How do you treat a patient with a gram-negative infection with resistance to imipenem but sensitivity to meropenem and negative for Carbapenem resistant organism by xpert Carba-R-assay?

The finding of meropenem susceptible, imipenem resistant GNR can be explained in Pseudomonas aeruginosa by efflux pump overexpression and porin (particularly OprD) loss. The opposite pattern in P. aeruginosa - imipenem susceptible, meropenem resistant – has often been attributed to overexpression of the mexAB efflux pump.

In Enterobacterales, meropenem susceptibility with imipenem resistance is usually due to porin loss together with the presence of an ESBL of plasmid AmpC. Meropenem would be p...