Bacteria, as a group of microorganisms, have a long-standing relationship with humans, animals, and plants. These microscopic living entities can be found as single cells or in groups of cells. Bacteria are known to exist in various environments, ranging from the depths of volcanic vents to the snow of Antarctica. They come in different shapes, such as spherical, rod-shaped, or spiral, and can be found in soil, water, and various organisms.
Some bacteria can be harmful, causing diseases in humans, animals, and plants, while others play beneficial roles in digestion, the production of certain vitamins, and even contribute to the immune system. The most effective medication against bacteria, known as antibiotics, was discovered by Alexander Fleming in 1928. Antibiotics can either kill bacteria or inhibit their growth, but their effectiveness has been decreasing due to overuse and misuse.
The major reason for the reduced effectiveness of antibiotics is their excessive or incorrect usage. This has led to the development of antibiotic-resistant bacteria, making these medications less potent. Antibiotic resistance not only poses a significant threat to the treatment of infections but also alters the microbial landscape in the human body, potentially making several antibiotics ineffective simultaneously.
The resistance of bacteria to multiple drugs, known as multidrug resistance, has become a growing concern. Initially, bacteria showed resistance to one or two antibiotics, but now some strains exhibit resistance to most or all antimicrobial agents. The most alarming form of resistance, extensively drug-resistant bacteria, is resistant to all antibiotics in some cases.
Research institutions worldwide are actively exploring new molecules that could serve as alternatives to antimicrobial agents. The aim is to find substances that can either break down or disrupt bacterial cells, rendering them ineffective and unable to develop resistance. This research involves studying toxins or proteins found in snake venom and plant seeds, among other sources.
For instance, a project focused on centipede venom and plant seeds was initiated. In this research, substances from the venom of a specific viper snake, which showed resistance to the antibiotic methicillin, were tested against the bacteria. Some components of the snake's venom demonstrated efficacy against the resistant bacteria, disrupting their protective mechanisms.
Similarly, proteins obtained from the seeds, leaves, or roots of plants, or even extracts using various solvent solutions, are being explored. The continuous reporting of such research suggests that any lead molecule found must undergo further investigation to confirm its potential as a viable alternative. Once confirmed, these molecules could be further developed into pharmaceuticals and introduced into the global market, providing new options for combating bacterial infections.
In this type of research, the use of nanoparticles is also crucial. Nanoparticles made of silver, if they are of the size of ten nanometers, exhibit highly effective antibacterial properties against a wide range of bacteria, particularly in the observation of intense heat. On the other hand, nanoparticles with a size of one hundred nanometers prove lethal for common cells as well. Research in the field of antimicrobial nanotechnology, particularly in the construction and biomedical applications, has gained popularity. The majority of this research is related to human diseases, such as in the field of cancer treatment.
This research in nanotechnology is not only focused on controlling other diseases but has also been conducted on bacterial infections. Specifically, infections caused by bacteria that can lead to severe and fatal diseases. For example, Methicillin-resistant bacteria, known as 'Staphylococcus aureus' and 'Listeria,' are bacteria that have caused complications in surgeries, persistent infections, and issues related to available treatments. Furthermore, it has been observed that bacteria resistant to any of the antibiotics in the antibiotic groups have become the most dangerous germs. Nanoparticles made of metals like gold, silver, copper, and others are being used, while liposomes, lactic acid, and glycolic acid have been experimented with in nanomaterials.
Additionally, it has been explored whether combining different nanoparticles or nanoparticles and antibiotics could enhance their effectiveness against resistant bacteria. Positive results have been obtained from experiments where nanoparticles made of two different metals, one being gold and the other being rhodium or ruthenium, have shown significant potential in combating gram-negative bacteria and treating wound infections. However, it has been challenging to see this effectiveness in different forms of nanoparticles.
It is essential to note that tests are conducted to identify resistance using any of the antibiotics in the antibiotic groups. Bacteria are placed on specific plates in a petri dish with artificial media in a laboratory setting, and then their growth or inhibition is observed with different antibiotics. This is a common method that can be employed in any diagnostic center or research institution.
However, now it is evident that bacterial resistance mechanisms are advancing rapidly, and in a very short time, many bacteria that cause infections are becoming resistant to most existing antibiotics. Therefore, it is now essential to recognize the resistance system of bacteria beforehand and continue experimenting with the use of antibiotics to develop new medicines and methods with slight modifications until completion.
In this regard, preparations are underway to use new technology regularly, such as the Global TB Program of WHO in May 2023, which has validated evidence regarding the use of targeted antiretroviral nanoparticles. This technology is being used to identify strains of TB that have become resistant at an extremely fast pace and pose a challenge in the field of international infection. Therefore, new techniques, such as next-generation sequencing or NGS, are being employed to identify such TB using targeted nanoparticles.
While one side is focused on the identification of resistant bacteria through a new process, the other side is searching for new ways of treatment by combining new antibiotics or antibiotics with nanoparticles. It is possible that as a medicine, some new molecules may appear soon, and it may be said that these nanoparticles and antibiotics, when combined, provide relief from resistance for some time. However, it is now apparent that bacteria can gradually increase their resistance against newly prepared medicines as well.
Therefore, it is now being felt that the genetics and apparent observation of bacteria using this new medicine for treatment of infection should be monitored, so that it can be determined when these bacteria are sensitive to this new medicine and when they have begun to make resistant changes for themselves. Nevertheless, nanoparticles have demonstrated their capability as an alternative to antibiotics. Now, it is up to the researchers to figure out how to use them so that resistance to antibiotics can be eliminated.