Inhibition of Enzymatic Acetylation-Mediated Resistance to Plazomicin by Silver Ions

Autor: David Ngo, Angel J. Magaña, Tung Tran, Jan Sklenicka, Kimberly Phan, Brian Eykholt, Verónica Jimenez, María S. Ramirez, Marcelo E. Tolmasky
Jazyk: angličtina
Rok vydání: 2023
Předmět:
Zdroj: Pharmaceuticals, Vol 16, Iss 2, p 236 (2023)
Druh dokumentu: article
ISSN: 1424-8247
DOI: 10.3390/ph16020236
Popis: Plazomicin is a recent U.S. Food and Drug Administration (FDA)-approved semisynthetic aminoglycoside. Its structure consists of a sisomicin scaffold modified by adding a 2(S)-hydroxy aminobutyryl group at the N1 position and a hydroxyethyl substituent at the 6′ position. These substitutions produced a molecule refractory to most aminoglycoside-modifying enzymes. The main enzyme within this group that recognizes plazomicin as substrate is the aminoglycoside 2′-N-acetyltransferase type Ia [AAC(2′)-Ia], which reduces the antibiotic’s potency. Designing formulations that combine an antimicrobial with an inhibitor of resistance is a recognized strategy to extend the useful life of existing antibiotics. We have recently found that several metal ions inhibit the enzymatic inactivation of numerous aminoglycosides mediated by the aminoglycoside 6′-N-acetyltransferase type Ib [AAC(6′)-Ib]. In particular, Ag+, which also enhances the effect of aminoglycosides by other mechanisms, is very effective in interfering with AAC(6′)-Ib-mediated resistance to amikacin. Here we report that silver acetate is a potent inhibitor of AAC(2′)-Ia-mediated acetylation of plazomicin in vitro, and it reduces resistance levels of Escherichia coli carrying aac(2′)-Ia. The resistance reversion assays produced equivalent results when the structural gene was expressed under the control of the natural or the blaTEM-1 promoters. The antibiotic effect of plazomicin in combination with silver was bactericidal, and the mix did not show significant toxicity to human embryonic kidney 293 (HEK293) cells.
Databáze: Directory of Open Access Journals
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