How Fast-Growing Bacteria Can Resist Antibiotics Pharmacology & Drug News

The results show that individuals that grow rapidly within bacterial colonies show a significantly higher expression of active ribosomes, particles within the cell that synthesize proteins. This helps the bacteria avoid the buildup of an important class of antibiotics called macrolides and thus resist therapy. These findings could be used to inform the development of improved antibiotic compounds that target this survival strategy.

Bacterial infections can cause food poisoning, pneumonia, sepsis, and other serious illnesses. Although they can be treated with antibiotics, the overuse of these drugs in recent years has meant that bacteria are becoming increasingly resistant to them, posing a major threat to global health.

For an antibiotic to be effective against infection, it must reach its target cell in a concentration sufficient to inhibit bacterial growth.

“Antibiotic resistance continues to threaten the viability of current treatments. We need to understand how individual bacteria within a colony can block the entry of antibiotics into their cells, so that we can address this mechanism with new therapies”, says Urszula Łapińska, PDRA at the university. from Exeter, UK. “Most of the existing data on drug permeability in bacteria has been obtained through measurements that take an average result from a large population or are derived from a small number of bacteria. This means that little is known about the variability of individual drug accumulation in many cases. cells in a bacterial colony.

To fill this gap, Łapińska and the team began with the hypothesis that variations in how bacteria respond to drugs might be driven by different rates of drug transport between individual cells. To test this, the team used a multi-analytical approach, combining microfluidics and microscopy, to determine which bacteria pose a threat to health, namely Escherichia coli, Pseudomonas aeruginosa, Burkholderia cenocepacia Y staphylococcus aureus and antibiotic-derived fluorescent probes by Dr. Mark Blaskovich of the University of Queensland. This approach allowed the team to examine interactions between common antibiotics and many individual live bacteria in real time, during drug dosing. By combining this approach with mathematical modeling techniques developed by Professor Krasimira Tsaneva-Atanasova of the University of Exeter, the team obtained data that they could use to quickly and efficiently identify individual antibiotic-resistant bacteria.

Their analyzes showed that rapidly growing individuals within a colony prevent the accumulation of macrolides in their cells, a finding that contrasts with current thinking that slow cell growth is the main contributor to survival without genetic variation. This avoidance is made possible by a significantly higher number of ribosomes prior to drug treatment, compared to slow-growing counterparts in individuals. Ribosomes activate essential cellular processes, including efflux, a system that pumps toxic substances, such as antimicrobial compounds, out of the cell.

Using this new knowledge, the researchers showed that chemical manipulation of the outer membrane of bacterial cells can eradicate fast-growing variants that exhibit low macrolide accumulation, contributing to our fight against antibiotic resistance.

“This work reveals a hitherto unrecognized survival strategy in some members of bacterial colonies,” concludes Dr Stefano Pagliara, Senior Lecturer in Microfluidics at the University of Exeter, UK. “This knowledge will directly benefit microbiologists and clinicians working to develop more effective antibiotic therapies. In the longer term, we hope that the use of our new approach in the clinical setting will help inform the design of improved medicines and help us in the fight against antibiotic resistance. »

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