxin B drastically decreasing the meropenem concentration needed for half-maximal activity against meropenem-resistant populations from 438 to 82.1 (ATCC 19606), 158 to 93.6 (N16870) and 433 to 76.0 mg/L (03-149-1). The maximum killing effect of combination treatment was similar among all three strains despite divergent meropenem MIC values (Emax=2.13, 2.08 and 2.15; MIC of meropenem=4, 16 and 64 mg/L, respectively). Escalating the dose of meropenem in hollow-fibre combination regimens from 2 g every 8 h to 8 g every 8 h resulted in killing that progressed from a >2.5 log10 cfu/mL reduction with regrowth by 72 h (2 g every 8 h) to complete eradication by 336 h (8 g every 8 h). Conclusion: Intensified meropenem dosing in combination with polymyxin B may offer a unique strategy to kill CRAB irrespective of the meropenem MIC.
AB - Objectives: The pharmacodynamics of polymyxin/carbapenem combinations against carbapenem-resistant Acinetobacter baumannii (CRAB) are largely unknown. Our objective was to determine whether intensified meropenem regimens in combination with polymyxin B enhance killing and resistance suppression of CRAB. Methods: Time-kill experiments for meropenem and polymyxin B combinations were conducted against three polymyxin B-susceptible (MIC of polymyxin B=0.5 mg/L) CRAB strains with varying meropenem MICs (ATCC 19606, N16870 and 03-149-1; MIC of meropenem=4, 16 and 64 mg/L, respectively) at 108 cfu/mL. A hollowfibre infection model was then used to simulate humanized regimens of polymyxin B and meropenem (2, 4, 6 and 8 g prolonged infusions every 8 h) versus N16870 at 108 cfu/mL over 14 days. New mathematical mechanismbased models were developed using S-ADAPT. Results: Time-kill experiments were well described by the mathematical mechanism-based models, with the presence of polymyxin B drastically decreasing the meropenem concentration needed for half-maximal activity against meropenem-resistant populations from 438 to 82.1 (ATCC 19606), 158 to 93.6 (N16870) and 433 to 76.0 mg/L (03-149-1). The maximum killing effect of combination treatment was similar among all three strains despite divergent meropenem MIC values (Emax=2.13, 2.08 and 2.15; MIC of meropenem=4, 16 and 64 mg/L, respectively). Escalating the dose of meropenem in hollow-fibre combination regimens from 2 g every 8 h to 8 g every 8 h resulted in killing that progressed from a >2.5 log10 cfu/mL reduction with regrowth by 72 h (2 g every 8 h) to complete eradication by 336 h (8 g every 8 h). Conclusion: Intensified meropenem dosing in combination with polymyxin B may offer a unique strategy to kill CRAB irrespective of the meropenem MIC.
UR - http://www.scopus.com/inward/record.url?scp=85014578475&partnerID=8YFLogxK
U2 - 10.1093/jac/dkw355
DO - 10.1093/jac/dkw355
M3 - Article
AN - SCOPUS:85014578475
VL - 72
SP - 153
EP - 165
JO - Journal of Antimicrobial Chemotherapy
JF - Journal of Antimicrobial Chemotherapy
SN - 0305-7453
IS - 1
ER -