Role of yceA-cybB-yceB operon in oxidative stress tolerance, swimming motility and antibiotic susceptibility of Stenotrophomonas maltophilia.

This article focuses on characterizing the yceA-cybB-yceB operon in *Stenotrophomonas maltophilia* and its role in oxidative stress tolerance, swimming motility, and antibiotic susceptibility. The operon, consisting of genes encoding two YceI-like lipocalin proteins (YceA and YceB) and a cytochrome b561 (CybB), is up-regulated in response to oxidative stressors such as hydrogen peroxide and menadione but not by antibiotics. Functional analyses revealed that deletion of this operon compromises tolerance to menadione-induced oxidative stress, increases susceptibility to fluoroquinolone and β-lactam antibiotics, and enhances swimming motility. The findings suggest that the primary physiological role of the yceA-cybB-yceB operon is to alleviate oxidative stress, which indirectly contributes to antibiotic resistance, rather than directly mediating antibiotic capture or resistance mechanisms.