Emergence of a novel FRI-type carbapenemase; blaFRI-12 in Enterobacter asburiae located on an IncR plasmid

Carbapenem-resistance in Enterobacter spp due to acquisition of mobile carbapenemases is of concern. An Enterobacter spp grew on ChromID CARBA medium and was positive for the mCIM carbapenemase detection assay. Susceptibility testing showed resistance to aztreonam and reduced susceptibility to imipenem. Conventional PCR using FRI primers detected a bla_FRI gene. Whole genome sequencing reveled a new variant; bla_FRI-12 was closest in sequence to bla_FRI-5 differing by 13 amino acids and was found on a unique 110Kb IncR plasmid. Given the intrinsic nature of Enterobacter spp. to be carbapenem non-susceptible, blaFRI-types may be under reported globally.