Mechanisms of Antimicrobial Resistance in Bacteria, General Approach

Antibiotic resistance is a type of drug resistance where a microorganism is able to survive exposure to an antibiotic. While a spontaneous or induced genetic mutation in bacteria may confer resistance to antimicrobial drugs, genes that confer resistance can be transferred between bacterial in a horizontal fashion by conjugation, transduction or transformation. Thus, a gene for antibiotic resistance that evolves via natural selection may be shared. Evolutionary stress such as exposure to antibiotics then selects for the antibiotic resistant trait. Many antibiotic resistance genes reside on plasmids, facilitating their transfer. If a bacterium carries several resistance genes, it is called multidrug resistant (MDR) or, informally, a superbug or super bacterium. The emerging resistance in today’s world has created a major public health dilemma. The major driving force behind the emergence and spread of antibiotic-resistant pathogens is the rapid rise of antibiotic consumption. This trend reflects the growing medicalisation of societies worldwide, with its identification of microbial pathogens as the cause of infectious diseases. Antibiotics promise cure. This together with their ease of use, the usually short treatment requirements, and, for many parts of the world, availability without prescription by a doctor results in a demand that is increasingly met by a growing supply of generic drugs produced in emerging market economies. The same escalation in consumption has occurred in the animal welfare sector, prompting concerns about the transmission of antibiotic resistance through the food chain. An additional set of threats that facilitate the spread of antibiotic-resistant pathogens comes from unpredictable disasters that disrupt human livelihoods and bring about crowding, mass migration, famine and unsafe water supplies. Conflicts within and between states, environmental degradation and climate change can provide scenarios in which infectious diseases thrive and antibiotic resistance may come to the forefront.