New Drugs Against Bacteria
March 3, 2014
Polish researchers have isolated a group of non-toxic compounds and developed a range of new drugs to combat bacteria that resist existing antibiotics. The compounds can chiefly be used against E-coli bacteria, say the researchers, who hail from the Polish Academy of Sciences’ Institute of Organic Chemistry (IChO) in Warsaw.
In recent years there has been a rapid increase in the number of bacterial infections that are difficult to treat or completely resist available antibiotics. Many strains of bacteria have developed defense systems that neutralize traditional antibiotics such as penicillin. Most antibiotics are derivatives of a limited number of compounds that work against bacterial cells.
The search for new groups of antibacterial compounds is a challenge for scientists, says Prof. Zofia Lipkowska from the Institute of Organic Chemistry, who is the head of the research project. Lipkowska adds, “Compared with modern drugs for chronic diseases, the search for a new generation of antibiotics is not particularly profitable [for pharmaceutical companies] and is not their most important objective.”
The IChO researchers have tested and developed methods for the synthesis of about 100 new compounds in collaboration with a team led by Prof. Jolanta Solecka at the National Institute of Public Health/National Institute of Hygiene in Warsaw. The IChO scientists have managed to obtain non-toxic compounds that do not affect red blood cells after getting into the bloodstream. The antibacterial drugs developed by the researchers can be used for disinfecting disposable medical supplies and equipment. For example, they help protect patients from hospital infections during procedures such as catheterization. Cardiac catheterization involves passing a thin flexible tube (catheter) into the right or left side of the heart, usually from the groin or the arm. The compounds can also be used externally, for example to support the treatment of wounds that are difficult to heal. The compounds are not toxic for skin cells and the dermis.
The new antibacterial drugs latch onto bacteria cells, penetrate into their membranes and change their structure.
The unique structure of the compounds allows them to remain stable in the patient’s body.
The compounds belong to a new class of nanoparticles called dendrimers and owe their strength to their branched structure. Dendrimers are manmade, nanoscale compounds with unique properties that are used in the health and pharmaceutical industry as both enhancements to existing products and as entirely new products. Dendrimers—the name derives from the Greek dendron, or tree—have a tree-like structure. They are highly branched, star-shaped macromolecules with nanometer-scale dimensions. They are constructed by the successive addition of layers of branching groups. Each new layer is called a generation. The final generation incorporates the surface molecules that give the dendrimer the desired function for pharmaceutical, life science, chemical, electronic and materials applications. Dendrimers fall under the broad heading of nanotechnology, which involves the manipulation of matter in the size range of 1-100 nanometers (one million nanometers equal one millimeter) to create compounds, structures and devices with novel, pre-determined properties.
Dendrimers were first described in 1983 as spherical nanoparticles 2 to 10 nanometers in size that can connect more layers to their core.
The antibacterial drugs developed by the Warsaw researchers have been submitted for patenting. The researchers continue to examine the effectiveness of the new drugs and have conducted studies on resistant strains of E-coli bacteria in hospitals. They now plan to conduct toxicity studies on living organisms.
“We will ask experts and businesses to assess how the compounds should be introduced into production and commercial use,” says Lipkowska. She adds, however, that the procedure is time-consuming, so it will take at least 10 years before the new drugs appear in pharmacies.
The compounds developed by the Warsaw researchers have already gained international recognition, for example during the Taipei International Invention Show and Technomart in Taipei, Taiwan. Of 650 inventions exhibited there, the Polish drugs won one of four platinum medals handed out by the organizers.
The Warsaw team received a grant from the National Center for Research and Development for their research.