The purpose of this study was to generate ultrathin fibers based on polylactide (PLA) biopolyester with antimicrobial controlled release capacity to treat bacterial infections. To achieve this objective, gentamicin antibiotic was encapsulated into pure PLA fibers, a blend of PLA–collagen and coaxial fibers containing a skin of PLA and a core of collagen using the electrospinning technique. The morphology of the gentamicin‐loaded fibers and the antibiotic distribution within the fibers were examined by SEM and TEM. The drug delivery profile of the different electrospun fibers was analyzed using a spectrophotometric method. The performance for treating common possible post‐surgical infections was investigated against Staphylococcus epidermis, Pseudomonas aeruginosa and Escherichia coli. The morphology of the electrospun fibers as well as the hydrophilicity of the polymer blends ultimately determined the antibiotic release characteristics. The results indicated that such drug‐loaded fibers can serve as advanced delivery platforms with strong and timing controllable antibacterial properties.