The Silent Pandemic: Antimicrobial Resistance, a Global Threat with Ancient Roots.

A silent pandemic is underway that is causing more than a million deaths each year worldwide: antimicrobial resistance. According to World Health Organization forecasts, this phenomenon could become the leading cause of death by 2050. It represents one of the most pressing global health threats, compromising the effectiveness of life-saving therapies and making infections increasingly difficult to treat. Although antimicrobial resistance is often considered a recent phenomenon, it was first recognized in the early stages of antimicrobial use, with reports predating Alexander Fleming's discovery of penicillin in 1928. In this context, the present review examines selected representative cases of the early recognition of antimicrobial resistance through the analysis of the initial evidence of microbial adaptation associated with the use of pre-antibiotic chemotherapeutic agents such as Salvarsan, as well as the first reports of reduced clinical efficacy of sulfonamides and penicillin. These observations have contributed to the current understanding of resistance as a dynamic process driven by microbial adaptive mechanisms and amplified by the selective pressure exerted by antimicrobial use.