Redefining extended-spectrum β-lactamases: Balancing science and clinical need

The current β-lactamase classifications have reached a high level of complexity, making them less accessible to clinicians, infection control professionals, hospital management and politicians. From the clinical perspective, a revised comprehensible nomenclature scheme is therefore needed. The term extended-spectrum β-lactamases (ESBLs) has reached a broader audience over time, but is currently restricted to functional class 2be/molecular class A, clavulanic acid inhibited enzymes with activity against extended-spectrum cephalosporins. The proposed new classification expands the definition of ESBL to other clinically important acquired β-lactamases with activity against extended-spectrum cephalosporins and/or carbapenems. The classical class A ESBLs have been designated ESBL_A in this classification, whereas plasmid-mediated AmpC and OXA-ESBLs are classed as miscellaneous ESBLs (ESBL_M). Lastly, the carbapenemases have been designated ESBL_CARBA, ESBLs with hydrolytic activity against carbapenems. We believe that this simplified classification may encourage new groups of healthcare professionals to engage in the effort to prevent the spread of acquired β-lactamases.