In-vitro activity of new carbapenem antibiotics: comparative studies with meropenem, L-627 and imipenem against pathogenic Nocardia spp.

MICs of two new carbapenems, meropenem and L-627, and imipenem were determined against 98 strains of the Nocardia asteroides group (i.e. N. asteroides sensu stricto, Nocardia farcinica and Nocardia nova), 46 strains of Nocardia brasiliensis and 17 strains of Nocardia otitidiscaviarum. Meropenem and L-627 were less active against the N. asteroides group than imipenem. Among the three species of the N. asteroides group, N. nova was the most sensitive to all the carbapenems. Meropenem was more active than imipenem against both N. brasiliensis and N. otitidiscaviarum with MIC50 values of 28.3-53.3 mg/L. L-627 was less active than meropenem.