September 22, 2022

Researchers focus on how bacterial cells adapt and resist antibiotics

Treatment for serious infections caused by common bacteria relies on ‘last resort’ antibiotics, but the growing resistance of ‘superbugs’ puts patients at risk of possible death.

Microscopic images of Acinetobacter show a healthy bacterial cell with no colistin treatment on the left, then with colistin treatment, and a third with a disintegrated cell after exposure to higher level colistin treatment. Image credit: Flinders University

Flinders University researchers are focusing on how bacterial cells adapt and resist antimicrobial drugs – with a new paper focusing on the hospital strain of Acinetobacter baumannii and its cellular response to colistin, an important antibiotic.

The World Health Organization names antibiotic resistance as one of the greatest threats to global health, food security and development, with rising numbers of infections – including pneumonia, tuberculosis, gonorrhea and salmonellosis – becoming more difficult to treat as fewer antibiotics are used to treat them. efficient.

Antibiotic resistance leads to longer hospital stays, higher medical costs and increased mortality, researchers warn.

Around the world, there are fewer and fewer new antibiotics being identified and produced for medical use – and this is compounded by the growing antibiotic resistance seen in bacterial strains causing infections. If we can understand bacterial mechanisms, like this, we can potentially apply new therapies to treat patients, especially those with multidrug-resistant bacterial infections.

Dr. Sarah Giles, Flinders Microbial Researcher.

“We noted that the bacterial strain A baumannii had a two-part signaling system that altered its potential response to antibiotic treatment,” says Dr. Sarah Giles, as part of an NHMRC-Flinders University postgraduate scholarship study.

This observed “two-component signal transduction” involves a response regulatory protein in the StkR/S system acting as a repressor and, when genetically suppressed, hundreds of transcriptional changes are observed.

Transcriptional changes affect the composition of the outer membrane of the bacterial cell, resulting in resistance to colistin.

“Colistin is known as an antibiotic of ‘last resort’ and therefore it is essential to identify and understand the mechanisms contributing to bacterial resistance to antibiotics.” says lead researcher Professor Melissa Brown.

Antimicrobial resistance (AMR) occurs when bacteria, viruses, fungi, and parasites change over time and no longer respond to drugs, making infections harder to treat and increasing the risk of spreading disease. serious illnesses and even death.

Acknowledgement: The study was funded by the National Health and Medical Research Council (grant 535053) to Professor MH Brown.

Source:

Journal reference:

Giles, Sask., et al. (2022) StkSR two-component system influences colistin resistance in Acinetobacter baumannii. Microorganisms. doi.org/10.3390/microorganisms10050985.