Conducting polymers have been increasingly used as biologically interfacing electrodes for biomedical applications due to their excellent and fast electrochemical response, reversible doping–dedoping characteristics, high stability, easy processability, and biocompatibility. These advantageous properties can be used for the rapid detection and eradication of infections associated to bacterial growth since these are a tremendous burden for individual patients as well as the global healthcare system. Herein, a smart nanotheranostic electroresponsive platform, which consists of chloramphenicol (CAM)-loaded in poly(3,4-ethylendioxythiophene) nanoparticles (PEDOT/CAM NPs) for concurrent release of the antibiotic and real-time monitoring of bacterial growth is presented. PEDOT/CAM NPs, with an antibiotic loading content of 11.9 ± 1.3% w/w, are proved to inhibit the growth of Escherichia coli and Streptococcus sanguinis due to the antibiotic release by cyclic voltammetry. Furthermore, in situ monitoring of bacterial activity is achieved through the electrochemical detection of β-nicotinamide adenine dinucleotide, a redox active specie produced by the microbial metabolism that diffuse to the extracellular medium. According to these results, the proposed nanotheranostic platform has great potential for real-time monitoring of the response of bacteria to the released antibiotic, contributing to the evolution of the personalized medicine.