Repurposing β-Lactams for the Treatment of Infections: An In Vitro Study

() causes tuberculosis-like lung infection in both immunocompetent and immunocompromised patients. Current standard therapy against infection is lengthy and difficult to adhere to. Although β-lactams are the most important class of antibiotics, representing 65% of the global antibiotic market, they have been traditionally dismissed for the treatment of mycobacterial infections, as they were considered inactive against mycobacteria. A renewed interest in β-lactams as antimycobacterial agents has shown their activity against several mycobacterial species, including , or ; however, information against is lacking. In this study, we determined the in vitro activity of several β-lactams against . A selection of 32 agents including all β-lactam chemical classes (penicillins, cephalosporins, carbapenems and monobactams) with three β-lactamase inhibitors (clavulanate, tazobactam and avibactam) were evaluated against 22 strains by MIC assays. Penicillins plus clavulanate and first- and third-generation cephalosporins were the most active β-lactams against . Combinatorial time-kill assays revealed favorable interactions of amoxicillin-clavulanate and cefadroxil with first-line treatment. Amoxicillin-clavulanate and cefadroxil are oral medications that are readily available, and well tolerated with an excellent safety and pharmacokinetic profile that could constitute a promising alternative option for therapy.