Resistance to Synthetic Antibacterials Can Occur Before They’re Invented

Researchers have discovered a process by which bacteria populations can generate resistance to synthetic antibacterial drugs long before they are put to clinical use. According to the Universitat Autònoma de Barcelona (UAB) and University of Maryland, Baltimore County (UMBC) researchers who made the discovery, this is the first time such a mechanism against synthetic drugs has been seen. The findings are published in Frontiers in Microbiology.

Sulfonamides are a class of synthetic antibiotic. Resistance to sulfonamides in a clinical setting has become widespread in recent years. In the current study, researchers aimed to identify the origin of mobile genetic elements that carry resistance to these antibiotics by analyzing large volumes of bacterial genomes.

The researchers discovered that sulfonamide-resistant genes appeared in two ground bacteria families— Rhodobiaceae and Leptospiraceae—over 600 million years ago through a mutation in the drug’s target gene. When use of the antibacterial became widespread, so too did the resistance gene.

These results were surprising as it was previously thought that resistance genes to synthetic antibacterial drugs would only begin to develop after use became widespread. These findings demonstrate that this is not necessarily true and, according to the researchers, should be taken into account in future drug development programs.

"The discovery confirms the need to use a combined multidrug treatment capable of attacking diverse resistance mechanisms within the hospital environment,” said Ivan Erill from the Department of Biology at the UMBC. He also warns that the origin of the resistance genes in bacteria residing in subsoil and aquifers highlights the need to reduce agricultural use of antibacterials.