ESBLt

ESBLt is not a widely recognized term in peer‑reviewed microbiology or clinical pharmacology. In most scientific and clinical contexts, the abbreviation ESBL refers to extended‑spectrum beta‑lactamases, enzymes produced by certain bacteria that confer resistance to many beta‑lactam antibiotics. If encountered, ESBLt may be a typographical variant or an informal/context‑specific label rather than a standard designation. This article describes ESBLs in general and notes the uncertainty around the term ESBLt.

Extended‑spectrum beta‑lactamases are enzymes that hydrolyze a broad range of beta‑lactam antibiotics, including penicillins and cephalosporins, and they may also inactivate aztreonam. They are predominantly encoded on plasmids, enabling rapid horizontal transfer among Gram‑negative bacteria such as Escherichia coli, Klebsiella species, and others in the Enterobacterales order. The most clinically relevant families include TEM, SHV, and CTX‑M types, with CTX‑M enzymes currently the most widespread globally. ESBLs can be inhibited by some beta‑lactamase inhibitors, but their activity often reduces the effectiveness of many common antibiotics, complicating treatment.

Epidemiology and impact: ESBL‑producing organisms are encountered in both hospital and community settings and are associated with higher morbidity and mortality compared with non‑ESBL infections. Risk factors include recent antibiotic exposure, hospitalization, invasive devices, and comorbid conditions. Diagnostics rely on phenotypic tests that show resistance to third‑generation cephalosporins and confirmatory genotypic tests for bla genes.

Treatment and control: Carbapenems have been a mainstay for serious ESBL infections, though stewardship and newer agents (such as beta‑lactamase inhibitor combinations) are shaping current practice. Infection control measures, surveillance, and prudent antibiotic use are essential to limit spread. If ESBLt appears in a given source, it is advisable to consult current literature to determine whether it denotes ESBL context or a nonstandard usage.