Method can reduce costs and be performed in laboratories with less equipment

Superbugs or multidrug-resistant bacteria are one of the biggest concerns of current science regarding the treatment of patients in a hospital environment. Resistant to the vast majority of common antibiotics present throughout the world, their existence encourages the search for more accessible approaches to properly diagnose and treat the infections they cause.

Within this context, researchers from the Instituto de Medicina Tropical (IMT), from the Faculdade de Medicina da Universidade de São Paulo (FMUSP), identified a new structure capable of adhering to the cellular structure of one of the main agents causing hospital infections, Acinetobacter baumannii. This is aptamer A01, whose finding was described in an article in the journal Frontiers in Cellular and Infection Microbiology, in June this year.

Aptamers, in general, consist of small sequences of single-stranded DNA or RNA, forming a three-dimensional structure capable of binding to a specific target with high affinity and specificity. “Due to this link, they can be used to identify certain targets and, if these targets belong to infectious agents, they can be used for diagnosis”, explains IMT researcher and first author of the article, Marina Farrel Côrtes.

Adopting their own methodology based on whole cells, the IMT scientists were able to select, from a set of trillions of random sequences, the structure of A01. 

For this, different selection protocols were tested, combined and optimized until reaching an ideal methodology.

“The technique we developed involves less equipment and less costly steps so that the selection and identification of aptamers can be carried out by laboratories with less access”, says Marina.

During laboratory tests, aptamer A01 showed a preference for binding to Acinetobacter baumannii over other agents such as Klebsiella pneumoniae and Candida albicans. In addition to contributing to the early diagnosis of infections by this bacterium, the expectation is that eventually A01 and other promising aptamers can be used as a treatment tool, since its binding to a specific target can lead to its inactivation.

Acinetobacter baumannii

Acinetobacter baumannii is one of the main causative agents of nosocomial infections, which can lead to pneumonia, urinary and skin infections, among others. Its resistance to antibiotics makes this bacterium a threat of high lethality, with contamination and deaths recorded in several countries.

For scientist Marina Côrtes, this makes the creation of new detection methods even more urgent. “Early diagnosis is extremely important since rapid identification favors targeted treatment, which is more assertive. The earlier the diagnosis, the sooner treatment can be started and the greater the chances of success,” she says.