The Role of Drug Resistance in Emergence and Re-emergence of Diseases

Background: Today, the problem of emerging infectious diseases have overshadowed many of the health beliefs and attracted the attention of the scientific societies, and interestingly, many of the scientists believe that not only the emergence of contagious diseases is not merely a new phenomenon, but also it has happened several times and thus had a huge role in the history of the health developments. The increased antibacterial resistance today have made the problem of infectious diseases even more complicated, so that the infections caused by microorganisms resistant to antibiotics have become the most important preoccupation of the physicians. Aim: The purpose of this study is to express the role of drug resistance in emergence and re-emergence of diseases. Methods: This study is conducted with retrospective method while reviewing the previous studies in this field referring to scientific websites: Ovid, Blackwell Synergy, Pub Med, Elsevier, Science and Google Scholar, with relative key words. Findings: Emergence of infectious diseases and re-emergence of some others is not a new phenomenon; as the ecosystem is changing constantly and thereby changes large and small environments, in which humans and their associated microbes live, and they themselves engage in this trend. The factors that cause emergence and re-emergence of infectious diseases are quite various; however, the influence of humans on the ecosystem is of key importance. The microbial factors that comprise over 60% of the biomass are an important part of the internal and external environment of the human body, and in other words, have surrounded the human body from inside and outside. This is while, based on current information, only 0.5% of the 2-3 billion existing microbial species are identified. Conclusion: The issue of emergence and re-emergence is the subject of the past, present and future medicine history and is the continued problem of public health and therefore should be considered with utmost seriousness by policymakers of the educational and research affairs and also attended by the professors and researchers of the universities of medical sciences in the country, including Medical and veterinary and even agricultural schools.