Glucose potentiates florfenicol killing of antibiotic-resistant V. parahaemolyticus by enhancing proton motive force and reactive oxygen species

Florfenicol is valued for its clinical safety, particularly its reduced bone marrow toxicity compared to other old antibiotics of chloramphenicols. However, the rise of bacterial resistance threatens its efficacy. To address this, we evolved a florfenicol-resistant strain of Vibrio parahaemolyticus (VP-RFFC) and used metabolomics to identify a suppressed glucose metabolic state as a key vulnerability. We found that exogenous glucose potentiated florfenicol's killing effect against the resistant strain in a dose- and time-dependent manner in vitro. It also played a role in vivo. Mechanistically, glucose reactivation rewired central carbon metabolism in two ways: 1) it fueled the pyruvate cycle, enhancing the proton motive force (PMF) to promote florfenicol uptake; and 2) it stimulated the pentose phosphate pathway, increasing reactive oxygen species (ROS) production to amplify antibiotic lethality. Thus, our work identifies glucose-mediated metabolic reprogramming as a potent strategy to resensitize resistant pathogens to florfenicol, by simultaneously increasing drug influx and oxidative damage.