https://www.selleckchem.com/products/bibo-3304-trifluoroacetate.html Cephalosporins, which belong to the beta-lactam therapeutic class, are increasingly used throughout the world. Few large studies on this issue have been conducted, and most of them have been performed as part of penicillin hypersensitivity studies. We described our 26-year experience exploring cephalosporin drug hypersensitivity, from which we identified epidemiological and cross-reactivity data. We included 476 patients who reported drug hypersensitivity reaction (DHR) to cephalosporin and underwent an allergy workup between January 1992 and July 2018 in the Allergy Unit of the University Hospital of Montpellier (France). According to their structural side chain R1 homology, we worked with 4 classes of cephalosporins. Logistic regression analysis was used to search for risk factors for hypersensitivity to cephalosporin (positive skin test [ST] or drug provocation test [DPT] results). Cephalosporin hypersensitivity was proven in 22.3% of the patients referred in our Unit, according to positive ST (51.red in less than 10% of the positive patients. Almost a quarter of the tested patients were confirmed as hypersensitive to cephalosporins; sensitivity of skin testing was 51.9%, and thus, half of the positive patients needed a DPT to prove the diagnosis. Almost a quarter of the tested patients were confirmed as hypersensitive to cephalosporins; sensitivity of skin testing was 51.9%, and thus, half of the positive patients needed a DPT to prove the diagnosis. Efflux pumps are transmembrane proteins associated with bacterial resistance mechanisms. Bacteria use these proteins to actively transport antibiotics to the extracellular medium, preventing the pharmacological action of these drugs. This study aimed to evaluate in vitro the antibacterial activity of 1,8-naphthyridines sulfonamides, as well as their ability to inhibit efflux systems of Staphylococcus aureus strains expressing different levels of th