In vitro susceptibility of nonfermenting Gram-negative rods to meropenem-vaborbactam and delafloxacin.

Aim: Meropenem-vaborbactam and delafloxacin activities were not assessed against Achromobacter spp. ( Achr ), Burkholderia cepacia complex ( Bcc ) and Stenotrophomonas maltophilia ( Smal ). Methodology: A total of 106 Achr , 57 Bcc  and 100 Smal  were tested with gradient diffusion test of meropenem-vaborbactam, delafloxacin and comparators. Results: Meropenem-vaborbactam MIC ₅₀ were 4 μg/ml for Achr , 1 μg/ml for B. cepacia , 2 μg/ml for B. cenocepacia and B. multivorans , and 32 μg/ml for Smal . Delafloxacin MIC ₅₀ were 4 μg/ml for Achr , 0.25 μg/ml for B. cepacia and B. multivorans , 2 μg/ml for B. cenocepacia , and 0.5 μg/m for Smal . meropenem-vaborbactam MICs were fourfold lower than meropenem for 28.3% Achr , 77.2% B. cepacia , 53.8% B. cenocepacia and 77.2% B. multivorans . Conclusion: Meropenem-vaborbactam and delafloxacin are in vitro active against Bcc and Achr .