β-Lactamase Nomenclature

Abstract

There are ever-growing and at times unwieldy numbers of β-lactamases, especially in the TEM, SHV, and CTX-M families. To provide a degree of organization and to aid investigators proposing new enzymes, we have maintained an Internet database initially for extended-spectrum and inhibitor-resistant β-lactamases (2) but now more generally for other β-lactamase families, once they have more than a few members (http://www.lahey.org/studies/webt.html). Most β-lactamase investigators will contact one of us for an enzyme number when they believe a new designation is needed, and journal editors will often ask authors to validate their choice with us before a manuscript is accepted. No such requirement exists in picking an enzyme name for GenBank. The choice is left entirely to the submitter (1). Recently Li and Li published a Letter to the Editor briefly describing five extended spectrum β-lactamases designated CTX-M-42 through CTX-M-46 (3). Unfortunately, CTX-M-42 through CTX-M-45 have already been assigned to other investigators who have used these numbers for unique sequences. To avoid future confusion we propose that the enzymes be renamed as shown in Table ​Table11. TABLE 1. Proposed new enzyme names We also encourage authors, reviewers, and editors with questions about β-lactamase nomenclature to contact one of us prior to publication.