Antibiotics
Antibiotics are a class of molecules used for the treatment and prevention of bacterial infections. Before their introduction in clinical practice, there was no effective treatment for a number of diseases, such as pneumonia, typhoid fever, or gonorrhea.
The first natural antibiotic isolated was penicillin, in 1928, by Fleming and co-workers.
The discovery of penicillin by Sir Alexander Fleming in 1928 provided us with access to a new class of compounds useful at fighting bacterial infections: antibiotics. Ever since, a number of studies were carried out to find new molecules with the same activity.
Microorganisms belonging to Actinobacteria phylum, the Actinomycetes, were the most important sources of antibiotics. Bioactive compounds isolated from this order were also an important inspiration reservoir for pharmaceutical chemists who realized the synthesis of new molecules with antibiotic activity.
(From National Library of Medicine)
Pharmaceutical companies and universities began studies in this field, and identified several new bioactive molecules. The antibiotics era started, and its golden age
was between the 1950s and 1970s, a period when the most known important classes of antibiotics were discovered. These bioactive compounds are produced naturally from different species of fungi and bacteria, but the most attractive class of microorganisms that are able to produce these secondary metabolites are Actinobacteria, in particular, Actinomycetes. The importance of this order is due to their abilities to produce different classes of antibiotics in terms of chemical structure and mechanisms of action. Current research suggests that Actinomycetes are also a prime resource in the finding of new natural products, thanks to their unique enzymatic sets that permit generating compounds that are potentially useful for diverse purposes. Moreover, different genera and species of Actinomycetes are able to produce the same class of antibiotics and, in few cases, the same chemical compound, indicating that the metabolic paths have been strictly preserved among the order.
Nature's beauty is also found in the complexity of evolution, the engine that moves life in order to adapt itself to environmental changes. The fundamental unit of evolution is the mutation, or rather, the change, in the genetic material and the process through which the variation happens.
How Antibiotics Work
(From Quantum Supremacy: How the Quantum Revolution will Change Everything, by Michio Kaku)
Using modern technology, scientists have gradually deduced how certain kinds of antibiotics work. Penicillin and vancomycin, for example, interfere with the production of a molecule called peptidoglycan, which is essential for creating and strengthening the cell wall of the bacteria. These drugs therefore cause the bacteria's walls to fall apart.
Another class of drugs, which are called quinolones, throws a monkey wrench into the bacteria's reproductive chemistry, so that its DNA does not function properly and hence cannot reproduce.
Another, which includes tetracycline, interferes with the bacteria's ability to synthesize a key protein. And yet another class stops the cells from producing folic acid, which in turn interferes with the bacteria's ability to control chemicals flowing across the cell wall.
Given these advances, why is there a bottleneck?
For one, these new antibiotics take a long time to develop, often over ten years. These drugs must be carefully tested to make sure that they are safe, which is a time-consuming and costly process. And after a decade of hard work, the final product often cannot pay the bills. The bottom line for many pharmaceutical companies is that the sales must compensate for the cost to make these drugs.
Antibiotic Resistance
According to the World Health Organization (WHO), antibiotic resistance is currently one of the biggest threats to global health, food security, and development. (See Superbugs)
Through mutations, bacteria become antibiotic-resistant and the infections they cause are harder to eradicate. According to WHO, at least 700,000 people die each year due to drug-resistant diseases, including 230,000 people who die from multidrug-resistant tuberculosis. Several diseases associated with the urinary and respiratory tracts, or sexually transmitted infections, are becoming untreatable. Lower respiratory infections remained the deadliest communicable disease, causing 3.0 million deaths worldwide, especially in low-income countries.
Different causes have contributed to antibiotic-resistance crisis, including factors related to their overuse, inappropriate prescribing, and extensive use in agriculture and breeding.
The WHO and other organizations, such as the Centers for Disease Control and Prevention (CDC), have developed different programs for reducing this phenomenon, with the goal of improving the diagnosis and optimizing therapeutic regimens, in addition to adopting a prevention policy, as well control tracking and prescribing practices.
Recently, scientists have shed new light on another concerning topic: the abuse
of antibiotics in clinics. So far, it seems that abuse of these drugs could cause resistance in commensal bacteria flora. These bacteria are regarded as potential threats. Indeed, if spread out in the environment, they could become vectors for antibiotic resistance in pathogens or could create pathologies in immunocompromised people. In this context, the great diversity of the metabolites with antibiotic activity produced by the Actinomyces is an important tool to tackle the antibiotic-resistance crisis.