Fatal Carbapenem Resistance Development in Pseudomonas Aeruginosa Under Meropenem Monotherapy, Caused by Mutations in the Oprd Outer Membrane Porin.

A 13-year old neutropenic boy succumbed to bacteremia and sepsis with a Pseudomonas aeruginosa strain that rapidly developed resistance to carbapenems during meropenem monotherapy. Whole genome sequencing of the susceptible and resistant blood culture isolates revealed the meropenem-resistant phenotype to be caused by truncation of the oprD gene, which added to a pre-existing inactivated mexR gene.