OXA-48-like carbapenemases in - novel genetic environments and a challenge for detection.

OXA-48-like enzymes represent the most frequently detected carbapenemases in Enterobacterales in Western Europe, North Africa and the Middle East. In contrast to other species, the presence of OXA-48-like in leads to an unusually susceptible phenotype with low MICs for carbapenems and piperacillin-tazobactam, which is easily missed in the diagnostic laboratory. So far, there is little data available on the genetic environments of the corresponding genes, -like, in In this study susceptibility phenotypes and genomic data of 13 OXA-48-like-producing were investigated (OXA-48,  = 9; OXA-181,  = 3; OXA-162,  = 1). Ten isolates were susceptible to meropenem and ertapenem and three isolates were susceptible to piperacillin-tazobactam. The gene was chromosomally located in 7/9 isolates. Thereof, in three isolates was inserted into a genomic island. Of the three isolates harbouring one was located on an IncX3 plasmid and two were located on a novel MOB plasmid, pOXA-P12, within the new transposon Tn. In 5/6 isolates with plasmidic location of like, the plasmids could conjugate to recipients . , -carrying plasmids could conjugate from other Enterobacterales into a recipient. These data show a high diversity of -like genetic environments compared to other Enterobacterales, where genetic environments are quite homogenous. Given the difficult-to-detect phenotype of OXA-48-like-producing and the location of -like on mobile genetic elements it is likely that OXA-48-like-producing can disseminate, escape most surveillance systems, and contribute to a hidden spread of OXA-48-like.