Laboratory-produced substance has been tested in Acinetobacter isolates

ResearchPhotos: Bruno Todeschini

Chemical compound to inhibit superbacteria

Resveratrol analog molecules proven effective against Acinetobacter baumannii

Resveratrol analog molecules could bring some hope in the fight against an antibiotic resistant superbacteria. A variety of international studies have shown that the substance that is found in black grapes and red wine have bactericidal and antioxidant properties (thus lessening the negative effects caused by free radicals, which are toxic substances produced by the body). An investigation carried out at PUCRS has also proven it to be effective against Acinetobacter micro-organisms, especially Acinetobacter baumannii, which is one of the main agents of infections in hospitals and health stations, as it mostly targets ICU patients.

School of Biosciences professor Sílvia Dias de Oliveira has studied this bacteria extensively, whereas Chemistry professor André Arigony Souto, has synthesized different resveratrol analog molecules. Both researchers have decided to join forces and have been working on synthetic compounds of resveratrol analogs (synthesized in laboratories) in Acinetobacter isolates since 2014.


Experiments have shown that, within a given concentration, resveratrol analogs are able to stop the growth of Acinetobacter baumannii. Then, other drugs used to treat infections were combined. “By using the compound, we have been able to reduce the concentration of the medications. In some cases, we were able to reverse the resistance to that specific drug”, explains Sílvia. This means that even isolated compounds that adapt to the effect of antimicrobial drugs, are susceptible to them when associated with this resveratrol analog.

Outstanding results have been achieved with polymyxin B, an obsolete and highly toxic antibiotic (which mainly affects the kidneys). It has recently risen back to prominence as a response to the lack of modern drugs to fight Acinetobacter. And to make matters worse: resistance to polymyxin B has been reported in a number of academic investigations, which urges the need for research into other alternatives.

The group has also studied antimicrobial tobramycin because it can be inhaled. “As Acinetobacter causes respiratory infections, we have chosen this target for tests, as we envisioned a useful future for it”, explains Sílvia.

In order to determine the potential effect of antimicrobials, tests were repeated indefinitely. Some isolated bacteria compounds were subject to 50 analysis sessions. A multitude of factors could be held accountable for alterations in the results. Reactions change according to the micro-organism’s isolate under investigation. Differences were so subtle that investigators had to ponder whether it is best to combine the compound and the drug simultaneously or at intervals. The first hypothesis was accepted.

Future investigations will try to unveil the compound’s mechanism of action. The antimicrobials are internalized into many bacterial cells which will then be expelled, thus reducing its concentration in order to remain active. “We anticipated that the substance has a potential inhibitory action, and causes the drug to concentrate, which makes it reach the target more easily”, elucidates the professor.


The next stage, which includes testing in animals, is dependent upon funding for analyses of toxicity and activity. In cells, the product has proven to be beneficial. “It’s cheap to synthesize and we would be able to produce it in large scale”, ascertains Arigony. At the laboratory, the group was able to produce 20 grams of the drug. Both the process and the level of purity remained unaltered. “If it works in an in vivo model and arouses the interest of any industries, we will show that it’ll be easy to produce”, complements he.

Biozeus, a drug development company that works together with pharmaceutical industry company and research institutes, assisted PUCRS in drafting the proposal. In September, the company and other researchers delivered a workshop at PUCRS in order to assess the financial potential of projects.


Undergraduate research students

Chemistry student Natália Cézar: excitement to develop a new drug

Sponsored by Praias, a multidisciplinary research program, accountable to the Office of the Vice President for Research, Innovation and Development, the project features two undergraduate research students, and resources used to acquire supplies. As students work on their experiments, they learn about one another’s areas of expertise. Three pairs of students have joined the program in its previous editions.

“Students can gain a lot from observing different methods! They can see that science is integrative, they can think outside the box. They might be able to explore other possibilities when working in a different scenario”, says Arigony. Natália Cézar, 21, 5th semester Chemistry student, heartily agrees. “A research project provides me with a wonderful scientific experience because I can put in practice everything I have learned as an undergraduate student, and learn something new, not necessarily in Chemistry, but also in Biology, for we work mostly in na interdisciplinary way.” For her, one of the highlights of the project is to participate in a drug development project. “It may be useful to many people. And it is based on the research and tests we have conducted at the laboratories.” The project also features Marina Monteiro, Pharmacy student.


Atop WHO list

For the first time, in 2017, the World Health Organization (WHO) published a list of antibiotic resistant bacteria, which calls for future research and production of new medications. Twelve families of pathogenic agents appear in the document. In the first of the three urgency categories defined by WHO lie bacteria of the following genus: Acinetobacter, Pseudomonas and Enterobacteriaceae, such as Klebsiella, Escherichia coli, Serratia and Proteus. They can cause serious and often fatal health conditions such as blood infections and pneumonia. In addition to designing new medications, other measures are essential, such as infection prevention actions and awareness to the correct use of existing antibiotics.

Source: UN

The project researchers


Sílvia Dias de OliveiraSílvia Dias de Oliveira, who has a Bachelor’s, a Master’s and a PhD in Veterinary Medicine from UFRGS, has a vast experience in microbiology. She studies organisms that affect animal and human health. She wrote a Master’s thesis and a doctoral dissertation on Salmonella. She has been teaching at PUCRS since 2002, as she began working in health care. She began to characterize the resistance of bacteria isolates at São Lucas Hospital until she arrived at Acinetobacter, whose incidence is high not only in Porto Alegre, but all over the world. “We’re living in a chaos, under the constant warning of the World Health Organization as to the resistance to antimicrobials, and we have decided to seek alternative solutions.”

She has filed an application for a method of detection and quantification of milk bacillus, under analysis by the INPI. The project was designed in collaboration with professor Carlos Alexandre Ferreira, who also works at the Laboratory of Immunology and Microbiology, of the School of Biosciences, and with former Cell and Molecular Biology student, Fernanda Cattani.


André Arigony SoutoAndré Arigony Souto has seven patents filed, some of which having been granted overseas. One of them was even licensed by Eurofarma but, after conducting tests with animals, the company decided to discontinue it. “To develop a drug is not an easy task because huge investments are needed and the chances for success are rather low”, says he, as he mentions the strict criteria used by the Health Surveillance Agency. But he will not quit researching products that can exert an impact on society. By synthesizing resveratrol analog molecules, he is able to design compounds to fight diseases. He is such an avid enthusiast of the idea that he takes the substance himself. It all started because he wanted to know why the French, despite relying on such a healthy fat diet, have a low incidence of cardiovascular problems. Wine consumption could be partially accountable for it.

Dr. Arigony, who holds a PhD in Chemistry from the Universidad Complutense de Madrid (Spain), and a Master’s and a Bachelor’s degree completed at PUCRS, claims that his engagement to this type of study is attributable to the University’s policy of technology transfer. He has been a professor at PUCRS since 1998.

Patent applications

The project needs to be published and examined by the National Institute of Industrial Property (INPI) as a condition for the granting of the patent, which will earn it a 20-year protection. INPI’s letters patent certifies that the invention has reached three levels: world novelty (analyzed up to the application date), inventive activity (obviousness) and industrial scale reproduction. Patent protection has also been claimed to The Patent Cooperation Treaty.

Source: PUCRS Technology Transfer Office